HAZARDOUS-MATERIALS RESPONSE TEAMS IN SWITZERLAND … · HAZARDOUS-MATERIALS RESPONSE TEAMS IN SWITZERLAND 6 CHIMIA 2004, 58, No. 1/2 minutes after an accident, damage is very often

HAZARDOUS-MATERIALS RESPONSE TEAMS IN SWITZERLAND 4CHIMIA 2004, 58, No. 1/2

Dear reader

You hold a very special issue of CHIMIA in your hands. It is dedicated toa fringe area of industrial chemistry. The preparedness for hazardous-ma-terials incidents is crucial for the acceptance of chemistry in the generalpublic. Since laymen cannot fully understand chemical risks they act oninstinct with aversion to chemistry. It is the task of the chemical industryto gain full public confidence in their activities in research, production, andtransportation. In line with the Responsible Care Program, private fire bri-gades of Swiss-based chemical companies play therefore a key role in theHazMat incident management. The American phrase Hazardous-Materi-

als Response Teams points out nicely that HazMat incident management is teamwork of dif-ferent specialists.

The thread of this special issue has its origin in the organization and concept of interventionof Swiss Hazardous-Materials Response Teams. Four basic tasks of HazMat response teamsare presented in the next articles. The reader can participate in the rich experience of the au-thors. With the recent sad accidents in road tunnels, worst case scenarios such as burningtrucks with dangerous goods in a tunnel gained more attention. Some technical weak pointswere identified, especially in tunnels more than ten-years old. Another operational area is inthe laboratory. Quantities of chemicals are small but the range of hazardous properties of the,in many cases, unknown substances is almost unlimited. Risk can be reduced by a state ofthe art safety concept. The ultimate decision on complete success or flop of a hazardous ma-terials incident response is strictly linked with the decontamination procedures. Simple, time-ly performed measures are of outmost importance. The last two contributions close the circle.They highlight the role of chemical experts as advisors to the officer in charge and as trainersof firefighters. In incidents with hazardous materials chemical characteristics under atmo-spheric conditions are determinant. So application and demonstration of basic principles aremore important than highly sophisticated treatises.

The chemical industry and the volunteers in the Hazardous-Materials Response Teams arewell trained and ready for action. What ails you?

Dr. Walter JuckerDSM Nutritional Products, Werk SisselnHead of vitamin production and logisticsBuilding 324/3084334 SisselnE-Mail: [email protected]

With great pleasure the Editorial Board of CHIMIA warmly thanks the coordinating guest edi-tor Dr. Walter Jucker acknowledging his strong efforts in planning and efficient collation of thepresent most attractive variety of contributions to the topic ‘Hazardous-Materials ResponseTeams in Switzerland’.

EDITORIAL


Chimia 58 (2004) 5–9© Schweizerische Chemische Gesellschaft

ISSN 0009–4293

Organization and Concept of Intervention of the Chemical DefenceBases in Switzerland

Urs Ludescher*

Abstract: In contrast to radiological risks, which are the responsibility of the federal authorities, the cantonshave to deal with chemical risks. In agreement with the chemical defence concept of the Swiss Fire FightersAssociation (SFFA) each canton should have a network of chemical defence bases enabling efficient inter-vention on site within thirty minutes of a chemical accident. Due to the drafting of the ‘Ordinance of 27 Feb-ruary 1991 on Protection against Major Accidents’ after the disastrous chemical fire in Schweizerhalle on1 November 1986, it has been possible to reduce the chemical risks in Switzerland considerably. This couldbe achieved primarily by reduction of the amounts of hazardous materials in the facilities subject to the or-dinance, but also by structural measures, the establishment of powerful intervention forces, and interventionplanning. The responsibility for the training of chemical defence specialists is divided between the SFFA andthe cantons. The SFFA organizes training courses for officers-in-charge for chemical accidents and forinstructors for chemical defence; the cantons and the chemical industry in turn are responsible for the basictraining of specialists and officers for chemical defence.

Keywords: Chemical accidents · Chemical defence concept · Intervention forces · Swiss Fire Fighters Association · Training requirements

1. Legal Fundamentals

In the field of protection against radioactiveradiation the production, use, storing, trans-port, and disposal of radioactive materialsis regulated in the ‘Ordinance of 30 June1976 for Radioactive Protection’.

On the other hand the Swiss FederalGovernment left the regulation of chemicaldefence from the beginning to the cantonsand municipalities. For the protection of thepopulation the ‘Concept for a CoordinatedAC-Protection’ of 19 February 1981 wasdrafted and approved by the federal gov-ernment on 19 May 1981. Subsequently thegovernments of all the cantons accepted theconcept by letter. Up to the moment of thecreation of the ‘Ordinance of 27 February1991 on Protection against Major Acci-dents’ [1], which was one of the conse-quences of the catastrophic fire of a ware-

*Correspondence: Dr. U. LudescherChemical Consultant of the Swiss Fire Fighters AssociationBlattenrain 9Postfach 130CH-9050 AppenzellTel.: +41 71 780 10 82E-Mail: [email protected]

house containing herbicides, fungicidesand pesticides in Schweizerhalle on 1 No-vember 1986, this concept, which wasrevised and published again on 24 January1990 as the ‘Concept Coordinated AC-Pro-tection’ [2], was the only legal basis for theformation of an organization for chemicaldefence in the cantons.

2. The Chemical Defence Conceptof the Swiss Fire FightersAssociation

According to the existing clear legalfundamentals, specialists from the Schoolfor Radiation Protection at the Swiss Insti-tute for Atomic Reactor Research, who areresponsible for training in radiation protec-tion, developed towards the end of the1970s the ‘Directions for the Radiation Protection for Fire Fighting Service’ and aclear concept for the training of interven-tion forces of the fire brigades in radiationprotection.

Thanks to the initiative of the com-mander of the fire brigade of the chemicalcompany LONZA AG at that time, RudolfSandmeier, the first courses for chemical

defence were organized on the trainingground of LONZA AG in Visp. The point ofmain effort of those courses, however, wasthe control of big hydrocarbon fires.

In order to give the cantons a feasible in-strument for the planning and realizationfor chemical defence, in 1983 the SwissFire Fighters Association (SFFA) began todraft a chemical defence concept suitablefor use in practice. The first version of thisconcept, presented at an international sem-inar on hazardous materials for fire fightersin Munich in March 1984, was further im-proved and refined to be presented to can-tonal authorities at a national conference ofthe SFFA in Bern in June 1985. There arefour important cornerstones characterizingthis concept:1. Each canton should have a network of

chemical defence bases enabling inter-vention on site thirty minutes maximumafter a chemical accident in areas withconsiderable chemical risks – i.e. inregions with factories dealing with haz-ardous materials and in regions withroads and railways transporting largeamounts of dangerous goods. Thisdemand is the result of the experiencethat without intervention within thirty


minutes after an accident, damage isvery often disproportionately large oreven irreparable.

2. In the event of a chemical accident notonly the responsible chemical defencebase has to be called in, but also thenearest local fire brigade and theregional support base unless the latter isidentical with the chemical defencebase. The main task of the local firebrigade is the rescue of persons andanimals in danger as well as the con-tainment of the scene of the accident.The regional support base brings theheavy fire fighting equipment intoaction whereas the chemical defencebase as a rule only turns out with itschemically trained specialists and therequired equipment.

3. Every chemical defence base has tobring its resources of staff and equip-ment into line with the existing chemi-cal risks in the area of intervention. Thisincludes recruiting, training, and inte-gration of an adequate number of quali-fied chemical consultants to advise theofficer-in-charge of the interventionforces in case of a chemical accident.The extent of these resources can bededuced from the possible accident sce-narios and the corresponding interven-tion plans.

4. As the responsibility for the protectionof the population against chemical dan-gers in principle is completely up to thecantons according to the ‘ConceptCoordinated AC-Protection from 24January 1990’ [2], each canton has toappoint an expert for chemical defence.Among other activities this cantonal ex-pert for chemical defence has the fol-lowing tasks:– Issue of directives for the training

and further education of the special-ists from the chemical defence bases;

– Supervision of the training and inter-vention planning of the chemical de-fence bases;

– Recruitment of chemical consultantsfor the chemical defence bases;

– Regular examination of the chemicaldefence organization in the cantonwith regard to staff, equipment andtraining.

Parallel to the creation of the chemicaldefence concept the SFFA drafted and pub-lished in 1985 ‘Directives for ChemicalDefence for Fire Brigades/Directives forthe Training of Chemical Defence Special-ists’ [3]. In these directives the most impor-tant principles for the organization of chem-ical defence on the federal, cantonal, andregional level have been formulated as wellas the main tasks of the chemical defencespecialists at the different levels. Further-

more concrete statements are made in thesedirectives concerning the scope and profun-dity of the training of these specialists andthe responsibilities for this training.

Because in the event of a chemical acci-dent the local fire brigade is almost invari-ably the first intervention unit to arrive onthe scene, a ‘Handout for the Behavior ofLocal Fire Brigades in Case of ChemicalAccidents’ [4] was created in order to helplocal fire brigades to take the right immedi-ate measures without disregarding theirown safety. In June 1985 the SFFA organ-ized a conference for the authorities of thecantons responsible for chemical defenceand informed them about the chemicaldefence concept and the directives andhandouts concerning chemical defence.The president of the central committee andthe chemical consultant of the SFFA askedthe representatives of the cantons to trans-late the chemical defence concept into ac-tion in order to realize an efficient chemicaldefence organization in the whole ofSwitzerland. Even after this conferenceseveral cantons were still not convinced ofthe chemical risks existing on their territo-ry and the necessity to develop an efficientchemical defence organization. As a resultthe president of the central committee andthe chemical consultant visited the respon-sible authorities of these cantons and triedto persuade them in a personal discussion tocreate the necessary structures for an effi-cient chemical defence organization. Buteven these efforts proved unsuccessful – af-ter all this was the period before the fire ofSchweizerhalle!

3. The Chemical Fire of Schweizer-halle and its Consequences

The date of the 1 November 1986 is adeep rift in the history of the chemicalindustry, not only in Switzerland, but also inthe rest of Europe. The population hadhardly recovered from the shock of thenuclear power plant disaster at Tschernobylin the Ukraine with radioactive contamina-tion of large parts of Europe on 26 April1986, when a new disaster happened in thenight of 1 November 1986. As the result ofa major fire in a warehouse containing agro-chemicals, tens of thousands of people inthe nearby city of Basel were woken up ter-rified in the middle of the night by the wailof the sirens and extremely strong smellswhich caused a true disturbance. As largevolumes of heavily contaminated waterfrom the fire extinguishers entered the riverRhine directly from the site of the fire, acatastrophic number of dead fish wasobserved the following day. Hundreds oftons of dead eels and fishes drifted downriver towards the sea. The river Rhine wastemporarily biologically dead for long

stretches. Even at a distance of several hun-dreds of kilometers from the fire drinkingwater supplies taking water from the Rhinehad to be shut down for safety reasons. Inmany countries all over Europe – but espe-cially in Switzerland – the confidence in thechemical industry was severely shaken. Butthe disastrous fire of Schweizerhalle, thecause of which – in spite of extensive in-vestigations – has never been discovered,prompted the political authorities to takeaction. In analogy to the ‘Council Directive96/EC of 9 December 1996 on the Controlof Major-Accident Hazards Involving Dan-gerous Substances’ [5] (Seveso-Guidelineof the European Union), in Switzerland the‘Ordinance of 27 February 1991 on Protec-tion against Major Accidents’ (Ordinanceon Major Accidents [1]) – based on article10 of the ‘Federal Law of 7 October 1983Relating to the Protection of the Environ-ment’ [6] – was drafted in an exceptionallyshort time. At the same time the EuropeanUnion tightened up the Seveso-Guideline.

Beyond that the fire of Schweizerhallehad far-reaching consequences for thechemical defence forces, the interventionplanning of the fire brigades and the pre-caution measures in the field of retention ofextinguishing water. After Schweizerhallenew chemical defence bases were set upand existing bases in Switzerland were re-inforced. Even cantons which hitherto hadstaunchly resisted the acknowledgement ofthe chemical risks existing on their territo-ry, began to develop chemical defenceorganizations. The Federal EnvironmentOffice subsidized these developments withinvestment contributions. The ‘Ordinanceon Major Accidents (OMA)’ requires highchemical risk enterprises to agree an inter-vention plan with the public interventionforces and obliges the cantons to coordinatethe intervention planning. Therefore theauthorities of the cantons responsible forthe execution of the ‘OMA’ began to elabo-rate the intervention plans together with theenterprises in question and the chemicaldefence bases. The ‘OMA’ obliges all theenterprises subjected to the ordinance tosubmit a short report to the authority of thecanton wherein the hazardous materialsstored and the measures already taken toprevent major accidents are listed. If theshort report cannot exclude serious risk tothe population or the environment in theevent of a major accident, the canton has tooblige the enterprise to do a detailed riskanalysis. Such risk analyses show quiteoften that the risk for serious harm to thepopulation or the environment can only bereduced to a tolerable extent if the amountsof hazardous materials are limited or basinsto retain dangerous liquids and contami-nated extinguishing water are built. Sincethe ‘OMA’ came into force on 1 April 1991hundreds of millions of Swiss Francs have


been invested in the construction of suchbasins.

4. Chemical Defence within theBounds of the Protection of the Population

In view of the planned new army reor-ganization (Army XXI) and the completerestructuring of the civil protection to thepopulation protection on 13 February 1998,the Conference of Governments of the Can-tons for the Coordination of Fire-Fighting(CGCFF) appointed an 11-membered groupof experts in order to develop a forward-looking concept for the organization of fire-fighting in Switzerland. The group of ex-perts developed the concept in the form of22 principles named ‘Fire-Fighting 2000plus’ [7] at the end of 1998, so that it couldbe adopted by the plenary meeting of theCGCFF on 12 February 1999.

These principles emphasize among other items that– rescue, fire-fighting and damage pre-

vention as an overall concept are thetasks of the fire brigades (principle 5);

– local, regional and professional firebrigades should have a modular struc-ture and special equipment should beprovided regionally (principle 8);

– in the event of a disaster the civilian au-thorities have to rely on support by thearmy. As in case of big disasters inpeacetime for the short term mostly only military equipment without troopsis needed, the military authoritiesshould take the steps to supply the civilian authorities with the equipmentneeded (principle 20).

These principles clearly show that withinthe bounds of population protection, chem-ical defence – belonging to the interventionforces which have to be provided regional-ly according to principle 8 – is of great im-portance. The special army equipmentneeded by the civilian authorities in theevent of a chemical disaster can be found inthe corps equipment of the ‘Disaster ControlRegiment 1’ in the containers number 2(Chemical Defence/Radioprotection) andnumber 8 (Environment Protection).

5. Training of the Specialists forChemical Defence

The fire-fighting organization inSwitzerland designates the training ofinstructors of all fields to the SFFA where-as the cantons are responsible for the re-mainder of the training. After the ‘Direc-tives for Chemical Defence for FireBrigades/Directives for the Training ofChemical Defence Specialists’ [3] came in-

to effect in 1985 the training of the chemi-cal defence specialists should have beenorganized and carried out by the responsi-ble authorities of the cantons. Because mostcantons did not have the necessary know-how and specialist staff to carry out thechemical defence training courses, the SFFA decided to take direct control of thewhole chemical defence training as long asthe cantons did not have enough trainedchemical defence specialists and officers attheir disposal. In the years from 1986 till1992 the SFFA organized and carried outsix basic courses for chemical defence spe-cialists and officers. After this period it wasassumed that most of the chemical defencebases of the cantons had enough chemicaldefence specialists and officers at their dis-posal to guarantee efficient and safe inter-vention and adequate training. In 1993 theSFFA did not carry out any chemical de-fence training courses, but made the neces-sary preparations to realize the new chemi-cal defence training concept, namely thetraining of officers-in-charge for chemicalaccidents and of instructors for chemicaldefence. In the following year the firsttraining courses based on the new conceptwere carried out: a course for officers-in-charge for chemical accidents in Rorschachand a course for instructors for chemical de-fence in Vernier near Geneva. Since thattime the new division of the responsibilityfor training in the field of chemical defence– training of officers-in-charge and of in-structors by the SFFA and basic training ofspecialists and officers by the cantons andthe chemical industry – has proven worth-while.

6. Tasks and Responsibilities of theChemical Defence InterventionForces

Every chemical defence base should beable to deal independently with chemicalaccidents in its area of action. In order toestablish the optimal – not maximal! – nec-essary equipment and personnel of a chem-ical defence base as well as the needs fortraining, it is essential that correspondingscenarios are developed. Starting fromthese scenarios the corresponding plans ofaction have to be drafted. It cannot be ex-cluded – unless this has been done before –that these scenarios are the cause and start-ing point for additional safety measures inthe field of prevention of major accidents.The plans of action of stationary plantsdealing with hazardous materials have to beworked out together with the owner of theplant and to be periodically checked by anexercise.

According to the revised ‘Directives forthe Chemical Defence for Fire Brigades’([8], edition 1997) of the SFFA the inter-

vention forces for chemical defence have –beside others – the following tasks:– to recognize and avert immediate dan-

gers, protect human beings from dan-gers or to evacuate them from the dan-ger zone and protect themselves fromthe effects of chemical substances;

– to minimize as far as possible the effectsof chemical accidents on the environ-ment (ground, water, air);

– to preserve material assets and preventdamage as far as the actual situation ofdanger allows this;

– to elaborate plans of action for objectsendangered by hazardous materials;

– to proceed in a tactically correct way inthe event of a chemical accident toreduce the dangers for the interventionforces and uninvolved persons to a min-imum;

– to reduce the chemical risks after anaccident to a degree that specialists areable to start the rehabilitation measureson the site.

7. Identification of Hazards

A rapid and complete identification ofthe existing hazards is the most importantpoint of every intervention after a chemicalaccident, i.e. the knowledge of all haz-ardous materials involved in the event andof their effects on human beings and theenvironment.

An important aid for the identificationof hazards are the orange plates with UN-and danger numbers, the danger labels, theR- and S-sentences and for transport, thewritten instructions on the vehicle.

In order to take the correct measures im-mediately the intervention forces have attheir disposal beside other aids: ‘ERI-Cards’ [9] with the additional Swiss file on‘Oil, Chemical and Radiation Defence’[10], the chemical databank IGS and thesafety data sheets (Fig. 1).

8. Standard Operation Procedures

It has already been explained in section6 that in order to establish the necessaryequipment and personnel of a chemical de-fence base the development of the corre-sponding scenarios for chemical accidentsis absolutely essential. Furthermore it hasbeen said that on the basis of these scenar-ios plans of action have to be drafted.

In order to deal in a rapid and efficientway with a chemical accident without dis-regarding their own safety it is advisable forthe intervention forces to work out certainstandard operation procedures and to checkthem in exercises. Possible standard opera-tion procedures are for instance:


– Condensing/washing out of gases andvapors after an outbreak of toxic, corro-sive or inflammable gases which have ahigher or the same density as air (Fig.2);

– Sealing leaky tanks or other containersfilled with corrosive, toxic, inflamma-ble liquids or liquids harmful to the environment as well as pumping suchliquids from the leaky tanks or contain-ers to reserve tanks with the necessaryprecautions to prevent dangerous elec-trostatic charging;

– Containment of chemical spillages andcontaminated extinguishing water (Fig.3);

– Fighting gas fires;– Decontamination of persons affected by

hazardous materials.In accordance with the plans of action

additional standard operation proceduresmay be elaborated. The more frequentlysuch standard operation procedures arepracticed the more successful and smooth-ly the intervention will proceed in the eventof an emergency.

9. Emergency Documents andPocket Guides for ChemicalDefence Interventions

Parallel to the rapid development of thechemical industry in the sixties and seven-ties of the past century the transport of haz-ardous goods on road and rail increasedenormously. Several transport accidents in-volving hazardous materials showed veryrapidly that the fire brigades did not havethe necessary equipment, protective clothesand knowledge at their disposal to deal suc-cessfully with this new form of threat. Fur-thermore no written instructions and guide-books on efficient and safe action in case ofan accident with hazardous materials wereavailable at that time.

In that situation the former chief of thefire brigade of the chemical companyLONZA AG in Visp, Rudolf Sandmeier,and the former chief of the professional firebrigade of Bern, Hans Bürgi, decided tocreate together with Dr. Michael Gut,responsible for the transport of dangerousgoods at the Swiss Society of Chemical In-dustries, a guidebook which should enablethe fire brigades to intervene after accidentswith the involvement of hazardous materi-als in a safe and efficient way. The result ofthe work of the three pioneers was a file inA4 format, containing tactical and technicalinstructions for chemical accidents as wellas useful information and charts. Further-more the file contained for every UN-Num-ber a leaflet with the most important prop-erties and dangers as well as instructions onhow to deal with the substance and the pro-tective equipment and extinguishing agentto be used. The file with a red cover com-monly named the ‘Red File’ was publishedunder the name ‘Intervention Documentsfor the Transport of Dangerous Goods’jointly by the Swiss Society of ChemicalIndustries, the Federal Office for Police andthe SFFA which later was also responsiblefor the sale of the file. As the number of haz-ardous materials classified by an UN-num-ber and therefore also the number of datasheets in the ‘Red File’ increased dramati-cally at the end of the 1970s the documen-tation system was changed from substanceto group data sheets. Instead of creating onedata sheet for every substance several sub-stances with similar properties are united ina group, and the information concerningdangers, protective clothing, interventioninstructions and so on are given with stan-dardized phrasing on one group data sheet.The information given on a group data sheetcorresponds to the most dangerous sub-stance of the group. Instead of far more than1000 substance data sheets – filling besidethe existing file two more files – the ‘RedFile’ contained roughly 180 group datasheets. In the mid-1990s the department ofroad traffic was reassigned on the occasion

Fig. 1. ‘ERI-Cards’ and the Swiss file ‘Oil, Chemical and Radiation Defence’ are valuable tools to define correct measures of the intervention forces

Fig. 2. ‘Hot exercise’ of fire fighters with the goal of cooling a hydrocarbon fire


of the reorganization of the federal admin-istration from the Federal Office for Policeto the Federal Office for Roads. As a con-sequence the federal administration beganto withdraw step by step from the updateand publication of the ‘Red File’, namednow ‘File for Intervention after Chemicaland Radiological Incidents’. In July 1999finally the Federal Office for Roads wrote aletter to the affected authorities and partnersinforming them about the immediate with-drawal from the cooperation concerning the‘Red File’. The affected fire fightingauthorities therefore decided to replace the‘Red File’ by ‘ERI-Cards’ (EmergencyResponse Intervention-Cards) which havebeen drafted by the European Associationof Chemical Industries (CEFIC). These‘ERI-Cards’ correspond closely to thegroup data sheets of the ‘Red File’. As the‘Red File’not only contained the group datasheets but also quite a number of other im-portant intervention documents, these doc-uments were united, updated, completedand published in the additional file ‘Oil,Chemical and Radiation Defence’ [10] sup-plementing the information given by the‘ERI-Cards’ [9]. The ‘ERI-Cards’ and theadditional file ‘Oil, Chemical and Radio-logical Defence’were given to the interven-tion forces during 2002.

As it was realized at an early stage thatin most cases local fire brigades arrive firston the site after a chemical accident, in1985 the ‘Handout for the Behavior ofLocal Fire Brigades in Case of ChemicalAccidents’ [4] was created in addition to the‘Directives for Chemical Defence for FireBrigades/Directives for the Training of

Chemical Defence Specialists’ [3]. Thishandout was revised in 1990 and 1999 andadapted to new legal regulations and newfindings gained from accidents and provedits worth in the practical training as well asin emergencies.

In 1996 the ‘Directives for ChemicalDefence for Fire Brigades/Directives forthe Training of Chemical Defence Special-ists’ [3] was completely revised, united andpublished 1997 under the title ‘Directivesfor Chemical Defence for Fire Brigades’[8].

Further documents and handouts for in-terventions after chemical accidents are the‘Handout for the Decontamination afterChemical Accidents’ [11], published 1999,and the ‘Handout for Fire Fighting Inter-ventions in Tunnels’ [12], published 2000.Still in discussion in the Committee forChemical Defence of the SFFA is the elab-oration of a ‘Handbook for Chemical De-fence’. The objective of this Handbookwould be to combine and unite all the basicknowledge, findings and principles for in-terventions which are of importance for thetraining as well as emergencies.

Received: November 19, 2003

[1] ‘Protection against Major Accidents (Ordi-nance on Major Accidents, OMA)’, SR814.012, Feb. 27, 1991.

[2] ‘Concept Coordinated AC-Protection’,Jan. 24, 1990.

[3] ‘Directives for the Chemical Defence forFire Brigades/Directives for the Trainingof Chemical Defence Specialist’, SFFA,1985.

Fig. 3. When the explosion hazard is containedby a foam layer, chemical defence specialistsstart their job of sealing containers containinghazardous materials

[4] ‘Handout for the Behavior of Local FireBrigades in Case of Chemical Accidents’,SFFA, 1999.

[5] Council Directive 96/82 EC, ‘Control ofMajor-Accident Hazards Involving Dan-gerous Substances (Seveso-Guideline ofthe European Union)’, Dec. 9, 1996.

[6] Federal law, ‘Protection of the Environ-ment (LPE)’, SR 814.01, Oct. 7, 1983.

[7] ‘Fire-Fighting 2000 plus’, Conference ofGovernments of the Cantons for the Coor-dination of Fire-Fighting, Feb. 12, 1999.

[8] ‘Directives for the Chemical Defence forFire Brigades’, SFFA, 1997.

[9] ‘Emergency Response Intervention Cards(ERI-Cards)’, CEFIC, Brussels, 2000.

[10] ‘Oil, Chemical and Radiation Defence’,Gebäudeversicherung Kanton Zürich,2002.

[11] ‘Handout for Decontamination afterChemical Accidents’, SFFA, 1999.

[12] ‘Handout for Fire Fighting Interventions inTunnels’, SFFA, 2000.

b) Corrosive Effect on MaterialsSelection of appropriate containers and

materials is crucial for safe handling of acidsand bases. There is no cheap, all-purposematerial for acids and bases. Only skilledcorrosion specialists can provide technicaladvice. For example iron is suitable for high-ly diluted or concentrated sulfuric acid. Butin the range between 20% and 80% it is at-tacked quickly. As in chemical reactions,higher temperatures speed up corrosion. Theoxidation process is often paired with hydro-gen and toxic gas production.

c) Basic Principles When HandlingAcids and Bases

To prevent aggravation of the situationsome rules must be applied strictly.• Do not splash water into acids or bases,

since – spilled material spreads;– the heat of hydration can cause lo-

cal spots with water above boiling



ISSN 0009–4293

Spills of Acids and Bases

Felix Gsell*

Abstract: Due to their hazardous characteristics acids and bases present an intrinsic risk in the event ofspillage. To prevent injuries from chemical contamination, HazMat unit personnel use protective suits andproper decontamination procedures. Nitrous acid is especially insidious since it causes severe burns withwounds that take a long time to heal. In addition it produces hydrogen and nitrous oxide gases by redox re-actions with metals. Risk assessment for a production site and case studies of incidents are presented.

Keywords: Decontamination · Nitration · Nitrous acid · Protective equipment · Risk assessment

Introduction

EMS-Dottikon AG is a chemical pro-duction site with about 400 employees and200 plants and buildings. The company pro-vides fine chemicals for the life sciencesand plastics industries. Since the roots ofEMS-Dottikon AG go back to the produc-tion of explosives (former name Schweiz-erische Sprengstoff Fabrik) nitration is stilla core business of the company. Thesechemical reactions require large amounts ofacids and bases such as nitrous acid, sulfu-ric acid, hydrochloric acid, acetic acid,acetic anhydride, propionic acid, phospho-rous oxychloride, thionyl chloride, andcaustic soda. In these processes, the usedacids with by-products are purified to highgrade 98% sulfuric acid and 99% nitrousacid. The origin of these used acids are ab-sorption units and waste products of nitra-tion and oxidation reactions. Handlingacids is therefore daily business in the 90-year history of EMS-Dottikon AG.

The private fire brigade was founded in1938. In the years since then, the firebrigade has evolved from relatively modestbeginnings to a well-equipped HazMat basefor part of canton Aargau. About 100 vol-unteers form the crew. This includes an an-alytical team and a paramedic team.

*Correspondence: F. GsellEMS-DOTTIKON AGPostfachCH–5605 DottikonTel.: +41 56 616 81 11Fax: +41 56 616 81 20E-Mail: [email protected]

Hazard Potential of Acids andBases

a) Corrosive Effect on HumansThe main danger is inhalation of acid

vapors. These vapors cause pulmonary ede-ma (alveoli become damaged and the lungsfill with water) or severe damage to the de-stroy respiratory tract. Reversible or evenirreversible damage can hinder respirationfor life.

The second danger is the corrosive ef-fect on eyes, mucous membranes and skin(Fig. 1). The worse effects are based on pro-tein degradation paired with exothermicgeneration of heat. The extent of the dam-age is dependent on concentration, potency,temperature, and time of impact. Theexothermic properties of protein degrada-tion explain why corrosion damage oftenalso results in burns. By-products can enterblood vessels and result in a toxification ofthe patient.

Fig. 1. Severe skin cor-rosion on a contami-nated hand


point resulting in the eruption of aciddrops;

– the release of enormous quantities ofHCl occurs with acid chlorides.

• Physical isolation is preferred to dilu-tion or neutralization.

• No organic binder materials for oxidiz-ing acids due to the fire hazard.

• Neutralization should only be carriedout with decontamination.

• Provide fire protection and ventilatebasements as counter measure to possi-ble hydrogen production.

• Collect spilled liquids to avoid uncon-trolled run-off.

• Adjust to pH range 5 to 9 before dispos-al to sewers.

• Inform the responsible authority and ad-vise waste water treatment plant manag-er, who will have an emergency plan.

Risk Assessment for Handling ofAcids and Bases

Fundamentally EMS-Dottikon AG en-sures that incidents do not have conse-quences in residential areas. Therefore han-dling of chemicals is limited. The fire chiefdetermines the acceptable quantities basedon the toxic effects of the chemicals. Safe-ty of internal transports has to be secured byproper transportation and strictly executedpackaging guidelines.

Case 1Hydrogen chloride in pressurized con-

tainers is used in a plant. The distance to thenext residential area is about 600 m. With asimple dispersion model, ‘Modell für Ef-fekte mit toxischen Gasen (MET)’ [1], theplume extension area is determined basedon worst case scenarios. In this case about40% of the material is suddenly released byspontaneous evaporation (flash fraction).Weather conditions are less important withspontaneous evaporation. A guide value<500 kg HCl per container was determined.The intervention of the fire brigade pro-vides additional safety.

Case 2In a tank farm 30 to of vitriolic nitrous

acid should be stored. With aqueous liq-uids, spontaneous evaporation is not rele-vant. Therefore estimation of pool size is anindicator for evaporation. Normally a sur-face area <200 m2 is recommended. Evap-oration is favored by warm temperatureswithout turbulence. For the risk assessmenta warm summer night is assumed. Again in-tervention of fire brigade is not taken intoaccount. With nitrous acid it is importantthat water is only used to knock down va-pors and does not come into contact withthe acid.

Case 3When limitation of surface areas or

quantities cannot provide adequate protec-tion, chemicals have to be handled in con-tainment. Escaped material is vented andneutralized in a scrubber or adsorbed. Asneutralization agents, chemicals such assuitable acids, bases or other chemicalssuch as thiosulfate for bromine or ammoniasolution for dimethylsulfate are used.

Protective Equipment

Staff are protected by working in aclosed operation mode or by venting vaporsat the source. Despite these precautions, in-cidents can be triggered by mishap, techni-cal failure or human error. Therefore per-sonal protective equipment should be wornin the plant. In the intervention mode of thefire brigade, contamination of HazMattechnicians is likely. In our fire brigade wehave defined different protection levels.

Rescue MissionAn immediate rescue is vital for the pa-

tient. Therefore a rescue mission is per-formed in fire-protective clothing, breath-ing apparatus, gloves and boots. This equip-ment enables fast intervention even in veryhigh vapor concentrations. The officer-in-charge is responsible for adequate fire pro-tection (at least a powder extinguisher) anda proper decontamination of patients andfire services personnel and material.

Intervention Against SpillsThe officer-in-charge or the scientific

officer should define the appropriate pro-tection level. Light PVC suits with bootsand breathing apparatus or gas-tight protec-tive suits are possible.

First Aid Material

Principally decontamination is per-formed with water. Speed is essential (seearticle of F. Geissmann in this special issue[3]). Since we have especially good experi-ence with Previn® (www.prevor.com) thisoption is described here. Previn is an am-photeric substance and therefore suitable tobind acids, bases and other chemicals. Withthe adsorption of chemicals their hazardouseffect is contained. Two things are impor-tant:1) Previn has to be used immediately.2) Corrosion lesions are often also burns.

Therefore, after removal of chemicals, atreatment similar to burn patientsshould follow.

To demonstrate the excellent effect ofPrevin, experience gained from three ni-trous acid contaminations is presented.

Case Study 1A new product was synthesized in a pi-

lot plant by means of a nitration reaction.The reaction mixture, nitrous acid, sulfuricacid and products, was transferred with amembrane pump into a second vessel withice. Collectively we observed events in thereactor and through the inspection glass ofthe transfer pipe. Suddenly color in the in-spection glass turned from red/brown toblack. A decomposition reaction had oc-curred. The pressure increase resulted in theinspection glass bursting. Unfortunately achemist was hit on the leg by the reactionmixture. We started immediately with de-contamination with plenty of water. The ef-fect was disappointing. The accident result-ed in an absence from work for more thanone month since the skin lesion healed bad-ly. This painful experience was the motiva-tion to look for an alternative decontamina-tion procedure. The reason for this incidentwas a broken pump membrane. As a conse-quence lubricant entered the reaction mix-ture and started the decomposition process.

Case Study 2An employee found that a feed pump of

an acid recycling plant was not working. Onthe pressure side the pipe was plugged. Hestarted to disassemble the pipe without re-leasing the pressure. The employee re-ceived acid splashes in his face. Instinctive-ly he went under the shower. About 3 minlater paramedics treated the corrosion withPrevin. The typical yellow, ulceratingwound was not observed (Fig. 2). The clin-ical picture and statements of the victim in-dicated a burn. He was absent from workfor eight days.

Case Study 3An employee pumped warm 99% ni-

trous acid with a dosing pump. A valve inwrong position led to a rupture of a pipeconnection and nitrous acid splashed thehead of the employee. Helmet and protec-tive shield prevented the worst. Some acidentered an ear. The wound was immediate-ly decontaminated with Previn and thentreated as a burn. The employee was onlyabsent from work for two days.

Intervention Concept for Incidentswith Acids and Bases

The procedure is always more or lessthe same.

1. Urgent Measures– Prevent entry of persons or cars to the

scene.– Check if sufficient fire services person-

nel are available. If not, call for morefire fighters.

– Remove all ignition sources.

2. Rescue People and Animals– Rescue patients with protective equip-

ment.– Start immediately with first aid and de-

contamination.– Check for missing people. If there are

any, start manhunt.

3. Prevent Propagation– Cordon off the scene.– Isolate spilled material.– Improve fire protection if necessary.– Prevent entry of chemicals in sewer sys-

tem, water bodies or soil.– Knock down toxic vapors.– Seal the leak.

4. Salvage Measures– Do everything to ensure a safe situation

and prevent collateral damage.

Spills With Corrosive Chemicals

Case Study 1 – Nitrous Acid 60%Nitrous acid 60% was delivered in 600 l

plastic containers to a galvanization facto-ry. The driver parked his truck in a streetwith an upwards gradient. With a hand fork-lift he transported the pallet with the con-tainer. Due to the downward slope the ship-ment started to move and could not bestopped. The container fell on the floor andcracked. Part of the acid leaked onto aparked car and then on the tarred forecourt.The production of nitrous oxide began im-mediately. Before sinks could be closed,about 50 l of the acid ran into the sewer sys-tem. The entry to the scene was blocked andthe local fire brigade called for the HazMatunit.

Actions of Local Fire Brigade:– Ensure that no persons are involved.– Notification of the waste water treat-

ment plant.– Tightening the sink by fire services per-

sonnel protected with breathing apparatus.– Cordon off the scene and installation of

a provisional decontamination place– Traffic management.

Actions of HazMat Unit:– Ensure that in fact no persons are in-

volved.– Secure remaining nitrous acid in the

container.– Disperse non-organic binding material.– Dispose of binding material in fiber

drums.– Neutralization of the scene with sodium

bicarbonate.– Rinse the scene with plenty of water.– Check pH-value in the sewer near

wastewater treatment plant.– Check equipment with pH indicator

strips and decontaminate if necessary.

Case Study 2 - Nitrous Acid and Ex-plosives

Explosives are produced by dosing re-actant to vitriolic nitrous acid. By-productsmust be destroyed by gentle oxidation. Thisreaction has to be well controlled otherwisea violent decomposition starts.

Decomposition can result in a detona-tion of the explosive. Reactors are equippedwith an emergency vessel for quenchingwhen decomposition starts. In 2002 thisemergency measure had to be used in ourcompany. With quenching, considerableamounts of nitrous oxide were produced.The toxic gases were washed out partly by

the deluge system and partly by water sprayfrom the monitors. The analytical team tooksamples in the surroundings to check fordanger to the local population. Within resi-dential areas at no time was the MAK limitthreshold exceeded. Results and measuringtubes were handed over to the police. A bigchallenge were about 100 kg explosive pel-lets remaining together with 50% nitrousacid in the emergency vessel. The Officer-in-charge, plant chemist and productionmanager decided to pump the suspensionwith a peristaltic pump (ELRO pump). Thispump produces practically no friction. Toseparate acid and pellets, the suspensionwas transferred to an open suction filter.HazMat technicians involved wore full pro-tective suits. To minimize the risk onlythree people were in the endangered area.The combination of a long suction pipe anda short pressure pipe with the ELRO pumpwas once more a success (Fig. 3).


[1] ‘Technischer Behelf für den Schutz bei C-Ereignissen, MET (Modell für Effekte mittoxischen Gasen)’, Zentralstelle fürGesamtverteidigung, EDMZ Bern, 1991,Nr. 581.031d (out of stock): today it is in-tegrated in [2].

[2] H.D. Nüssler, ‘Gefahrengut Ersteinsatz’,Storck Verlag, Hamburg, 2000, ISBN 3-923190-33-6.

[3] F. Geissmann, Chimia 2004, 58, 33.


Fig. 2. Typical wound caused by nitrous acid corrosion. The healingprocess is well advanced.

Fig. 3. HazMat technicians in gas-tight protective suits install long suc-tion pipe (left) and short pressure pipe (right) for a pumped transfer ofchemicals with an ELRO pump



ISSN 0009–4293

Emergency Response Organisation for Toxic Gas Emissions

Gérard Zufferey*

Abstract: Toxic gas emissions are the most severe chemical incidents, since chemicals disperse quickly from thesource to the site and residential areas. Risk is minimised by design measures, alarm systems, and emergency re-sponse planning. Site personnel and people living in the vicinity must be informed and trained on the correct ac-tions to take. The organization for possible incidents consists of a main command and control centre, a forwardcommand centre and the fire brigade.

Keywords: Alarm system · Command and control centre · Emergency response planning · Toxic gas emissions ·Training facilities

Monthey Chemicals’ Site

The chemicals’ complex at Montheycomprises three chemical manufacturingcompanies – Ciba Specialty Chemicals,Huntsman, and Syngenta Crop Protection –together with a fourth company providinginfrastructure and utility services, Cimo(Compagnie industrielle de Monthey).There are 80 different production buildingswith a workforce of 2400 employees, while27 tank farms with a total of over 600 ves-sels contain a wide range of chemical prod-ucts.

1. Toxic Gases

The chemical products mentionedabove include a number of toxic gases, suchas chlorine, ammonia, phosgene, sulphurdioxide, and trimethylamine. Their charac-teristics differ greatly, as shown by the tableof physical and chemical properties(Table). A similar table will provide somedata of immediate use to the officer incharge of a HazMat unit, who can therefore

*Correspondence: G. ZuffereyChef Protection d’entrepriseCIMO, Compagnie industrielle de Monthey SACH–1870 MontheyTel.: +41 24 470 3652Fax: + 41 24 470 3639E-Mail: [email protected]

adapt his or her emergency response strate-gy appropriately. Definitions of several keyparameters now follow:

Olfactory safety factor (OSF) is the ra-tio of the exposure limit as time-weightedaverage (TWA) to the olfactory threshold.The lower the value, the longer will it takethe plant personnel to detect a leak.

Three ERPG (Emergency ResponsePlanning Guide / American IndustrialHygiene Association) values have the fol-lowing significance:– ERPG-1 is the maximum airborne con-

centration below which it is believedthat nearly all individuals could be ex-posed for up to 1 h without experiencingmore than mild transient adverse healtheffects or perceiving a clearly defined,objectionable odour.

– ERPG-2 is the maximum airborne con-centration below which it is believedthat nearly all individuals could be ex-posed for up to 1 h without experiencingor developing irreversible or other seri-ous health effects or symptoms whichcould impair an individual’s ability totake protective action.

– ERPG-3 is the maximum airborne con-centration below which it is believedthat nearly all individuals could be ex-posed for up to 1 h without experiencingor developing life-threatening health ef-fects.

In the case of the IDLH (ImmediatelyDangerous to Life and Health) parameter, it

is worthy of note that the National Institutefor Occupational Safety (USA) has pub-lished a revised table of IDLH values,which in certain cases are up to twentytimes lower than their original values. TheIDLH value is defined as an atmosphericconcentration of any toxic, corrosive, or as-phyxiant substance that poses an immediatethreat to life or would cause irreversible ordelayed adverse health effects or would in-terfere with an individual’s ability to escapefrom a dangerous atmosphere within 30min following the failure of his or herbreathing apparatus.

2. Accidental Release of Toxic Gas

If a gas escapes, its physicochemicalproperties and physical state influence itsdiffusion, while its chemical structure de-termines its toxicity. In addition to the prop-erties of the substance, other factors affectits dispersion rate, such as the quantity re-leased, the meteorological conditions (windspeed and direction, atmospheric pressure,relative humidity, temperature, etc.) and thetopography of the local environment.

The manifestations of chemical poison-ing can be divided into two main groups: lo-cal disturbances and generalised disorders.

Disorders that are local or restricted tocertain regions of the body develop in threestages:– Irritations of the eye and respiratory

tract, followed by a prickling sensationin the skin (face, hands).


– Ocular burning and shooting pains, asensation of heaviness in the chest, res-piratory discomfort that may persisteven after the toxic atmosphere has re-ceded.

– Respiratory distress, cyanosis.These problems are caused by halo-

genated chemicals (chlorine, bromine, io-dine and fluorine compounds), certain ni-trogen compounds (oxides of nitrogen, am-monia) and a number of sulphurcompounds.

Generalised disorders involve:– Symptoms of excitation or convul-

sions accompanied by aggressive-ness, headaches or nausea. Symptoms of depression, drowsiness or even co-ma.

– Feelings of dizziness or muscular weak-ness.

– Digestive disorders.– Rapid breathing, symptoms of depres-

sion, respiratory discomfort, respiratoryarrest.These generalised disorders are induced

by anoxiants such as nitrogen, hydrogenand fluorine, by narcotic gases such asvapours from varnishes, solvents, ethers,certain hydrocarbons, or again, chlorinatedproducts, as well as by cellular toxins suchas carbon monoxide and hydrogen sul-phide.

Finally, all these toxic gases can befound in the products of combustion result-ing from a fire; an aspect often neglected inan emergency.

3. How to Minimise the Risk of aLeak and/or Mitigate Its Effects

3.1. Design MeasuresThe first question that must be asked is

whether it is advisable to store the product. Incertain cases, admittedly rare, it is possible tofind another solution. At Monthey, for exam-ple, it has been decided to give up the storageof phosgene, replacing this by a system ofsynthesis on demand, with a supply system tothe production buildings through a maxi-mum-safety network (double containment,dry air purge through the jacket, on-line phos-gene detection, analytical monitoring of thevented purge air and, in the event of an alarm,production stop and system purge).

If it proves necessary to store the prod-uct, it is advisable to implement all the safe-ty measures dictated by the risk analysis. Itcould be necessary to install a gas detectionsystem, which is possible for the principaltoxic gases, or failing that, a leak detectionsystem, depending on the case concerned.

At Monthey, we have implemented an-other precautionary measure by equippingall our tank farms with a water – or waterand emulsifier – deluge system, which notonly protects the tanks, but also creates awater curtain between the sections of thetank farm and at its perimeter.

3.2. Organisational Measures3.2.1. Alarm System

To limit the consequences of an inci-dent, it is vital that both the site personnel

Properties Ammonia Chlorine Sulphur Trimethyl- Phosgenedioxide amine

Boiling point –33 °C –34 °C –10 °C 3 °C 8 °C

Relative vapour density 0.6 2.5 2.3 2 3.4(air = 1)

Solubility in water 520 g/l 7 g/l 113 g/l 500 g/l –(at 20 °C)

Explosive limits in air 16–25 vol % – – 2–11.6 vol % –

Olfactory threshold 5 ppm 0.05 ppm 1 ppm 0.05 ppm 0.5 ppm

Exposure limit: 20 ppm 0.5 ppm 0.5 ppm – 0.02 ppmtime-weighted average (TWA)

OSF (TWA/olfactory threshold) 4 10 0.5 – 0.04

Short-term exposure limit (STEL) 40 ppm 0.5 ppm 0.5 ppm – 0.04 ppm

IDLH 300 ppm 10 ppm 100 ppm – 2 ppm

ERPG–1 25 ppm 1 ppm 0.3 ppm 0.1 ppm n/a

ERPG–2 150 ppm 3 ppm 3 ppm 100 ppm 0.2 ppm

ERPG–3 750 ppm 20 ppm 15 ppm 500 ppm 1 ppm

Table. Physical and chemical properties of some toxic gases

and the neighbouring population are giventhe alarm as quickly as possible. At Mon-they, every building is equipped withalarms. If a toxic product escapes, we are ina position to set off the site gas alarm by onesingle action. In this case the site externalsirens go off, the alarms within the build-ings are activated and the illuminated pan-els (site gas alarm) light up. In every build-ing on the site as well as in the local policestation, devices connected to the telephonesystem simultaneously give a prerecordedalarm message. Information telephone No.5 on the site also transmits a prerecordedmessage advising what action is to be tak-en. Local radio programs are automaticallyinterrupted to allow a prerecorded messageto be broadcast in several languages advis-ing what action to take. Members of the firebrigade are automatically alerted by meansof individual pagers. In short, all the actionsmentioned above will have been imple-mented only a few seconds after the alarmis raised. It goes without saying that all em-ployees know what action to take followingthis first alarm, and they are trained to doso. Regular exercises are carried out duringthe monthly alarm tests or as part of thesafety days held in the site buildings. Turn-ing now to the local population in the townof Monthey: they will be alerted quicklywhen the municipal alarm sirens are acti-vated, as well as by the message broadcaston local radio. In addition, numerous train-ing and information activities are providedin the community by the civic authorities


and the site management in order to makethe population aware of what action to takein the event of an alarm.

3.2.2. Emergency Response PlanningAmong the organisational measures we

can cite the establishment of an emergencyresponse plan for every building and everytank farm on the site. In addition to other in-formation this includes the location of thebuilding and the route to it for the firebrigade, the hydrants, the specific hazardsand risks, a list of products and their exactlocations, the feed and return lines for util-ities and products, the means of combatingthe fire, the detection and extinguishingsystems, the emergency exits and personnelassembly points, the locations of machin-ery, freight and personnel lifts, materialsafety data sheets and the containment fa-cilities for fire runoff water.

3.2.3. The Site Plan for CatastrophicIncidents

In contrast to the above-mentioned emer-gency response plans, which relate to theparticulars of individual buildings or tankfarms, the site catastrophic incident plan hasbeen drawn up for incidents whose conse-quences go beyond the boundaries of thesite. It sets out to define the alarm schedulefor all the organisations involved, the opera-tional deployment plan and the tasks as-signed to all the internal and external emer-gency services at the site. This plan has beenworked out in close cooperation with the re-gional administrative authorities, the emer-gency services and the police forces ofneighbouring municipalities and the Can-tons of Valais and Vaud. Regular meetings ofall the partners as well as exercises allow itsefficacy to be tested. The last full-scale exer-cise, carried out in 2000, involved 250 emer-gency service personnel being called out.

3.2.4. Organisation for Possible Incidents

The organisation set up to deal with pos-sible incidents at the Monthey site has theobjectives of dealing effectively with allphysical, biological, or chemical incidents,all emergencies relating to a product or aproblem of safety or security, or all othercritical situations that could impact negative-ly on persons or the environment, or on thewell-being or good name of the companies.

This organisation must therefore takeadequate measures to deal with an incidentor reduce its negative effect to a minimum,and must ensure that there is good coopera-tion with the authorities and public ser-vices, and that the authorities, the site per-sonnel, the media, the public and any otherinterested parties receive complete andaccurate information.

This organisation comprises a maincommand and control centre, manned by a

chief of staff, an officer responsible forcommunications, an officer responsible forprotection of the site companies, and achemicals adviser. This staff may be aug-mented by several specialists.

The function of the staff is:– To assess the situation, to make the nec-

essary decisions concerning the generalsafety of the site personnel, the fire-fighters, the site itself and the local pop-ulation, to ensure that all internal andexternal organisations have been alert-ed, to call out the specialists whosepresence is necessary, to ensure the co-ordination of emergency activities car-ried out by several bodies and special-ists, to give support to the officer incharge of emergency services, to takecharge of organising public relations, toliaise with the authorities, officials andthe media.

– A forward command and control centreat the incident site, comprising a firebrigade officer in charge and an execu-tive from the management of the affect-ed zone. With the support of the firefighting unit and possibly other support-ing services, the officer in charge of thefire-fighters implements an emergencyresponse strategy appropriate to the inci-dent, following the fire-fighters’ motto:‘Save, contain, extinguish, protect’.

3.2.5. The Works Fire Brigade at theMonthey site

The works fire brigade at the Montheychemicals complex consists of a unit of pro-fessional fire-fighters together with a com-pany of volunteer auxiliaries.

The 18 professional fire-fighters arecommanded by a station officer and are di-vided into three teams. This ensures thatthere are always four men permanentlypresent on the site and ready for any emer-gency response. They can be out of the firestation in less than 3 min. This state ofreadiness is maintained around the clock,seven days a week and 24 h a day.

The auxiliary company is composed of60 volunteer fire-fighters who normallywork in the various companies on the site.These volunteers are divided into threegroups with different skills: HazMat and ra-dioactive protection specialists concernedwith chemical incidents as well as fire fight-ing, appliance operators, and the measure-ment group. The latter group is equipped toidentify the presence or absence of toxicgases in the atmosphere and to take samplesof air, water, and soil.

The works fire brigade has five vehiclesat its disposal, including an ambulance, plusspecialised equipment suitable for chemicalincidents.

The Cimo fire brigade also acts as anemergency response centre for chemical in-

cidents and radioactive protection for theFrench-speaking part of the Canton ofValais.

In addition, we can also count on thesupport of a medical service with two doc-tors and five paramedics, as well as a groupof twelve first aiders trained to provideemergency medical treatment.

4. Emergency Response Strategyfor Toxic Gas Escapes

The officer in charge first of all decidesthe direction to take when approaching theincident site, selecting a route so as to havethe wind coming from behind. He has thefire-fighters equipped with full fire fightingsuits and self-contained breathing appara-tus. If possible, he makes an initial analysisof the situation, which consists of investi-gating the type of gas and localising theleak, consulting the documentation, in par-ticular the toxicological values, anticipatingthe movement of the gas cloud and evaluat-ing the risks to the local population and theenvironment. He arranges for the vehiclesto draw up at an appropriate distance fromthe emission: a minimum of 60 m awayfrom minor leaks, at least 100 m away frommajor leaks.

After having made a swift reconnais-sance, immediately communicating the re-sults to the main command and control cen-tre, he organises the emergency response:deployment of a minimum number of per-sonnel in breathing apparatus and protec-tive suits; deployment of personnelequipped to carry incident victims to safe-ty, setting up of a water curtain, taking ex-plosimetric and toxicity measurements sys-tematically around the incident site, at-tempting to stop the leak, blocking off thedrains and sewer system, redefining the in-cident zone on the basis of the measurementresults (Fig. 1), installing a decontamina-tion facility.He then ensures that operations are con-ducted appropriately as the situationevolves.

5. HazMat Unit Equipment

Dealing with chemical incidents re-quires the use of special equipment, whichin the case of items such as electrical cables,pumps, power tools, and radios must be ex-plosion proof. Protective clothing and hosesmust be resistant to chemical attack, withthe use of stainless steel couplings. TheHazMat specialists have earthing equip-ment to prevent the build-up of electrostat-ic charge, as well as the facilities and prod-ucts necessary for decontamination. A sys-tem for recovering liquids, with severalseparate stainless steel tanks having a total


capacity of 3000 l, forms part of the basicequipment of the HazMat unit appliance.

6. Training Facilities on the Monthey site

The Cimo fire brigade has an exercisesite (Fig. 2), on which part of the plant hasbeen reproduced. There is a simulatedhouse (‘burn building’), a steelwork tower13 m high, an open arena (400 m2) forlarge-scale fire fighting exercises, a pit witha reservoir, a rail track with a wagon (prac-tice in stemming leaks), a tank (emergen-cies in a confined space) and an installationfor demonstrating dust explosions.

The exercise site is used not only by theCimo fire-fighters for training purposes, butalso for safety days and fire safety school-ing for site personnel. Local fire brigades inthe region together with those from citiessuch as Lausanne and Neuchâtel also usethe facilities (burn building) for trainingsessions in the chemical incident sector.

Received: December 5, 2003

Fig. 1. Zone demarcation plan as basic strategy for emergency response to toxic gas emissions. The tasks fire protection and hazardous materialsresponse are managed by two officers reporting to the officer in charge.

Fig. 2. Training facilities on the Monthey site with burn building, steelwork tower, open arena, tank,and railway wagon.



ISSN 0009–4293

Inflammable Liquids – Hazards and TheirPrevention

Otto Ebener*

Abstract: Spillages and fires with inflammable liquids are an enormous challenge for a task force. Only well-equipped and well-trained organisations are in a position to fulfil these tasks. This means firemen should beaware of the dangerous properties of inflammable liquids. The equipment and training must be continuallyexamined and, if necessary, adapted.

Keywords: Earthing · Explosion limits · Inflammable liquids · Phase plan for chemical incidents · Threefold fire protection

1. Introduction

In many instances fire brigades in thechemical industry have to combat fires orchemical spillages of inflammable liquids.It is not always easy for the head of opera-tions to make the correct decision. Besidesa good tactical training, an exact knowledgeof the dangers involved with inflammableliquids is required. In order that the hazardscan be recognised, one must be familiarwith certain concepts. This article is de-signed to assist in recognising and over-coming hazards.

2. Inflammable Liquids and TheirProperties

The fire triangle tells us that besidesfuel – in this case the inflammable liquid –sufficient oxygen and an ignition sourcemust also be present for a fire to occur.

If one observes a liquid fire closely, it willbe noticed that it is not the liquid that burns,but the nascent vapours arising from it.

2.1. Vapour Pressure and LiquidVapours

If during a liquid fire only the vapoursburn, the question arises as to how thesevapours originate.

*Correspondence: O. EbenerLonza AGWalliserwerkeCH-3930 VispTel.: +41 27 948 5071Fax: +41 27 947 5071E-Mail: [email protected]

If a liquid is heated to its boiling point, alarge quantity of vapour is formed. Vapoursare formed not only by heating the liquid,but also by the surrounding temperature.This process is known as evaporation.

This evaporation is due to the vapourpressure. The leader of the task force mustknow that the higher the vapour pressure ofa liquid, the more vapour can be formed onthe surface of the liquid. If the liquid isheated, the rate of evaporation increases. Ifthe temperature drops, the rate of evapora-tion automatically falls [1].

This is well illustrated taking gasolineas an example. At 20 °C gasoline is highlyflammable, at –30 °C very little vapour isformed and ignition is not possible.

Liquids with higher vapour pressuresthus constitute a potentially greater hazard.

2.2. Flash PointThe flash point is defined as the tem-

perature at which sufficient vapours areformed at the surface of a liquid for ignitionto occur when in contact with a source of ig-nition. If the ignition source is removed, theflame extinguishes. If liquids with differentflash points are mixed, the lower value is de-

cisive. Inflammable liquids are classifiedaccording to their flash points.

2.3. Fire PointThe fire point is defined as the temper-

ature at which sufficient vapours areformed at the surface of a liquid, so that af-ter ignition with a source of ignition thevapours continue to burn independently.

The fire point usually lies only slightlyabove the flash point. The higher the boilingpoint of a liquid, the larger the differencebetween its flash point and fire point [1].

2.4. Spontaneous Ignition Temperature

Another important parameter is thespontaneous ignition temperature ofinflammable liquids. If this temperature is reached, the liquid vapours ignite bythemselves. No ignition source is neces-sary [1].

2.5. Flash Point/Fire Point/Sponta-neous Ignition Temperature [2](Table)

Fuel Flash point Fire Point Spontaneous Ignition Temperature

Diesel oil 76 °C 90 °C 350 °C

Paraffin 21 °C 23 °C 400 °C

Gasoline –30 °C –25 °C 470 °C

Carbon disulphide –20 °C –20 °C 120 °C

Table.

deployment measures. Measurements mustbe taken during the whole operation.

Results are bound to the place and time.Attention must be paid to employ the mostreliable people for measuring explosivehazards.

The explosion measurement is the lifeinsurance for the operating firemen.


2.6. Static ChargingIf inflammable liquids have to be trans-

ferred by flowing from one container toanother, then this leads to a charge separa-tion. By internal friction in the liquid andby friction on the pipe or tubing walls, aseparation of positive and negativecharged particles takes place. If thischarge cannot flow during its formation,since the liquid or tubing is non-conduct-ing, then a so-called static charging willoccur. If an earth connection is in thevicinity, there will be an instantaneous dis-charge with the formation of a spark. Theenergy is sufficient to ignite vapours of in-flammable liquids [3].

For the industrial chemical fire brigade,‘earthing’ is therefore considered to be ex-tremely important. Today it is usual to erecta pipe construction from the earthing pointin the forwards direction of the leaking con-tainer (Fig. 1).

In factory fire brigades, conducting firehoses and fittings are generally employed.These are checked at regular intervals, andin particular after deployment.

The earthing system can thus be consid-erably simplified and made more practicalfor deployment, since the parallel earthingcables can be omitted.

The potential compensation is also apossibility. Here all points in the system(fireman, reservist, pump, generator) areconnected with each other and thus preventthe build-up of different potentials.

2.7. Classification of InflammableLiquids

The flash point is taken as the referenceparameter for classifying inflammable liq-uids. The following classes are differentiat-ed:

F1: Flash point under 21 °CF2: Flash point 21–55 °CF3: Flash point 55–100 °C

2.8. Explosion Limits The explosion limit is an essential con-

cept for the chemical industry fire brigade.If inflammable vapours do not immediatelyignite, explosive air/vapour mixtures areformed.

The lower and upper explosion limitsare important terms in this connection. Thelower explosion limit (LEL) is the lowestconcentration of vapour in the air that is stillignitable. If the concentration lies underthis level, the mixture is too ‘lean’ and can-not be ignited.

The upper explosion limit (UEL) is thehighest concentration of vapour in air that isstill ignitable. If the concentration liesabove these limits, the mixture is said to betoo ‘rich’ [2].

The region between the lower and upperexplosion limits is called the explosive re-gion (Fig. 2).

In order to be able to safely contain thedanger of explosion, permanent explosionmeasurements are of critical importance.Besides having a thorough knowledge ofthe equipment, all chemical industry fire-men must be schooled in the behaviour ofinflammable gases and vapours. All spe-cialists must be able to interpret the meas-urements and to take the necessary tactical

Fig. 1. Earthing to prevent electrostatic charging [4]

Fig. 2. Explosion limits [5]

ing attack. The threefold fire protection orextinguishing attack has today become gen-erally accepted in Switzerland.

3.2. Threefold Fire ProtectionThe three extinguishing materials pow-

der, foam, and water are deployed in this or-der in fire protection (Fig. 3).

Powder: rapidly available and a verygood initial extinguisher.

Foam: leaking liquids are covered withfoam. The foam cover must be continuallykept under surveillance, if necessary re-newed.

Water: cools the surroundings and pro-tects the task force.

The threefold fire protection is set upfor every spillage involving inflammableliquids without fire. The most acute at-tention is required from the fire-hoseleaders, because they must be able to inter-vene immediately during the whole opera-tion.

3.3. Threefold Extinguishing AttackIn the case of the threefold extinguish-

ing attack the three extinguishing agentspowder, foam, and water are utilised in thisorder (Fig. 4):

Water: to cool and maintain the sur-roundings. By removal of heat the extin-guishing action is also directly supported.

Foam: extinguishes the burning liquidand provides a closed blanket of foam toprevent back ignition.


2.9. Hazards for the Task ForceIn cases of a spillage, liquids spread

very fast. The liquid vapours thus formedare all heavier than air and so flow down-wards. Cellars, ditches, sewers etc. are par-ticularly hazardous places. Various acci-dents both at home and abroad have shownthat these vapours can travel for kilometres.Thus highly dangerous situations can ariseboth for the task force and for the popula-tion. If there is an ignition, flames canspread very rapidly or even explosions arelikely.

For the task force the following mostimportant hazards can be deduced• Fire hazard• Explosion hazard

All other dangers that can additionallyarise from inflammable liquids (burns, acidburns etc.) are not considered here.

However in order to meet these dangerssafely, the various points must be taken in-to consideration in the case of an incident.

3. Measures for Fighting Spillagesof Inflammable Liquids

In order to deal with all types of chemi-cal accidents, a general phased plan hasbeen worked out by the chemical firebrigade. This plan covers six phases andpractically every large chemical industryfire brigade employs it today.

3.1. Phase PlanPhase 1• Approach

– Wind direction– Distance

• Self Protection – Breathing apparatus– Operational equipment

• Reconnoitring/identification of sub-stances involved – Warning signs/danger notices– Transport papers– Condition of the apparatus to be

utilised

Phase 2• Rescue

– Rescue of endangered/injured peoplefrom zone 1

– Initial decontamination of patients• Containment

– Precipitation of gases and vapours – Construction of the threefold fire

protection/extinguishing attack• Fencing off

– Formation of zones 1 + 2 – Chemical fire defence zone with en-

try and exit – Set-up decontamination site

Phase 3• Restrain/collect/temporary storage

– Full protection, light chemical pro-tection, breathing apparatus

– Chemically resistant containers Basic principle: collection before sealing

Phase 4• Sealing


– Suitable sealants

Phase 5• Pumping/absorbing


– Chemically suitable pumps – Binding material

Phase 6• Decontamination/clean-up

– Decontamination of personnel andmaterial with suitable means

All incidents can be handled accordingto this phase plan. Each phase must be in-tensively trained with the task force.Spillages with inflammable liquids are ad-ditionally classified into two categories:• Spillages without fire• Spillages with fire

Accordingly one speaks of the threefoldfire protection or the threefold extinguish-

Fig. 3. Threefold fire protection with heavyweight means [4]

out with all extinguishing agents at the ex-ercise area.

Every two years the fire brigade carriesout a further education course on the topic‘threefold fire protection and extinguishingattack in chemical fire defence’. Firemenfrom all over Switzerland and the neigh-bouring countries participate in thesecourses.

The exchange of experience with otherorganisations and a targeted training hascontributed to a well-organised works firebrigade that can fulfil its duties (Fig. 5).


[1] K. Klingsohr, ‘Brennbare Flüssigkeitenund Gase’, Die roten Hefte Nr. 41, 7. Auf-lage, Verlag Kohlhammer, Stuttgart, 2002.

[2] S. Schönhacker, ‘Gefahren ABC,Brennbare Flüssigkeiten Teil 1 und 2’,http://gefahren-abc.schoenhacker.at,2002.

[3] R. Sandmeier, ‘Dangerous goods’, inter-nal lecture of works fire brigade Lonza.

[4] Schweizerischer Feuerwehrverband,Gümligen, File Oil/Chemical IndustriesFire Brigade.

[5] T. Hofer, ‘Hazards of Chemicals’, internallecture of works fire brigade Lonza.

Powder: supports the extinguishing at-tack in the extinguishing phase and as asafeguarding extinguisher.

The threefold extinguishing attack isconsidered to be the state of the art in firefighting. In order that the threefold extin-guishing attack can be effectively imple-mented, a good basic training and repeatedexercises are necessary. In exercises andcourses frightening deficiencies are repeat-edly brought to light; on the one hand in thetactical implementation of an attack, and onthe other hand in the practical implementa-tion by the hose-leaders.

3.4. Personal EquipmentIn operations involving inflammable

liquids great attention must be paid to thepersonal equipment of the task force.

The fire-protection equipment utilisedtoday offers excellent heat protection on ac-count of the various extremely resistant out-er materials. This protection is however on-ly ensured if the equipment is worn and de-ployed according to regulations. Today itmust be clear that coats are completely but-toned up and collars turned up. This situa-tion requires a continuous sensitisation anda regular exercising, so that these require-ments also become generally accepted.

Particular attention must be paid tolooking after one’s personal equipment.Only intact and well looked-after protectiveequipment fulfils the task.

When working with toxic or corrosivesubstances, full protective suits or lightchemical protective suits are used. Thesesuits must be evaluated against the set re-quirements. Utilisation of such suits re-quires additional training. On this topicalone it would be possible to write a reportof several pages.

4. Lonza’s Fire Brigade and ItsTraining Opportunities

4.1. Organisation and TasksLonza’s fire brigade is a private emer-

gency organisation founded in 1925. From 1967 onwards the present chemi-

cal industrial fire brigade was formed underthe leadership of the then commandant of the fire brigade, Rudolf Sandmeier.Lonza’s fire brigade was responsible for the tactical and material development of fire fighting for the whole of the Swiss chemical industry. We are still proudof this.

Today we are a nationally recognised in-dustrial fire brigade, consisting of six full-time professionals and 84 militia firemen.

Lonza’s fire-brigade equipment is spe-cially tailored to the requirements of the in-dividual plants. It includes all necessary ve-hicles and equipment for fire- and spillagefighting. Since no similar fire brigade ispresent in the immediate vicinity, theequipment is very extensive. By order of theCanton of Valais, the works fire brigade isalso the chemical defence base for the Ger-man-speaking part of the canton.

4.2. Training OpportunitiesA suitable training area is necessary in

order for an industrial fire brigade to becomprehensively trained.

Thanks to the far-sightedness and skillof the responsible persons, it is today stillpossible for the works fire brigade to trainall sections of the chemical fire defence onits own exercise ground.

Particularly important are the facilitiesfor exercising the threefold extinguishingattack. Fire exercises in a production plant,in a tank farm and in a lorry can be carried


Fig. 4. Threefold extinguishing attack; the state of the art in fire-fighting.Picture by the Works Fire Brigade Lonza Ltd.

Fig. 5. Solvent fire. Picture by the Works Fire Brigade Lonza Ltd.



ISSN 0009–4293

Pumped Transfer of Liquefied Gases

Felix Ochsner*

Abstract: The transfer of liquefied gases comprises a special hazard potential. Therefore special equipment andexpertise is necessary. It is not possible for every HazMat base to hold its own equipment. Therefore in Switzer-land the Flüssiggaspikett der Ostschweiz and DSM Nutritional Products, Sisseln, can be called out to provide helpif incidents with liquefied gases occur. A case study of a real mission is presented. Furthermore technical specifi-cations of key items and the experience of the author are provided.

Keywords: Ammonia · Hazardous materials technician · Railway accident · Training facility · Transfer of liquefied gases

Introduction

Liquefied gases are often transferredand/or stored in stationary facilities in largequantities. If incidents involving liquefiedgases occur, the emergency services de-ployed must take special safety aspects intoaccount and require specialised equipmentto deal with the situation. The number ofHazMat Units that can be called out to pro-vide help if incidents with liquefied gasesoccur is therefore very small. In Switzer-land these comprise the HazMat Unit ofDSM Nutritional Products (DNP) in Sis-seln, for the past six years, and the Flüs-siggas-Pikett der Ostschweiz (EasternSwitzerland Liquefied Gas Emergency Ser-vice) for the past two years. The specialisedequipment used by these two units is com-patible.

Our company, the DNP production siteat Sisseln, stocks large quantities of liquidammonia. In order to be prepared for anyemergencies that might occur, our HazMatUnit has therefore been provided with theequipment necessary for handling liquefied

*Correspondence: F. OchsnerDSM Nutritional ProductsHauptstrasse 4CH–4334 SisselnTel.: +41 62 866 24 97Fax: +41 62 866 20 75E-Mail: [email protected]

gases. This was done based on our own ex-pertise together with advice from BASF,which could call on some experience, hav-ing been equipped for liquefied gas inci-dents for several years.

Our HazMat Unit specialists have hadregular drills involving the use of thisequipment, not only as dry runs but also‘live’ with liquid ammonia. We have usedthe experience gained with these exercisesto continually update and optimise thechecklists and equipment.

Two years ago we were able to demon-strate our operational readiness in terms ofboth personnel and equipment when a railtank wagon containing liquid ammonia wasderailed in a shunting mishap at Brugg, andits contents had to be transferred by pumpfollowing careful preparation work.

Hazard Potential

The expression ‘liquefied gases’ is usedin this article for all gases liquefied underpressure at ambient temperature, such aspropane, butane, ammonia, carbon dioxide,chlorine and ethylene oxide.

Liquefied gases represent a potentialhazard that must not be underestimated, notonly during storage but especially whenthey are transported. Many properties (tox-icity, combustibility, colour, smell) of thevarious liquefied gases can vary consider-ably, but they all have the following in com-mon:• They can be liquefied under pressure.• In the vessel they are under pressure,

which increases when the vessel isheated.

• When they evaporate, the volume of gasis many times that of the liquid (propane260 times; butane 220 times).

• They are heavier than air.• They can inflict cold burns.• They can cause suffocation.• When pumped, they tend to cavitate and

therefore require special pumps.• With liquefied combustible gases the

danger also exists of a ‘boiling liquidexpanding vapour explosion’ (BLEVE)occurring.

These points and many other safety as-pects must be taken into account should anincident occur. The following description ofone such occurrence is intended to illustrate– or at least address – the questions to beclarified when dealing with an incident. Itmust be acknowledged that the ‘chaosphase’ of this particular incident was veryshort, since it was quickly established thatthere was no immediate danger to theemergency personnel or to local residents.The planning phase allowed enough timefor appropriate technical and organisation-al preparations to reduce the residual riskinvolved in the pumped transfer operationto an acceptable minimum.

Description of Incident

On the morning of October 3, 2001, arail tank wagon loaded with some 20 toammonia was derailed on an industrial sid-ing as a result of operator error (Fig. 1). Thederailed wagon came to rest on the ballastimmediately next to the track and was notdamaged. Despite this, the railway manage-


ment would not accept the responsibilityfor lifting the full tank wagon back onto therails. It was therefore necessary to emptythe wagon before doing so.

A meeting was held at the site of the in-cident to discuss the various possibilitiesfor a recovery operation, the advantagesand disadvantages of each option beingcompared and evaluated. At this initialmeeting, but also during the subsequent re-covery operation, the overall command fellto the officer in charge from the Central FireBrigade, as set out in cantonal regulations.Other organisations involved were eachrepresented by one person on the advisorystaff of the officer in charge.

The following organisations were repre-sented at the initial meeting: railway, po-lice, Brugg Central Fire Brigade, EMSDOTTIKON HazMat Unit, and DNP Sis-seln HazMat Unit, plus a chemical consult-ant from Chemia Brugg, the company towhich the ammonia was to have been deliv-ered. Coordination with the specialists atthe Cantonal Office of Environmental Pro-tection, the suppliers of the ammonia tankwagon and the Flüssiggas-Pikett derOstschweiz was by telephone.

Among the points considered whencoming to a decision were the following:• The industrial siding is located some

10 m away from the Zurich-Brugg-Bernrailway line. (Fig. 2).

• Beyond the railway line a main roadruns parallel to it.

• The first houses of a residential area arelocated directly on this main road.

• The industrial buildings immediatelynext to the industrial siding are only oc-cupied during the daytime.

• A piping line to convey the wagon con-tents to the Chemia tank farm wouldhave to be about 200 m long.

• Suitable road tankers could reach thesite that day if required.

• It would take an empty rail tank wagonat least 12 h to reach the site.

• Rail traffic would have to be stoppedduring the pumped transfer operation.

• The capability to stop all road trafficquickly if necessary would have to beensured.

• Local residents would need to be orient-ed about the necessary action to betaken during the pumping operation.

• A time of some 10–12 h was estimatedfor preparing and carrying out thepumped transfer operation.

• Fire protection would have to be en-sured during the entire pumping opera-tion.

• The empty derailed tank wagon couldbe lifted back onto the rails even whenrail traffic is running again on the mainline.

Fig. 1. Derailed wagon with some twenty tonnes of ammonia. The stumbling block as cause of thederailment is visible; next to the wheel.

Fig. 2. General overview with railway line Zurich-Bern left, industrial buildings, derailed wagon rightand recovery wagon in the middle.

around the two tank wagons and the lique-fied gas pump was also performed directlyby this team, with the help of the appropri-ate checklist for each operation.

The other Fire Brigade and HazMatUnit personnel were equipped with theirfire protection clothing and had compressedair breathing apparatus ready for use shouldit be required. The measurement group andpolice on monitoring and cordoning dutieswore their normal working clothes but hadtheir filter masks ready for use.


The following procedure was decidedupon:• A replacement empty rail tank wagon to

be sent to the site from the Lonza Com-pany in Visp.

• The pumped transfer operation to be car-ried out in the night of October 4, 2001.

• The period of time during the night from23.30–05.00 during which there are nor-mally no passenger trains running was tobe used for the pumped transfer operation.

• The various tasks were assigned to thefive organisations involved in the oper-ation as follows:Brugg Central Fire Brigade: Overallcommand of operation, coordinationwith the authorities, fire protection,road safety measures, decontaminationfacility, logistics.DNP Sisseln HazMat Unit: Illuminationof the incident site, pumped transferwith liquefied gas pump, HazMat zonedemarcation, disposal of the ammoniasolution resulting from the operation.EMS DOTTIKON HazMat Unit: Mea-surement of hazardous substances in theatmosphere and support with site illu-mination.Brugg Police: Informing local residents,road traffic control.Swiss Federal Railways: Diversion ofrail traffic, switching off power to over-head contact lines and earthing them,lifting the empty derailed tank wagonback onto the rails.

Preparations for the actual pumpedtransfer operation could begin in the late af-ternoon of the day after the derailment:• The specialists in our HazMat Unit

marked out the incident zone. On thebasis of a detailed checklist (Table 1),they installed the required hose connec-tions between the two tank wagons andthe pump and also to the vessels filledwith water into which the residual con-tents would have to be discharged andthe system rinsed out on completion ofthe pumped transfer operation.

• Brugg Fire Brigade cordoned off a largearea around the site of the incident, setup the decontamination facility andmade the extensive preparations neces-sary for fire protection. These includedsetting up and testing the spray patternof the monitors necessary to contain anyleaking gas with a water spray, and in-stalling a powerful blower. Addition-ally, dry powder system hoses wereplaced in readiness.The following notes (Table 2) – taken

from the incident logbook but drasticallycondensed – outline the operation. All indi-vidual procedures were carried out on the

basis of prepared checklists and could beaccomplished without any difficultiesworth mentioning.

Equipment

A 2-man team (front officer and assis-tant) wearing heavy-duty full protectivesuits and long-duration compressed airbreathing apparatus supervised the opera-tion directly on site. The work required

1. Situate pump (1) at correct location.

2. Select adequate lengths of pressure hose (2) and hold in readiness.

3. Hold connecting flange (3) for derailed tank wagon in readiness.

4. Hold connecting flange (4) for recovery tank wagon in readiness.

5. Hold gas balance line (5) in readiness.

6. Hold connecting flange (6) for gas balance line to derailed tank wagon in readiness.

7. Hold connecting flange (7) for gas balance line to recovery tank wagon in readiness.

8. Make discharge hose for gas release (8) ready. 2-inch hoses from HazMat Unit appliance.

9. Make valves and fittings ready for recovery tank wagon adapter (9). In addition Nos. 83 and 25 from HazMat Unit appliance.

10. Take off cover of vacuum drum (10), remove ball, modify and fill with water.

11. Make water hose (11) ready, 1-inch hose from HazMat Unit appliance.

12. Make collector tank (12) from HazMat Unit appliance ready and fill with water.

13. Make nitrogen line (3) from HazMat Unit appliance ready.

14. Make electrical cables for pump ready and unreel from HazMat Unit appliance.

15. Hold pressure gauge ready but do not fit yet.

Table 1. Checklists for incidents involving liquefied gases

Preparations (normal fire protection equipment)


The following specifications (Table 3)give some details of two of the special itemsof equipment used:

Experience

Fortunately, incidents involving lique-fied gases are very rare. Dealing with themrequires not only specific technical knowl-edge in each case but also the use of specialequipment, which can on no account beheld by every HazMat Unit.When an incident occurs, protection of

the immediate environment and the safetyof the emergency site must be given firstpriority. Following this, the use of specialequipment must be agreed in detail withthe organisations involved and the proce-dure to be taken, including contingencyplans should problems occur (e.g. suddenleakage), must be planned in as fine adetail as possible.All emergency personnel must then be

informed in detail over the planned proce-dure, so that they can perform their tasks inawareness of the overall objectives.As a rule, the work involved in this

preparation will require considerably moretime than the actual use of the equipmentwhich follows.Comprehensive checklists are neces-

sary for the individual steps involved in us-ing the equipment. The specialists involvedmust be familiarised with the use of thesechecklists, which can only be achieved byhaving carried out regular exercises.The work must be supervised constant-

ly and purposefully, and must also berecorded in writing.Should concerns of safety or problems

arise, the work must be immediately inter-rupted and the subsequent procedure speci-fied by the officer in charge. Any changesmade to the procedure must be advised toall personnel involved in the incident ingood time.The concentration of individuals deal-

ing with an incident tends to flag with time.Whenever necessary, some of the personnelmust be relieved in good time, but thelonger the operation lasts, the more the su-pervision must be intensified.

The safety of local residents and inci-dent personnel must always be given firstpriority.

The following points must therefore betaken into account during incidents involv-ing liquefied gases:• Should an incident occur, all work with

liquefied gases must be left to specialists.• These specialists and their special equip-

ment must be called out in good time.• Sufficient time must be allocated for

making preparations and carrying outthe operation.

Thursday, October 4, 2001

2320 hrs Railway Contact lines locked out and earthed

2330 hrs Brugg safety officer Cordons and traffic marshals in position

2333 hrs HazMat Unit officer Operation can beginin charge

2336 hrs HazMat Unit front officer Derailed wagon: main valve open

2337 hrs HazMat Unit front officer Recovery wagon: main valve open

2338 hrs HazMat Unit front officer Pressure at pump 7 bar; pressure equalisation flow

2340 hrs HazMat Unit front officer Gas balance line opened at both ends; stuffing box of derailed wagon valve tightened

2342 hrs HazMat Unit front officer Pump running

2345 hrs Measurement group Everything OK

2346 hrs HazMat Unit front officer Operation going OK; pressure in pump line 8 bar; pressure in gas balance line 6 bar; no valves leaking

2349 hrs HazMat Unit front officer Level in derailed wagon cannot be determined withthermal imaging camera

Friday, October 5, 2001

0013 hrs HazMat Unit officer Team in full protective clothing and front officer in charge relieved

0014 hrs Measurement group Everything OK

0015 hrs Brugg officer in charge Fire protection team relieved

0021 hrs HazMat Unit front officer Everything OK

0202 hrs HazMat Unit front officer Gas balance line closed

0210 hrs HazMat Unit front officer Pumped transfer finished

0211 hrs HazMat Unit officer Connections set up for nitrogen purgein charge

0223 hrs HazMat Unit front officer Nitrogen off. All valves closed; team with full protective clothing and front officer relieved

0224 hrs HazMat Unit officer Connections set up for gas release into water in charge tanks

0226 hrs Measurement group Ready for measurements at collector tank

0321 hrs HazMat Unit officer Pressure in discharge line 0 bar; line ready for in charge water

0324 hrs HazMat Unit front officer Water to rinse line; rinse begins

0330 hrs Brugg officer in charge Dry powder system and transfer line (2) withdrawn

0333 hrs Brugg officer in charge Rail track closed to Fire Brigade personnel and released for railway use

0400 hrs Brugg officer in charge Measurement group and monitors withdrawn

0402 hrs HazMat Unit officer HazMat Unit with breathing apparatus withdrawn in charge

0410 hrs Railway Swiss Federal Railways contact lines live again

0415 hrs Brugg officer in charge Water tender TLF 2, fire protection and decontamination facility withdrawn

0442 hrs Railway First train passes site of incident

0445 hrs Brugg officer in charge Remaining emergency services equipment withdrawn, leaving only the water tank into which the ammonia had been discharged at the site. The contents are drained into the public sewer within about eight hours.

Table 2. Timeline taken from the incident logbook


Training Facilities on the DNP Exercise Site

Our exercise site, which has been ap-proved by the authorities responsible, of-fers various possibilities for training, andcan also be rented by external emergencyorganisations and companies. The facilitieson offer include the following:• Practical training with portable fire ex-tinguishers.

• Extinguishing fires involving gases, liq-uids and solids (also suitable for fire-fighting and emergency rescue trains, asa rail track is only some 50 m away fromthe exercise ground).

• Demonstrations of BLEVE and boil-over.

• Exercise container for breathing appa-ratus.

More detailed information is availableat all times to anyone who is interested.Please contact the shift duty officer of ourWorks Fire Brigade: Tel.: +41 62 866 22 22or +41 79 763 96 26


Liquefied gas pump (Fig. 3):

Make, type: SIHI CEHY 4107/6 1F9AK4B4S, self-priming, low NPSH required

Capacity: max. 30 m3/h

Total head: approx. 110 m

Allowable pressure: 40 bar

Temperature range: –40 °C to 120 °C

Casing pressure rating: PN 25

Sealing technique: canned motor

Drive: canned motor

Motor rating: 37 kW

Casing gasket: Teflon

Interlocks: low level switch and low flow rate switch

Pressure hoses:

Make, type: Butapal-SD DN050 PO50BUW high pressure hose for liquefied gas to DIN 4815/3

Material: NBR

Inner wall: homogeneously smooth

Nominal diameter: DN 50

Flanges: DN 50 PN 40

Temperature range: –40 °C to +70 °C

Operating pressure: 25 bar with a safety factor of at least 4

Vacuum rating: 0.8 bar absolute

Earthing: manufactured with an integral steel wire helix and copper braid to dissipate electrostatic charge

Table 3.

Fig. 3. Liquefied gas pump with suction hose connected with casing and pressure hose above. Fortechnical specifications see text.

Examples of Limited QuantitiesTransported Through the GotthardTunnel

Legal BasisADR [1]: The second article states

that apart from some excessively dan-gerous goods, other hazardous goodsmay be transported internationally inroad vehicles that are subject to compli-ance with the conditions explained inAppendix A for the goods in question; inparticular as regards to their packagingand labeling; and the conditions ex-plained in Appendix B; in particular asregards the construction, equipment, andoperation of the vehicle carrying thegoods in question. The Swiss SDR [2]specifies, amongst other aspects, thetypes and quantities of hazardous goodspermitted to be transported through theGotthard tunnel.

Petrol can only be transported throughthe Gotthard tunnel up to a quantity of 50 l.Special authorization from either CantonUri or Ticino is required for quantities be-tween 50 and 500 l, whereas quantities ofmore than 500 l are prohibited. Up to 5 l ofethyl mercaptan can be carried without per-mission. Quantities between 5 l and a max-imum of 50 l require special authorization,above is prohibited in the Gotthard tunnel.Transportation of a mixed load of sub-stances is subject to authorization withrespect to the total quantities: transport of



ISSN 0009–4293

Fire-Fighting and Hazardous-MaterialsResponse Units in the Gotthard Road-Tunnel

Norbert Cathomas*, Benno Bühlmann, Anton Mulle, Hermann Christen, and August Husner

Abstract: In the Gotthard tunnel, the transport of hazardous material is limited in quantity. The total amount of haz-ardous material has nonetheless increased in the last few years. The technical and organizational measures takento deal with this fact are outlined in the following article. Moreover, problems related to a fire in a tunnel (those thatare linked to an incident with chemical substances) will be addressed. Some of the most important findings aris-ing from the fire of October 24, 2001 will be illustrated and some suggestions on how the fire brigade and the haz-ardous-materials response teams act in such cases will be presented.

Keywords: Fire fighting · Poisonous gases · Road-tunnel · Technical safety measures · Tunnel fire

Risk Potential

The potential risks for the north andsouth of the Gotthard tunnel lie – except forthe densely populated southern part of Can-ton Ticino – mainly in rail and road trans-port. Hazardous goods may only be carriedthrough the tunnel in limited quantities. Inaddition, if certain quantity thresholds areexceeded, the transport of these goods hasto be approved or they are otherwise pro-hibited. Therefore, Canton Uri and Ticinohave access to data regarding quantities ofhazardous goods. This data shows that thetransport and quantity of hazardous goodshas increased in the last few years, withoutthe inclusion of illegally transported mate-rial (Fig. 1).

*Correspondence: N. CathomasAmt für Umweltschutz UriKlausenstrasse 4CH–6460 AltdorfTel.: +41 41 875 24 20Fax: +41 41 875 20 88E-Mail: [email protected]

400 l of petrol (UN 1203) and 10 l of nitro-cellulose in solution (UN 2059) would bethe maximum to be permitted by the rele-vant Canton Uri or Ticino.

According to the quantities of the haz-ardous goods transported, there is an in-crease in the risk of hazardous materials be-ing involved in an accident. The entirefreight traffic (including non-hazardousgoods) has increased by 7–9% per year. Forsafety reasons, the traffic has been restrict-ed to approximately 4,000 vehicles in bothdirections per day since the day of the tun-nel fire in 2001 (Fig. 2).

Fortunately, there have not been manyincidents involving hazardous goods todate. Yet equally dangerous, and more com-mon, are fires in tunnels. During large firessuch as Mont-Blanc 1999, Gotthard 2001,or Tauern 2002, the danger of poisonousgases, poor vision, and limited oxygen sup-ply is by no means less severe than in caseof an accident with hazardous goods. Poi-sonous gases are composed of CO, CO2,HCl, NOx, soot, and other traces of toxinssuch as PAK, dioxins, etc.

Technical Safety Measures

The main objective of these measures isto keep traffic flowing and, in case ofproblems, to provide the drivers with a safe-ty area and (if necessary) with an escape.

The entire tunnel has safety areas thatare built at regularly occurring intervals.


There are two fire extinguishers in eachsafety room and in each SOS-cabin and anemergency telephone that is directly linkedto the central control station in Göschenenor Airolo. On the eastern side of the trafficlane there are a total of 64 rooms to shelterin and 11 lay-bys. On the western side thereare 22 lay-bys (approximately one every

750 m) that have an SOS-cabin built next tothem. Moreover, there are additional SOS-cabins every 125 m. The SOS-boxes aremonitored by camera. In the event of theuse of a fire extinguisher, a signal is sent tothe central control station.

The security shaft is built parallel to thetunnel on the eastern side of the traffic lane.

Fig. 1. The recorded and therefore authorized quantities of hazardous goods transportedthrough the Gotthard tunnel have increased in both directions (north and south). Even in theyear 2001, when the tunnel was closed for a period of two months due to a fire, it increased.(Source: Authorization of the Cantons; Evaluation of the Offices for Environmental Protectionof Canton Ticino and Uri).

Fig. 2. The total number of private cars as well as industrial vehicles in the Gotthard tunnelhas increased up to the year 2000. In the year 2001, the tunnel was closed for two monthsdue to a fire. Since the reopening of the tunnel, different measures have been taken in orderto increase the safety of the people traveling through the tunnel (see text) which has drastical-ly decreased the accident rate. (Source: Management of the Gotthard Tunnel and Fire Brigade(‘Schadenwehr Gotthard’)).

Every 250 m, there is a door that leads to asafety room. On the other side of the safetyroom, another door leads to the securityshaft. The security shaft as well as the safe-ty rooms are ventilated with excessive pres-sure, which reduces the possibility of po-tential toxins and poisonous gases of enter-ing from the traffic lane (Fig. 3).

Water supplies for the fire-brigade arelocated on the eastern side of the traffic laneat each of the safety rooms. The main piperuns inside the security shaft and is suppliedby water tanks that are located at each por-tal.

Further measures in the tunnel are– Ventilation system: six ventilation sta-

tions supply fresh air and, in case of anaccident, the required excessive airpressure.

– Radio reception: radio announcementsare broadcast on three different FM fre-quencies and in four languages every 20min or, in case of an accident, immedi-ately.

– Information for the drivers: differenttraffic signs in four languages (e.g. toencourage the drivers to keep at a safedistance, etc.) and indications about es-cape routes are placed to inform thedrivers and to increase their chance ofescape. These large signs also bringvariation into the driver’s view and helpto prevent him falling asleep.

– Monitoring of traffic: traffic is moni-tored by 68 traffic checkpoints with 85cameras placed inside the tunnel andeleven monitors in the central controlstation in Göschenen and Airolo. Slowmoving traffic and stationary vehiclesare detected and signaled to the controlcenter on duty.

– Emergency power supply: Electricity issupplied from the two portals. If poweris down on one side (e.g. in the north),the other portal supplies the entire re-quirement of electricity. If both powerstations are simultaneously unable toprovide electricity, an emergency powersupply is activated. This is able to sup-ply energy to the infrastructure (trafficsigns, emergency fresh-air ventilation,lights) for a period of 2 h.

Additional Measures in the Event of Fire – Implemented After the Fire of October 2001

1) The entire traffic lane area/shaft isequipped with automatic fire safety lids.In case of a fire, the air draft in the par-ticular area is reduced and the fire safe-ty lids within 300 m of the fire area areopened automatically. Fire safety lidsoutside this area are then closed.


2) The entrances to the safety rooms arepainted with special colors and there-fore easier to recognize.

3) Special instructions about how to be-have in case of an accident or a fire arebroadcast on the radio in four languagesevery 20 min. Information signs andcolored direction indicators were set up.

4) Marks on the floor and traffic signs in-dicate the recommended distance be-tween heavy vehicles, which must bemaintained even in a traffic jam.

5) A deployment strategy has been createdand will be tested for its practicalitynext year.

Organizational Security Measures

The traffic flow as well as the tunnel in-frastructure are both controlled by twostructurally identical central control sta-tions in Airolo and Göschenen. As a result,each station can immediately take over incase of a system failure of the other station.One station controls the entire tunnel infra-structure and systems as well as the trafficflow for a period of two weeks, before su-pervision is given to the other station for thenext two weeks.

Since 1980, there have been fire brigadebases at each portal, which are also part ofand organized by the Gotthard ResponseForce. An emergency team comprising fourofficers is on duty 24 h a day, 365 d a year.It takes less than 3 min for the emergencyteam to be activated, i.e. to be on their wayto the accident. Both fire brigade units are

equipped with two water-tank vehicles (in-cluding additional rescue equipment) whichare capable of changing the direction oftravel in the tunnel using a built-in turret de-vice. Moreover, the units are equipped withindependent oxygen supplies (closed circuitbreathing apparatus), which last up to 4 h.

Primarily, the men on the team are em-ployees of the workshops in Airolo andGöschenen. Since their main responsibilityis the maintenance of the tunnel system andhighways (except for the men of the firebrigade on duty), they are therefore ex-tremely familiar with the tunnels. Manymembers of the Gotthard security force arealso part of the local fire brigade. There area total of 100 firemen available on bothsides of the tunnel.

Response Strategy

The Swiss ‘Chemiewehren’ (hazardous-material response teams) can be comparedwith the TUIS-industrial fire brigade inGermany. However, the equipment andmethod of operation may vary dependingon the geographical location. In the area ofthe Gotthard tunnel, the headquarters of thehazardous-material response teams are inBellinzona (south) and Altdorf (north). Thetraveling times from Altdorf and Bellinzonato the tunnel of about 30 and 45 min, re-spectively, are somewhat long. As a result,the fire units at the north and south portal ofthe tunnel have been equipped and instruct-ed to handle chemical incidents as well. Theresponsibility of the intervention team Got-thard (Schadenwehr Gotthard/Centro d’in-

tervento San Gottardo) is to handle fire de-partment duties during an incident withhazardous substances. However, the actualtask of dealing with the chemicals involvedwill then be fulfilled by the hazardous-ma-terial response team based in Bellinzonaand Altdorf. If the highway entrance to theGotthard tunnel is jammed, the units ap-proach the tunnel portal by using mainroads. The equipment located in Göschenenand Airolo is sufficient for the personnel ofthe headquarters (Bellinzona and Altdorf)to handle a chemical incident, i.e. their staffcould be simply flown to the portals by hel-icopter without the additional machinery orequipment.

The hazardous-material response teamsof Uri include units of the fire brigade of thecompany Dätwyler AG and the fire brigadeof Schattdorf as well as officers and in-structors of other fire brigades. Chemicalengineers and experts for ecology are re-cruited by the Office for EnvironmentalProtection and integrated into these teams.This has the advantage that the experts arealready members of the response team anddo not have to be alerted first. Moreover,they are already familiar with the availableequipment and strategy. Decisions regard-ing the severity of the environmental dam-age can be taken immediately.

Deployment Strategy

Alarm signals are set off:• at SOS-notification stations in the tun-

nel and are transmitted to the central sta-tion;

• by drivers who call the police, i.e. thecentral alarm station of Canton Uri orTicino;

• by self-triggering devices in the tunnel.

In the event of a fire or the potential forfire, the tunnel’s fire units are alerted andapproach the scene, depending on severityetc. from one or both sides of the tunnel.Their main tasks are to rescue people indanger, extinguish the fire, accompany theother drivers to the emergency exits, andtransmit information and updates to thecentral control station. The central controlstation is responsible for the deployment ofadditional units, the supply of equipmentand necessary material, and, in case of achemical accident, alerting the hazardous-material response teams in Altdorf andBellinzona.

In the event of a major incident, the fol-lowing teams and units are deployed:• ambulance and rescue teams (treat the

injured);• helicopter-rescue teams (transport in-

jured);• police (control traffic, inform the media);

Fig. 3. Technical safety measures of the Gotthard tunnel


• local fire brigade (block streets to acci-dent scene);

• locally based fire units (support of de-ployed units).

• hazardous-material response teams inAltdorf and Bellinzona (if hazardousmaterials are involved).The response teams have their own

meeting points and quarters on each side ofthe tunnel.

The tunnel ventilation extracts the tox-ins that occur during a fire or chemical leak-age to the outside of the tunnel. Althoughthese emission shafts are located in veryscarcely populated areas, it cannot com-pletely be ruled out that people or animalsin the immediate vicinity of the shaftsmight be harmed. These emissions havebeen calculated and the consequences wereassessed in the context of the emergencyplan. The necessary steps, e.g. closing offthe area, informing the local inhabitants, orthe measurement of the air quality, areknown to the intervention teams.

Experience and Measures

There has only been one chemical inci-dent in the immediate vicinity of the tunnel,but not inside the tunnel itself. The worst in-cident so far was the fire of October 24,2001. The experience gained from thatevent are described at this point:

The hazardous-material response teamsof Canton Uri and Ticino were alerted andadvised to support the fire brigade of theGotthard tunnel and to measure the concen-tration of toxins.

In the central area of the fire, a high tem-perature remained even after the fire wasextinguished. Only with the use of a large,mobile ventilator of the Canton Uri re-sponse team (which had to be transportedacross the Gotthard mountain), was it pos-sible to cool down the area by dispersingfine spray.

Once an incident is over, a competentand knowledgeable authority has to offi-cially reopen the tunnel for the units with-out protective gear and equipment. OnOctober 24, 2001, this authority was givento the response team from Canton Uri. Withthe measurements of toxins (short-term-tubes and Ex/O2 measurements), it waspossible to determine that there was nolonger a particular chemical threat for the

units to be deployed. Nonetheless, theywere advised to wear dust masks and to re-main in the tunnel only as long as necessary.

The structural damage (static stability ofthe tunnel ceiling) had to be assessed beforemore control units could be deployed. In thecentral area where the fire had been most de-structive, the situation was not considered tobe safe enough and the ceiling had first to beadditionally supported.

The tragic balance of the accident wasthat eleven people died of suffocation dueto the toxic gases of the fire. They were un-able to find the lit entrances to the safetyrooms in the darkness or were surprised bythe rapidly spreading smoke wall whilethey were still in their cars. Dead bodieswere found within 1.3 km of the center ofthe fire. The smoke cloud spread over a dis-tance of 3 km north of the actual fire site.Twelve people suffered from symptoms ofsmoke poisoning.

Traffic Safety Measures After the Fire

• More checks on truck drivers regardingthe safety and functionality of their ve-hicles as well as maximum loading ca-pacity and quantities of hazardousgoods. Accordingly, checkpoints onSwiss transit routes, where drivers arestopped and controlled, will be set up inthe coming years.

• Maintaining a minimal distance of 150m for trucks. The most efficient methodturned out to quickly stop each vehicleat the entrance of the tunnel and thusforce them to keep a safe distance.

Problems

1) The fire of October 24, 2001 demon-strated that toxic gases were responsiblefor a substantial number of the fatalitiesand injuries.

2) Although the safety infrastructure (shel-ters) in the tunnel was indicated, it wasdifficult to find them due to the ex-tremely poor vision in the tunnel.

3) The drivers were only informed in thecase of an emergency how to behave.There were no preventive measures atthat time.

4) The potential for devastating fires in-creases with the quantity and frequencyof heavy vehicles, especially if severaltrucks loaded with freight are drivingright behind each other.

5) Only with precise organization and up-dated deployment schedule can efficientand quick deployment among the differ-ent security forces be guaranteed.

The technical and organizational mea-sures that have been implemented since thefire of October 24, 2001 are described above.

Tips

Avoid breakdowns. Do you haveenough petrol? (7% of all breakdowns oc-cur as a result of insufficient petrol). Switchon the radio when you enter the tunnel.Even in case of slow traffic or traffic jams,keep a distance of 50 m to the next car, soyou can see what is happening in front ofyou.

If Your Car Catches Fire...

Try to leave the tunnel. If you are unableto do so, try to get to the next lay-by. Oth-erwise, roll on to the side of the traffic lane,leave the keys in the ignition switch, andwalk to the closest shelter or the closestSOS-station.1) Request first-aid2) Try to put out the fire with the fire ex-

tinguisher available at the SOS-stations3) Help the injured, if possible4) Go to the nearest shelter

For further information about the Gott-hard road tunnel, please visit the website:www.gotthard-strassentunnel.ch.

For the homepage of the hazardous-ma-terial response team Uri, please go to:www.chemiewehr-uri.ch.


[1] Economic Commission for Europe, ‘Euro-pean Agreement concerning the Interna-tional Carriage of Dangerous Goods byRoad (ADR)’, 1957, version ‘ADR 2003’,UNECE.

[2] Schweizer Bundesrat, ‘Verordnung überdie Beförderung gefährlicher Güter aufder Strasse (SDR)’, 2002, SR 741.621.

To optimise the efficacy of an immediateresponse, it is essential that whoever takesaction should be able to find the equipmentneeded without delay, in particular the ex-tinguisher appropriate to the hazard to becombated. For this purpose it is commonpractice in laboratories to banish extin-guishers intended for Class A fires (solidmaterials that do not melt, such as wood,paper, etc.), in favour of those suitable forClass B (liquids or solid materials that melt,liquid fuels, resins, etc.), Class C (gases)and Class D (metals, sodium, magnesium,etc.) fires, which are more likely in view ofthe substances that are actually present.This subject therefore requires muchthought to be given to the choice of emer-gency response facilities suitable for labo-ratories. It is thus necessary to procure spe-cific equipment, of an industrial type but ofsmaller dimensions, i.e. in sizes normallyencountered in office buildings.

Emergency Response File

The third stage consists of drawing upemergency response plans that are just asrigorous as those assigned to the productionplant.

We now take a look at the experience ofGivaudan SA at Vernier, Switzerland. Fol-lowing successive expansions of the siteaccompanied by an increase in the numberof buildings, the emergency services felt theneed to have help and support available oth-er than that committed to memory, in theform of written documentation. Initially,the emergency response files consisted ineffect of the architects’plans with the build-ing numbers and an indication of the accessand escape routes. The need for reliable andprecise information at all times has resulted



ISSN 0009–4293

Fire Safety in Chemical Laboratories

Remi Parent*

Abstract: Fire safety in chemical laboratories is often the stepchild in industrial safety concepts. This is dueto the small quantities of chemicals handled and underestimation of loss of research results and infra-structure. Managing fire safety in chemical laboratories depends more on prevention than the work of firefighters. In this article the safety policy of Givaudan is described in detail.

Keywords: Chemical laboratories · Emergency response file · Employee training · Risk assessment · Safety concept

Introduction

Although companies recognise the strategicimportance of addressing the fire risk in industrial laboratories, this is frequentlyoverlooked when compared with the poten-tial risks inherent in manufacturing activi-ties. This is mainly because of the muchgreater quantities of chemicals that are gen-erally handled on a production scale. Al-though few companies could effectively re-tain their market position if they lost theirresearch and development or quality con-trol facilities, laboratory personnel are notalways made aware of this aspect of theirremit.

Nevertheless, the risk of a fire is alwayspresent and constitutes by far the leadingcause of serious losses in laboratories. Inorder to address this problem, it is thereforeessential to pursue a policy of fire preven-tion coupled with appropriate and ongoingstaff training.

Potential Risks

The obligatory first stage in implement-ing this policy consists of determining thepotential risks specifically associated withlaboratory operations.

*Correspondence: R. ParentSafety and Environment ManagerGivaudan Suisse SAChemin de la Parfumerie 5CH-1214 VernierTel.: +41 22 780 91 11Fax: +41 22 780 91 50E-Mail: [email protected]

Two main categories of risk become apparent from this preliminary analysis:The dangers associated with chemicalsstored at these locations:• Flammable liquids and solids• Chemical incompatibility between sub-

stances• Combustive materials• Peroxides• Substances with spontaneous combus-

tion tendencies• Substances that give off a flammable

gas on contact with water• Flammable gases used as reagents and

for instruments• Incorrect labelling• Use of substances that are inappro-

priate, have not been verified or havedeteriorated

• Electrostatic dischargeDangers due to the human factor:• Boredom with routine, overconfidence,

apathy• Deviations from operating instructions• Disregard for hygiene and safety

regulations• Poor use of laboratory space (bench,

fume cupboard)• Disregard for standard procedures

Emergency Response Concept

A second stage, equally necessary, con-sists of mitigating the potentially disastrouseffects of a laboratory fire. Experience fromcatastrophic situations that have occurred inthe past, at various sites, shows that themost effective response is nearly alwaysthat provided by the person who discoversthe fire, because of his or her quick action.

• Specific equipment• Collateral risks • Location of safety devices, emergency

stop buttons, emergency showers, eyebath fountains and fire blankets

• Assembly points for building personnel• Location of fire alarm control panels,

extinguishers, axial-feed hose reels,smoke vents and other fire safety equip-ment

Employee Training

Management of the human factor is afundamental element in any effective policyfor fire prevention. The Vernier site hastaken a number of steps to pursue thisobjective, every employee being madeaware of safety matters as soon as he or shetakes up employment. An ongoing safety


in this documentation evolving into what itis today, a complete working file for inter-nal and external emergency response per-sonnel. In addition, because of the veryaccurate information which it contains, it isalso invaluable for training plant personnel.

Its standardised structure conforms tothe following general layout:

General section:• The situation of the site (area, capacity)• A description of the company

– Its economic sector– A description of its activities– The number of personnel employed

during the day and at night• A schematic diagram of the company

– The job titles and names of companymanagers

– The means of contacting them • An accurate description of the imme-

diate environment

– Residential areas, schools and otherindustries within successive radii of500 m, 500 to 1000 m, 1000 to 1500m, etc.

• The local topography, geology andhydrology

• Location of pillar and undergroundhydrants

• Firefighting equipment• All the assembly points on the site• A list of all conventional signs and

notices• ‘Reflex action’ instruction cards

– FIRE – ACCIDENT – POLLUTION– Fire safety and evacuation instruc-

tions

Section specific to the buildingconcerned:• Location and category of stored chemi-

cals

Fig. 2. Property damage by smoke impact on ex-pensive LC-MS equipment

Fig. 1. Heavy fire and smoke damage in researchlaboratories can result in considerable businessloss due to delayed launch of new products


orientation then continues for as long as anemployee remains with the company.

This safety awareness strategy startsimmediately when a new employee is welcomed, by issuing him or her with thecompany’s safety booklet, in which generalinformation is presented on essential sub-jects, in particular:• Occupational hygiene• Emergency response actions• Fire precautions• Environmental protectionThe booklet also includes reminders in theform of a memory-jogging quiz:• Where is the nearest manual call point?• Where is the nearest appropriate extin-

guisher?• Where is the nearest emergency

shower?• Where is the assembly point for the

building personnel?Plus the appropriate rules for employee action:• How to make the installations safe• How to prevent a chain reaction• How to use the extinguishing equipment

without taking any risks

Every two years the complete work-force of Givaudan at the Vernier site,together with the personnel employed in thefield, receives practical instruction on thehandling of extinguishers and their use fordifferent classes of fire. This training isgiven by the company’s professional firebrigade. In addition, fire drills are held reg-ularly to practise evacuation of the build-ings.

In the particular case of the laboratorypersonnel, a certain number of Good Labo-ratory Practice topics are regularly re-freshed, particularly the following points:• Not working at a cluttered laboratory

bench• Never using damaged glassware• Storing only minimum quantities of

chemicals• Correctly labelling all containers• Not permitting work to be carried out

unsupervised• Using fire-resistant safety cabinets

Additionally, nine times a year a safetyawareness day is organised so as to coverthe entire workforce. This day involves asmall group of twenty or so employeescoming together each time, and is morethan just a simple information day, since itoffers a real forum for constructive dia-logues and exchange of ideas between allthe employees on the site.

The company also has an internal emer-gency response structure comprising a unitof voluntary firefighters, some 60 employ-ees normally employed in all sectors of the

company. They take part in regular trainingsessions and drills carried out directly onequipment suitable for their emergencyresponse function, in particular:• A water tender• Two appliances equipped with dry pow-

der extinguishing systems, capacities750 kg and 1000 kg

• Six motor pumps

In conclusion, it is essential to remem-ber that precautionary measures are alwaysmuch more effective than those offered byemergency response facilities, even themost sophisticated ones – ‘Prevention isbetter than cure’. An incident of anydescription is always the result of a multi-tude of seemingly insignificant causes, andit is only by carrying out a systematic analy-sis of all these anomalies, even those thatappear to be trifling, that a company cantruly claim to have significantly reduced itspotential hazards.




ISSN 0009–4293

Decontamination After ChemicalIncidents

Felix Geissmann*

Abstract: Incidents with release of chemicals are insidious. The HazMat team has not only to overcome theimmediate consequences of a spill but also the decontamination of casualties, fire service personnel andequipment. By following the zone concept and correct procedures, emergency services personnel can min-imise the risk of contamination. Training of proper decontamination principles is a demanding task. Provendecontamination procedures are described in detail and some case studies are presented.

Keywords: Decontamination procedures · Hazardous materials incident · Rescue chain · Training of HazMat teams · Zone concept

1. Introduction

Decontamination of protective clothing andequipment is, in the majority of cases, theminimum action necessary following de-ployment of a fire service or a HazMat unit in response to a release of hazardoussubstances in solid, liquid or gas form.

The following article is concerned onlywith chemical contamination and does notcontain any information about deconta-mination following incidents involvingradioactive or biological materials.

It should be stressed here that preventingcontamination is always easier, less time-consuming and less hazardous than carryingout decontamination after an incident. By fol-lowing the correct procedures, emergencyservices personnel can minimise the risk ofcontamination and hence the need for subse-quent decontamination.

The author of this article was the head ofa fire service and HazMat unit for many

*Correspondence: F. GeissmannSchweizerisches Institut zur Förderung der SicherheitWKL - 32.3.07CH-4002 BaselTel.: +41 61 696 60 51Fax: +41 61 696 70 72E-Mail: [email protected]

years, as well as being a HazMat and Radiation Protection instructor. He alsofounded and headed the HAZMAT schoolat Siegfried Ltd in Zofingen.

2. Hazard Potential

Chemicals can be released as solids,liquids or gases during an incident. Otherthings being equal, the hazard potential of amaterial is a function of its physical state,with gases posing a greater hazard thansolids, whereas the risk of contaminationdecreases with increasing distance from theincident (Table 1).

In addition to the released chemicalsthemselves, contaminated extinguishingwater and, not least, waste liquids from thecleaning of casualties and equipment pose acontamination risk.

Humans and animals can absorb haz-ardous substances through the skin, eyes,and respiratory and digestive tracts, result-ing in poisoning and/or chemical burns.

Substances with a latency period areparticularly insidious, as the onset of harm-

Solid Liquid Gas

Casualties High High High

Emergency services personnel Low High High

Population Low Medium High

Environment Low Medium Low

Table 1. Hazard potential in terms of physical state

ful effects can be delayed by hours or evendays. The inhalation of lung irritants thathave a latent effect can lead, days later, to afatal pulmonary oedema if the proper cor-rective action is not taken quickly enough(e.g. the administration of dexamethasonespray) (Table 2).

If fire service vehicles and equipmentbecome contaminated, there is a risk thatthis contamination will be transferred to thefire station and pose a further hazard to per-sonnel. A range of substances can cause se-rious corrosion problems if no correctivemeasures are taken. Cases have beenreported in which the breathing apparatusused at an incident had to be replaced.

3. The Zone Concept

Swiss emergency services personnel aretaught that the first unit to arrive at the sceneof an incident should cordon off ‘zone 1’(also known as the hot zone) after takingany immediate action necessary. Taking thewind direction into account, the perimeter


of this zone should be established at a dis-tance of 60–100 m from the incident. Toprotect any nearby residents and ensure thatemergency services have enough room tocarry out operations, ‘zone 2’ (also knownas the warm zone) should then be set upwith boundaries extending 150–500 m fromthe incident. This zone is not usually cor-doned off completely, but traffic controlpoints are established to divert traffic wellaway from the incident area.

The actual HazMat zone is then estab-lished inside zone 1 by the specialists fromthe HazMat unit. In order to keep potentialcontamination to a minimum, this zoneshould be as small as possible without put-ting emergency services personnel in anyunnecessary danger. As the amounts andproperties of the substances involved are ofcentral importance in evaluating spacerequirements, this evaluation should onlybe carried out by persons with relevantchemistry knowledge and chemical inci-dent experience.

In addition to the provisional decontam-ination station at the perimeter of zone 1, aprofessional decontamination station is es-tablished at the exit point on the perimeterof the HazMat zone where rescued people,emergency services personnel and materialcan be decontaminated (Fig. 1).

4. Principles of Decontamination

Time is a crucial factor in decontamina-tion, with the principle of speed rather thanperfection being particularly applicable tothe decontamination of persons. In spite ofthe speed required, close attention shouldbe paid that contamination is not trans-ferred to uncontaminated areas.

If contamination cannot be ruled outcompletely at a chemical incident, a provi-sional decontamination station with watersupply should be established at the perime-ter of zone 1 by the first unit to arrive at thescene.

If in doubt, it is always better to de-contaminate one time too many than toofew.

5. Decontamination of Casualties

All persons leaving a contaminated orpotentially contaminated zone must bechecked for contamination at the decon-tamination station. All cases of suspectedor actual contamination should undergo immediate decontamination.

The first priority, however, is to rapidlyevaluate casualties using the ABCs of firstaid. For example, it makes no sense to thor-

Substance Effect

Ammonia immediate

Hydrogen chloride immediate

Chlorine latent

Ozone latent

Sulfur dioxide latent

Nitrous gases latent

Table 2. Types of lung irritants

Fig. 1. Zone concept and cordon off measures as defined in Swiss file Oil, Chemical andRadiation Defence. For details see section 3.


oughly decontaminate a casualty if he orshe has already stopped breathing.

If contamination is suspected, an addi-tional check for chemical burns, thermalburns and poisoning is carried out.

Uninjured persons or those showing nosymptoms should at least remove all affect-ed items of clothing and thoroughly cleanall potentially contaminated skin areas withsoap and water. Intensive mechanical clean-ing, such as scrubbing with a brush, shouldbe avoided as this can damage the skin andlead to chemicals being absorbed morequickly. Similarly, lukewarm and not hotwater should be used for cleaning, as hotwater causes the pores to open, which alsopromotes absorption.

Pressure washers are helpful for decon-tamination of materials but not for decon-taminating persons. In view of the high riskof injury involved, this procedure is com-pletely inappropriate [1].

One often-debated question is whetherspent decontamination fluid must be col-lected. The simple and logical answer isthat if a person has been contaminated withchemicals, this must have been caused by arelease of chemicals, and the amount re-leased will always be significantly greaterthan the amount on the casualty’s skin. Ittherefore makes no sense expending largeamounts of time and energy collecting de-contamination fluid.

In practice, either during exercises or areal emergency, the most frequently ob-served errors are:• Time being lost as a result of too much

talking.• Failure to have casualties remove all af-

fected items of clothing, e.g. shoes,socks and underwear.

• Failure to recognise that contaminantsmay be deposited on the inside of res-cue-masks worn by casualties.

• Clean body areas being contaminatedunnecessarily as a result of incorrectprocedures.

• Overreaction, i.e. decontaminating allpersons who were in the zone withoutfirst carrying out a triage. If the numberof persons is large, decontamination fa-cilities can rapidly become over-stretched, which in turn can prevent the‘real’ casualties from receiving propertreatment.

The rescue chain can be split up intofour phases:

Phase 1:Removal/First Aid by the Fire ServiceTaking suitable precautions to ensure theirown safety, fire service personnel removethe casualty from the contaminated zone as

quickly as possible in order to limit expo-sure to the hazardous substance. Life-sav-ing measures are initiated.

Phase 2:Gross Decontamination/First Aid by theFire ServiceThe effect of the harmful substance on the casualty is reduced by removing all affected clothing and washing the skin. This eliminates the risk to persons outsideof zone 1.

Phase 3:Secondary Decontamination by the FireService, Ambulance Service or Samari-tans (Volunteer Emergency Service)The affected body areas receive furthertreatment specific to the hazardous sub-stance. The aims are to prevent both the casualty’s condition from worsening andcontamination of the transport vehicle andhospital.

Phase 4:Transport by Hospital or Fire Service Am-bulance or REGA (Swiss Air Rescue)Supervised transport to a hospital or doc-tor’s office.

6. Decontamination of EmergencyServices Personnel

In the event of skin contact or suspected oractual contamination of fire protective cloth-ing, emergency services personnel should betreated identically to other casualties (Fig. 2).

7. Decontamination of Vehicles andEquipment

To keep decontamination work to a min-imum, only absolutely essential materialsand equipment should be taken into thecontamination zone.

Fig. 2. Decontaminationof a HazMat unit mem-ber in a protective suit.In most cases water is asuitable decontamina-tion reagent.


A station should be set-up and markedat the perimeter of the HazMat unit zone orzone 1 where all material can be checkedand, if necessary, undergo at least grosscleaning before leaving the zone.

Cleaning with water, soapy water or aneutralisation solution is sufficient in mostcases, apart from those involving extremelytoxic or environmentally hazardous chemi-cals, where the appropriate cleaningmethod should be selected by a suitablyqualified person.

‘Dry cleaning’, which is common forradioactive decontamination, is, at most,suitable for use with substances that reactvery strongly with water, e.g. sodium.However, wet cleaning must still be car-ried out following gross dry decontamina-tion.

Small items of equipment should bepacked in plastic sacks after gross deconta-mination and brought to a suitable place for secondary decontamination.

If items of personal protective equip-ment such as gloves, boots or fire protectionjackets are contaminated with critical orpoorly water-soluble substances, they mustbe incinerated. Depending on the chemicalsinvolved, disposal in a special waste incin-erator may be necessary.

Protective suits contaminated with wa-ter-soluble materials can be cleaned usingplenty of water and used again followingdrying and inspection. If, however, the suitshave come into contact with chemicalswhich can only be removed using aggres-sive chemical or mechanical cleaning meth-ods, for safety reasons they must be dis-posed of in an appropriate incinerationplant.

8. Case Histories

Case 1A faulty hose line resulted in a chemical

worker being splashed with concentratedsodium hydroxide solution. Instead of go-ing straight to the emergency shower, hewent to the infirmary where he was imme-diately (correctly) decontaminated usinglarge amounts of water. He then put hiswork clothing back on and prepared toleave. Just at this moment the author of thisarticle arrived and almost instinctivelychecked a damp patch on the man’s cloth-ing using pH paper. The paper turned darkblue immediately, indicating that the cloth-ing was still soaked with sodium hydroxidesolution. The work clothing was removedagain immediately and decontamination ofthe skin was repeated.• Never put contaminated clothing back

on.

• Infirmaries should always have spareouter garments and underwearavailable. Spare clothing should also be carried by emergency services vehi-cles.

Case 2As a result of an error a chemical work-

er sprayed himself with chlorobenzene. Atthe infirmary all clothing was removed im-mediately and placed in a plastic sack. Theworker was rubbed from head to toe underthe shower with polyethylene glycol andrinsed down with lukewarm water and soap.This process was repeated (6 times) untilpractically no odour could be detected onthe skin. • Always have polyethylene glycol 400

available for use with poorly water-sol-uble substances.

• Consider how best to determine if de-contamination has been successful.

• Use only lukewarm and not hot water.

Case 3During a chemical incident two chemi-

cal workers were sprayed over much oftheir bodies with a poorly water-solublephenol derivative. Following initial grossdecontamination using water, soap andpolyethylene glycol, arrangements weremade for the casualties to be transported tohospital. The ambulance personnel weregiven 5 l of polyethylene glycol and verbalinstructions for secondary decontaminationat the hospital.• Hospitals that are not specialised in deal-

ing with chemical incidents have neithersufficient specialist knowledge nor suit-able decontamination materials. Precioustime can be lost if hospital personnel haveto hunt down information.

Case 4A case is imaginable where a small area

on the thigh contaminated with phenol wasincorrectly decontaminated using ethanol.The casualty could die as a result of the in-creased absorption caused by the harmfulmaterial being spread over an area >100cm2 [2].• Under no circumstances should sol-

vents such as ethanol, acetone or ben-zene be used to clean skin.

9. Equipment

HazMat specialists and occupationalphysicians have developed commerciallyavailable kits that contain the equipmentand supplies needed for decontaminationand administering first aid for chemicalburns, thermal burns and poisoning.

10. Training

Experience shows that correct decon-tamination measures can be very complex.In the wrong situation, thinking that one canget by with a little bit of ‘theory’ can havedisastrous consequences. When carryingout decontamination exercises, it is impera-tive that food colouring or some other visi-ble agent be used as a ‘contaminant’ so thatthe success of the measures employed is ob-vious. This is the only way in which thor-ough removal or undesired transfer of thecontaminant can be identified. If, after a de-contamination exercise, colour is found onthe door handles and seats of the emergencyservices vehicles, the exercise should defi-nitely be repeated.


[1] vfdb, Vereinigung zur Förderung desdeutschen Brandschutzes, ‘RichtlinieDekontamination bei Feuerwehreinsätzenmit gefährlichen Stoffen und Gütern’, vfdb-Richtlinie 10/04, 1998.

[2] BASF, Aktiengesellschaft, ‘BASF Medi-zinische Leitlinien bei akuten Einwirkungenvon chemischen Substanzen, Phenol(C6H5OH)’, 1999.

tion actions are discussed. The operation ofthe chemical analysis group is coordinated.The chemical science officer proposes spe-cific methods to end and limit the conse-quences of a spill e.g. the treatment of theretained fire fighting water or the contami-nated soil (Fig. 1 and 2 [3]).

The chemical science officer has the du-ty to estimate and report to the environ-mental department the most significantdanger arising from the chemicals to soil,



ISSN 0009–4293

Tools and Procedures of the ScienceOfficer in the Management ofHazardous-Material Incidents

Stephan Rönninger* and Thomas Glarner

Abstract: A chemical science officer ensures with his know-how, his experience based on continuous improvementand with the help of databases, optimal advice to the operational crew. In the event of incidents with hazardousmaterials, great attention must be given to self-protection of the operational crew, to the shelter of residents, to theenvironment and to the prevention of destruction of assets. While minimizing the hazard, the chemical science of-ficer works closely with the officer-in-charge, environmental authorities, police and chemical analysis groups.

Keywords: Chemical hazard · Chemical science officer · Propagation models · Soil contamination

1. Risk Assessment: The Need forChemical Knowledge

Incidents with all kinds of chemicalssuch as known and unknown solid-, liquid-,and gaseous substances are called haz-ardous materials incidents. These incidentslead to negative press whether there is a fireor not. In such cases local or/and regionalfire brigades need specific know how fromchemical science officers about the chemi-cal resistance of the tools used in dealingwith the incident.

1.1. The Science Officer in theIncident Management Organization

Well-trained officers-in-charge of thefire brigades are experts in the fire fightingbusiness. They know the correct tactical ac-tions for fire fighting operations. But theyhave minimum experience and knowledgeabout the hazards and necessary conse-quences for operations involving chemi-cals. In the canton Aargau chemical scienceofficers are summoned for support of theofficer-in-charge [1]. Four experts arenamed for all regional fire brigades. Inoperation they are executive members ofthe authorities [2]. Centralized notificationauthorities summon them on the basis of

*Correspondence: Dr.-Ing. S. RönningerF. Hoffmann-La Roche Ltd.CH–4070 BaselTel.: +41 61 688 69 74Fax: +41 61 688 88 92E-Mail: [email protected]

action plans depending upon the alarmreceived.

Chemical science officers are assignedto the chemical officer-in-charge to provideadvice. Their advice has first priority for thesafety of the operational team. They sug-gest the protection equipment required,how to decontaminate and clean injuredpeople and operational material.

Prevention measures are proposed tolimit damage. Cordoning off and evacua-

Fig. 1. Depth of liquid in soil [3]; amount of liquid [m3] per soil [m2] in relation to enter soil


water or air. The goal is to limit the dangerto the operational crew, the local residentsand to minimize the contamination of theenvironment. The knowledge of the chemi-cal science officer can also be of impor-tance for the authorities and journalists.

1.2. Continuous DutyAt the hectic start of the operation,

chemists and engineers without continuouspreparedness and education on how to han-dle chemical spills are of little help as ad-visers. Education at universities and the ex-pertise on the job in industry is an importantbasis. However experience in actual haz-ardous chemical manufacturing sites andthe elaboration of realistic incident scenar-ios are an important mandate for chemicalscience officers. Knowledge of the locationof hazardous goods provides efficient sup-port. Scenarios are developed for the simu-lation of realistic effects [4]. The speed of

spreading gases requires modeling to eval-uate the risk followed by timely warning atthe right places. For a correct scenario withrealistic spreading models the worst casescenario is used for a first impression [5].Together with the knowledge of the strip-ping tools of the fire brigades the forecastcan be realistic. With ongoing measure-ments of air and analyzing the weather andwind situation the recommendations can beadapted. The basic chemical knowledge ofredox reactions, toxicities and spontaneousreactions of certain chemicals providesenormous support to the operational crew.

Based on results of the analysis groupand the information on spreading models atthe site of the incident, the risks are re-eval-uated to support the operational crew. The‘Model of Effects with Toxic Gases’ (MET)[5] is helpful for making decisions. Thiswas originally developed for military use.This booklet is easy to handle and guaran-

Fig. 2. Depth of liquid in soil as function of time [3]; time [h] in relation to enter soil [m]

tees a quick and realistic evaluation of theendangered area.

For maximum effectiveness chemicalscience officers are trained in interpretingtoxic values by attending conferences andhaving discussions about real accidents andtheir solutions.

2. Links and Helpful Tools

The first information tools are the sens-es. The eyes and nose are not only used foridentification of the escaped chemical butalso for self protection. The observations ofphysical conditions near the accident andfeedback from the fire fighters about thephysical state, viscosity, color, etc., all haveto be taken into consideration to assess thedanger from the start.

2.1. Gaining Information at the Site of the Incident

The best knowledge of the installationcan be given by the plant manager and bythe people present during the accident. Ma-terial Safety Data Sheets, transportationdocuments, storage lists, risk assessmentsfor authorities, and installation schemes arehelpful tools to gain an overview of the pos-sible range of the consequences of an inci-dent. For accidents on the road the directcontact to the responsible shipping agent –and not just to his telephone answering ma-chine – is required. Chemical informationservices like TUIS or ICE [6] and centers oftoxicology are helpful tools. Local authori-ties provide information about soil, waste-water collection systems, ground water,inhabited areas and other endangeredplaces.

If there is no information available tothe contrary, the reaction of the involvedchemical with water should be observed. Aquick measurement of the pH-value of ex-tinguishing water is helpful to identify thesubstance. Air measurements with analyz-ing instruments such as gas-tubes and si-multaneous air monitoring sets minimizethe time required for identification and re-duces the range of possible chemicals. Itgives essential information about chemicalgroups, redox reactions or acid/base behav-ior to be considered.

2.2. More Detailed InformationThe information collected on site is

compared to book knowledge to provideoptimal input for the officer-in-charge.• Initial information about groups of

compounds; also accessible by firebrigades: ERI-Cards [6]

• Useful manuals for initial information:– Zürcher Giftgesetz [7]– Gefahrengut Ersteinsatz [8]– Gefahrengut im Umgang mit

Chemikalien [9]

solidated advice to the officer-in-charge. Inthe hectic of the operation this assures thatno important fact is overlooked. The chem-ical science officers can be located at dif-ferent places to support the officers-in-charge of different sections.

3. Tips and Tricks from Incidentswith Hazardous Materials

The tasks of the chemical science offi-cers can be demonstrated based on real in-cidents. The variety of different incidentsand the elements of surprise should not beunderestimated. Aggravating situations liketunnels, bridges, traffic, power lines, con-gested areas, etc. must be borne in mind.

3.1. Small Damage by PackagedGoods

Different chemicals and the shipping ofpackaged goods challenge both laypersonsand chemical science officers when itcomes to identification of the hazard. Firstclues for the identification of hazards oftenare given by the senses eyes, ears, and nose.Additionally transportation papers are help-

ful unless they are marked ‘miscellaneous’or ‘not otherwise specified’ (NOS).

On a muggy, warm day with light windfrom the north-east an incident with a trans-port of hazardous goods occurred. Thetransportation paper mentioned ‘dicyclo-pentadien’ and ‘miscellaneous’ as freight.The fire brigade had to treat the spill seri-ously as dicyclopentadien (UN No. 2048;easy inflammable, from 26 °C spontaneous,very intensive reaction (caused by perox-ides), poorly water soluble, extinguish onlyfrom far distance).

Odor, color, and the description fromthe persons who detected the accident andthe first information of the fire brigade didnot fit to dicyclopentadien. More than 1 hlater the trade name of the substance in-volved was known. The internet searchcould be run at the site. Finally the chemi-cal was identified as unproblematic syn-thetic hydrophobic modified acryl polymer(emulsifier). In parallel the Material SafetyData Sheet from the supplier was received.

Suddenly the evaluation of the risk forthe wastewater was more important than theinitial hazard of an explosion under the pre-vailing weather conditions. It had to be de-


• Manual for specific information:– Handbuch der gefährlichen Güter [10]

• Very detailed information:– Gefahrengutschlüssel [11]

• Material Safety Data sheet from the pro-ducerDirect connection to the internet on site

becomes more and more necessary. Forsome useful Web-pages see the list of liter-ature (updated: date of submission).

2.3. Analysis of InformationCurrent weather data and specific meas-

urements have to be analyzed continuously.It is very important to decide where andwhen the analysis team should measure andwhich methods should be used. This has tobe done in accordance with the advice ofchemical science officers. Checklists suchas ‘Checklist for Chemical Science Offi-cers’ (Fig. 3) and a ‘Place-Time-Value’chart (Fig. 4) are used to collect and map allinformation. The chemical science officerneeds all this information for a broad as-sessment of the danger to fire fighters, pub-lic, soil, water, and air.

It is best to have a team of two to threechemical science officers to provide con-

Fig. 3. Checklists for chemical science officers


termined where the escaped material wouldgo if it started raining. It was accepted thatthe small amount of substance could bewashed away into the local sewage watersystem.

3.2. Decontamination and ZoningAs the first priority environmentally

hazardous substances should be preventedfrom dispersing. For safe operation, zoninghas to be defined [12].

At the exit of the central zone, deconta-mination will be conducted based on the ad-vice of the chemical science officer. In mostcases water with defined additives is ade-quate. Normally a solution of 1% is pre-pared for the following:– tensides for lipophilic substances and

hydrocarbons;– sodium hydrogen carbonate for acids;– citric acid for bases;– Sodium thiosulfate for oxidative sub-

stances such as chlorine or bromine.A very good method to stop the decom-

position of nitric acid is the reaction withurea (7 kg of urea/1000 l; H2N-CO-NH2 +2 HNO3 →CO2 + 2 N2 + 3 H2O + O2).

In some cases polyethylenglycol orPrevin® [13] could be used to clean con-taminated persons before they are trans-ported for medical treatment.

3.3. Hazard Potential of Transporta-tion with Liquid Pressurized Gases

Near a city a tank wagon with 20 t ofliquified ammonia derailed. No ammonialeak was detected. The initial shock of theaccident wore off. Measurements and ac-tions could be decided and prepared with-out time pressure. The chemical science of-ficer calculated the spread of ammoniabased on ‘Technischer Behelf für denSchutz bei C-Ereignissen’ (MET) [5]. Ta-bles such ‘Maximalen Arbeitsplatzkonzen-trationen’ (MAK) [14], ‘Immediately Dan-gerous to Life or Health concentrations’(IDLH) [15], ‘Emergency Response Plan-ning Guidelines’ (ERPG) [16] and ‘Tempo-

rary Emergency Exposure Limits’ (TEEL)[17] are helpful to the operational group.

Definition of Emergency ResponsePlanning Guidelines (ERPGs) [16]:

ERPG-1: The maximum concentrationin air below which it is believed nearly allindividuals could be exposed for up to 1 hwithout experiencing other than mild tran-sient adverse health effects or perceiving aclearly defined objectionable odor.

ERPG-2: The maximum concentrationin air below which it is believed nearly allindividuals could be exposed for up to 1 hwithout experiencing or developing irre-versible or other serious health effects orsymptoms that could impair their abilitiesto take protective action.

ERPG-3: The maximum concentrationin air below which it is believed nearly allindividuals could be exposed for up to 1 hwithout experiencing or developing life-threatening health effects.

Definition of Temporary Emergency Ex-posure Limits (TEELs) [17]:

TEEL-0: The threshold concentrationbelow which most people will experienceno appreciable risk of health effects.

The definitions of TEEL-1 to TEEL-3are equal to ERPG-1 to ERPG-3. TEEL-values are calculated ERPGs of a variety offunctions of toxicities data e.g. LD, LC.

Today the ERPG-values [16] are avail-able for basic chemicals but are only rarelyused. They have the advantage of givinglimits for short-time exposure where themajority of inhabitants could suffer for atleast 1 h. They are devised in categories as‘mild transient adverse health effects orperceiving a clearly defined objectionableodor’ or ‘experiencing or developing irre-versible or other serious health effects orsymptoms that could impair their abilitiesto take protective action’ or worst ‘experi-encing or developing life-threateninghealth effects’.

The extent of the leakage and the under-lying soil are the most important factors for

the dispersion of harmful substances at thebeginning [18]. The weather plays an im-portant role for concentrations in the areasurrounding the accident. Sunlight, rain,turbulent wind or calm have great influenceon the size of the endangered areas. Stablewind directions at night with grate dispens-ing and high concentrations are problemat-ic. For commerce reasons a tank-to-tanktransfer at night might be better becausetraffic can be stopped completely.

In case of a release theoretical propaga-tion calculations [5] would have beenchecked against the results by the chemicalanalysis group. These results should befilled in a place-time-value chart (Fig. 4) tohave a quick overview of the current situa-tion and predictions on how the gas willpropagate. The risk for the population dur-ing tank-to-tank transfer was assessed bythe response team and the police in order tomake a decision for a further shut off or anevacuation.

In the chaotic start of an accident, theo-retical calculations such as pool evaporationare impossible. Tables were used to evaluatethe amount of the spill (Fig. 5 and 6 [19]).

3.4. The Most Probable AccidentInvolving Hazardous Goods: Trans-port of Fuel and Combustibles

The hectic traffic situations cause acci-dents again and again. Based on hazardousmaterial transportation statistics, accidentsinvolving hazardous materials are seldom.The probability of accidents with fuel andcombustibles is higher.

One morning with fog, low visibilityand white frost, a tank truck with fuel (UN1203) turned over at the inflow to a motor-way so that the fuel leaked out of the bot-tom side. Concerns about the explosionhazard led to a road block of 15 km in bothdirections. The leak could not be stopped.Most of the fuel ran through a separate sew-er water system to a retention basin.

The emission of odor was low becauseof the weather conditions. More than onechemical analysis group controlled the ex-plosion hazard online by using an alarmvalue of 20% of the lower explosion limiton different sites. Specific canals and shaftswere measured. The possible escape of fuelfrom a dike received intensive attention. Forsafety reasons the overrun was coated withadhesive agent.

In a risk analysis and under time pres-sure it had to be considered whether a trans-mission line near the accident should beswitched off. Based on weather data and theincident it was decided not to switch it off.But it was possible to take this action quick-ly if necessary.

The highway could be reopened step bystep with the cleanup. A flushing of thesewer water system was proposed for thenext day.

Fig. 4. Place – Time –Value chart

shipped between different locations. Acci-dents can happen not only during produc-tion, transport, storage but also during ap-plication. Therefore it is important to beprepared for such accidents at all times andunder all circumstances. Chemical firebrigades with chemical resistant materialand the know how of chemical science offi-cers guarantee that the negative effects ofincidents with hazardous materials are keptat low level.

AcknowledgementsWe would like to thank Dr. W. Jucker, Roche

AG, Sisseln, Mr. M. Schmid, Section Environ-mental in the Building Department of CantonAargau, Mr. H. Schwab, Swiss National Rail-ways, K. Gimmel ‘Emergency management’,Lonza AG, Visp, and Mrs. C. Comerci, F. Hoff-mann-La Roche, Ltd., for the assistance withthis article.


[1] a) M. Schmid, A. Meyer, ‘Das Aargau-ische Chemiewehrkonzept’, Schweizeri-sche Feuerwehr Zeitung 1968, 2, 80–87;b) Schweizerisches Gesetz, ‘Verordnungüber Organization der Schadensdienstezur Abwehr von Gewässer-, Boden- undLuftverunreinigungen (Schadensdienst-verordnung)’, 25.11.1991.

[2] W. Hofer, ‘Sind wir gerüstet?’, UmweltAargau 1988, 2.

[3] SBB Geschäftsbereich Betriebsführung,Betriebswehrstelle, ‘Dossier Einsatzpla-nung’, Anhang 3.6 (Eplb-A36/doc/ba),Januar 2000.

[4] W. Hofer, ‘Der Chemiefachberater trai-niert bei der Siegfried CMS AG in Zofin-gen’, Umwelt Aargau 2000, 9, 5.

[5] ‘Technischer Behelf für den Schutz bei C-Ereignissen, MET (Modell für Effekte mittoxischen Gasen)’, Zentralstelle für Ge-samtverteidigung, EDMZ Bern, 1991, Nr.581.031d (out of stock); today integratedin [8].

[6] ‘Emergency Response Intervention Cards(ERICards)’, International ChemicalEnvironment (ICE); in Switzerland:TUIS Schweiz, Novartis Service AG,

Tel.: 061 696 33 33; Internet: http://www.ericards.net/german/index.asp.

[7] ‘Giftgesetz, Giftklassen, EG-Richtlinien’,Kantonales Laboratorium, Fehrenstrasse15, Postfach, CH-8030 Zürich (out ofstock, will not be updated).

[8] H.D. Nüssler, ‘Gefahrengut Ersteinsatz’,Storck Verlag, Hamburg, ISBN 3-923190-33-6, 2000.

[9] H. Dembeck, ‘Gefahren im Umgang mitChemikalien’, W. Kohlhammer-VerlagGmbH, Stuttgart, ISBN 3-17-011277-5,1996.

[10] G. Hommel, ‘Handbuch der gefährlichenGüter, Transport- und GefahrenklassenNeu’, Springer Verlag, Berlin, ISBN 3-540-20348-6, 2004.

[11] Kühn-Birret, ‘Gefahrgutschlüssel’, Eco-med Verlag, D-Lansberg/Lech, ISBN 3-609-77030-9, 2003.

[12] F. Geissmann, ‘Decontamination afterChemical Incidents’, Chimia 2004, 58,33–36.

[13] Hanke + Seidel GmbH & Co. KG;Instructions for Use: http://www.hanke-seidel.com/previn/index.html.

[14] ‘Maximale Arbeitsplatz Konzentration(MAK)’, Internet: http://www.bge.de/asp/dms.asp?ur =/TRGS900/INHALT.HTM.

[15] ‘Documentation for immediately danger-ous to life or health concentration(IDLHs)’, Internet: http://www.cdc.gov/niosh/idlh/intridl4.html or ‘TGAH Liste1987 / NIOSH 1990’ (old and so some-times high values) IDLH.

[16] ERPG-values are available from AmericanIndustrial Hygiene Association (AIHA),2700 Prosperity Ave., Suite 250, Fairfax,VA 22031; Tel. +1 703 849 8888, see also:http://tis.eh.doe.gov/web/chem_safety/doe_reg.html.

[17] Temporary Emergency Exposure Limits(TEELs); Internet: http://tis-hq.eh.doe.gov/web/chem_safety/teel.html.

[18] F. Ochsner, ‘Liquified Gases’, Chimia2004, 58, 21–22.

[19] W. Bögerhausen, K. Gimmel, Ereignis-dienste, Lonza AG, CH-3930 Visp,Schweiz, 2003, personal information forpublication.

[20] G. Zufferey, ‘Release of Toxic Gases andTheir Detection’, Chimia, 2004, 58, 13–16.


The complex deployment required aconstructive partnership between the oper-ational crew, police, chemical hazard crew,chemical science officer, authorities, chem-ical analysis teams, road-maintenance crewand the electric power company. There is apossibility to estimate the amount spilledby using Fig. 6 [19].

3.5. Chemistry in FarmingIn daily life chemicals are present all the

time without being recognized as hazard-ous. Economic farming depends very oftenon hazardous chemicals such as fertilizersor pesticides. The knowledge of processesin farming is also important for the chemi-cal science officer. A simple fire of a stor-age room with fertilizers at a farm can re-quire the presence of a chemical science of-ficer. Support about the physical and toxicproperties of nitric gases or about the ab-sorption of the fire water are typical ques-tions chemical science officers have to an-swer. In order to ensure adequate disposal,he gives advice about the retention of extin-guishing water, the handling of residuals,and the handling of nitric gases.

The chemicals added to storage grass inbig silos together with high ambient tem-perature can cause critical conditions. Wetgrass with these added chemicals forms ni-trous gases. The boiling point of nitrogendioxide (21 °C) allows a lake to be formedof this hazardous chemical. The nitrogendioxide has to be vented and absorbed bymore than one water gun. The chemical an-alyzing team has the duty to monitor thedisposal and guarantee the MAK limits[14], IDLH [15] or ERPG values [16].Housing and weather conditions, tempera-ture, humidity, sun shine, wind, etc., allhave to be considered [20].

4. Conclusions

Chemical substances are common ineveryday life. They have to be stored and

Fig. 5. Estimated spill of a gas [19] Fig. 6. Estimated spill of a liquid [19]T



ISSN 0009–4293

Training Hazardous-Materials ResponseTeams and Chemistry Students throughPractical Experimentation

Ernst Hungerbühler* and Markus Gisler*

Abstract: Large quantities of hazardous substances are required to meet the needs of today’s industrial society.During the manufacture, transport, and use of these substances – whether they serve as raw materials, intermedi-ate products or energy carriers – accidents and damage cannot be totally excluded despite all the efforts and tech-nical knowledge that may go into their prevention. Incidents involving hazardous chemicals always represent a sub-stantial risk for accident response teams, the general population, and the environment. In order to keep damageto a minimum, special attention must be given to training the specialists involved. It is possible to demonstrate therisks resulting from hazardous materials and the most suitable methods of effectively combating such risks by theuse of thought-provoking practical experiments. This is shown with a number of examples.

Keywords: Characteristics of liquid and gas fires · Chemical hazards · Education and experimentation · Explosion and explosion prevention experiments · Training hazardous-materials response teams

Introduction

Identifying potential dangers resultingfrom accidents with chemicals (Fig. 1 and2) or their incorrect handling and success-fully combating these requires specializedknowledge.

Correspondence: Prof. Dr. E. HungerbühlerUniversity of Applied Sciences Basel (FHBB)Gründenstrasse 40CH–4132 MuttenzTel.: +41 61 467 43 88Fax: +41 61 467 44 57E-Mail: [email protected]. M. GislerClariant (Switzerland) AGTechCenter ReinachRothausstrasse 61CH–4132 Muttenz 1 Tel.: +41 61 469 79 97E-Mail: [email protected]

§Alongside their activities as Head of the ChemistryDepartment at the University of Applied Sciences,Basel, and as Group Leader R&D Dyestuffs atClariant, respectively, the authors are also consult-ants in chemical matters to the Canton of Aargauand head and deputy-head, respectively, of thechemical and oil protection unit of the Rheinfeldenfire service.

As the officers in charge of units first re-sponding to a ‘chemical incident’ are notnormally specialists but all-round fire fight-ers, they must be able to rapidly identify –by means of checklists (Fig. 3 and 4) andsimple pictures, such as the fire triangle be-low (Fig. 5), immediately comprehensiblewarning signs (Fig. 3), hazard labels (Fig.4) or transport documents, – what particu-lar dangers might result from the materialsinvolved. This makes it possible for the cor-rect measures to be taken to effectivelycombat the problem (Fig. 6) and to protectpeople, property, and the environment,without the fire-fighting team being ex-posed to unnecessary risks.

Nowadays, in the event of an emergencyalarm, it is possible to call on chemicalsspecialists from hazardous-materials re-sponse teams in the chemical industry andon chemicals consultants to help in com-bating an incident. Only by means of on-go-ing training (Fig. 7) and practical exercisesinvolving cooperation between fire-fight-ing services, hazardous-materials responseteams from the chemical industry, chemi-cals consults, civil defense units, and possi-bly those responsible in organizations at thelocal authority level is it possible for thesevarious specialists to function as an effec-tive team that can give valuable support tothe person in charge of operations in anemergency.

Teaching through Experimentation

By means of specifically tailored train-ing courses, the Chemistry Department ofthe University of Applied Sciences, Basel,increases the awareness and motivation ofchemistry students and industrial safety of-ficers to make an active contribution tochemical safety and environmental protec-tion (Fig. 8 and 9).

In order to encourage an interest in peo-ple to become chemicals consultants or firefighters with a chemistry background, theChemistry Department of the University ofApplied Sciences, Basel, has included aspecial module dealing with chemical safe-ty in its Basic Chemistry course for first-year students. One section of this module,which is being constantly expanded, pro-vides practice-oriented visualization ofchemical safety and environmental protec-tion using interesting and thought-pro-voking experiments.

The aim of these experiments is to makeour specialized audience more aware of theproblems that can result from an accidentinvolving hazardous materials and to givethem confidence in their personal protectiveequipment, in the materials used to combatincidents and in the measuring devices attheir disposal.

Since we have been making it possiblefor students to be actively involved in ex-


Fig. 1. Stein-Säckingen 1991, derailment of tank cars containing gasolineand resultant fire (Picture: Rheinfelden fire service)

Fig. 2. Stein-Säckingen 1991, gasoline tank cars after extinction of fire andtreatment with foam (Picture: Rheinfelden fire service)

331203

Hazard ID Number

UN- Number

1st digit main hazard1 explosive material2 gas3 flammable liquid4 flammable solid material5 oxidizer (fire-intensifying material)6 toxic material7 radioactive material8 corrosive material9 other hazards

X must not come into contact withwater or extinguishants containingwater!

Hazard identification numbers

2nd & 3rd digits additional hazards0 no meaning - filler following

first digit2 emission of gases3 highly flammable5 oxidizing6 toxic

8 corrosive9 violent reaction (spontaneous

decomposition or polymerization)

Fig. 3. Hazard ID number 33: highly flammable liquid, Material number1203: gasoline [1]

Fig. 4. Hazard labels

CoolingWater SprayFogFoamMetal GratingDry Chemical

Stop Fuel Addition/Re-lease, Remove Fuel

SmotheringFoam

CO2Steam

XFuel

Oxygen

Igni

tion

Ener

gy

HeatFlame SparksLight

OxygenAirNitratesPeroxidesChlorates

SolidsWoodDustsMetalsTextiles

LiquidsGasolineKeroseneAlcoholsOils, Fats

GasesNatural GasPropane, ButaneAcetyleneHydrogen

Fuel

Oxygen

Igni

tion

ener

gy

Fig. 5. The fire triangle or ‘Infernal triangle’ Fig. 6. Fire-fighting methods and extinguishants

Flashing withignition source

Extinguishingwithout ignition source

Continued burningwithout ignition

source

Flashpoint

Firepoint

Tem

pera

ture

Vapor phase above flammable liquid No flashing with

ignition source


Fig. 7. Practice makes perfect; emergency drill at the Siegfried chemicalaccident training center [2]

Fig. 8. Trainee Susanne Mauperforming an experiment:steel wool and a 4.5-voltflashlight battery are used toset fire to ether in a beaker

Fig. 9. Students watching an exper-iment in class: ammonium bichro-mate NH4Cr2O7 burns (even with-out external oxygen) to formchrome-III-oxide Cr2O3 and nitro-gen N2

Fig. 10. Flash point and fire point

Fig. 11. Combustion of a paper handkerchief soaked in pure alcohol re-sults in complete destruction

Fig. 12. A paper handkerchief soaked in 50% water-alcohol solution re-mains intact both during and after combustion

Fig. 13. A paper handkerchief soaked in 50% water-alcohol solution re-mains intact after combustion


periments, we have observed an impressiveincrease in the attention they pay to the sub-ject of chemical safety and their greaterpleasure in professional experimentation.Recently students who have become used tothis form of experimentation have also hadthe opportunity to demonstrate the know-how they have acquired to school pupils in-terested in science, to both former and po-tential chemistry students and to visitorsand thus to give them an insight into howtraining in chemical safety and the work en-vironment can be bolstered by means ofpractical experimentation.

Flammable Liquids

Hazard ID numbers:30: flammable liquid (flash point be-

tween 21oC and 100 oC)33: highly flammable liquid (flash point

below 21oC)The flash point of a liquid is a material-

specific value indicating the temperature atwhich the substance in question catches fireupon contact with a source of ignition un-der standardized experimental conditions(Fig. 10). For gasoline, the literature gives–20 °C [1], and for fuel oil or diesel fuel>55 °C [1]. Accordingly, fuel oil cannot beset alight at room temperature through con-tact with an ignition source – quite unlikegasoline! Only when the fuel oil has beenheated to 60–70 °C can it also be set on fire.

By increasing the surface area of a mate-rial, e.g. by vaporization or adsorption in aporous carrier such as an oil binding agent, itbecomes possible for substances, such asdiesel oil that would not otherwise catch fireto be set alight at room temperature.

The boiling point and vapor pressure ofa liquid, also material-specific values, tell

us something about the evaporation proper-ties of the substance and its propensity toform an explosive hazardous material/mix-ture with air. Hazardous mixtures of thiskind can be identified with an explosimeterand evaluated.

Flammable organic liquids can also beevaluated on the basis of their miscibilitywith water: hydrophilic liquids are misciblewith water. In the event of fire, such mix-tures can be effectively extinguished bymeans of cooling and diluting with water orby being covered with a carpet of foam. Thegood cooling effect of water (high specificevaporation temperature) can be demon-strated easily by means of the experiment(Fig. 11 to 13).

Hydrophobic liquids mix poorly withwater or not at all. In addition, if they alsohave a lower specific gravity than water, e.g.gasoline, these liquids float on the surface ofthe water and cannot be extinguished simplywith water in the event of fire. Foam acts asan ideal extinguisher by completely cuttingthe burning material off from the oxygencontained in the air, which leads to the firebeing smothered. Alternatively, a fire of thistype can be extinguished using CO2 or pow-der, although in this case the powder residuethat settles everywhere can make large-scaleadditional cleaning necessary.

Explosive Vapor-Air Mixtures

Wüthrich defines an explosion as thesum of the phenomena that occur in theevent of the rapid release of energy [3]. Hespecifies a chemical explosion by the ener-gy release of forces between valence elec-trons as opposed, for instance, to a nuclearexplosion with reactions occurring insidethe nucleus [3].

We use the term ‘explosion’ here as asynonym for chemical explosion.

The minimum concentration of a flam-mable substance in the air (vol/vol %) atwhich the mixture can still explode is re-ferred to as its lower explosive limit (LEL)(Fig. 14). With the aid of an explosimeter(for function, see Fig. 15), it is possible todetect a potentially hazardous situationconsiderably below the LEL and to takesuitable measures.

Explosions of Detonating Gases(Hydrogen/Oxygen or Hydrogen/ Atmospheric Oxygen Mixtures)

Experiment 1: Exploding BalloonsThree balloons are filled with pure oxy-

gen, pure hydrogen (diameter less than 30cm), and a mixture of approx. two parts byvolume hydrogen and one part by volumeoxygen (diameter less than 20 cm), respec-tively. Using a candle on a stick, the ballooncontaining the oxygen is first ignited andnoted as a blank value, since oxygen itselfis known not to burn. Then follows the bal-loon with pure hydrogen, which explodeswith a muffed bang and creates a clearlyvisible fireball. The balloon filled with thedetonating gas mixture should only be ex-ploded when those present have protectedtheir ears and opened their mouths slightlysince it explodes with a violent, very loudbang.

Experiment 2: Exploding CanAn empty one-liter can with the lid re-

moved has a hole approx. 2 cm in diametermade in the bottom, which is closed with abung. The can is placed on a smooth surfacewith the opening facing downward and hy-drogen gas is then slowly introduced into it

safe

mixturetoo lean

too littlefuel

too littleoxygen

mixturetoo rich

FlammableRange

UELUpper Explosive Limit

LELLowerExplosive Limit

dilute with air

Explosion

0 100 Fuel [Vol%]

Fig 14. Explosive range and explosive limits


H2

Air (O2)Mix

Flame flaresback �

explosion

SinteredMetal Plate

Sensor Cell(Catalytic

Surface)

Combu-stion

Reaction

Gas Mixture to be Measured

ReferenceCell

Oxygen

Fuel Nitrogen

Fig. 15. How the sensor cell of an explosimeter works: The vaporous com-bustible material is burnt on the catalytically active surface of the sensorcell. The meter measures the difference in temperature between the sen-sor cell and a reference cell

Fig. 16. Can with hydrogen

Fig. 17. Hosepipe model toshow how combustible va-pors with a high specificgravity can spread. Acetonevapors created in thecollecting vessel above(impregnated cotton-woolswab) spread through thecoiled hosepipe, ignite oncontact with the ignitionsource at the end (candle),then flare back and set fire tothe supply of acetone

Fig. 18. Simulation of sewer, course of fire in a four-meter-long acrylic glasstube filled with a mixture of propane gas and air

FireballSafety screen

CoarseWire Cage

GasLighter

Contraction � Explosion

Wire mesh � Flame stops

Deflagration: Flame passes through

Foam Pad � Flame stops

STOP

STOP

Fuel + Air

Fuel + Air

Fuel + Air

Fig. 19. Sewer experiments, effects of obstructions, schematic represen-tation

Fig. 20. Bleve of a gas lighter, schematic diagram

Important

This publication has been compiled tothe best of the authors’ knowledge andbelief and is intended solely for special-ists. Anyone using the information itcontains, particularly with regard to per-forming experiments, does so at his/herown risk and on his/her own responsibil-ity. All the experiments described hereare potentially dangerous and should un-der no circumstances be attempted bylaypersons. Unjustifiable risks involvingpotential harm to persons or propertymay occur if experiments are not cor-rectly performed or if alterations aremade to experimental parameters (quan-tities, etc.). The authors accept no liabil-ity for any direct or indirect damage thatmight result from the experiments de-scribed being carried out. In case of ac-cident, it is always advisable to keep sen-sible extinguishing materials at hand(extinguishing blankets, CO2) togetherwith a bucket of water that can be usedfor cooling purposes in the event of fire.Ensure that you switch off any exposedfire alarms before performing the exper-iments.Never carry out an experiment in front ofan audience for the first time; but onlyperform experiments that you have al-ready documented well in advance andin a way that you have already found tobe safe and successful. Check even themost insignificant alterations to previ-ous experiments in advance by means ofappropriate testing!

AcknowledgementsWe would like to thank Hildolf Schwald for

providing us with some of the experiments andfor his technical assistance. We also thank Wal-ter Hohl, Andre Büttler and our first-year chem-istry students (2002/2003) for their help in ex-panding our collection of experiments. And fi-nally thanks to Robert Bannister, one of ourprofessors of English at the FHBB, for transla-tion.

Received: January 5, 2004

[1] G. Hommel, ‘Hommel interaktiv, Hand-buch der gefährlichen Güter’, Springer-Verlag, Berlin, Heidelberg, 2003.

[2] Chemiewehrschule Siegfried AG, CH-4800 Zofingen, www.chemiewehrschule.ch

[3] K. Wüthrich, Chimia 2003, 57, 757.[4] W. Bartknecht, ‘Explosionsschutz und

Anwendungen’, Springer-Verlag, Berlin,Heidelberg, 1993.

[5] F. Roessler, Chimia 2003, 57, 791.[6] I. Obermüller, Chimia 2003, 57,784.


to force out the atmospheric oxygen untilthe can is full of sufficient H2 for the upperexplosive limit of 74% [1] to have been sub-stantially exceeded. The can acts like a div-ing bell and retains the hydrogen with itslower specific gravity (Fig. 16).

When the bung is removed and the es-caping gas ignited, air penetrates into thecan from the lower open end and mixes withthe hydrogen. The flame continues to burnfor a while, but becomes increasinglysmaller until the flame flares back into thecontainer and a violent explosion occurswith a loud bang.

Measures

A comprehensive overview of explo-sion prevention has been published byBartknecht [4]. Roessler provides a detaileddescription of the safety aspects of catalyt-ic hydrogenation [5].

Inerting, e.g. by means of nitrogen, CO2or argon, can frequently prevent an explo-sive gas atmosphere by excluding oxygen.Relieving pressure, accurate knowledge ofreactions including risk analysis and stafftraining are additional important measuresto ensure that processes involving hydrogencan be implemented safely.

Obermüller has recently described anexplosion prevention concept for a reactionin an oxygen atmosphere on a productionscale [6].

Experiment to Visualize the Hazardsof Flammable Vapors in a Sewer orVentilation System

This situation can never be excluded inthe event of an accident involving flamma-ble liquids or gases on the road, in a build-ing or in a laboratory, which makes it es-sential for measures to be taken in order tokeep an incident of this kind within limits(Fig. 17).

Sewer ExperimentsVarious constructional measures, such

as fire-walls, fire-doors, and fire-preventioncovers, can contain the spread of fire for acertain period of time and thus frequentlyprevent greater damage. Flammable vaporsin a sewer represent a very great hazard topeople and infrastructure should the lowerexplosive limit be exceeded. As there isgenerally no possibility of inerting meas-ures being taken, it is only possible to pre-vent damage by means of venting or creat-ing compartments or to limit damage in theevent of ignition.

In practice, fire-fighters can createfoam barriers in a sewer filled with flam-mable vapors by pumping extinguishingfoam into the sewer.

The hazards and behavior of flammablevapors and gases in sewers can easily bedemonstrated by a set of two acrylic glasstubes which are filled with a propane/airmixture. As shown in the experiments illus-trated (Fig. 18 and 19), these can success-fully contain an explosion in one section ofthe sewer.

When the connection between the twotubes is not obstructed, after ignition at oneend, the flame front passes through the twotubes.

A pad of fire-fighting foam or a wiremesh screen inserted between the two tubesseparates the tubes into two fire compart-ments and will prevent the flame fromspreading. In these cases, the remaininggas/air mixture in the second tube can be ig-nited from the opposite end.

A ring-shaped contraction between thetwo tubes leads to an explosion in the sec-ond tube.

Bleve of a Gas Lighter

BLEVE is an acronym for Boiling Liq-uid Expanding Vapor Explosion.

Bleves are among the most dangerousincidents with which fire-fighting teams areconfronted. Bleves occur when containersof liquids or liquid gases are heated or di-rectly exposed to a fire. Without externalcooling, the contents of the tank are heated,the pressure inside increases, and the tem-perature of the combustible contents soonpasses boiling point. The section of the con-tainer skin that is exposed to the fire overthe vapor phase heats up faster than the sec-tion filled with the combustible liquid andsuffers a faster loss of stability.

The increasing internal pressure, cou-pled with the diminishing stability of theskin of the container can cause the contain-er to burst. The contents that have been un-der pressure empty virtually instantaneous-ly. The rapidly expanding vapor cloudburns in a huge fireball.

Only by means of massive cooling withwater is it possible to keep a container ofcombustible material intact when it is locat-ed inside a fire, such as an 80,000-liter tankcar of gasoline (Fig. 1).

ExperimentA small-scale bleve can be demonstrated

by means of a disposable gas lighter (Fig. 20).An evaporating dish containing a few

milliliters of ethanol is placed behind a pro-tective screen and a gas lighter put inside it.The alcohol is then set alight. A wire-meshcage placed around the dish prevents anymetal fragments from being scattered. Afterjust a few minutes, the gas tank of thelighter bursts and the burning vapor cloudcreates a fireball approximately 50 cm indiameter.