WOOD 120

Risk Management

Paul McFarlane

Office: FSC 4038

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Risk ManagementThere’s a fine line between taking a calculated risk

and doing something dumb

Risk ManagementThere’s a fine line between taking a calculated risk

and doing something dumb

Risk ManagementThere’s a fine line between taking a calculated risk

and doing something dumb

Risk Management• Risk Management process

1. Identify risk

- define business threats

2. Assess risk

- assess vulnerability to

threats

� likelihood & impacts of

specific threats

3. Control risk

- identify & implement risk

reduction techniques

4. Review controls

- check effectiveness

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Business Risk Management

OperationalStrategic

People

TechFinancial

Compliance Types of

Risk

Business Risk Management

OperationalStrategic

People

TechFinancial

Compliance Types of

Risk

Wood Dust

What are the risks?

Wood dust risks

1. Operational risks

�Explosions

- Lakeland mill, 2012

- Babine FP, 2012

�Fires

- numerous

2. People risks

�Cancer- Wood dust classified as Class 1 carcinogen

� Worksafe BC

� International Agency for

Research on Cancer

(IARC)

Lakeland mill

1. Operational Wood Dust Risks

- Recent BC experience• January 20, 2012

�Explosion and fire at

Babine Forest

Products Company

in Burns Lake

�2 workers killed and

19 injured

• April 23, 2012

�Explosion and fire at

Lakeland Mills Ltd.

in Prince George

�2 workers killed and

22 injured

Photo

s: V

ancouver

Sun

How many major sawmill fires

do you think there were in BC

between 2008 and 2016?

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Wood dust explosions & fires• Wood dust and air create explosive mixtures

• Explosions occur when

�minimum threshold concentration of dust particles is

- present in air and

- exposed to an ignition source

• Minimum ignition T�Wood < 500 oC

• Freshly extinguished match ~ 500°C

• Sparks >550°C

• Lower explosion limit (LEL) for wood dust is 40 g/m3 air�Most explosive

- dry dust <25%MC

- fine dust <500 µm

The Fire Triangle

• Fuels

�Wood dust,

fibres, chips,

flakes, etc

• Oxidizers

�Gases

- Oxygen, chlorine

�Liquids

- hydrogen peroxide, nitric acid

• Ignition sources

- Sparks, flames, static

electricity, heat

Explosion Pentagon

or other oxidizersor layer of dust

- LEL wood

= 40 mg/L

- closed room

- bag house

- cyclone etc

Cascading explosions

Source: Forest Industry Task Force 2013

Video of dust explosion hazard

• https://www.youtube.co

m/watch?v=3d37Ca3E

4fA

• Check all out

• Focus on 2min 45 – 5

min

• Demonstrates

propagation

mechanism

Examples of wood dust accumulation

BC example: explosion propagation

source (BCSA 2014)

Before

After

Results of Lakeland Mill’s Investigation 1

• WorkSafeBC investigated the Lakeland Mills

explosion

• The key findings were that;

�The initial ignition occurred when a gear-reducer cooling fan

failed

- a rotating shaft generated friction & reached a temperature >577oC

�As a result the airborne dust around the gear reducer ignited

- This was located in a contained area of about 3m2

� surrounded by a conveyor, a steel-plated ceiling and exterior wall

�The explosion travelled east to west through the mill's

operating level, destroying the mill, killing and injuring the

workers

�A few seconds later the bag-house erupted in flames

Results of Lakeland Mill’s Investigation 2

• The WSBC also identified that there

were:

- no dust collection systems in the area

- ineffective dust-control measures- ineffective maintenance & inspection of motor cooling fans

�Waste conveyors in the

basement did not adequately

capture fine dust

�Supervisors inadequately

monitored clean-up and

maintenance work

• WorkSafeBC concluded the

explosion & fire were preventable

• Company fined

Industry’s responses 1

• Minimize dust accumulation

�Effective dust collection

system & good housekeeping

- If ignition sources are

present, use cleaning

methods that do not generate

dust clouds

- Ground machinery

- Control all potential sources

of open flames and sparks

- Ensure no hot surfaces

contact dust

- Check hard-to-access areas

Industry’s responses 2

• Worker education (risks,

housekeeping & grinding/welding)

• Install safety devices in dust

collection system

• Ensure site smoking policies and

procedures are being followed

• Establish emergency procedures

�Exit routes designed and marked

�At least one emergency drill completed

and documented per year

2. People Wood Dust Risks

- Cancer

10 most most common workplace

carcinogens in BC (Worksafe BC 2013)

• Solar radiation (164,900 exposed)

• Diesel engine exhaust (DEE) (108,000 exposed)

• Wood dust (58,100 exposed)

• Polycyclic aromatic hydrocarbons (not including

environmental tobacco smoke) (46,600 exposed)

• Crystalline silica (44,800)

• Benzene (40,300 exposed)

• Lead and compounds (20,700 exposed)

• Environmental tobacco smoke (17,300 exposed)

• Formaldehyde (10,400 exposed)

• Ionizing radiation (10,000 exposed)

Categories for carcinogens• International Agency For Research on Cancer (IARC) = cancer research agency of WHO

�classifies carcinogens using the following categories - Class 1 -- Known human carcinogen- Class 2A -- Probable human carcinogen- Class 2B -- Possible human carcinogen- Class 3 -- Not classifiable for human carcinogenicity- Class 4 -- Probably not carcinogenic to humans

• WorksafeBC� uses the following categories

- A1 Confirmed human carcinogen- A2 Suspected human carcinogen- A3 Confirmed animal carcinogen with unknown relevance to humans- A4 Not classifiable as a human carcinogen- A5 Not suspected as a human carcinogen

• Consider the 5 IARC and ACGIH categories as broadly equivalent

Industrial

safety focus

Health effects of wood dust

• Wood dust = class 1 carcinogen

�known human carcinogen based on human evidence

- International Agency for Cancer Research 1995

• increased risk of adenocarcinoma in nasal cavities and paranasal sinuses

• other types of nasal cancers and cancers at other sites (nasopharynx, larynx and Hogkinsons disease) have been reported in some studies but insufficient evidence to draw firm conclusions

- US Dept of Health & Human Services 2000

Wood dust & cancer:

exposure risks• Individuals exposed to wood

dust on the job in a sawmill have

a 50% increased risk of

developing lung cancer

• People exposure and wood dust

through a hobby

had no increased risk of

developing lung cancer.

• In general, occupational

exposures responsible for ~10 -

30% of lung cancers in men

Anatomy of the human respiratory system

Nasopharyngeal

system

Tracheobronchial

system

Pulmonary

system

Why is

respiratory

exposure so

important?

ICRP Deposition Model International Commission on Radiological Protection

Nasopharyngeal system

• beyond the nostrils have 2 cavities

�inspired air is forced along a convoluted path

- contacts large SA

-warmed & moistened

�nasal surfaces covered by

-mucus layer

- ciliated cells

�Reasonably effective at removing particles

>1µm

Defense mechanisms

• Nasopharynx system� Impingement on mucus/hairs

�Moved by cilia to back of mouth

� Swallow or expectorate

� Sneeze reflex

• Tracheobronchial system� Constriction of bronchi in response to particles

� Cough reflex- shift particles trapped in mucus- expectorate or swallow

• Pulmonary system� Specialized cells (phagocytes) ingest deposited matter

� Transported out of lungs by cilia

� Not always effective

� Some material penetrates alveolar membrane & reaches blood stream

Protective measures• Prevent inhalation of

wood dust

�Exposure limits 1-2.5

mg/m3

�Cover details later in

course

�Use suitable masks

• Fine dust most important

�Secondary manuf

�Sanding

• Long term exposure is an

important factor

Take home messages

• Wood dust can be dangerous

�If appropriate control measures are not in place

• Major risks

�Operational

-Explosions, fires

�Personal

-Cancers

-Bronchitis, asthma, allergies

• All risks can be adequately dealt with if

appropriate measures are taken