MIT Incident

Coordinator-Lead Contact MeetingJune 18, 2013

Presented by Dan Herrick

Thanks to Susan Leite, Eric Hammond, Bob Edwards

Background Information

• A graduate student came to their EHS Coordinator and asked if an SOP was needed for using decalin (decahydronaphthalene).

• Project involved dissolving high molecular weight polyethylene in decalin (which would be heated).

• Student forwarded the MSDS:

Decalin SDS Excerpt

Source: Sigma Aldrich

Also from SDS:7. HANDLING AND STORAGE

Precautions for safe handling

Avoid contact with skin and eyes. Avoid inhalation of vapour or mist.

Keep away from sources of ignition - No smoking. Take measures to prevent the build up of electrostatic charge.

Conditions for safe storage

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage.

Handle and store under inert gas. Air and light sensitive. Heat sensitive.Handle and store under inert gas. Air and light sensitive. Heat sensitive.

10. STABILITY AND REACTIVITY

Chemical stability: Stable under recommended storage conditions.

Possibility of hazardous reactions: no data available

Conditions to avoid: Heat and light accelerate peroxide formation. Conditions to avoid: Heat and light accelerate peroxide formation. Heat, flames and sparks.

Materials to avoid: Oxidizing agents.

Hazardous decomposition products formed under fire conditions. - Carbon oxides

Other decomposition products - no data availablehttp://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=D251&brand=SIAL&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Fsial%2Fd251%3Flang%3Den

Coordinator said “Yes, write an SOP.”

And so the student went on his merry way.• 6 months later, at 8:30 pm, a text message:FRM:Michael Hastie

SUBJ:CHEMICAL SPILL

MSG:The Operations Center has received a report of a chemical spill in Bldg X Rm xxx - Chemical involved is 200cc of decalin - No injuries have been reported - EHS, CP, ERG responding(End)

• Next day, a note from an EHS Rep:From:

Subject: Lab all clear

Date: April 5, 2013In case you were around earlier and saw the signs about the chemical spill, everything is now clean and the lab is open for business.

Uh Oh!Uh Oh!

What happened?• A different grad student needed to perform viscosity

measurements on the UHMWPE/decalin solution.  These measurements are done at elevated temperature.

• Student was using hot plate (with stirring) to heat approx. 200 mL of solution in regular glass bottle (with cap) to desired temperature of 140 C.  At some point during this operation, cap blew off the bottle and the contents of the bottle sprayed about the lab.  Student dialed EHS but may have gotten the wrong number, at which time he was transferred to campus police.

• Amongst others, EHS responded. Area was secured, Clean Harbors worked with EHS to clean lab.

• No injuries, no serious damage.

The Requisite Pictures

Why did it happen?• The direct cause of this incident was poor management of change

(MOC) procedures.

• Usual procedure: heat an oil bath and suspend the decalin/PET sample container within the oil bath.

• On day of incident, to speed up heating, oil bath was omitted, but the hot plate was set to the same dial setting set point (not temperature set point) as when an oil bath was present.  No thermometer was used in this experiment.

• Given the lack of an oil bath and the tendency for hot plates to heat unevenly, it is likely that while attempting to reach 140 C this temperature was eclipsed.  Decalin’s boiling point is 190 C.  It is likely that this temperature was locally approached such that vapor expansion in that local area caused this incident.

Why did it happen?• Procedure was altered (removal of oil bath) without

consideration of the possible consequences, and insufficient controls were in place for this change, since no temperature monitoring was done.

• Heating of samples in lab where incident occurred was not specifically called out in original SOP.

• Work was not being conducted in a fume hood (as SOP requires), which would have contained odorous vapors.

• Since only 12 mL needed for viscosity measurement, it’s unclear why 200 mL were being heated.

How can a similar occurrence be avoided?• Carefully consider any changes to a procedure,

especially one involving heating of solvent-based materials.

• When changing a heating procedure, monitor the temperature of the solution in the new procedure.  Stay below the solvent’s boiling point and carefully attend the experiment.

• Perform all work involving heated solvents in a fume hood.

• Limit volumes of all materials used to only that which is needed.