Chemical Hazards of Electrical Fires
By Michael Lee
A recent fire in an older structure raised an interesting firefighter safety issue regarding electrical fires in high-voltage equipment. It was prompted by a sticker on transformer boxes in the back yard at the incident scene and got me thinking about how many of our new personnel even knew what it meant.
I later put it out for discussion, asking, "Can anyone tell me what 'PCB' stands for?" I was advised by our younger, tech-savvy firefighters that PCB meant "printed circuit board — everyone knows that!"
When I asked if they knew about another definition for PCB, it was the older personnel who had to step in, indicating it could be time to pass old knowledge to new ears. PCBs — or polychlorinated biphenyls — are a viscous liquid, non-flammable in nature. They are very stable in that they can be heated to their boiling temperature without going through a decomposition phase or bursting into flames.
From 1930 to 1977, PCBs were utilized in commercial applications for specialized electric equipment, specifically transformers, circuit breakers, capacitors, motors and fluorescent light ballasts. They served in heat transfer and hydraulic systems and were also used in certain plastics, wax and rubber products.
It was discovered in the 1960s that exposure to PCBs could further down the line cause cancer, birth defects, liver damage, impotence and even death. In 1979, the government, through the use of the Toxic Substances Control Act, banned the manufacturing, sale and distribution of PCBs. But while PCB manufacturing ceased, companies were allowed to continue using equipment already manufactured that contained this chemical "indefinitely."
It allowed for PCB use to continue in a "totally enclosed manner;" that is, within equipment that has been designed and constructed so as to ensure no exposure of PCBs to humans or the environment. This equipment has an expected life span of 40 to 85 years. If repaired rather than completely withdrawn, law requires the replacement of the PCB fluid with a mineral oil-based fluid.
Transformers may contain upwards of 200 gallons of PCBs on average, but larger ones can conceivably contain more than 1,000 gallons. While new equipment is manufactured with the mineral oil-base, occasional routine maintenance of the units by energy company personnel on both types of units with the same hoses and pumping equipment can cause even mineral oil-based units to be contaminated with PCBs. It means firefighters must consider the possibility that equipment utilized for high voltage energized equipment may still contain PCBs until their service life is complete.
Class C fires in any setting should prompt company officers to consider the possibility of PCBs. Any call involving any high voltage equipment, arcing, electrical overloading or short-circuiting could be sufficient to ignite the cooling oil contained in the equipment containers. Fires to energized electrical equipment would not only cause vapors from burning PCBs to be released into the air, but a highly toxic byproduct of burning PCBs, polychlorinated dibenzo-p-dioxins dioxins.
Fires involving energized electrical equipment should prompt the use of full PPE, SCBA and the use of a hose line to perform a gross decon of all personnel that may have been exposed to smoke from these types of fire.
Meanwhile, any water run-off from moderate electrical fires should prompt the IC to contact local public health officials and to consider contacting water departments to advise them of possible PCB contamination in the water run-off system. Diking and damming would be thoughts to consider in reducing the environmental impacts associated with PCB contaminated water run-off.
Any PPE and equipment that comes into contact with PCBs should be considered contaminated and taken out of service. Ensure proper disposal is enacted through correct EPA disposal sites.
The Environmental Protection Agency requires all current electrical equipment that may still contain PCBs to be plainly marked. In addition, as per the EPA, owners of equipment still utilizing PCBs in any of their equipment should contact the local fire department to advise them of their presence. When was the last time you were informed of possible PCB contaminated electrical equipment in your district?
Ensure your personnel are familiar with the various PCB labels and how serious fires in this type of equipment can be. Try asking your members, "What does PCB stand for?"
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