POLYCHLORINATED BI-PHENYLS (PCB’s) are a common chemical hazard, in spite of the fact that use has been banned since 1979. They are widely used in older electrical equipment as an insulating (di-electric) fluid. They generally have a consistency of light machine oil. They are noted for their high resistance to electrical flow, non-reactivity and low vaporization rates.
Normally, PCBs are found in sealed electrical equipment such as capacitors and transformers, and as such, do not provide a common problem. However, if they leak from electrical components, a substantial exposure results, and the equipment
should not be handled.
Special precautions must also be taken to dispose of damaged items containing PCB. If you encounter old, discarded electrical equipment covered by an oily substance, DO NOT HANDLE IT! Notify your supervisor immediately, as the substance may be PCB. If you are accidentally contaminated by a suspected PCB fluid, wash the affected area
immediately with warm, soapy water. Do not wait!
A much greater health threat exists if PCB’s are involved in a fire. They can then vaporize which means the smoke they create can be extremely toxic. Further, PCB’s undergo chemical change and break down into various DIOXINS or FURANS, which are some of the most toxic substances known to man—even more deadly than cyanide.
Do not fight fires in electrical service rooms, or any affected electrical equipment, if PCB’s are present or suspected! Personnel in the immediate area should be evacuated upwind, and out of range of the smoke. Under no circumstances should attempts at fire fighting be made inside a building that contains burning PCB’s except to save human life trapped inside—and then only by firefighters with proper equipment and training. Not only can DIOXINS be breathed, but they
can also be absorbed through the skin.
Evidence regarding the cancer-causing propensities of PCB’s is conflicting. NIOSH lists PCB’s as a “suspected” carcinogen. However, if altered by fire into a DIOXIN state, they are deadly. Even after a PCB fire is extinguished, severe hazards remain. The soot, ash and fire fighting residues will all contain toxic material, so clean-up should be completed only by specially trained and equipped specialists.
The way to avoid the problems posed by a world containing PCB’s is to AVOID CONTACT, and by using extraordinary measures of fire protection. Use good housekeeping, Keep combustibles away from electrical panel boxes and the like. Keep dry chemical fire extinguishers available to extinguish small fires near electrical equipment. Post fire watches when welding near electrical components.
PCB’s are a serious hazard that warrants precaution.Take great care to avoid exposure!