Fluorescent light ballasts manufactured before 1984 can contain small quantities of Polychlorinated Biphenyls (PCBs). Ballasts made without PCBs are labeled "PCB-free." If it's not labeled, assume the ballast contains PCBs.
PCBs are a hazard if the ballasts leak, are burned in a fire (producing dioxins), or if they are disposed of improperly. PCBs are liquid, and are easily absorbed into the bloodstream through the skin, eyes, or mucous membranes, so special precautions should be taken when handling them.
Workers chronically exposed to PCBs are at increased risk for certain health problems. The main health effect is a form of dermatitis called Chloracne.
PCBs can also cause skin irritation and nervous system depression (effects similar to solvent overexposure), and can also affect liver function. The International Agency for Research on Cancer says that PCBs are "probably carcinogenic to humans."
What to do:
-- Inspect ballast for leaks or damage before you handle it.
-- Wear proper protective equipment: safety glasses or goggles and gloves made of Butyl, Neoprene, Teflon, Viton, Saranex, or Barricade.
-- Wash hands thoroughly with soap and water
* immediately after handling contaminated materials
* if you get the oil on your hands
* before eating, smoking, or using the washroom.
-- Dispose of PCB-containing ballasts properly according to local Regulations.
-- Remove contaminated clothing before leaving the work site and launder separately or dispose of it.
-- Do not smoke, eat, or drink in the work area.
-- Protect the ballasts from open flame or fire.
More information on PCBs from Environment Canada:
www.ec.gc.ca/pcb/eng/index_e.htm 
