Polychlorinated biphenyls (PCBs) - Benchmarks, Standards and Guidelines Established to Protect Public Health

The following is a description of some the benchmarks, standards and guidelines EPA used to evaluate environmental conditions in the aftermath of the World Trade Center disaster.

Polychlorinated biphenyls, or "PCBs", have been used as coolants and lubricants in transformers, capacitors, and other electrical equipment because they are good insulators. The manufacture of PCBs was stopped in the U.S. in 1977 because of evidence they build up in the environment and can cause harmful health problems. Products made before 1977 that may contain PCBs include old fluorescent lighting fixtures, electrical devices containing PCB capacitors, and old hydraulic oils.

All measurements of airborne PCBs at sites surrounding the WTC work zone have been below EPA's screening level. The EPA screening level is set well below exposure levels shown to cause cancer in animals, as well as those associated with any other health effects. The screening level is based on continuous exposure for a year to an average concentration of 730 ng/m3*. Because measured PCB levels have been significantly lower, we do not expect increased risks of health problems as a result of PCBs from the WTC site.

The EPA screening level is set well below exposure levels shown to cause cancer in animals, as well as those associated with any other health effects.

* The unit, ng/m3, is the mass of PCBs in nanograms (a billionth of a gram) in a cubic meter of air.

View Monitoring Data for PCBs in Air