What Are PCBs?
Polychlorinated biphenyls, or PCBs, are a group of man-made organic chemicals made of carbon, hydrogen and chlorine atoms, according to the EPA. Because they do not burn easily, are chemically stable, have a high boiling point and insulate electricity, they were used in hundreds of industrial and commercial applications, including electrical, heat transfer and hydraulic equipment, plasticizers in paints, plastics and rubber products, and pigments, dyes and carbonless copy paper.
The EPA says PCB production was banned in 1979 by the Toxic Substances Control Act, though its rules allow some inadvertent generation of PCBs in excluded manufacturing processes, and that PCBs may still be present in products and materials made before the ban, including transformers and capacitors.
On health, the EPA says it found clear evidence that PCBs have significant toxic effects in animals, including non-human primates, and that they can affect an animal’s immune, reproductive, nervous and endocrine systems. IARC classifies both PCBs and dioxin-like PCBs as carcinogenic to humans, Group 1.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe EPA describes polychlorinated biphenyls, or PCBs, as a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. US EPA ↗
- Government sourceThe EPA says PCBs were used in hundreds of applications, including electrical, heat transfer and hydraulic equipment, plasticizers in paints, plastics and rubber, and pigments, dyes and carbonless copy paper. US EPA ↗
- Regulatory filingThe EPA says PCB production was banned in 1979 by the Toxic Substances Control Act, though its rules allow some inadvertent generation of PCBs in excluded manufacturing processes. US EPA ↗
- Government sourceThe EPA says PCBs may be present in products and materials produced before the 1979 ban, including transformers and capacitors. US EPA ↗
- Government sourceThe EPA says it found clear evidence that PCBs have significant toxic effects in animals, including non-human primates, affecting the immune, reproductive, nervous and endocrine systems. US EPA ↗
- Government sourceAn IARC working group classified both PCBs and dioxin-like PCBs as carcinogenic to humans (Group 1). International Agency for Research on Cancer ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.