PBT photo identifier


What are Polychlorinated Biphenyls (PCBs)?

New Publication on inadvertent generation of PCBs in pigments.

PCBs are a group of 209 manmade compounds that generally occur as complex mixtures. While the largest use of PCBs was in electrical equipment, there are many other sources of PCBs. PCBs are very persistent, lasting for decades in the environment. Like other persistent, bioaccumulative, and toxic (PBT) chemicals, PCBs are transported long distances and generally move easily between air, water and land, so they are found throughout Washington. PCBs also accumulate in organisms, becoming more concentrated in organisms like orcas at the top of the food chain.

One of the major ways people are exposed to PCBs is through our diet, such as eating fish that contain PCBs. PCBs have been shown to have toxic effects to the immune, reproductive, nervous, and endocrine system in humans and other organisms. PCBs also cause cancer in animals, and are considered likely to cause cancer in humans.

Bioaccumulation of PCBs

Bioaccumulation of PCBs
(Image courtesy of Seattle Post Intelligencer)

PCBs were produced for commercial uses from about 1929 to 1977. The 1976 Toxic Substances Control Act (TSCA) bans certain uses and restricts PCB concentrations to low levels. The largest use of PCBs was for heat transfer fluids in electrical transformers and capacitors. PCBs were also used as plasticizers, wax and pesticide extenders, and lubricants. Many products used to contain PCBs at high levels, such as carbonless copy paper and caulk used to seal cracks in homes and buildings.

PCBs are still found in old products produced before commercial production of PCBs ended, such as in electrical transformers. They can also be found in new products as a contaminant or intentionally added below regulated levels. There is still inadvertent production of PCBs during manufacturing of chemicals such as dyes and pigments.

Why are we doing a PCB Chemical Action Plan (CAP)?

PCBs are a current priority for Ecology in several geographic areas such as the Lower Duwamish Waterway, the Spokane River, the Wenatchee River, and Lake Washington. Ecology also estimated releases of PCBs to the Puget Sound basin as part of the Puget Sound Toxics Loading Study.

Concerns are growing about PCBs as a contaminant in new products. Ecology is also working to develop human health criteria for water quality standards, and PCBs are a key chemical of concern in this process. A PCB CAP will take an inclusive look at the sources of PCBs in Washington and make recommendations to reduce exposures.

CAP development

Ecology convened an Advisory Committee to develop the PCB Chemical Action Plan. The role of the committee is to provide information, share stakeholder perspective, and contribute to identifying solutions. The Departments of Ecology and Health are responsible for the final CAP, but input from the committee and others is essential to developing findings and recommendations.