Manufacture, use and disposal of PCBs was restricted in many countries in the 1970s. Japan banned production in 1972, Canada in 1977. The Organisation of Economic Cooperation and Development (OECD) restricted their use in February 1973, and phased them out by end-1988. The OECD set the maximum permissible levels of contamination of fluids and soils at 50 parts per million (ppm). Waste or equipment containing PCBs over 100 ppm was to be disposed of by high temperature incineration without allowing their release into the environment. As a result, PCB levels in human tissue declined in a number of countries between the 1970s and 1980s.

In the US, production of PCBs was stopped and the Toxic Substances Control Act passed in 1976, strictly regulating use of PCBs. The maximum permissible level of PCBs in food items was set at 5 parts per million by the US Food and Drug Administration. As a result, levels of PCBs in human tissue declined from 12 per cent of the US population in 1979 to virtually none in the late 1980s.

But implementing the regulations has not been easy. The US Environmental Protection Agency (EPA) has found it difficult to locate thousands of PCB storage sites, and clean-up operations have proved very costly. Cleaning up a single 750-gallon (2,839-litre) spill of PCBs cost the US Department of Defense over $ 1 million. The average priority abandoned waste site cleaned up by the EPA cost it $ 6.5 million.