Regulation of PCBs at the 50 ppm Level

TSCA s ban on the manufacture, processing, and distribution of PCBs applies to all PCB concentrations in any mixture or medium. Therefore, an important first act by the EPA in implementing its PCB control program was to establish a regulatory cutoff point based on the concentration of PCBs. Because enormous amounts of PCBs were used in the past with little control on disposal practices, PCBs are widely dispersed and found worldwide at low concentrations. As explained by EPA  

Because PCBs are now so pervasive, the effect of not having a cut-off concentration would be to extend the prohibitions and other requirements of 6(e) of TSCA to almost all human activity. Many foods, such as fish and milk, as well as the human body often contain detectable concentrations of PCBs.  

In a 1978 rulemaking, the Agency initially established a 500 part per million (ppm) regulatory cutoff in order to regulate disposal of most PCBs. This was followed by another final rule in 1979, with the effective date of July 2, 1979, which lowered the 500 ppm cutoff point to 50 ppm, with the 

The court subsequently granted a joint motion by EPA and the Environmental Defense Fund for a stay of its mandate striking down the 50 ppm regulatory cutoff for 18 months, after which any party could request that the mandate issue. The EPA reacted by issuing rules that incorporated the 50 ppm cutoff, and the court hfted its stay in 1984.  

Materials with concentrations of PCBs below 50 ppm generally are not regulated under TSCA. Instances where use, disposal, or distribution is 

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