PCB-containing electrical equipment in surface and underground mines has been documented during U.S. Environmental Protection Agency (EPA) Region 8, mine inspections conducted over the last 25 years.  PCB-containing electrical equipment is likely to be in mines world-wide because electrical systems in mines follow the same general patterns as any other industry.  The abandonment of this equipment is likely to contribute to world wide PCB contamination. Despite the fact that manufacture of PCBs has been prohibited in the US and many other countries, PCBS are still authorized by the PCB regulations for use in electrical equipment, primarily as dielectric fluids (or contaminants in dielectric fluids).  The mining industry has been an extensive user of PCB-containing electrical equipment, and some of this equipment continues to be abandoned both underground and on the surface.  PCBS are among the 12 chemicals designated as persistent organic pollutants (POPs) that are targeted by the UN Stockholm Convention of May 2001, when 90 nations, the US, and the EC agreed to reduce or eliminate PCB production, use, and/or release.  POPs are highly stable toxic organic compounds that persist in the environment and accumulate in fat.  PCBs are one of several truly global environmental pollutants. The oceans are the largest “sink” of PCBS, the consequences of which remain unknown.  The median bioconcentration factors for PCBs from water into phytoplankton are between 10,000 and 1,000,000. Phytoplankton are basis of the ocean food chain and are the major source of atmospheric oxygen.  The health of ocean phytoplankton concentrations is likely to be an issue in climate change.