PCBs—which include upwards of 200 compounds—are a class of very toxic chemicals ubiquitously found in construction materials and electrical products in many buildings from the 1950s until 1978, when they were phased out. Despite the phase-out, PCBs may be found in products and materials produced before the 1979 PCB ban, such as:
Transformers and capacitors
Other electrical equipment including voltage regulators, switches, reclosers, bushings, and electromagnets
Oil used in motors and hydraulic systems
Old electrical devices or appliances containing PCB capacitors
Fluorescent light ballasts
Cable insulation
Thermal insulation material including fiberglass, felt, foam, and cork
Adhesives and tapes
Oil-based paint
Caulking
Plastics
Carbonless copy paper
Floor finishes
Because PCBs do not easily degrade, they can remain in the environment for long periods of time, accumulating in the environment and infiltrating plants, crops, fish, and small organisms. PCBs ultimately reach those who eat fish and animal products through this bioaccumulation. Because of this, nearly every human being carries some PCB in his/her body, which can also be passed from mothers to children during pregnancy and in breast milk. PCBs can remain in our bodies for many years, the longer we live, the more these toxins can build in our systems, increasing in strength over time.
Some evidence indicates that PCB manufacturers knew of the chemical’s dangers years before the 1979 ban. For example, as far back as 1937, corporate memos from Monsanto, which made Aroclor, a PCB compound, wrote about the links between PCBs and severe skin damage and acute liver atrophy in some employees. Memos from 1954 indicate that Monsanto knew that exposure to “negligible” amounts of PCB could be dangerous over time. Later, in the 1960s, Monsanto’s research confirmed that outflow from its PCB manufacturing plants contained “extremely toxic materials that killed fish in less than 24 hours.” By 1975, despite a number of scientific studies revealing that PCBs were cancer causing, the firm’s testing lab only admitted to PCBs as being “tumorigenic.” That lab was later discredited.