PCBs: The Electrical Industry's Toxic Legacy in Our Water and Bodies

Polychlorinated biphenyls are a family of 209 compounds — congeners — synthesised by adding chlorine atoms to biphenyl. Their industrial properties were extraordinary: extraordinarily stable, extraordinarily resistant to heat and electrical conduction, extraordinarily useful as dielectric fluids in electrical transformers, capacitors, and hydraulic fluids. Monsanto manufactured them under the trade name Aroclor; the US military used them extensively; they were embedded in the electrical infrastructure of every developed nation.

They were also known, within years of their commercial introduction in the 1930s, to cause serious health effects. Workers in PCB manufacturing plants and in industries that used them regularly developed chloracne — the disfiguring skin condition caused by chlorinated aromatic compounds — and liver disease. Monsanto's internal toxicology documents, revealed in litigation, showed awareness of these effects from the 1930s onward.

What PCBs share with asbestos, lead, and PFAS is not just toxicity — it is the pattern of concealment, the deliberate withholding of internal science from workers and the public, the funding of industry-friendly research to contest the independent findings, and the decades-long delay between what industry knew and what was publicly acknowledged.

The town of Anniston, Alabama sits alongside the only US Monsanto facility that manufactured PCBs, which operated from 1929 to 1971. What happened in Anniston is the most concentrated example of PCB corporate concealment documented in the United States.

For decades, Monsanto discharged PCBs into Snow Creek and Choccolocco Creek, which ran through predominantly Black neighbourhoods near the plant. Internal documents later produced in litigation showed that Monsanto knew the extent of contamination by the 1960s.

One internal memo from 1966 described dumping PCBs in the town's creek: a Monsanto employee watched a group of fish exposed to the discharge "turn belly up" within 10 seconds, shudder violently, and float downstream dead. The memo concluded: "We must protect ourselves from an uncontrolled situations such as the one in Anniston." The solution was not to stop discharging. It was to manage the public relations problem.

The health consequences When researchers finally surveyed Anniston residents in the late 1990s, they found PCB blood levels in Black Anniston residents that were, on average, approximately 27 times higher than national levels. The health disparities in the community — elevated rates of diabetes, neurological symptoms, and immune dysfunction — were consistent with the known effects of high PCB body burden.

The legal outcome In 2003, Solutia (the Monsanto spinoff that inherited the PCB liability) and Pharmacia agreed to a $700 million settlement with 20,000 Anniston residents — at the time, one of the largest environmental tort settlements in US history.

Two mass poisoning events in Japan and Taiwan in the late 20th century provided the most direct evidence of what high-level PCB exposure does to human health.

Yusho Disease, Japan, 1968 In 1968, approximately 14,000 people in western Japan consumed rice oil contaminated with PCBs (and related compounds including polychlorinated dibenzofurans) that had leaked from a heating system during manufacturing. The resulting condition — Yusho disease — produced chloracne, dark pigmentation, eye discharge, neurological symptoms, immune dysfunction, and elevated cancer rates. Children born to mothers with Yusho had lower birth weight, dark skin pigmentation at birth (darkening from chloracne), and developmental delays.

Yucheng Disease, Taiwan, 1979 Eleven years later, the same contamination scenario repeated in Taiwan — rice oil contaminated with PCBs and PCDFs affected approximately 2,000 people. Yucheng children born to exposed mothers showed persistent cognitive deficits, behavioural difficulties, and delayed development documented for over two decades after the event — providing the most extensive human prospective evidence for PCB's neurodevelopmental effects.

The population-level relevance These mass poisoning events involve exposures far higher than background environmental levels. Their relevance to general population PCB exposure is indirect — they provide mechanistic evidence for the types of effects (neurodevelopmental, immunological, hepatic) that environmental PCB research has subsequently found associations with at lower exposure levels.

Despite the 1977 US ban on PCB production, PCBs remain ubiquitous in the environment and in human bodies — a consequence of their extraordinary environmental persistence and their global dispersal during four decades of industrial use.

Current exposure routes • Fatty fish from contaminated water bodies — particularly Great Lakes fish, farmed salmon from PCB-contaminated feed, and some ocean species • Old electrical equipment — transformers and capacitors manufactured before 1979 may still be in service • Building materials — PCBs were used in caulking, paints, and fluorescent light ballasts in buildings constructed before 1979; renovation and demolition can release them • Breast milk — PCBs transfer from maternal fat stores to nursing infants

The NHANES biomonitoring picture NHANES data shows PCBs detectable in virtually all American adults over 40 — reflecting both current and historical exposure from before the ban. Concentrations have declined significantly since the ban but have not reached zero.

For PollutionProfile users If your work or residential history has involved proximity to old electrical infrastructure, PCB-contaminated waterways (particularly the Hudson River, Great Lakes, and other documented PCB hotspots), or pre-1979 building renovation, PollutionProfile's Historical Exposure Recorder is the tool for documenting that history. PCB exposure at concentrations associated with elevated body burden warrants discussion with a physician about monitoring for thyroid function, liver enzymes, and immune function markers — the target organ systems most consistently affected in the epidemiological literature.