Bayer’s Monsanto unit agreed Friday to pay $650 million to settle environmental contamination lawsuits brought by four major US cities — Chicago, San Diego, Baltimore, and Portland — over the presence of polychlorinated biphenyls (PCBs) in their waterways, stormwater systems, and municipal infrastructure.
PCBs were industrial chemicals widely used in electrical equipment and building materials from the 1930s until they were banned in 1979. Monsanto was the sole US manufacturer of PCBs for most of that period. The chemicals are persistent in the environment, accumulate in fish and wildlife, and are classified as probable human carcinogens linked to liver cancer, thyroid disorders, and developmental delays in children.
The Cities’ Claims
Each city alleged that Monsanto sold PCBs to manufacturers of caulk, paint, and fluorescent light ballasts with full knowledge that the chemicals would eventually leach into municipal stormwater systems and waterways. The cities have spent hundreds of millions of dollars testing, monitoring, and in some cases removing PCB-contaminated materials from public infrastructure.
Chicago’s lawsuit alleged PCBs in caulk used in over 600 public school buildings constructed between 1950 and 1979. Portland’s suit focused on PCB contamination in the Willamette River traced to industrial discharges decades ago.
Settlement Terms
The $650 million is split across the four cities based on documented remediation costs and population affected. Chicago receives the largest share at $240 million. The funds must be used for environmental remediation and public health monitoring programs.
Monsanto denied liability but agreed to the settlement to “avoid protracted litigation.”
Ongoing Litigation
Dozens of other municipalities, school districts, and states have filed similar PCB lawsuits against Monsanto. Washington State reached a $95 million settlement in 2024, and litigation continues in New Mexico, Ohio, and Massachusetts.