A St. Louis jury has awarded three plaintiffs a total of $46.5 million in damages in a lawsuit alleging that Monsanto and three other companies were negligent in its handling of polychlorinated biphenyls, or PCBs, a highly toxic and carcinogenic group of chemicals.

Yesterday’s 10-2 verdict in St. Louis Circuit Court awarded $17.5 million in damages to the three plaintiffs and assessed an additional $29 million in punitive damages against Monsanto, Solutia, Pharmacia and Pfizer, the St. Louis Dispatch reported.

PCBs were used to insulate electronics decades ago. Before switching operations to agriculture, Monsanto was the sole manufacturer of the compound from 1935 until 1977. The U.S. Environmental Protection Agency (EPA) banned PCBs in 1979, due to its link to birth defects and cancer in laboratory animals. PCBs can also have adverse skin and liver effects in humans. PCBs linger in the environment for many decades.

The lawsuit claims that Monsanto continued to sell the compounds even after it learned about its dangers and falsely told the public they were safe. Indeed, internal documents have surfaced showing that Monsanto knew about the health risks of PCBs long before they were banned. A document, dated Sept. 20, 1955, stated: “We know Aroclors [PCBs] are toxic but the actual limit has not been precisely defined.”