The Monsanto Corporation is in legal crosshairs over polychlorinated biphenyl chemicals, or PCBs, dumped in Los Angeles waterways until 1979, The LA Times reported. 

The city of Los Angeles filed suit against Monsanto at the beginning of March for allegedly knowingly polluting waterways in the nation’s second-largest city. Monsanto is named in the lawsuit along with its parent company, Bayer AG. Eastman Chemical subsidiary, Solutia, Inc. and the Pfizer subsidiary Pharmacia LLC are also named as defendants in the lawsuit.

PCBs are a class of chemicals that do not break down easily. Used in industrial applications including fireproofing and lubricating machinery, PCBs were developed by Monsanto and had been used since the 1930s until they were banned in the U.S. in 1979. Long-term exposure to PCBs has been associated with cancer and neurological developmental problems. 

Los Angeles is accusing Monsanto of failing to issue a warning to the city about the hazards PCBs posed to the health of humans, animals and the environment. Despite their ban over four decades ago, PCBs may still be present in waterways because they take a very long time to break down. 

As early as the 1950s, LA city officials allege that Monsanto knew about the environmental and human health risks associated with PCBs, according to leaked internal documents released in 2002. During that era, Monsanto ordered its staff not to eat near the chemicals. 

LA city officials are seeking compensation from Monsanto for the costs associated with the cleanup of local waterways such as the LA River. 

"It's time for Monsanto to clean up and pay up," said Los Angeles City Attorney Mike Feuer, on "The health and environmental impacts of PCBs -- impacts the city has been working hard to reduce in waters throughout LA -- are just jaw dropping. We allege Monsanto knew decades ago that PCBs are toxic and inevitably would cause widespread contamination," said Feuer, adding, “It's infuriating that Monsanto continued to manufacture and sell them -- and, we allege, deceive the public about them."

The complaint filed by Feuer claims that Monsanto dominated the PCB chemical market, accounting for over 99 percent or more of all the PCBs used or sold in the U.S. between 1929 and 1977. In addition, the complaint alleges that Monsanto engaged in deceptive practices in order to prolong the use of the controversial chemicals. 

Monsanto and its parent company, Bayer, face approximately 30,000 unresolved Roundup lawsuits after settling roughly 95,000 cases for $11 billion.