This story was updated at 6 p.m. PST

The City of Seattle is suing Monsanto for manufacturing a cancer-causing chemical  that’s contaminating the city’s Duwamish Waterway.

Monsanto was the sole producer of the chemicals PCBs from the 1930s through the ‘70s. They were used globally to make coolants, paints, lubricants and for other industrial purposes. PCBs also served a fire protection and safety protection for the electrical and other industries, according to the company.

In the lawsuit filed Monday, the city alleges that Monsanto continued to produce PCBs long after it knew the chemicals were dangerous to human health. Therefore, the company should help pay for the cleanup.

Monsanto spokeswoman  Charla Lord said the company is reviewing the lawsuit and its allegations.

“However, Monsanto is not responsible for the costs alleged in this matter,” she wrote in an email. “PCBs sold at the time were a lawful and useful product that was then incorporated by third parties into useful products. If improper disposal or other improper uses allowed for necessary clean up costs, then these other third parties would bear responsibility for those costs.”

The Lower Duwamish waterway is a Superfund site that will cost more than $300 million to decontaminate. The City of Seattle will be paying for part of the cleanup as well as for the construction of a new stormwater treatment plant.

Seattle and Spokane are among six western cities that have sued Monsanto over PCB contamination.