The federal government banned the use and production of polychlorinated biphenyls (PCBs) in 1979 after determining the chemicals are toxic. However, the state of Washington alleges that Monsanto knew as early as 1937 that the PCBs it produced were dangerous, but that company continued to allow them to pollute the state’s waterways.

In a lawsuit [PDF] filed today in a state court, Washington state Attorney General Bob Ferguson claims that Monsanto soured the state’s water for decades with the “most pervasive pollutants in U.S. history.” The state is now seeking damages from the agricultural chemicals giant to cover the cost of cleaning up the pollution.

“Monsanto is responsible for producing a chemical that is so widespread in our environment that it appears virtually everywhere we look — in our waterways, in people and in fish — at levels that can impact our health,” Washington Gov. Jay Inslee said during a press conference announcing the suit. “It’s time to hold them accountable for doing their fair share as we clean up hundreds of contaminated sites and waterways around the state.”

According to the state’s lawsuit — which also names two related companies, Solute and Pharmacia — Monsanto was the only company to produce PCBs from 1935 to 1979, when the Toxic Substances Control Act banned their manufacture.

PCBs, marketed and sold under the Monsanto brand name Aroclor, were used in many industrial and commercial applications, from paint and caulking to transformers, capacitors and coolants, among other uses.

The state claims that for decades before the Act passed, Monsanto knew of the chemical’s danger.

The lawsuit points to internal Monsanto documents going back to 1937, in which company employees allegedly warned of “systemic toxic effects” from prolonged exposure to PCB vapors. By the late 1960s, the state claims that Monsanto employees were privately citing evidence of global PCB contamination — information the company is accused of keeping from the public.

According to a 1967 memo, company officials boldly declared that there was “no practice course of action that can so effectively police the uses of the products to prevent environmental contamination.”

The company then went on to say it must work to prolong the production and sale of the chemical.

Another report from the company made it clear that profits were of more concern that pollution or health issues, noting that “there is too much customer/market need and selfishly too much Monsanto profit to go out” to cease PCB production.

“The company chose to conceal the toxicity and pervasive contamination of its chemicals in favor of profits,” the complaint states, adding that the chemical was produced for 10 more years after the report. .

The lawsuit seeks compensation for damages to the state’s natural resources, including the economic impact to the state and its residents, as well as any future costs that may result from presence of PCBs.

Ferguson says that damages could reach into the hundreds of millions of dollars or more.

While Seattle and Spokane, WA, — as well as Portland, OR, and some California cities — currently have pending lawsuits against Monsanto related to the cost of PCB contamination in water treatment, Thursday’s lawsuit is believed to be the first filed against the company by a state.

“This case is highly experimental because it seeks to target a product manufacturer for selling a lawful and useful chemical four to eight decades ago that was applied by the U.S. government, Washington State, local cities, and industries into many products to make them safer,” Scott S. Partridge, Vice President Global Strategy, Monsanto, said in a statement. “PCBs have not been produced in the U.S. for four decades, and Washington is now pursuing a case on a contingency fee basis that departs from settled law both in Washington and across the country. Most of the prior cases filed by the same contingency fee lawyers have been dismissed, and Monsanto believes this case similarly lacks merit.”

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