Monsanto may be looking forward to turning a new leaf with its potential $66 billion mega-merger with Bayer AG, but the agrochemical giant just can't shake its notorious past as the primary manufacturer of highly toxic and banned substances called polychlorinated biphenyls, or PCBs, that were once used for paints, electrical equipment and other products.

Monsanto manufactured about one billion pounds of PCBs for between the 1930s-70s before the U.S. Environmental Protection Agency (EPA) banned the chemical in 1979. PCBs are harmful to humans, wildlife and the environment. To this day, the toxins are dispersed throughout landfills, water bodies and even in the deepest part of the ocean.

In recent years, eight West Coast cities, the Port of Portland as well as Washington state have taken legal action against Monsanto to recover PCB cleanup costs. In Washington, for instance, Attorney General Bob Ferguson said that the state has spent tens of millions of dollars on cleanup efforts in bays, rivers, streams, sediment, soil and air throughout the state, all while the pollutants cause harm to protected salmon and orcas.

Monsanto has been dismissive of the lawsuits for a number of reasons, including "having nothing to do with the company's current business."

But the litigation is gaining momentum. Earlier this month, a California federal judge denied Monsanto's motion to dismiss separate public nuisance lawsuits filed by the cities of San Jose, Oakland and Berkeley. The cities are suing Monsanto for costs associated with PCB cleanup and stormwater system retrofit damages.

The cities also allege that Monsanto knew for decades that PCBs were dangerous but continued to sell them anyway. As stated in U.S. District Judge Edward J. Davila's Feb. 3 order, an internal Monsanto report identified PCBs as "nearly global environmental contaminants" but urged "a number of actions which must be undertaken to prolong the manufacture, sale and use of these particular Aroclors," which was the trade name of commercial PCB mixtures. Furthermore, an internal memo declared that despite the hazards of PCBs, Monsanto "can't afford to lose one dollar of business."

Judge Davila based his decision on California's new water code that gives cities a right to capture stormwater and put it to use.

"As cities are using stormwater for beneficial purposes, they have a right to recover for stormwater retrofit damages due to these PCBs," plaintiffs' attorney John Paul Fiske explained to EcoWatch. "Prior to the presence of PCBs, stormwater systems did not need to account for PCBs. Now that we have to account for PCBs, we have to spend extra money in order to remove or reduce or just basically manage the presence of PCBs in stormwater."

"What we've alleged is that the presence of PCBs in stormwater and large water bodies is a public nuisance because it disallows or interferes with the public's right to engage in normal public activities like fishing or bathing or swimming," he added.

Judge Davila ruled that the cities could continue to pursue damages against Monsanto. Monsanto may now file a motion to dismiss or stay this case.

Fiske's California-based law firm Gomez Trial Attorneys as well as Texas-based Baron & Budd are also representing San Diego, Long Beach, Seattle, Spokane, Portland, the Port of Portland and Washington state.

EcoWatch spoke with Fiske over the phone about the recent Northern California ruling.

Q. Monsanto has since shifted business operations to agriculture. Why should it be liable for something that they no longer manufacture?

A. Part of it is a factual answer and part of it is a legal answer. The factual answer is that Monsanto was, always has been, and always will be a chemical company. I'm not really sure what it means to be an agricultural company when one of the main products are GMO seeds that are not natural or pesticides such as glyphosate and Roundup. So the idea that Monsanto is not in the chemical business anymore is just not true. They are very much a chemical company and always has been dating back to things like Agent Orange.

The second issue is the legal answer. Corporations can play games all they want but they remain liable and responsible for the chemicals they produce. Companies can spin off, they can merge, they can come together, they can split apart. But so long as we can trace these chemicals back to the original manufacturer, which was old Monsanto then they are liable.

So that's why we're suing Monsanto, Pharmacia and Solutia. Because all companies come from the original Monsanto company and therefore they all maintain the same liabilities for PCBs.