Two days after California governor Jerry Brown extended a landmark climate change law, three municipalities in the state are suing 37 oil, gas and coal companies for negligence and public nuisance.

Courthouse News Service reports that Marin and San Mateo counties near San Francisco and the city of Imperial Beach filed three separate lawsuits in three separate California superior courts on Monday (July 16) against Exxon, Shell and 35 other firms. The suits claim that these companies knowingly emit dangerous greenhouse gases that contribute to global warming, which threatens their communities with sea level rise.

According to Inside Climate News, the lawsuits allege that approximately one-fifth of the state’s total emissions from 1965 to 2015 were caused by these corporations. From the article: “The lawsuits contend that the companies ‘concealed the dangers, sought to undermine public support for greenhouse gas regulation, and engaged in massive campaigns to promote the ever-increasing use of their products at ever greater volumes.’”

This is not the first time that municipalities have attempted to sue companies for negligence and public nuisance related to greenhouse emissions. But of particular interest in these cases is the accusation that the companies failed to warn the public that what they were producing was harmful.

The lawsuits, while difficult to prove, are not impossible to win, says a legal expert who spoke with Inside Climate News. “It’s easy enough to say these companies pulled fossil fuel out of the ground,” said Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia University. “Proving that these particular emissions that came from these fossil fuel companies led to this particular level of sea level rise and contribute X amount to harms that have happened or will happen—that’s a long chain of causation.”

The counties and city of Imperial Beach are looking for monetary compensation for climate change-related costs.

“Sea level rise is harming Imperial Beach and threatening our future,” said Serge Dedina, mayor of Imperial Beach, which has a 49 percent Latinx population. “As a low-income coastal community, we have no capacity to pay for the adaptation measures needed to protect ourselves from these impacts. It is unfair to force citizens, business owners and taxpayers to fend for ourselves when the source of the problem is so clear.”