Could the oil industry be held responsible for fueling the extreme heat that led to a woman’s death?
That’s the question at the heart of a novel lawsuit in Washington state. Misti Leon’s mother died from overheating during the hottest day in state history in June 2021, when temperatures climbed to 108 degrees Fahrenheit. Scientists said the unusual heat dome that descended on the Pacific Northwest would have been “virtually impossible” without climate change. So last year, Leon sued Exxon Mobil, BP, Chevron, Shell, and other oil majors for wrongful death, alleging that they had known for decades that fossil fuel emissions would lead to destructive consequences, but deceived the public about it, delaying action that could have prevented her mother’s death. An estimated 1,200 people in the region perished from the heat during that simmering week in June.
Earlier this month, a King County judge ruled against the oil companies’ motions to dismiss Leon’s lawsuit, allowing it to proceed toward trial. The ruling was a signal that this kind of case has merit, said Mike Meno, the communications director at the Center for Climate Integrity, a nonprofit supporting climate accountability cases. “It’s the latest type of legal liability that the oil companies are absolutely terrified of and are going to fight like hell to try to escape,” he said.
More than a decade after investigations found that Exxon Mobil had known about the dangers of global warming since the 1970s but publicly downplayed the threat, lawsuits against oil companies have proliferated. There are nearly 40 of these cases pending across the country, according to Margaret Barry, who manages a climate litigation database at Columbia Law School’s Sabin Center. After years of delay tactics from the oil industry, at least five of these lawsuits — from Massachusetts, Vermont, Connecticut, the District of Columbia, and Honolulu — have proceeded to the discovery stage, in which both sides try to uncover evidence to bolster their case in court. That’s the last major step before a trial, when oil executives would be forced to defend their actions in front of a jury.
Some cases are on hold as judges wait to hear how the Supreme Court handles a lawsuit from Boulder, Colorado, this fall. The city and county of Boulder allege that Exxon Mobil and Suncor Energy violated state laws by concealing the dangers of their products and they want money to pay for the rising costs of improving infrastructure to deal with heat waves, wildfires, and floods. The outcome could affect existing climate lawsuits, or push plaintiffs to take different approaches.
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In the meantime, the industry has been mobilizing a counterattack against the lawsuits with the help of the Trump administration and Republican politicians. The American Petroleum Institute, the oil industry’s biggest lobbying group, has said that one of its priorities for 2026 was to “stop extreme climate liability policy.” The industry has begun challenging “attribution science,” a rapidly developing field that seeks to quantify how climate change, and even emissions from specific companies, have intensified extreme weather.
The flurry of activity suggests that the industry feels like it’s under threat, Meno said. “Quite simply, Big Oil is in panic mode.”
Republicans are trying to pass laws to grant oil majors immunity to these kinds of lawsuits, with success in several states so far. Utah, Iowa, Tennessee, Oklahoma, and Louisiana have recently signed laws shielding fossil fuel companies from lawsuits related to greenhouse gas emissions, while Montana and Utah (again) reformed existing laws to narrowly define what counts as a “public nuisance,” effectively blocking lawsuits against oil companies to recover damages from climate change under that legal theory. The effort has gone national: Republicans in both chambers of Congress introduced bills this spring that would give oil companies broad immunity from lawsuits seeking to hold them accountable for climate damages, with the backing of the American Petroleum Institute.
In April, an investigation from ProPublica revealed a coordinated effort behind these “liability shield” laws from conservative groups tied to the activist Leonard Leo. Evidence provided to Grist from the watchdog group Fieldnotes shows that Koch Industries and Exxon, in particular, have extensive ties to the organizations pushing for these laws, including the American Legislative Exchange Council and the American Tort Reform Association.
“If these companies have done nothing wrong and they think the law is on their side, why are they lobbying Congress for immunity?” Meno said.
Oil executives have also gotten help from the federal government, following an executive order from President Donald Trump last year directing the attorney general to prioritize blocking climate lawsuits by states. This May, the Justice Department responded to Minnesota’s climate lawsuit against Big Oil with a lawsuit of its own, just as the state’s case was moving into the discovery phase. It said Minnesota was undermining “American energy dominance” and attempting to regulate greenhouse gases, which should fall under the purview of federal law — echoing the oil industry’s well-known argument. In a related development, Robert Levy, a longtime Exxon lawyer, recently joined the Department of Justice in the newly dubbed “Energy and Natural Resources Division” (instead of the “Environment and Natural Resources Division”).
As oil companies have worked to delay these lawsuits, the scientific backing supporting some of these cases has gotten stronger. A new, major report from the National Academies of Sciences, Engineering, and Medicine concludes that the existing science linking climate change to extreme weather has become increasingly robust, particularly for extreme heat, extreme cold, and heavy rainfall. Though the report doesn’t make recommendations about how the findings should be used, it has drawn an unusual level of scrutiny. Last month, ahead of the report’s release, the opposition research firm Argus Insight requested to see internal communications between the members of the panel working on the report and any emails they might have exchanged with academics and lawyers involved in researching legal strategies for climate court cases.
“We saw pushback to not the science itself, but the process,” said Carly Phillips, a senior scientist at the Union of Concerned Scientists’ climate litigation hub. “For me, that was really illustrative, because the science is really sound.” She sees the opposition as an attempt to discredit scientific evidence before it has a chance to be heard in court.
Earlier this year, Republican attorneys general pressured the National Academies of Sciences and the Federal Judicial Center, the research agency for federal judges, to remove a chapter on climate science from their updated reference manual for judges, but only the Judicial Center complied. Trump entered the debate on Sunday, ordering officials to review the conduct of the National Academies of Sciences. “Our Taxpayers should not be funding Climate Fraud, and Judges should never have relied upon it,” Trump wrote on Truth Social.
Big Oil ostensibly hopes to avoid the fate of Big Tobacco, which paid hundreds of billions of dollars to settle lawsuits demonstrating that companies lied about the health risks of smoking. As the legal theories for those seeking to hold oil companies accountable for global warming evolve, the fossil fuel industry has to keep up, Justin Anderson, a lawyer for Exxon, explained at a panel on climate litigation held by the Federalist Society in November.
“Why do they keep adapting and changing their theories?” Anderson asked. “It’s kind of obvious. I have to win every time. I have to win every case that is brought. They just need to find one they can get through.”
