Is the oil industry accountable for contributing to the extreme heat that caused a woman’s death?
This question is central to an unprecedented lawsuit in Washington state. In June 2021, Misti Leon’s mother succumbed to heatstroke on the hottest day recorded in the state’s history, with temperatures soaring to 108 degrees Fahrenheit. Scientists have noted that the rare heat dome over the Pacific Northwest would have been “virtually impossible” without the impacts of climate change. Last year, Leon filed a wrongful death lawsuit against Exxon Mobil, BP, Chevron, Shell, and other major oil companies, claiming they had long been aware of the harmful effects of fossil fuel emissions but misled the public, delaying necessary actions that could have saved her mother. During that intense week in June, an estimated 1,200 people in the region died due to the heat.
Earlier this month, a judge in King County decided against the oil companies’ attempts to dismiss Leon’s case, allowing it to move forward to trial. Mike Meno, communications director at the Center for Climate Integrity, a nonprofit that supports climate accountability cases, interpreted this decision as an indication of the case’s validity. “It’s a new form of legal liability that terrifies the oil companies, and they will vigorously contest it,” he stated.
Over a decade has passed since investigations revealed that Exxon Mobil understood the risks of global warming as early as the 1970s but publicly minimized the danger. Since then, lawsuits against oil companies have multiplied. According to Margaret Barry, who oversees a climate litigation database at Columbia Law School’s Sabin Center, nearly 40 such cases are pending nationwide. Despite the oil industry’s delay tactics, at least five lawsuits — from Massachusetts, Vermont, Connecticut, the District of Columbia, and Honolulu — have reached the discovery phase, where both parties gather evidence to support their cases. This phase is the last major step before a trial, during which oil executives would have to defend their actions before a jury.
Some cases are paused as courts await the Supreme Court’s decision on a lawsuit from Boulder, Colorado, this fall. Boulder city and county claim Exxon Mobil and Suncor Energy broke state laws by hiding the hazards of their products, seeking compensation for the escalating costs of infrastructure improvements to manage heatwaves, wildfires, and floods. The decision could influence current climate lawsuits or encourage plaintiffs to seek alternative strategies.
Meanwhile, the oil industry is actively fighting back against these lawsuits with support from the Trump administration and Republican lawmakers. The American Petroleum Institute, the largest lobbying group for the oil industry, has declared that a top priority for 2026 is to “halt extreme climate liability policy.” The industry is also challenging “attribution science,” which aims to quantify how climate change, and even emissions from specific companies, have intensified extreme weather.
These developments indicate the industry feels threatened, according to Meno. “Simply put, Big Oil is in panic mode.”
Republicans are working to pass legislation granting oil companies immunity from such lawsuits, successfully doing so in several states. Utah, Iowa, Tennessee, Oklahoma, and Louisiana have enacted laws protecting fossil fuel companies from lawsuits related to greenhouse gas emissions. Montana and Utah have amended existing laws to narrowly define “public nuisance,” effectively blocking climate change-related lawsuits against oil companies under this legal theory. Nationally, Republicans in Congress proposed bills this spring to provide broad immunity to oil companies from climate damage lawsuits, with support from the American Petroleum Institute.
In April, a ProPublica investigation uncovered a coordinated effort behind these “liability shield” laws, led by conservative groups associated with activist Leonard Leo. Information from the watchdog group Fieldnotes reveals extensive connections between Koch Industries, Exxon, and the organizations advocating for these laws, including the American Legislative Exchange Council and the American Tort Reform Association.
Meno questioned, “If these companies are innocent and believe the law supports them, why are they lobbying Congress for immunity?”
Oil companies have also received federal assistance, following an executive order from President Donald Trump directing the attorney general to focus on blocking state climate lawsuits. In May, the Justice Department countered Minnesota’s climate lawsuit against Big Oil with a lawsuit of its own, just as the case entered the discovery phase. The department argued that Minnesota’s actions undermined “American energy dominance” and attempted to regulate greenhouse gases, a matter it claimed should be governed by federal law. Notably, Robert Levy, an Exxon lawyer, recently joined the Department of Justice in its newly named “Energy and Natural Resources Division”, a rebranding from the “Environment and Natural Resources Division.”
As oil companies delay these lawsuits, scientific evidence supporting these cases has strengthened. A recent report from the National Academies of Sciences, Engineering, and Medicine suggests that scientific links between climate change and extreme weather, particularly extreme heat, cold, and heavy rainfall, have become more robust. Although the report does not offer recommendations on using these findings, it has attracted unusual scrutiny. Last month, prior to the report’s release, the opposition research firm Argus Insight requested access to internal communications among panel members involved in the report and any emails they may have exchanged with academics and lawyers working on climate litigation strategies.
“The opposition wasn’t against the science itself, but the process,” said Carly Phillips, a senior scientist at the Union of Concerned Scientists’ climate litigation hub. “This was telling to me because the science is robust.” She perceives the opposition as an effort to undermine scientific evidence before it can be presented in court.
Earlier this year, Republican attorneys general pressured the National Academies of Sciences and the Federal Judicial Center, a research agency for federal judges, to remove a chapter on climate science from their updated reference manual for judges; only the Judicial Center complied. Trump entered the discussion on Sunday, instructing officials to review the National Academies of Sciences’ conduct. “Our Taxpayers should not be funding Climate Fraud, and Judges should never have relied upon it,” Trump wrote on Truth Social.
The oil industry appears to be trying to avoid the outcome faced by Big Tobacco, which paid hundreds of billions in settlements after lawsuits proved they lied about smoking’s health risks. As legal strategies evolve for those seeking to hold oil companies accountable for global warming, the fossil fuel industry must adapt, explained Justin Anderson, a lawyer for Exxon, during a panel on climate litigation hosted by the Federalist Society last 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.”
