After years of delays, some oil companies are about to stand trial in lawsuits brought by state and local governments about damages caused by climate change.

There are more than 30 cases filed by state attorneys general, cities, counties and tribal nations against companies including Exxon Mobil, BP and Shell, according to the nonprofit Center for Climate Integrity, whose president, Richard Wiles, told Stateline, “It’s all building toward more cases in more places using more legal theories to hold these companies accountable.”

Active cases have been brought by Boulder County, Col., California, Massachusetts, Michigan, Minnesota and New York City. Many show oil companies’ own research projecting the dangers of climate change decades ago, after which the industry denied the threat and attacked scientific consensus about the crisis.

Investigations in 2015 from the Los Angeles Times and Inside Climate News showed that companies like Exxon knew about the dangers of greenhouse gas emissions for decades, but minimized those threats, reported Grist. And in April, the GOP-majority House’s Committee on Oversight and Accountability conceded “the extensive efforts undertaken by fossil fuel companies to deceive the public and investors about their knowledge of the effects of their products on climate change and to undermine efforts to curb greenhouse gas emissions.”

Elsewhere, governments themselves are being sued for violating human rights and for failure to protect everyday people (Maine Youth Action, the Sierra Club and the Conservation Law Foundation are suing that state).

Finally, lawmakers are considering seeking financial compensation from oil companies, based on research linking costly damages and fossil fuel emissions. “This is a growing field,” said Delta Merner, the lead scientist for the nonprofit Union of Concerned Scientists’ Science Hub for Climate Litigation. “It has a role to play in litigation and in policy, because it gives us that precision.”