On Friday, the state of California filed a lawsuit against five of the world's largest oil firms, alleging that their activities caused tens of billions of dollars in harm and misled the public by downplaying the hazards presented by fossil fuels.

Filed by the San Francisco Superior Court, it is the most recent and major lawsuit to target oil, gas, and coal firms for their part in creating climate change. It also demands a mitigation fund be established to pay for future losses caused by climate-related disasters in the state.

The case names five firms as defendants: Exxon Mobil, Shell, BP, ConocoPhillips, and Chevron, as well as the American Petroleum Institute, a Washington-based industry trade body. Seven other states and numerous municipalities have also sued oil and gas firms recently.

See this: Exxon downplayed global warming after 'accurate' predictions

California has been hit hard by climate-change-related severe weather, including wildfires, floods, sea-level rise, scorching heat, and even tropical storms.

Richard Wiles, the president of the Center for Climate Integrity, a nonprofit organization that tracks climate litigation, called the case the most "significant, decisive, and powerful climate action directed against the oil and gas industry in US history."

Ryan Meyers, general counsel of the American Petroleum Institute, accused the state of waging a "meritless" and politicized lawsuit, adding that Congress should decide climate policy and not the court system.

Intentionally misleading the public since 1950

The lawsuit details that, in the 1950s, the companies intentionally downplayed the risks of fossil fuels even though they knew it would facilitate global warming, in addition to claiming alternative fuel investments while profiting.

According to the complaint, the deception "caused a delayed societal response to global warming. And their misconduct has resulted in tremendous costs to people, property, and natural resources, which continue to unfold each day."

The lawsuit demands the establishment of a fund to compensate for future losses caused by climate disasters in California, which is at the forefront of climate change-fueled wildfires, floods, and other extreme weather occurrences.

California Governor Gavin Newsom remarked Friday that the lies Big Oil has been perpetrating have been ongoing "for more than 50 years."

Fossil fuel companies began facing lawsuits in 2017 and have attempted to avoid state court hearings on procedural grounds.

In May, the US Supreme Court declined to hear an appeal in two cases, indicating that they might proceed.