Rather than acknowledge the dangers of climate change, the lawsuit said the fossil fuel industry worked to undermine the scientific consensus around the problem "with pseudo-science, fabricated doubt, and a well-funded, sustained public relations campaign to promote their spin."

“We know that our need to mitigate, to take action, to respond in the future is going to escalate over time as climate change worsens,” said Pederson. “We really want to make sure that we have the resources to do that.”

An Oregon county is the latest US municipality to launch a legal challenge against oil producers over allegations the companies deceived consumers about the environmental dangers of fossil fuels.

The heat wave had dramatic impacts across the Pacific Northwest, where many communities lack air conditioning because of the typically mild climate. Searing temperatures crumbled streets, caused baby birds to jump to their deaths and killed millions of sea creatures along the coastline. Emergency departments were overwhelmed with patients suffering heat-related ailments.

Oregon is facing increased costs from climate related impacts including worsened air quality, increased heat related deaths and increased risk of wildfires. In a recent report, the Union of Concerned Scientists (UCS) found that the world’s 88 largest fossil fuel companies—including ExxonMobil, BP, Chevron, and Shell—and cement manufacturers are responsible for over a third of area burned by wildfires across Western North America in the last 40 years.

"Because defendants have polluted the atmosphere with enormous amounts of methane and carbon dioxide, which remain aloft for decades, and they continue to do so without restraint, extreme heat events will reoccur with increasing intensity and frequency,” the county argues in the lawsuit.

Major fossil fuel entities and trade associations including Koch Industries, the American Petroleum Institute, and the Western States Petroleum Association, as well as consulting behemoth McKinsey & Company, were slapped with the latest climate liability lawsuit today with the filing of a complaint in the Oregon Circuit Court in Multnomah County, Oregon.

The county also seeks $1.5 billion in future damages to cover costs associated with future extreme heat events as well as another $50 billion to study, plan, and upgrade public health care services and infrastructure to “weatherproof” itself against extreme heat. This would include mitigation measures such as expanding healthcare and emergency services, adding new insulation and HVAC systems to buildings, tearing out asphalt and planting more trees, among others, Pederson said.

Multnomah County, which encompasses the state's most populous city Portland, said combined historic carbon pollution from use of the companies' products -- and their decision to mislead the public about their impacts -- was a big factor in exacerbating the heat wave.

Starting in the 1970s, ExxonMobil’s own scientists found compelling evidence that the burning of fossil fuels was transforming the planet’s climate. That didn't stop them from waging a decades-long disinformation campaign — revealed in detail by Inside Climate News in 2015 — to discredit scientific consensus on climate change.

Starting on June 25 of 2021, the three day heat dome caused temperatures of 108°, 112°, and 116° Fahrenheit, shattering previous heat records and resulting in 69 fatalities.

The county is seeking $50 million in actual damages for the 2021 heat dome, $1.5 billion in future damages and $50 billion to better prepare for the changing climate.

"This is an event that is directly attributed to the impacts that we are seeing on our climate because of the actions of fossil fuel companies and their agencies that have been pressing for decades to deny climate science," County Chair Jessica Vega Pederson told the AFP.

Multnomah County and other parts of Oregon were trapped under hot air from June 24-29. For two days, temperatures were above 90 degrees and for three days, they topped 100. Portland hit a high of 116 degrees during the heat event. 

“The climate crisis is already costing us money today," said county chair Jessica Vega Pederson. "We are not looking for a payout. We're looking to be paid back."

“We are confident that, once we show what the fossil fuel companies knew about global warming and when, and what they did to deny, delay and deceive the public, the jury will not let the fossil fuel companies get away with their reckless misconduct,” Worthington said.

“While other communities are seeking to hold Big Oil accountable for the costs of hurricanes, rising seas, and wildfires, Multnomah County is the first to demand that oil companies stand trial for fueling the devastating 2021 heat dome,” said Richard Wiles, the president of the Center for Climate Integrity, in a statement. “Communities should not be forced to pay the price for these catastrophic climate damages while the companies that caused the crisis perpetuate their lies and rake in record profits.”

The 2021 event, which lasted from June 24 through 29, 2021, saw temperatures in Portland reach an unprecedented high of 116 degrees. The remarkable heat event resulted in the deaths of 69 people in Multnomah County due to hyperthermia—with loss of life taking place throughout the entire Pacific Northwest.