The federal government announced a $241.5 million settlement with Marathon Oil on Thursday for alleged air quality violations at the company’s oil and gas operations in the Forth Berthold Indian Reservation in North Dakota.

The Environmental Protection Agency and Department of Justice said the settlement requires Marathon to reduce climate- and health-harming emissions from those facilities and will result in over 2.3 million tons worth of pollution reduction.

“This historic settlement — the largest ever civil penalty for violations of the Clean Air Act at stationary sources — will ensure cleaner air for the Fort Berthold Indian Reservation and other communities in North Dakota, while holding Marathon accountable for its illegal pollution,” said Attorney General Merrick B. Garland.

Marathon officials did not immediately respond to a request for comment. Houston-based Marathon operates 169 well pads in North Dakota, where the company extracts oil and natural gas.

While Marathon is the country’s 22nd-largest oil producer based on 2022 data, the federal agencies said, it’s also the seventh-largest emitter of greenhouse gas emissions in the oil and gas industry. Much of its emissions come from flaring, the industry practice of burning off waste gases, which also releases methane, a particularly potent contributor to climate change.

The settlement calls for Marathon to eliminate the equivalent of over 2.25 million tons of carbon dioxide emissions over the next five years, which the agencies said was tantamount to taking 487,000 cars off the road for one year, and will also eliminate nearly 110,000 tons of volatile organic compound missions.

The agencies said the case is the first of its kind against an oil and gas producer for “violations of major source emissions permitting requirements under the Clean Air Act’s Prevention of Significant Deterioration program.” They also said it’s the largest-ever penalty imposed for “stationary source violations,” which include facilities such as oil and gas tank systems.

The complaint alleged that these and other Clean Air Act violations at nearly 90 Marathon facilities resulted in thousands of tons of illegal pollution.

The settlement is part of a lawsuit and consent decree officially filed Thursday in federal court in North Dakota.