BILLINGS, Mont. (AP) -- The Trump administration on Tuesday rolled back an Obama-era rule that forced energy companies to capture methane, which is thought to be a key contributor to climate change and is released in huge amounts during drilling on U.S. and tribal lands.
A replacement rule from the Interior Department rescinds mandates for companies to reduce gas pollution, which Trump administration officials say already is required by some states.
Within hours of the announcement, attorneys general for California and New Mexico filed a lawsuit in federal court seeking to reinstate the 2016 rule.
"We've sued the administration before over the illegal delay and suspension of this rule and will continue doing everything in our power to hold them accountable to our people and planet," California Attorney General Xavier Becerra said.
The change by Trump could save companies as much as $2 billion in compliance costs over the next decade. It comes a week after the U.S. Environmental Protection Agency proposed weakening a separate methane emissions rule affecting private land and some public lands.
"We're for clean air and water, but at the same time, we're for reasonable regulations," Deputy Interior Secretary David Bernhardt told reporters.
Methane is a component of natural gas that's frequently wasted through leaks or intentional releases during drilling operations. The gas is considered a more potent contributor to climate change than carbon dioxide, although it occurs in smaller volumes.
Bernhardt and other Interior officials were unable to immediately say how much the new rule would affect methane emissions. But a U.S. Bureau of Land Management analysis provided to The Associated Press said all the reductions projected to occur under the original 2016 rule were lost with Tuesday's change.
The prior regulation would have cut methane emissions by as much as 180,000 tons a year. Emissions of potentially hazardous pollutants known as volatile organic compounds, which can cause health problems if inhaled, would have been reduced by up to 80,000 tons a year.
The change could also result in the loss of $734 million in natural gas that would have been recovered over the next decade under the old rule. Those savings would have offset some of the industry's compliance costs.
Democratic U.S. Sen. Tom Udall of New Mexico criticized the rollback as a "giveaway to irresponsible polluters."
An estimated $330 million a year in methane is wasted on federal lands, enough to power about 5 million homes.
Kathleen Sgamma, president of Western Energy Alliance, said the old rule improperly put the Bureau of Land Management in the role of regulating air quality, which she said should instead be done by the EPA or state agencies.
The Obama rule has been tied up in the courts since its adoption. It was put on hold in April by a federal judge in Wyoming.
Energy companies said it was overly intrusive and that they already have an economic incentive to capture methane so they can sell it. However, that's not always practical in fast-growing oil and gas fields, where large volumes of gas are burned off using flares.
Flaring has been a common practice in Montana, Wyoming, North Dakota, New Mexico and other states.