Supreme Court Lets Biden Plans on Mercury and Methane Move Forward

Republican-led states and industry groups argued that the Environmental Protection Agency had moved too fast and imposed onerous regulations.

The Supreme Court said on Friday that it would not stop the Biden administration from enforcing rules to reduce emissions of two pollutants: mercury, a hazardous neurotoxin, and methane, a potent greenhouse gas.

The court’s brief orders did not give reasons, which is typical when the justices act on emergency applications. There were no noted dissents.

The orders followed recent decisions limiting the Environmental Protection Agency’s authority to address climate change, water pollution and air pollution that drifts across state lines.

The case concerning mercury began in the spring after the Biden administration moved to tighten emissions standards for hazardous air pollutants from coal-fired power plants.

Under the new guidelines, operators of the plants must, among other things, continuously monitor for some toxins and face stricter limits on a type of coal called lignite, the lowest grade of coal. Power plants have up to three years to comply, with a fourth year available if needed.

Republican attorneys general and industry groups filed suit to block the regulations and asked a federal appeals court to temporarily block the rules from going into effect while their suit was pending. The court denied the request and set an expedited schedule for hearing the case.

In August, several industry groups and state attorneys general asked the Supreme Court to step in.

They said that allowing the standards to take effect would lead to “both swift and irreparable” consequences. The new requirements, they added, did “not come with any meaningful public health benefit” and the E.P.A. could not credibly argue any harm from delaying the rules.

The challengers urged the justices to move quickly and to add the case to its term that begins on Monday.

“Given the nature and effect of E.P.A.’s error, there is much to be lost, and little to be gained, from prolonging these proceedings,” they wrote.

Solicitor General Elizabeth B. Prelogar, in the government’s response, pushed back, saying that delaying the rules harmed “the government and the public.”

She added that the E.P.A. had determined that it needed to revise its emissions standards because new technology made it more efficient and easier to limit pollutants.

About 90 percent of the country’s coal-fired power plants can already meet the new standards, Ms. Prelogar wrote. She added that only two units, both part of a Montana facility, would require “substantial upgrades” to meet the federal rules.

The case on methane arose from a rule the E.P.A. issued in March that gave states two years to submit their own plans for cutting methane emissions from oil and gas facilities and included “presumptive standards” to guide them.

More than 20 Republican-led states and many industry groups challenged aspects of the rule in the U.S. Court of Appeals for the District of Columbia Circuit.

The challengers also asked the appeals court to pause the rule while the court considered the matter. A unanimous three-judge panel of the court rejected that request in a terse order.

In an emergency application asking the Supreme Court to intervene, the lawyers for the states said they needed at least three years to submit their plans given “the hundreds of thousands of new facilities now covered by the rule and the complexity of the rule’s requirements.”

The agency “simply selected a two-year period without any meaningful engagement with these concerns,” they wrote, adding that “if states do not complete this herculean task in just two years, E.P.A. itself will directly regulate these existing sources.”

The states’ emergency application said the agency had also acted unlawfully by announcing “presumptive standards,” which they said “represent E.P.A.’s attempts to gut the states’ standard-setting authority.”

Lawyers for the states said the public interest favored pausing the Biden administration’s plan, which they said would “decrease oil and natural gas production” and “force the closure of many wells and the loss of jobs.”

Ms. Prelogar, representing the agency, responded that two years was sufficient, particularly given the urgency of climate change, and that the challengers misunderstood the agency’s guidance. “The ‘presumptive standards’ that E.P.A. included as part of the emission guidelines do not prevent states from adopting a different approach, but simply give states a model that they may rely on if they choose,” she wrote.

She urged the justices to leave the E.P.A.’s plan in place while appeals moved forward, writing that “the government and the public will suffer irreparable harm if a stay is granted.”

“Climate change,” Ms. Prelogar wrote, “is the nation’s most pressing environmental challenge; the primary cause of climate change is the buildup of greenhouse gases in the atmosphere; methane is a highly potent greenhouse gas that drives climate change and additionally results in ground-level ozone; and the oil and gas industry is the largest industrial emitter of methane in the United States.”