US Supreme Court Declines to Pause EPA Mercury and Methane Regulations

By Andrew Chung, John Kruzel

WASHINGTON – On Friday, the U.S. Supreme Court decided against pausing new federal air pollution regulations from President Joe Biden’s administration, which aim to impose stricter limits on mercury and methane emissions. This action came in response to challenges brought forth by several states, predominantly led by Republican governors, as well as various industry groups.

The justices rejected emergency requests from these states and various companies in the power, mining, oil, and gas sectors, seeking to suspend the Environmental Protection Agency (EPA) rules while lower court litigation is ongoing.

These regulations, established under the significant Clean Air Act, are designed to reduce harmful mercury and other metals emitted by coal-fired power plants, as well as methane and other volatile organic compounds released during oil and gas production.

The new mercury rule imposes a 67% reduction in toxic metal emissions from all coal plants, while it establishes a 70% cut for lignite coal plants. The methane rule curtails flaring—burning off excess methane during extraction—and mandates monitoring for leaks at well sites and compressor stations. It also introduces a program aimed at detecting and reporting major methane emissions from "super emitters."

Opponents of the regulations assert that the EPA has overstepped its authority by implementing these rules, which they claim threaten the stability of the U.S. electricity supply and infringe upon states’ rights to set their own emissions standards.

The EPA contends that the regulations will significantly benefit public health and help combat climate change. According to the agency, the mercury rule will help mitigate the risks of heart attacks, cancer, and developmental delays in children, while efforts to reduce methane emissions will have an immediate positive effect on limiting global warming, as methane is more potent than carbon dioxide and dissipates from the atmosphere more quickly.

A group of challengers, including state governments and fossil fuel industry representatives, have initiated several lawsuits in the U.S. Court of Appeals for the District of Columbia Circuit. The court previously denied requests to delay the implementation of the regulations in July and August.

The Supreme Court, which holds a 6-3 conservative majority, has curtailed the EPA’s authority in significant ways in recent years. Notably, in June, the court halted the EPA’s "Good Neighbor" rule aimed at reducing ozone emissions that could harm air quality in neighboring states. Additionally, in 2023, the court limited the agency’s capacity to enforce protections for wetlands and combat water pollution. In 2022, it imposed restrictions on the EPA’s authority under the Clean Air Act to lower carbon emissions from coal and gas power plants.