Multi-State Coalition Files Amicus Brief Supporting EPA Authority on Greenhouse Gas Emissions

A broad coalition of 20 attorneys general, led by California’s Rob Bonta and New York’s Letitia James, has filed an amicus brief supporting the Environmental Protection Agency’s (EPA) authority to regulate greenhouse gas emissions from power plants. The filing, submitted to the U.S. Court of Appeals for the D.C. Circuit, seeks to uphold federal standards that mandate significant reductions in carbon pollution from the nation’s fossil fuel-fired power sector.

Why States Are Challenging Power Plant Regulations

The legal dispute centers on the EPA’s 2024 final rule, which establishes updated emission guidelines for existing coal-fired and new natural gas-fired power plants. According to the Environmental Protection Agency, these standards are essential to meeting national climate goals and protecting public health from the impacts of climate change.

Industry groups and several states have challenged the rule, arguing that the agency has overstepped its statutory authority granted by the Clean Air Act. These challengers contend that the EPA’s reliance on technologies like carbon capture and storage (CCS) imposes mandates that are not yet technically feasible or economically viable for widespread implementation across the power grid.

The Legal Arguments for EPA Authority

The coalition of states backing the EPA argues that the agency is acting well within the scope of the Clean Air Act. In their official filing, the attorneys general emphasize that the Supreme Court’s decision in West Virginia v. EPA did not strip the agency of its power to regulate emissions. Instead, they assert that the current rule uses established, “best system of emission reduction” (BSER) metrics that reflect modern technological advancements.

The participating states include:

• California
• New York
• Colorado
• Connecticut
• Delaware
• Hawaii
• Illinois
• Maine
• Maryland
• Massachusetts
• Michigan
• Minnesota
• New Jersey
• North Carolina
• Oregon
• Pennsylvania
• Rhode Island
• Vermont
• Washington
• Wisconsin

How This Case Compares to Prior Climate Litigation

This litigation represents the latest chapter in a long-standing struggle over federal environmental oversight. The table below highlights the evolution of these regulatory efforts.

What Happens Next

The case will now proceed through the D.C. Circuit Court of Appeals. Legal observers expect the court to examine whether the EPA’s specific technological requirements constitute a “system” of emission reduction that satisfies the requirements set forth in the Clean Air Act. A decision from the D.C. Circuit is likely to be appealed to the Supreme Court, given the high stakes for both the energy industry and national environmental policy.

As the case progresses, the EPA maintains that the standards provide a flexible, long-term pathway for utilities to modernize their infrastructure while ensuring grid reliability. Opponents continue to warn that the regulations could lead to premature plant closures and increased electricity costs for consumers.