⚖ Oral Arguments, with Context

The D.C. Circuit hears Sierra Club versus the Environmental Protection Agency. The dispute concerns federal air-pollution standards for facilities that burn solid waste. These rules cover very small municipal garbage burners and institutional waste incinerators. The underlying standards date to 2005, and an earlier court challenge led the agency to reconsider them. In 2025, EPA revised the standards and definitions, but continued to leave other kinds of burners outside this rule. Examples include crematories and units used to destroy confiscated contraband. EPA also excluded rudimentary combustion devices, saying the standards and controls developed for other incinerators were not appropriate for those devices. The central question is whether the Clean Air Act requires standards for every incinerator within its definition, or gives EPA discretion to choose which additional categories to regulate. EPA will argue that it lawfully reviewed the standards for the categories already regulated, without having to extend them to every other kind of burner. The dispute also concerns whether that periodic review required the agency to revisit the scope of its older rule. Listen for the difference between deciding how to group incinerators and deciding whether a whole kind of incinerator gets federal emissions standards at all.

Sierra Club v. EPA (No. 25-1182) — U.S. Court of Appeals for the D.C. Circuit, argued November 12, 2026.