DC Circuit grills EPA over reclassification of toxic chemical emission standard

A D.C. Circuit panel heard arguments Monday on an EPA rule, finalized in January 2020, that lets industrial facilities emitting under 10 tons of a single toxic chemical or 25 tons combined reclassify as minor polluters and exit Clean Air Act 'Maximum Achievable Control Technology' standards entirely. Sierra Club attorney Sanjay Narayan argued this lets a facility meet the pollution standard once, then stop following it altogether, so long as it stays under the threshold.

Judge Gregory Katsas, a Trump appointee, pressed on whether the EPA has discretion to define major sources more permissively, noting the court owes the agency no deference post-Loper Bright. EPA attorney Laura Glickman countered that Congress's use of present-tense language in the statute means classification should reflect current emissions, not historical ones, and that Congress could have written in an anti-backsliding provision if it wanted one.

The Sierra Club notes the administration moved in February 2026 to let coal plants emit 50% more mercury and in May 2025 exempted 68 power plants from emissions standards after soliciting exemption requests.

The full dispatch is available from the source below.