StacksVerified U.S. regulatory reference

40 CFR §57.401

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Except as provided in subpart E, each NSO shall require the smelter owner to prevent all violations of the NAAQS in the smelter's designated liability area (DLA) through the operation of an approved supplementary control system (SCS).