US lawFederal (United States)RegulationsTitle 40 CFR — Protection of EnvironmentChapter I — ENVIRONMENTAL PROTECTION AGENCYPart 146 — UNDERGROUND INJECTION CONTROL PROGRAM: CRITERIA AND STANDARDSSubpart C — Criteria and Standards Applicable to Class II Wells146.2140 C.F.R. § 146.21Applicability.Last amended: 2016Year: 2026Length: 16 wordsOfficial source Cite as 40 C.F.R. § 146.21 (2026)This subpart establishes criteria and standards for underground injection control programs to regulate Class II wells.Next40 C.F.R. § 146.22