CFR > Title 40 > Chapter I > Subchapter N > Part 421 > General Provisions CFR > Title 40 > Chapter I > Subchapter N > Part 421 > General Provisions Current as of: 2024 | Check for updates | Other versions § 421.1 Applicability § 421.3 Monitoring and reporting requirements § 421.4 Compliance date for pretreatment standards for existing sources (PSES) § 421.5 Removal allowances for pretreatment standards
