CFR›Title 40›Chapter I›Part 439›Subpart E ContainsSections 439.50–439.52CorpusDaily eCFRDisplayed edition2026-04-27Last updated2026-04-27 Subpart E—Research Sections 439.50 § 439.50 Applicability. 439.51 § 439.51 Special definitions. 439.52 § 439.52 Effluent limitations attainable by the application of the best practicable control technology currently available (BPT). Previous D Subpart D—Mixing/Compounding and Formulation Next General General