§ 421.20 Applicability: description of the primary aluminum smelting subcategory
§ 421.21 Specialized definitions
§ 421.22 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available
§ 421.23 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable
§ 421.24 Standards of performance for new sources
§ 421.26 Pretreatment standards for new sources