Part 421 - NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY
- Subpart A - BAUXITE REFINING SUBCATEGORY (§§ 421.10 — 421.16)
- Subpart B - PRIMARY ALUMINUM SMELTING SUBCATEGORY (§§ 421.20 — 421.27)
- Subpart C - SECONDARY ALUMINUM SMELTING SUBCATEGORY (§§ 421.30 — 421.37)
- Subpart D - PRIMARY COPPER SMELTING SUBCATEGORY (§§ 421.40 — 421.47)
- Subpart E - PRIMARY ELECTROLYTIC COPPER REFINING SUBCATEGORY (§§ 421.50 — 421.57)
- Subpart F - SECONDARY COPPER SUBCATEGORY (§§ 421.60 — 421.67)
- Subpart G - PRIMARY LEAD SUBCATEGORY (§§ 421.70 — 421.77)
- Subpart H - PRIMARY ZINC SUBCATEGORY (§§ 421.80 — 421.87)
- Subpart I - METALLURGICAL ACID PLANTS SUBCATEGORY (§§ 421.90 — 421.97)
- Subpart J - PRIMARY TUNGSTEN SUBCATEGORY (§§ 421.100 — 421.107)
- Subpart K - PRIMARY COLUMBIUM-TANTALUM SUBCATEGORY (§§ 421.110 — 421.117)
- Subpart L - SECONDARY SILVER SUBCATEGORY (§§ 421.120 — 421.127)
- Subpart M - SECONDARY LEAD SUBCATEGORY (§§ 421.130 — 421.137)
- Subpart N - PRIMARY ANTIMONY SUBCATEGORY (§§ 421.140 — 421.147)
- Subpart O - PRIMARY BERYLLIUM SUBCATEGORY (§§ 421.150 — 421.157)
- Subpart P - PRIMARY AND SECONDARY GERMANIUM AND GALLIUM SUBCATEGORY (§§ 421.180 — 421.187)
- Subpart Q - SECONDARY INDIUM SUBCATEGORY (§§ 421.190 — 421.197)
- Subpart R - SECONDARY MERCURY SUBCATEGORY (§§ 421.200 — 421.207)
- Subpart S - PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY (§§ 421.210 — 421.217)
- Subpart T - SECONDARY MOLYBDENUM AND VANADIUM SUBCATEGORY (§§ 421.220 — 421.227)
- Subpart U - PRIMARY NICKEL AND COBALT SUBCATEGORY (§§ 421.230 — 421.237)
- Subpart V - SECONDARY NICKEL SUBCATEGORY (§§ 421.240 — 421.247)
- Subpart W - PRIMARY PRECIOUS METALS AND MERCURY SUBCATEGORY (§§ 421.250 — 421.257)
- Subpart X - SECONDARY PRECIOUS METALS SUBCATEGORY (§§ 421.260 — 421.267)
- Subpart Y - PRIMARY RARE EARTH METALS SUBCATEGORY (§§ 421.270 — 421.277)
- Subpart Z - SECONDARY TANTALUM SUBCATEGORY (§§ 421.280 — 421.287)
- GENERAL PROVISIONS (§§ 421.1 — 421.5)
- Subpart AA - SECONDARY TIN SUBCATEGORY (§§ 421.290 — 421.297)
- Subpart AB - PRIMARY AND SECONDARY TITANIUM SUBCATEGORY (§§ 421.300 — 421.307)
- Subpart AC - SECONDARY TUNGSTEN AND COBALT SUBCATEGORY (§§ 421.310 — 421.317)
- Subpart AD - SECONDARY URANIUM SUBCATEGORY (§§ 421.320 — 421.327)
- Subpart AE - PRIMARY ZIRCONIUM AND HAFNIUM SUBCATEGORY (§§ 421.330 — 421.337)