{"data":{"id":"us/40-cfr-63.7499","jurisdiction":"us","citation":"40 CFR 63.7499","heading":"What are the subcategories of boilers and process heaters?","body":"The subcategories of boilers and process heaters, as defined in § 63.7575 are:\n(a) Pulverized coal/solid fossil fuel units.\n(b) Stokers designed to burn coal/solid fossil fuel.\n(c) Fluidized bed units designed to burn coal/solid fossil fuel.\n(d) Stokers/sloped grate/other units designed to burn kiln dried biomass/bio-based solid.\n(e) Fluidized bed units designed to burn biomass/bio-based solid.\n(f) Suspension burners designed to burn biomass/bio-based solid.\n(g) Fuel cells designed to burn biomass/bio-based solid.\n(h) Hybrid suspension/grate burners designed to burn wet biomass/bio-based solid.\n(i) Stokers/sloped grate/other units designed to burn wet biomass/bio-based solid.\n(j) Dutch ovens/pile burners designed to burn biomass/bio-based solid.\n(k) Units designed to burn liquid fuel that are non-continental units.\n(l) Units designed to burn gas 1 fuels.\n(m) Units designed to burn gas 2 (other) gases.\n(n) Metal process furnaces.\n(o) Limited-use boilers and process heaters.\n(p) Units designed to burn solid fuel.\n(q) Units designed to burn liquid fuel.\n(r) Units designed to burn coal/solid fossil fuel.\n(s) Fluidized bed units with an integrated fluidized bed heat exchanger designed to burn coal/solid fossil fuel.\n(t) Units designed to burn heavy liquid fuel.\n(u) Units designed to burn light liquid fuel.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 63—NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES","Subpart DDDDD—National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"5373155c5dddc1f647472f87229eb075c18106abd01ca7ff370efb0070e8f444","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-63.7495","next":"us/40-cfr-63.7500"},"notice":"GroundRules: Original legal text. Not legal advice."}