{"data":{"id":"us/40-cfr-63.9942","jurisdiction":"us","citation":"40 CFR 63.9942","heading":"What definitions apply to this subpart?","body":"Terms used in this subpart are defined in the Clean Air Act, in § 63.2, and in this section as follows:\nChlorine plant bypass scrubber means the wet scrubber that captures chlorine gas during a chlorine plant shut down or failure.\nDeviation means any instance in which an affected source subject to this subpart, or an owner or operator of such a source:\n(1) Fails to meet any requirement or obligation established by this subpart, including but not limited to any emission limitation (including operating limits) or operation and maintenance requirement;\n(2) Fails to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the operating permit for any affected source required to obtain such a permit; or\n(3) Fails to meet any emission limitation in this subpart during startup, shutdown, or malfunction, regardless of whether or not such failure is permitted by this subpart.\nEmission limitation means any emission limit, opacity limit, or operating limit.\nLaunder off-gas system means a system that collects chlorine and hydrochloric acid fumes from collection points within the melt/reactor system building. The system then removes particulate matter and hydrochloric acid from the collected gases prior to discharge to the atmosphere.\nMagnesium chloride storage bins means vessels that store dried magnesium chloride powder produced from the spray drying operation.\nMelt/reactor system means a system that melts and chlorinates dehydrated brine to produce high purity molten magnesium chloride feed for electrolysis.\nPrimary magnesium refining means the production of magnesium metal and magnesium metal alloys from natural sources of magnesium chloride such as sea water or water from the Great Salt Lake and magnesium bearing ores.\nResponsible official means responsible official as defined in § 63.2.\nSpray dryer means dryers that evaporate brine to form magnesium powder by contact with high temperature gases exhausted from gas turbines.\nWet scrubber means a device that contacts an exhaust gas with a liquid to remove particulate matter and acid gases from the exhaust. Examples are packed-bed wet scrubbers and venturi scrubbers.\nWork practice standard means any design, equipment, work practice, or operational standard, or combination thereof, that is promulgated pursuant to section 112(h) of the Clean Air Act.","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 TTTTT—National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium Refining"],"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":"53e6ad017aa581d17c2d557c36168ee834990c16ef69d1157f58e900654c8718","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-63.9941","next":"us/40-cfr-table-1-to-subpart-ttttt-of-part-63"},"notice":"GroundRules: Original legal text. Not legal advice."}