§ 68.130
List of substances.
(a) Regulated toxic and flammable substances under section 112(r) of the Clean Air Act are the substances listed in Tables 1, 2, 3, and 4. Threshold quantities for listed toxic and flammable substances are specified in the tables.
(b) The basis for placing toxic and flammable substances on the list of regulated substances are explained in the notes to the list.
Table 1 to § 68.130—List of Regulated Toxic Substances and Threshold Quantities for Accidental Release Prevention
[Alphabetical Order—77 Substances]
Chemical name
CAS No.
Threshold quantity (lbs)
Basis for listing
Acrolein [2-Propenal]
107–02–8
5,000
b
Acrylonitrile [2-Propenenitrile]
107–13–1
20,000
b
Acrylyl chloride [2-Propenoyl chloride]
814–68–6
5,000
b
Allyl alcohol [2-Propen-l-ol]
107–18–6
15,000
b
Allylamine [2-Propen-l-amine]
107–11–9
10,000
b
Ammonia (anhydrous)
7664–41–7
10,000
a, b
Ammonia (conc 20% or greater)
7664–41–7
20,000
a, b
Arsenous trichloride
7784–34–1
15,000
b
Arsine
7784–42–1
1,000
b
Boron trichloride [Borane, trichloro-]
10294–34–5
5,000
b
Boron trifluoride [Borane, trifluoro-]
7637–07–2
5,000
b
Boron trifluoride compound with methyl ether (1:1) [Boron, trifluoro [oxybis [metane]]-, T-4-
353–42–4
15,000
b
Bromine
7726–95–6
10,000
a, b
Carbon disulfide
75–15–0
20,000
b
Chlorine
7782–50–5
2,500
a, b
Chlorine dioxide [Chlorine oxide (ClO2)]
10049–04–4
1,000
c
Chloroform [Methane, trichloro-]
67–66–3
20,000
b
Chloromethyl ether [Methane, oxybis[chloro-]
542–88–1
1,000
b
Chloromethyl methyl ether [Methane, chloromethoxy-]
107–30–2
5,000
b
Crotonaldehyde [2-Butenal]
4170–30–3
20,000
b
Crotonaldehyde, (E)- [2-Butenal, (E)-]
123–73–9
20,000
b
Cyanogen chloride
506–77–4
10,000
c
Cyclohexylamine [Cyclohexanamine]
108–91–8
15,000
b
Diborane
19287–45–7
2,500
b
Dimethyldichlorosilane [Silane, dichlorodimethyl-]
75–78–5
5,000
b
1,1-Dimethylhydrazine [Hydrazine, 1,1-dimethyl-]
57–14–7
15,000
b
Epichlorohydrin [Oxirane, (chloromethyl)-]
106–89–8
20,000
b
Ethylenediamine [1,2-Ethanediamine]
107–15–3
20,000
b
Ethyleneimine [Aziridine]
151–56–4
10,000
b
Ethylene oxide [Oxirane]
75–21–8
10,000
a, b
Fluorine
7782–41–4
1,000
b
Formaldehyde (solution)
50–00–0
15,000
b
Furan
110–00–9
5,000
b
Hydrazine
302–01–2
15,000
b
Hydrochloric acid (conc 37% or greater)
7647–01–0
15,000
d
Hydrocyanic acid
74–90–8
2,500
a, b
Hydrogen chloride (anhydrous) [Hydrochloric acid]
7647–01–0
5,000
a
Hydrogen fluoride/Hydrofluoric acid (conc 50% or greater) [Hydrofluoric acid]
7664–39–3
1,000
a, b
Hydrogen selenide
7783–07–5
500
b
Hydrogen sulfide
7783–06–4
10,000
a, b
Iron, pentacarbonyl- [Iron carbonyl (Fe(CO)5), (TB-5-11)-]
13463–40–6
2,500
b
Isobutyronitrile [Propanenitrile, 2-methyl-]
78–82–0
20,000
b
Isopropyl chloroformate [Carbonochloridic acid, 1-methylethyl ester]
108–23–6
15,000
b
Methacrylonitrile [2-Propenenitrile, 2-methyl-]
126–98–7
10,000
b
Methyl chloride [Methane, chloro-]
74–87–3
10,000
a
Methyl chloroformate [Carbonochloridic acid, methylester]
79–22–1
5,000
b
Methyl hydrazine [Hydrazine, methyl-]
60–34–4
15,000
b
Methyl isocyanate [Methane, isocyanato-]
624–83–9
10,000
a, b
Methyl mercaptan [Methanethiol]
74–93–1
10,000
b
Methyl thiocyanate [Thiocyanic acid, methyl ester]
556–64–9
20,000
b
Methyltrichlorosilane [Silane, trichloromethyl-]
75–79–6
5,000
b
Nickel carbonyl
13463–39–3
1,000
b
Nitric acid (conc 80% or greater)
7697–37–2
15,000
b
Nitric oxide [Nitrogen oxide (NO)]
10102–43–9
10,000
b
Oleum (Fuming Sulfuric acid) [Sulfuric acid, mixture with sulfur trioxide]
1
8014–95–7
10,000
e
Peracetic acid [Ethaneperoxoic acid]
79–21–0
10,000
b
Perchloromethylmercaptan [Methanesulfenyl chloride, trichloro-]
594–42–3
10,000
b
Phosgene [Carbonic dichloride]
75–44–5
500
a, b
Phosphine
7803–51–2
5,000
b
Phosphorus oxychloride [Phosphoryl chloride]
10025–87–3
5,000
b
Phosphorus trichloride [Phosphorous trichloride]
7719–12–2
15,000
b
Piperidine
110–89–4
15,000
b
Propionitrile [Propanenitrile]
107–12–0
10,000
b
Propyl chloroformate [Carbonochloridic acid, propylester]
109–61–5
15,000
b
Propyleneimine [Aziridine, 2-methyl-]
75–55–8
10,000
b
Propylene oxide [Oxirane, methyl-]
75–56–9
10,000
b
Sulfur dioxide (anhydrous)
7446–09–5
5,000
a, b
Sulfur tetrafluoride [Sulfur fluoride (SF4), (T-4)-]
7783–60–0
2,500
b
Sulfur trioxide
7446–11–9
10,000
a, b
Tetramethyllead [Plumbane, tetramethyl-]
75–74–1
10,000
b
Tetranitromethane [Methane, tetranitro-]
509–14–8
10,000
b
Titanium tetrachloride [Titanium chloride (TiCl4) (T-4)-]
7550–45–0
2,500
b
Toluene 2,4-diisocyanate [Benzene, 2,4-diisocyanato-1-methyl-]
1
584–84–9
10,000
a
Toluene 2,6-diisocyanate [Benzene, 1,3-diisocyanato-2-methyl-]
1
91–08–7
10,000
a
Toluene diisocyanate (unspecified isomer) [Benzene, 1,3-diisocyanatomethyl-]
1
26471–62–5
10,000
a
Trimethylchlorosilane [Silane, chlorotrimethyl-]
75–77–4
10,000
b
Vinyl acetate monomer [Acetic acid ethenyl ester]
108–05–4
15,000
b
1
The mixture exemption in § 68.115(b)(1) does not apply to the substance.
Note:
Basis for Listing:
a Mandated for listing by Congress.
b On EHS list, vapor pressure 10 mmHg or greater.
c Toxic gas.
d Toxicity of hydrogen chloride, potential to release hydrogen chloride, and history of accidents.
e Toxicity of sulfur trioxide and sulfuric acid, potential to release sulfur trioxide, and history of accidents.
Table 2 to § 68.130—List of Regulated Toxic Substances and Threshold Quantities for Accidental Release Prevention
[CAS Number Order—77 Substances]
CAS No.
Chemical name
Threshold quantity (lbs)
Basis for listing
50–00–0
Formaldehyde (solution)
15,000
b
57–14–7
1,1-Dimethylhydrazine [Hydrazine, 1,1-dimethyl-]
15,000
b
60–34–4
Methyl hydrazine [Hydrazine, methyl-]
15,000
b
67–66–3
Chloroform [Methane, trichloro-]
20,000
b
74–87–3
Methyl chloride [Methane, chloro-]
10,000
a
74–90–8
Hydrocyanic acid
2,500
a, b
74–93–1
Methyl mercaptan [Methanethiol]
10,000
b
75–15–0
Carbon disulfide
20,000
b
75–21–8
Ethylene oxide [Oxirane]
10,000
a, b
75–44–5
Phosgene [Carbonic dichloride]
500
a, b
75–55–8
Propyleneimine [Aziridine, 2-methyl-]
10,000
b
75–56–9
Propylene oxide [Oxirane, methyl-]
10,000
b
75–74–1
Tetramethyllead [Plumbane, tetramethyl-]
10,000
b
75–77–4
Trimethylchlorosilane [Silane, chlorotrimethyl-]
10,000
b
75–78–5
Dimethyldichlorosilane [Silane, dichlorodimethyl-]
5,000
b
75–79–6
Methyltrichlorosilane [Silane, trichloromethyl-]
5,000
b
78–82–0
Isobutyronitrile [Propanenitrile, 2-methyl-]
20,000
b
79–21–0
Peracetic acid [Ethaneperoxoic acid]
10,000
b
79–22–1
Methyl chloroformate [Carbonochloridic acid, methylester]
5,000
b
91–08–7
Toluene 2,6-diisocyanate [Benzene, 1,3-diisocyanato-2-methyl-]
1
10,000
a
106–89–8
Epichlorohydrin [Oxirane, (chloromethyl)-]
20,000
b
107–02–8
Acrolein [2-Propenal]
5,000
b
107–11–9
Allylamine [2-Propen-1-amine]
10,000
b
107–12–0
Propionitrile [Propanenitrile]
10,000
b
107–13–1
Acrylonitrile [2-Propenenitrile]
20,000
b
107–15–3
Ethylenediamine [1,2-Ethanediamine]
20,000
b
107–18–6
Allyl alcohol [2-Propen-1-ol]
15,000
b
107–30–2
Chloromethyl methyl ether [Methane, chloromethoxy-]
5,000
b
108–05–4
Vinyl acetate monomer [Acetic acid ethenyl ester]
15,000
b
108–23–6
Isopropyl chloroformate [Carbonochloridic acid, 1-methylethyl ester]
15,000
b
108–91–8
Cyclohexylamine [Cyclohexanamine]
15,000
b
109–61–5
Propyl chloroformate [Carbonochloridic acid, propylester]
15,000
b
110–00–9
Furan
5,000
b
110–89–4
Piperidine
15,000
b
123–73–9
Crotonaldehyde, (E)- [2-Butenal, (E)-]
20,000
b
126–98–7
Methacrylonitrile [2-Propenenitrile, 2-methyl-]
10,000
b
151–56–4
Ethyleneimine [Aziridine]
10,000
b
302–01–2
Hydrazine
15,000
b
353–42–4
Boron trifluoride compound with methyl ether (1:1) [Boron, trifluoro[oxybis[methane]]-, T-4-
15,000
b
506–77–4
Cyanogen chloride
10,000
c
509–14–8
Tetranitromethane [Methane, tetranitro-]
10,000
b
542–88–1
Chloromethyl ether [Methane, oxybis[chloro-]
1,000
b
556–64–9
Methyl thiocyanate [Thiocyanic acid, methyl ester]
20,000
b
584–84–9
Toluene 2,4-diisocyanate [Benzene, 2,4-diisocyanato-1-methyl-]
1
10,000
a
594–42–3
Perchloromethylmercaptan [Methanesulfenyl chloride, trichloro-]
10,000
b
624–83–9
Methyl isocyanate [Methane, isocyanato-]
10,000
a, b
814–68–6
Acrylyl chloride [2-Propenoyl chloride]
5,000
b
4170–30–3
Crotonaldehyde [2-Butenal]
20,000
b
7446–09–5
Sulfur dioxide (anhydrous)
5,000
a, b
7446–11–9
Sulfur trioxide
10,000
a, b
7550–45–0
Titanium tetrachloride [Titanium chloride (TiCl4) (T-4)-]
2,500
b
7637–07–2
Boron trifluoride [Borane, trifluoro-]
5,000
b
7647–01–0
Hydrochloric acid (conc 37% or greater)
15,000
d
7647–01–0
Hydrogen chloride (anhydrous) [Hydrochloric acid]
5,000
a
7664–39–3
Hydrogen fluoride/Hydrofluoric acid (conc 50% or greater) [Hydrofluoric acid]
1,000
a, b
7664–41–7
Ammonia (anhydrous)
10,000
a, b
7664–41–7
Ammonia (conc 20% or greater)
20,000
a, b
7697–37–2
Nitric acid (conc 80% or greater)
15,000
b
7719–12–2
Phosphorus trichloride [Phosphorous trichloride]
15,000
b
7726–95–6
Bromine
10,000
a, b
7782–41–4
Fluorine
1,000
b
7782–50–5
Chlorine
2,500
a, b
7783–06–4
Hydrogen sulfide
10,000
a, b
7783–07–5
Hydrogen selenide
500
b
7783–60–0
Sulfur tetrafluoride [Sulfur fluoride (SF4), (T-4)-]
2,500
b
7784–34–1
Arsenous trichloride
15,000
b
7784–42–1
Arsine
1,000
b
7803–51–2
Phosphine
5,000
b
8014–95–7
Oleum (Fuming Sulfuric acid) [Sulfuric acid, mixture with sulfur trioxide]
1
10,000
e
10025–87–3
Phosphorus oxychloride [Phosphoryl chloride]
5,000
b
10049–04–4
Chlorine dioxide [Chlorine oxide (ClO
2
)]
1,000
c
10102–43–9
Nitric oxide [Nitrogen oxide (NO)]
10,000
b
10294–34–5
Boron trichloride [Borane, trichloro-]
5,000
b
13463–39–3
Nickel carbonyl
1,000
b
13463–40–6
Iron, pentacarbonyl- [Iron carbonyl (Fe(CO)
5
), (TB-5-11)-]
2,500
b
19287–45–7
Diborane
2,500
b
26471–62–5
Toluene diisocyanate (unspecified isomer) [Benzene, 1,3-diisocyanatomethyl-1]
1
10,000
a
1
The mixture exemption in § 68.115(b)(1) does not apply to the substance.
Note:
Basis for Listing:
a Mandated for listing by Congress.
b On EHS list, vapor pressure 10 mmHg or greater.
c Toxic gas.
d Toxicity of hydrogen chloride, potential to release hydrogen chloride, and history of accidents.
e Toxicity of sulfur trioxide and sulfuric acid, potential to release sulfur trioxide, and history of accidents.
Table 3 to § 68.130—List of Regulated Flammable Substances
1
and Threshold Quantities for Accidental Release Prevention
[Alphabetical Order—63 Substances]
Chemical name
CAS No.
Threshold quantity (lbs)
Basis for listing
Acetaldehyde
75–07–0
10,000
g
Acetylene [Ethyne]
74–86–2
10,000
f
Bromotrifluorethylene [Ethene, bromotrifluoro-]
598–73–2
10,000
f
1,3-Butadiene
106–99–0
10,000
f
Butane
106–97–8
10,000
f
1-Butene
106–98–9
10,000
f
2-Butene
107–01–7
10,000
f
Butene
25167–67–3
10,000
f
2-Butene-cis
590–18–1
10,000
f
2-Butene-trans [2-Butene, (E)]
624–64–6
10,000
f
Carbon oxysulfide [Carbon oxide sulfide (COS)]
463–58–1
10,000
f
Chlorine monoxide [Chlorine oxide]
7791–21–1
10,000
f
2-Chloropropylene [1-Propene, 2-chloro-]
557–98–2
10,000
g
1-Chloropropylene [1-Propene, 1-chloro-]
590–21–6
10,000
g
Cyanogen [Ethanedinitrile]
460–19–5
10,000
f
Cyclopropane
75–19–4
10,000
f
Dichlorosilane [Silane, dichloro-]
4109–96–0
10,000
f
Difluoroethane [Ethane, 1,1-difluoro-]
75–37–6
10,000
f
Dimethylamine [Methanamine, N-methyl-]
124–40–3
10,000
f
2,2-Dimethylpropane [Propane, 2,2-dimethyl-]
463–82–1
10,000
f
Ethane
74–84–0
10,000
f
Ethyl acetylene [1-Butyne]
107–00–6
10,000
f
Ethylamine [Ethanamine]
75–04–7
10,000
f
Ethyl chloride [Ethane, chloro-]
75–00–3
10,000
f
Ethylene [Ethene]
74–85–1
10,000
f
Ethyl ether [Ethane, 1,1′-oxybis-]
60–29–7
10,000
g
Ethyl mercaptan [Ethanethiol]
75–08–1
10,000
g
Ethyl nitrite [Nitrous acid, ethyl ester]
109–95–5
10,000
f
Hydrogen
1333–74–0
10,000
f
Isobutane [Propane, 2-methyl]
75–28–5
10,000
f
Isopentane [Butane, 2-methyl-]
78–78–4
10,000
g
Isoprene [1,3-Butadinene, 2-methyl-]
78–79–5
10,000
g
Isopropylamine [2-Propanamine]
75–31–0
10,000
g
Isopropyl chloride [Propane, 2-chloro-]
75–29–6
10,000
g
Methane
74–82–8
10,000
f
Methylamine [Methanamine]
74–89–5
10,000
f
3-Methyl-1-butene
563–45–1
10,000
f
2-Methyl-1-butene
563–46–2
10,000
g
Methyl ether [Methane, oxybis-]
115–10–6
10,000
f
Methyl formate [Formic acid, methyl ester]
107–31–3
10,000
g
2-Methylpropene [1-Propene, 2-methyl-]
115–11–7
10,000
f
1,3-Pentadinene
504–60–9
10,000
f
Pentane
109–66–0
10,000
g
1-Pentene
109–67–1
10,000
g
2-Pentene, (E)-
646–04–8
10,000
g
2-Pentene, (Z)-
627–20–3
10,000
g
Propadiene [1,2-Propadiene]
463–49–0
10,000
f
Propane
74–98–6
10,000
f
Propylene [1-Propene]
115–07–1
10,000
f
Propyne [1-Propyne]
74–99–7
10,000
f
Silane
7803–62–5
10,000
f
Tetrafluoroethylene [Ethene, tetrafluoro-]
116–14–3
10,000
f
Tetramethylsilane [Silane, tetramethyl-]
75–76–3
10,000
g
Trichlorosilane [Silane, trichloro-]
10025–78–2
10,000
g
Trifluorochloroethylene [Ethene, chlorotrifluoro-]
79–38–9
10,000
f
Trimethylamine [Methanamine, N,N-dimethyl-]
75–50–3
10,000
f
Vinyl acetylene [1-Buten-3-yne]
689–97–4
10,000
f
Vinyl chloride [Ethene, chloro-]
75–01–4
10,000
a, f
Vinyl ethyl ether [Ethene, ethoxy-]
109–92–2
10,000
g
Vinyl fluoride [Ethene, fluoro-]
75–02–5
10,000
f
Vinylidene chloride [Ethene, 1,1-dichloro-]
75–35–4
10,000
g
Vinylidene fluoride [Ethene, 1,1-difluoro-]
75–38–7
10,000
f
Vinyl methyl ether [Ethene, methoxy-]
107–25–5
10,000
f
1
A flammable substance when used as a fuel or held for sale as a fuel at a retail facility is excluded from all provisions of this part (see § 68.126).
Note:
Basis for Listing:
a
Mandated for listing by Congress.
f
Flammable gas.
g
Volatile flammable liquid.
Table 4 to § 68.130—List of Regulated Flammable Substances
1
and Threshold Quantities for Accidental Release Prevention
[CAS Number Order—63 Substances]
CAS No.
Chemical name
Threshold quantity
(lbs)
Basis for listing
60–29–7
Ethyl ether [Ethane, 1,1′-oxybis-]
10,000
g
74–82–8
Methane
10,000
f
74–84–0
Ethane
10,000
f
74–85–1
Ethylene [Ethene]
10,000
f
74–86–2
Acetylene [Ethyne]
10,000
f
74–89–5
Methylamine [Methanamine]
10,000
f
74–98–6
Propane
10,000
f
74–99–7
Propyne [1-Propyne]
10,000
f
75–00–3
Ethyl chloride [Ethane, chloro-]
10,000
f
75–01–4
Vinyl chloride [Ethene, chloro-]
10,000
a, f
75–02–5
Vinyl fluoride [Ethene, fluoro-]
10,000
f
75–04–7
Ethylamine [Ethanamine]
10,000
f
75–07–0
Acetaldehyde
10,000
g
75–08–1
Ethyl mercaptan [Ethanethiol]
10,000
g
75–19–4
Cyclopropane
10,000
f
75–28–5
Isobutane [Propane, 2-methyl]
10,000
f
75–29–6
Isopropyl chloride [Propane, 2-chloro-]
10,000
g
75–31–0
Isopropylamine [2-Propanamine]
10,000
g
75–35–4
Vinylidene chloride [Ethene, 1,1-dichloro-]
10,000
g
75–37–6
Difluoroethane [Ethane, 1,1-difluoro-]
10,000
f
75–38–7
Vinylidene fluoride [Ethene, 1,1-difluoro-]
10,000
f
75–50–3
Trimethylamine [Methanamine, N, N-dimethyl-]
10,000
f
75–76–3
Tetramethylsilane [Silane, tetramethyl-]
10,000
g
78–78–4
Isopentane [Butane, 2-methyl-]
10,000
g
78–79–5
Isoprene [1,3,-Butadiene, 2-methyl-]
10,000
g
79–38–9
Trifluorochloroethylene [Ethene, chlorotrifluoro-]
10,000
f
106–97–8
Butane
10,000
f
106–98–9
1-Butene
10,000
f
106–99–0
1,3-Butadiene
10,000
f
107–00–6
Ethyl acetylene [1-Butyne]
10,000
f
107–01–7
2-Butene
10,000
f
107–25–5
Vinyl methyl ether [Ethene, methoxy-]
10,000
f
107–31–3
Methyl formate [Formic acid, methyl ester]
10,000
g
109–66–0
Pentane
10,000
g
109–67–1
1-Pentene
10,000
g
109–92–2
Vinyl ethyl ether [Ethene, ethoxy-]
10,000
g
109–95–5
Ethyl nitrite [Nitrous acid, ethyl ester]
10,000
f
115–07–1
Propylene [1-Propene]
10,000
f
115–10–6
Methyl ether [Methane, oxybis-]
10,000
f
115–11–7
2-Methylpropene [1-Propene, 2-methyl-]
10,000
f
116–14–3
Tetrafluoroethylene [Ethene, tetrafluoro-]
10,000
f
124–40–3
Dimethylamine [Methanamine, N-methyl-]
10,000
f
460–19–5
Cyanogen [Ethanedinitrile]
10,000
f
463–49–0
Propadiene [1,2-Propadiene]
10,000
f
463–58–1
Carbon oxysulfide [Carbon oxide sulfide (COS)]
10,000
f
463–82–1
2,2-Dimethylpropane [Propane, 2,2-dimethyl-]
10,000
f
504–60–9
1,3-Pentadiene
10,000
f
557–98–2
2-Chloropropylene [1-Propene, 2-chloro-]
10,000
g
563–45–1
3-Methyl-1-butene
10,000
f
563–46–2
2-Methyl-1-butene
10,000
g
590–18–1
2-Butene-cis
10,000
f
590–21–6
1-Chloropropylene [1-Propene, 1-chloro-]
10,000
g
598–73–2
Bromotrifluorethylene [Ethene, bromotrifluoro-]
10,000
f
624–64–6
2-Butene-trans [2-Butene, (E)]
10,000
f
627–20–3
2-Pentene, (Z)-
10,000
g
646–04–8
2-Pentene, (E)-
10,000
g
689–97–4
Vinyl acetylene [1-Buten-3-yne]
10,000
f
1333–74–0
Hydrogen
10,000
f
4109–96–0
Dichlorosilane [Silane, dichloro-]
10,000
f
7791–21–1
Chlorine monoxide [Chlorine oxide]
10,000
f
7803–62–5
Silane
10,000
f
10025–78–2
Trichlorosilane [Silane, trichloro-]
10,000
g
25167–67–3
Butene
10,000
f
1
A flammable substance when used as a fuel or held for sale as a fuel at a retail facility is excluded from all provisions of this part (see § 68.126).
Note:
Basis for Listing:
a
Mandated for listing by Congress.
f
Flammable gas.
g
Volatile flammable liquid.
[59 FR 4493, Jan. 31, 1994. Redesignated at 61 FR 31717, June 20, 1996, as amended at 62 FR 45132, Aug. 25, 1997; 63 FR 645, Jan. 6, 1998; 65 FR 13250, Mar. 13, 2000; 82 FR 4702, Jan. 13, 2017]