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Compressed Gas: Toxic and Hazardous Gas Classifications

Last Updated: June 20, 2019 11:04:40 AM PDT

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Learn the hazard class of toxic and hazardous gases.

Find everything you wanted to know about compressed gases including hazard class, description and hazards, Hazard Control Plan, regulatory information, signs symptoms of exposure, and more on the Toxic and Hazardous Gas Classifications Chart below or download the entire Toxic and Hazardous Gas Classifications Chart (PDF). Always follow Hazard Class Requirements and Safety Requirements for your material, based on hazard class.

Toxic and Hazardous Gas Classifications Chart 

GasMolecular FormulaCASPhysical State & DescriptionHazard Control PlanDescriptionHazardsCGSL Hazard Class
AcetyleneC2H274-86-2Dissolved gas - Colorless, odorlessCompressed gasColorless, odorlessFlammable, unstable, reactiveIV
AmmoniaNH37664-41-7Liquefied gasCompressed gasColorless, strong pungent odorCorrosive, non-flammableIII
[Threshold Limit Values ppm: 25; Permissible Exposure Limit  ppm: 50; Lethal Concentration ppm: 7338; Immediately Dangerous to Life or Health ppm: 500]
ArgonAr7440–37–1Compressed gasCompressed gasColorless, odorlessSimple asphyxiantIV
ArsineAsH37784–42–1Compressed gasArsineColorless, garlic or fish-like scentHighly toxic, flammable, pyrophoricI
[Threshold Limit Values ppm: 0.05; Permissible Exposure Limit  ppm: 0.05; Lethal Concentration ppm: 178; Immediately Dangerous to Life or Health ppm: 3]
Boron tribromideBBr310294–33–4LiquidCompressed gasColorlessToxic, corrosiveII
[Threshold Limit Values ppm: 1; Permissible Exposure Limit  ppm: 1; Lethal Concentration ppm: 380; Immediately Dangerous to Life or Health ppm: 50]
Boron trichlorideBCl310294–34–5Compressed gasCompressed gasColorlessCorrosiveIII
[Threshold Limit Values ppm: 5; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 2541; Immediately Dangerous to Life or Health ppm: 25]
Boron trifluorideBF37637–07–2Compressed gasCompressed gasColorless, strong irritating pungent odorToxic, corrosiveII
[Threshold Limit Values ppm: 1; Permissible Exposure Limit  ppm: 1; Lethal Concentration ppm: 864; Immediately Dangerous to Life or Health ppm: 25]
BromineBr27726–95–6LiquidBromineBrownish red liquid, suffocating odorHighly toxic, corrosive, oxidizerI
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 113; Immediately Dangerous to Life or Health ppm: 3]
Carbon dioxideCO2124-38-9Compressed gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV
[Threshold Limit Values ppm: 5000; Permissible Exposure Limit  ppm: 5000; Immediately Dangerous to Life or Health ppm: 40000]
Carbon monoxideCO630–08–0Compressed gasCarbon monoxideColorless, odorless, tastelessToxic, flammableIII
[Threshold Limit Values ppm: 25; Permissible Exposure Limit  ppm: 25; Lethal Concentration ppm: 3760; Immediately Dangerous to Life or Health ppm: 1200]
ChlorineCl27782–50–5Compressed gasChlorineGreenish-yellow, pungent odor similar to bleachToxic, corrosive, oxidizerII
[Threshold Limit Values ppm: 0.5; Permissible Exposure Limit  ppm: 1; Lethal Concentration ppm: 293; Immediately Dangerous to Life or Health ppm: 10]
Chlorine dioxideClO210049–04–4GasCompressed gasChlorine-like odorToxic, oxidizerII
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 250; Immediately Dangerous to Life or Health ppm: 5]
Chlorine trifluorideClF37790–91–2Liquefied gasCompressed gasColorless, strong irritating odorToxic, oxidizer, corrosiveII
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 299; Immediately Dangerous to Life or Health ppm: 20]
DeuteriumH27782-39-0Compressed gasCompressed gasColorlessFlammableIV
DiboraneB2H619278–45–7Liquefied gasDiboraneColorless, repulsively sweet odorHighly toxic, flammable, pyrophoricI
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 80; Immediately Dangerous to Life or Health ppm: 15]
DichlorosilaneSiH2Cl2 (HCl)4109–96–0Liquefied gasCompressed gasColorlessToxic, corrosive, flammableII
[Threshold Limit Values ppm: 2; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 314; Immediately Dangerous to Life or Health ppm: 50]
EthaneC2H674-84-0Compressed gasCompressed gasColorless, odorlessFlammableIV
EthyleneC2H474-85-1Compressed gasCompressed gasColorless, sweet musky odorFlammableIV
Ethylene oxideC2H4075–21–8Liquefied gasEthylene oxideColorless, faintly sweet odorToxic, flammableIII
[Threshold Limit Values ppm: 1; Permissible Exposure Limit  ppm: 1; Lethal Concentration ppm: 2900; Immediately Dangerous to Life or Health ppm: 800]
FluorineF27782–41–4Compressed gasHydrogen fluoridePale yellow, strong, irritating, pungentHighly toxic, corrosive, oxidizerI
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 185; Immediately Dangerous to Life or Health ppm: 25]
GermaneGeH47782–65–2Liquefied gasGermaneColorlessHighly toxic, flammable, pyrophoricII
[Threshold Limit Values ppm: 0.2; Permissible Exposure Limit  ppm: 0.2; Lethal Concentration ppm: 620]
HeliumHe7440-59-7Compressed or Liquefied gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV
HydrogenH21333-74-0Compressed gasCompressed gasColorless, odorless, tastelessFlammableIV
Hydrogen bromideHBr10035–10–6Compressed gasCompressed gasColorless, sharp, unpleasant, pungent odorToxic, corrosiveIII
[Threshold Limit Values ppm: 3; Permissible Exposure Limit  ppm: 3; Lethal Concentration ppm: 2860; Immediately Dangerous to Life or Health ppm: 30]
Hydrogen chlorideHCl7647–01–0Compressed gasCompressed gasColorless, strongly irritatingToxic, corrosiveIII
[Threshold Limit Values ppm: 5; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 2810; Immediately Dangerous to Life or Health ppm: 50]
Hydrogen cyanideHCN74–90–8LiquidHydrogen cyanideColorless, faint almond-like odorHighly toxic, flammableI
[Permissible Exposure Limit  ppm: 4.7; Lethal Concentration ppm: 40; Immediately Dangerous to Life or Health ppm: 50]
Hydrogen fluorideHF7664–39–3Liquefied gasHydrogen fluorideColorless, strong irritating odorToxic, corrosiveII
[Threshold Limit Values ppm: 0.5; Permissible Exposure Limit  ppm: 3; Lethal Concentration ppm: 1300; Immediately Dangerous to Life or Health ppm: 30]
Hydrogen iodideHI10034-85-2Liquefied gasCompressed gasColorless, pungent odorToxic, corrosiveIII
[Lethal Concentration ppm: 2860]
Hydrogen selenideH2Se7783–07–5Compressed gasHydrogen selenideColorless, very irritating odor like rotten eggsHighly toxic, flammableI
[Threshold Limit Values ppm: 0.05; Permissible Exposure Limit  ppm: 0.05; Lethal Concentration ppm: 51; Immediately Dangerous to Life or Health ppm: 1]
Hydrogen sulfideH2S7783–06–4Liquefied gasCompressed gasColorless, foul odor like rotten eggsToxic, flammable, corrosiveII
[Threshold Limit Values ppm: 10; Permissible Exposure Limit  ppm: 10; Lethal Concentration ppm: 712; Immediately Dangerous to Life or Health ppm: 100]
KryptonKr7439-90-9Compressed gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV
MethaneCH374-82-8Compressed gasCompressed gasColorless, odorlessFlammableIV
Methyl bromideCH3Br74–83–9Compressed gasCompressed gasColorless, odorless, nonflammableToxic, flammableII
[Threshold Limit Values ppm: 1; Permissible Exposure Limit  ppm: 1; Lethal Concentration ppm: 850; Immediately Dangerous to Life or Health ppm: 250]
Methyl chlorideCH3Cl74-87-3Compressed gasCompressed gasColorless, mildly sweet odorFlammableIV
[Threshold Limit Values ppm: 50; Permissible Exposure Limit  ppm: 50;  Immediately Dangerous to Life or Health ppm: 2000]
Methyl isocyanateCH3NCO624-83-9LiquidColorlessHighly toxic, flammableI
[Threshold Limit Values ppm: 0.02; Permissible Exposure Limit  ppm: 0.02; Lethal Concentration ppm: 22; Immediately Dangerous to Life or Health ppm: 3]
Methyl mercaptanCH3SH74–93–1Liquefied gasCompressed gasColorless, cabbage-like odorToxic, flammableII
[Threshold Limit Values ppm: 0.5; Permissible Exposure Limit  ppm: 0.5; Lethal Concentration ppm: 1350; Immediately Dangerous to Life or Health ppm: 150]
NeonNe1/9/7440Compressed gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV
Nickel carbonylNi(CO)413463–39–3LiquidForbidden at UCSDMusty or sooty odorHighly toxic, flammableI
[Threshold Limit Values ppm: 0.001; Permissible Exposure Limit  ppm: 0.001; Lethal Concentration ppm: 18; Immediately Dangerous to Life or Health ppm: 2]
Nitric oxideNO10102–43–9Compressed gasNitric oxideColorless, irritating odorHighly toxic, oxidizer, corrosiveI
[Threshold Limit Values ppm: 25; Permissible Exposure Limit  ppm: 25; Lethal Concentration ppm: 115; Immediately Dangerous to Life or Health ppm: 100]
NitrogenN27727-37-9Compressed or Liquefied gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV
Nitrogen dioxideNO210102–44–0Liquefied gasNitrogen dioxideReddish-brown color, irritating odorHighly toxic, oxidizer, corrosiveI
[Threshold Limit Values ppm: 3; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 115; Immediately Dangerous to Life or Health ppm: 20]
Nitrous oxideN2O10024-97-2Compressed gasCompressed gasColorless, faint sweet odorOxidizerIV
[Threshold Limit Values ppm: 50; Permissible Exposure Limit  ppm: 50]
OxygenO27782-44-7Compressed gasCompressed gasColorless, odorless, tastelessOxidizerIV
OzoneO310028-15-6In situ, dissolved gasOzoneColorless, sharp odorHighly toxic, oxidizerI
[Threshold Limit Values ppm: 0.05; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 9; Immediately Dangerous to Life or Health ppm: 5]
PhosgeneCOCl275–44–5Liquefied gasPhosgeneColorless, odor like freshly cut hay or grassHighly toxicI
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 5; Immediately Dangerous to Life or Health ppm: 2]
PhosphinePH37803–51–2Liquefied gasPhosphineColorless, odorlessHighly toxic, flammable, pyrophoricI
[Threshold Limit Values ppm: 0.3; Permissible Exposure Limit  ppm: 0.3; Lethal Concentration ppm: 20; Immediately Dangerous to Life or Health ppm: 50]
Phosphorus oxychloridePOCl310025–87–3LiquidPhosphorus oxychlorideColorlessHighly toxicI
[Threshold Limit Values ppm: 0.1]
Phosphorus pentafluoridePF57647-19-0Liquefied gasCompressed gasColorless, strong, irritating, pungent odorToxic, oxidizer, corrosiveII
[Permissible Exposure Limit  ppm: 261]
Phosphorus trichloridePCl312/2/7719LiquidCompressed gasColorless fuming liquid, pungent odorToxic, corrosiveII
[Threshold Limit Values ppm: 0.2; Permissible Exposure Limit  ppm: 0.2; Lethal Concentration ppm: 208; Immediately Dangerous to Life or Health ppm: 25]
PropaneC3H874-98-6Liquefied gasCompressed gasColorlessFlammableIV
[Permissible Exposure Limit  ppm: 1000]
Selenium hexafluorideSeF67783–79–1Compressed gasSelenium hexafluorideColorless, strong, irritating, repulsive odorHighly toxic, corrosiveI
[Threshold Limit Values ppm: 0.05; Permissible Exposure Limit  ppm: 0.05; Lethal Concentration ppm: 50; Immediately Dangerous to Life or Health ppm: 2]
SilaneSiH47803-62-5Compressed gasSilaneColorless, sharp repulsive odorPyrophoricI
[Threshold Limit Values ppm: 5; Permissible Exposure Limit  ppm: 5]
Silicon tetrachlorideSiCl410026–04–7LiquidCompressed gasColorless fuming liquid, irritating odorToxic, corrosiveII
[Threshold Limit Values ppm: 2; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 750; Immediately Dangerous to Life or Health ppm: 100]
Silicon tetrafluorideSiF4 (HF)7783–61–1Compressed gasCompressed gasColorless, strong irritating disagreeable odorToxic, corrosiveII
[Threshold Limit Values ppm: 3.2; Permissible Exposure Limit  ppm: 3.2; Lethal Concentration ppm: 922; Immediately Dangerous to Life or Health ppm: 30]
StibineSbH37803–52–3Compressed gasStibineColorless, odor like rotten eggsHighly toxic, flammableI
[Threshold Limit Values ppm: 0.1; Permissible Exposure Limit  ppm: 0.1; Lethal Concentration ppm: 178; Immediately Dangerous to Life or Health ppm: 5]
Sulfur dioxideSO27446–09–5Liquefied gasCompressed gasColorless, pungent odorToxic, corrosiveIII
[Threshold Limit Values ppm: 2; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 2520; Immediately Dangerous to Life or Health ppm: 100]
Sulfur hexafluorideSF62551-62-4Liquefied gasCompressed gascolorless, odorless, tastelessSimple asphyxiantIV
Sulfuryl fluoride 2F22699–79–8Liquefied gasCompressed gasColorless, odorless, strong irritatingToxic, corrosiveIII
[Threshold Limit Values ppm: 5; Permissible Exposure Limit  ppm: 5; Lethal Concentration ppm: 3020; Immediately Dangerous to Life or Health ppm: 1000]
Tellurium hexafluorideTeF67783–80–4Compressed gasTellurium hexafluorideColorless gas, repulsive odor, strong irritatingHighly toxic, corrosiveI
[Threshold Limit Values ppm: 0.02; Permissible Exposure Limit  ppm: 0.02; Lethal Concentration ppm: 25; Immediately Dangerous to Life or Health ppm: 1]
Titanium tetrachlorideTiCl47550–45–0LiquidTitanium tetrachlorideColorless, yellow or reddish brownHighly toxic, corrosiveI
[Permissible Exposure Limit  ppm: 1.3; Lethal Concentration ppm: 119; Immediately Dangerous to Life or Health ppm: 1.3]
Tungsten hexafluorideWF6 (HF)7783–82–6Compressed gasCompressed gasColorless, strong irritatingToxic, corrosiveII
[Permissible Exposure Limit  ppm: 30; Lethal Concentration ppm: 218; Immediately Dangerous to Life or Health ppm: 30]
Vinyl bromideC2H3Br593-60-2Liquefied gasCompressed gasColorless, sweet odorToxic, flammableIV
[Permissible Exposure Limit  ppm: .01; Lethal Concentration ppm: >40,000]
Vinyl chlorideC2H3Cl75-01-4Liquefied gasCompressed gasColorless, sweet odorToxic, flammableIV
[Lethal Concentration ppm: 150.000]
XenonXe7440-63-3Compressed gasCompressed gasColorless, odorless, tastelessSimple asphyxiantIV

 

Definition: Liquefied gas

Liquefied gas means a gas which when packaged under pressure, is partially liquid at temperatures above-50°C. A distinction is made between:

(i) High pressure liquefied gas: a gas with a
critical temperature between -50°C and+65°C; and

(ii) Low pressure liquefied gas: a gas with a
critical temperature above +65°C.

Compressed Gas Safety Level (CGSL) defined as ppm:

  • Class I = < 200 LC50
  • Class II = 201–2000 LC50
  • Class III >= 2001–5000 LC50
  • Class IV >= 5000

Class as defined in 2010 Fire Code:

  • Highly toxic = < 200 LC50
  • Toxic = 201–2000 LC50

Table references and resources:

  • 2010 California Fire Code
  • Compressed Gas Association
  • Immediately Dangerous to Life or Health Concentrations (IDLHs), published in 1994, National Institute for Occupational Safety and Health (NIOSH)
  • LC50 data: Lowest reported value, 1 hour adjusted, U.S. Dept. of Transportation
  • Registry of Toxic Effects of Chemical Substances, Canadian Centre for Occupational Health & Safety
  • Table AC-1 Permissible Exposure Limits for Chemical Contaminants, California Department of Industrial Relations, Title 8, Section 5155
  • Threshold Limit Values (TLV) and Immediately Dangerous to Life and Health (IDLH) Values (PDF), Matheson Tri-Gas
  • UCSD Hazard Control Plan (HCP) application 

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Important: This chart is intended for use by of California, San Diego (UCSD) employees only. Standards and requirements may differ at other institutions and businesses.

Questions? Contact the EH&S Chemical Hygiene Officer, (858) 822-1579.

Important: This chart is intended for use by University of California, San Diego (UCSD) employees only. Standards and requirements may differ at other institutions and businesses.