Oxirane

Athanor · official

C₂H₄O · 44.05 g/mol

Also called ethylene oxide, epoxide, EtO, epoxyethane

Rings

Open in Athanor

Drawn from its SMILES with RDKit

DangerExtremely flammable gas · Toxic if swallowed · Causes severe skin burns and eye damage · Causes serious eye damage · Toxic if inhaled · May cause respiratory irritation · May cause drowsiness or dizziness · May cause genetic defects · May cause cancer · May damage fertility; Suspected of damaging the unborn child · Causes damage to organs through prolonged or repeated exposure

Names and identifiers

IUPAC name: oxirane
Synonyms: ethylene oxide, epoxide, EtO
+ 39 more
epoxyethane, ETHYLENE OXIDE, Epoxyethane, 1,2-Epoxyethane, Oxacyclopropane, Dihydrooxirene, Anprolene, Oxidoethane, Oxyfume, Ethene oxide, Dimethylene oxide, Amprolene, Anproline, Aethylenoxid, Merpol, Oxiran, 1,2-Epoxyaethan, Oxyfume 12, T-Gas, Oxirene, Dihydro-, Ethyleenoxide, Oxiraan, Ethox, Etylenu tlenek, FEMA No. 2433, Rcra waste number U115, NCI-C50088, Etilene (ossido di), alpha,beta-Oxidoethane, Ethylene (oxyde d'), ENT-26263, ethyleneoxy, JJH7GNN18P, EPA Pesticide Chemical Code 042301, DTXSID0020600, CHEBI:27561, AI3-26263, CIBA-GEIGY 9138, Sterilizing gas ethylene oxide 100%
Molecular formula: C₂H₄O
Empirical formula: C₂H₄O
Molecular weight: 44.05 g/mol
Exact mass: 44.02621
CAS number: 75-21-8
PubChem CID: 6354
Canonical SMILES: C1CO1
Isomeric SMILES: C1CO1
InChI: InChI=1S/C2H4O/c1-2-3-1/h1-2H2
InChIKey: IAYPIBMASNFSPL-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Colorless gas or liquid (below 51 degrees F) ...[6]
6 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Ethylene oxide appears as a clear colorless gas with an ethereal odor with a flash point below 0 °F. Liquid less dense than water. Vapors heavier than air. May polymerize exothermically if heated or contaminated. If the polymerization takes place inside a container, the container may rupture violently. Vapors very toxic. Vapors irritate the eyes, skin, and respiratory system. Prolonged skin contact may result in delayed burns. Used to make other chemicals, as a fumigant and industrial sterilant. [1] CAMEO Chemicals
– Liquid; Other Solid; Liquid; Gas Vapor [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS COMPRESSED LIQUEFIED GAS WITH CHARACTERISTIC ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Colorless gas or liquid (below 51 °F) with an ether-like odor. [4] Occupational Safety and Health Administration (OSHA)
– Colorless gas or liquid (below 51 °F) with an ether-like odor. [5] The National Institute for Occupational Safety and Health (NIOSH)
–shown Colorless gas or liquid (below 51 degrees F) ... [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
Odor: Sweet[6]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
–shown Sweet [6] Hazardous Substances Data Bank (HSDB)cites U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.
– Reminiscent of bruised apples [6] Hazardous Substances Data Bank (HSDB)cites Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 562
– ... Ether-like odor [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
Melting point: -111.7 °C[6]
6 values
6 of 6 sources agree on it (most common value).
Value As written Source
−112.5 °C -170.5 °F (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−111.7 °Cshown -111.7 °C [6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
−111 °C -111 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−113 °C -171 °F [4] Occupational Safety and Health Administration (OSHA)
−112.5 °C -112.5 °C [7] PAC Chemical Database, U.S. Department of Energy
−113 °C -171 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: 10.6 °C @760 [mmHg][7]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
10.7 °C 51.3 °F at 760 mmHg (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
11 °C 11 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
11 °C 51 °F [4] Occupational Safety and Health Administration (OSHA)
10.6 °Cshown 10.6 °C @760 [mm Hg] [7] PAC Chemical Database, U.S. Department of Energy
11 °C 51 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Density: 0.8821 @ 10°C[7]
7 values
3 of 6 sources agree on it (most common value).
Value As written Source
– 0.8222 at 50 °F (EPA, 1998) - Less dense than water [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
– 0.882 at 10 °C/10 °C [6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
– Relative density (water = 1): 0.9 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.82 (liquid at 50 °F) [4] Occupational Safety and Health Administration (OSHA)
–shown 0.8821 @ 10°C [7] PAC Chemical Database, U.S. Department of Energy
– 0.82 (Liquid at 50 °F) [5] The National Institute for Occupational Safety and Health (NIOSH)
– 1.49(relative gas density) [5] The National Institute for Occupational Safety and Health (NIOSH)
Solubility in water: Solubility in water: miscible[3]
6 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Miscible (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– Soluble in benzene, acetone, ethanol, ether [6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
– Miscible with... carbon tetrachloride. [6] Hazardous Substances Data Bank (HSDB)cites Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V6: 997
– Miscible with water [6] Hazardous Substances Data Bank (HSDB)cites Schultze HC; in Kirk-Othmer Encyclopedia of Chemical Technology. 2nd ed., New York, NY: John Wiley and Sons, V8: 523-8 (1965)
–shown Solubility in water: miscible [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Miscible [5] The National Institute for Occupational Safety and Health (NIOSH)
log P: -0.3[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = -0.30 [6] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 4
–shown -0.3 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Vapor pressure: 1095 mmHg at 20 °C (68 °F, EPA 1998)[1]
4 values
2 of 4 sources agree on it (most common value).
Value As written Source
1095 mmHgshown 1095 mmHg at 68 °F (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
1310 mmHg 1,310 mm Hg at 25 °C (extrapolated) [6] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
1100 mmHg Vapor pressure, kPa at 20 °C: 146 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg 750 [mm Hg] @10.199999999999999 °C [7] PAC Chemical Database, U.S. Department of Energy
2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Flash point: -29 °C (-20 °F) (closed cup)[6]
4 values
2 of 3 sources agree on it (most common value).
Value As written Source
−18.0 to −17.8 °C -0.4 to 0 °F (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−29 °Cshown -20 °F (-29 °C) (closed cup) [6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-62
−18 °C -18 °C (open cup) [6] Hazardous Substances Data Bank (HSDB)cites Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V6 997
−29 °C -20 °F (liquid) [4] Occupational Safety and Health Administration (OSHA)
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Autoignition temperature: 429 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
429 °C 804 °F (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
429 °C 804 °F (429 °C) [6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-62
429 °Cshown 429 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity: 9.45 × 10⁻³ mPa.s (25 °C, gas) and 0.254 mPa.s (10 °C, liquid)[6]
Refractive index: Reported, but no value passed the checks.
The value and why
Inex of refraction: 1.3597 at 7 °C/D (could not be read; source [6])

Value	As written	Source
–	Ethylene oxide appears as a clear colorless gas with an ethereal odor with a flash point below 0 °F. Liquid less dense than water. Vapors heavier than air. May polymerize exothermically if heated or contaminated. If the polymerization takes place inside a container, the container may rupture violently. Vapors very toxic. Vapors irritate the eyes, skin, and respiratory system. Prolonged skin contact may result in delayed burns. Used to make other chemicals, as a fumigant and industrial sterilant.	[1] CAMEO Chemicals
–	Liquid; Other Solid; Liquid; Gas Vapor	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS COMPRESSED LIQUEFIED GAS WITH CHARACTERISTIC ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Colorless gas or liquid (below 51 °F) with an ether-like odor.	[4] Occupational Safety and Health Administration (OSHA)
–	Colorless gas or liquid (below 51 °F) with an ether-like odor.	[5] The National Institute for Occupational Safety and Health (NIOSH)
–shown	Colorless gas or liquid (below 51 degrees F) ...	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

Value	As written	Source
–shown	Sweet	[6] Hazardous Substances Data Bank (HSDB)cites U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.
–	Reminiscent of bruised apples	[6] Hazardous Substances Data Bank (HSDB)cites Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 562
–	... Ether-like odor	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

Value	As written	Source
−112.5 °C	-170.5 °F (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−111.7 °Cshown	-111.7 °C	[6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
−111 °C	-111 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−113 °C	-171 °F	[4] Occupational Safety and Health Administration (OSHA)
−112.5 °C	-112.5 °C	[7] PAC Chemical Database, U.S. Department of Energy
−113 °C	-171 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
10.7 °C	51.3 °F at 760 mmHg (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
11 °C	11 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
11 °C	51 °F	[4] Occupational Safety and Health Administration (OSHA)
10.6 °Cshown	10.6 °C @760 [mm Hg]	[7] PAC Chemical Database, U.S. Department of Energy
11 °C	51 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.8222 at 50 °F (EPA, 1998) - Less dense than water	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
–	0.882 at 10 °C/10 °C	[6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
–	Relative density (water = 1): 0.9	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.82 (liquid at 50 °F)	[4] Occupational Safety and Health Administration (OSHA)
–shown	0.8821 @ 10°C	[7] PAC Chemical Database, U.S. Department of Energy
–	0.82 (Liquid at 50 °F)	[5] The National Institute for Occupational Safety and Health (NIOSH)
–	1.49(relative gas density)	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	Miscible (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	Soluble in benzene, acetone, ethanol, ether	[6] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3793
–	Miscible with... carbon tetrachloride.	[6] Hazardous Substances Data Bank (HSDB)cites Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V6: 997
–	Miscible with water	[6] Hazardous Substances Data Bank (HSDB)cites Schultze HC; in Kirk-Othmer Encyclopedia of Chemical Technology. 2nd ed., New York, NY: John Wiley and Sons, V8: 523-8 (1965)
–shown	Solubility in water: miscible	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Miscible	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	log Kow = -0.30	[6] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 4
–shown	-0.3	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
1095 mmHgshown	1095 mmHg at 68 °F (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
1310 mmHg	1,310 mm Hg at 25 °C (extrapolated)	[6] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
1100 mmHg	Vapor pressure, kPa at 20 °C: 146	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg	750 [mm Hg] @10.199999999999999 °C	[7] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
−18.0 to −17.8 °C	-0.4 to 0 °F (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−29 °Cshown	-20 °F (-29 °C) (closed cup)	[6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-62
−18 °C	-18 °C (open cup)	[6] Hazardous Substances Data Bank (HSDB)cites Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V6 997
−29 °C	-20 °F (liquid)	[4] Occupational Safety and Health Administration (OSHA)

Value	As written	Source
429 °C	804 °F (USCG, 1999)	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
429 °C	804 °F (429 °C)	[6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-62
429 °Cshown	429 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 3
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 1
H-bond donors: 0
H-bond acceptors: 1
Rotatable bonds: 0
TPSA (Å²): 12.5
Formal charge: 0
XLogP3: -0.1 PubChem
Complexity: 10 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C2v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C54.53%
H9.15%
O36.32%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 0.02 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.12 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 1.81 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 44.05
log P ≤ 5 (Crippen): 0.02
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 1

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [8].

Flammable
Corrosive
Acute toxicity
Health hazard

NFPA 704[6]

H220Extremely flammable gas
H301Toxic if swallowed
H314Causes severe skin burns and eye damage
H318Causes serious eye damage
H331Toxic if inhaled
H335May cause respiratory irritation
H336May cause drowsiness or dizziness
H340May cause genetic defects
H350May cause cancer
H360FdMay damage fertility; Suspected of damaging the unborn child
H372Causes damage to organs through prolonged or repeated exposure

Precautionary statements: P203, P210, P222, P260, P261, P264, P264+P265, P270, P271, P280, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P318, P319, P321, P330, P363, P377, P381, P403, P403+P233, P405, P501

View all classifications (5)

[8] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH220, H301, H314, H318, H331, H335, H336, H340, H350, H360Fd, H372
[9] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (1 of 3652) of reports.
[9] European Chemicals Agency (ECHA) · 3,652 reports · DangerH230, H280, H301, H302, H314, H315, H318, H319, H331, H336, H360, H372
[9] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.9% (1 of 117) of reports.
[9] European Chemicals Agency (ECHA) · 117 reports · DangerH315, H317, H318, H411, H412

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 1 ppm [0.5 ppm Action Level][4]
PEL-C (Ceiling): 5 ppm [15 minute excursion limit][4]
PEL: [1910.1047] TWA 1 ppm 5 ppm [15-minute Excursion][5]
REL-TWA (Time Weighted Average): <0.1 ppm (<0.18 mg/m³)[4]
REL-C (Ceiling): 5 ppm (9 mg/m³)[10 minutes][4]
REL: Ca TWA <0.1 ppm (0.18 mg/m3) C 5 ppm (9 mg/m3) [10-min/day] See Appendix A[5]

First aid

Warning: Ethylene oxide is corrosive to moist tissues. Caution is advised. Signs and Symptoms of Acute Ethylene Oxide Exposure: Signs and symptoms of acute exposure to ethylene oxide may be severe, and include dyspnea (shortness of breath), cough, pulmonary edema, pneumonia, and respiratory failure. Lethargy, headache, dizziness, twitching, convulsions, paralysis, and coma may be observed. Cardiac arrhythmias and cardiovascular collapse may also occur. Gastrointestinal effects of acute exposure may include nausea, vomiting, and abdominal pain.[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[10]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Water flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. Get medical attention promptly. Breathing: Respiratory support Swallow: Medical attention immediately (liquid)[5]
Fresh air, rest. Refer for medical attention.[3]

Storage

Fireproof. Cool.[3]
Prior to working with this chemical you should be trained on its proper handling and storage. Before entering a confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. It must be stored to avoid contact with even small amounts of acids (such as nitric or sulfuric acids); alkalis (such as sodium bydroxide or potassium hydroxide); cataylic anhydrous chlorides of iron, aluminum or tin; iron or aluminum oxide; or metallic potassium hydroxide); catalytic anhydrous chlorides of iron, aluminum or tin; iron or aluminum oxide; or metallic…[6]
Store EtO in tightly closed cylinders or tanks in a cool, shaded, well-ventilated, explosion-proof area.[6]
Temperature: Ambient[6]

Incompatibilities

Forms explosive mixture with air. Dangerously reactive; may rearrange chemically and/or polymerize violently with evolution of heat, when in contact with highly active catalytic surfaces such as anhydrous chlorides or iron, tin and aluminum, pure oxides of iron and aluminum, and alkali metal hydroxides. Even small amounts of strong acids, alkalis, oxidizers can cause a reaction. Avoid contact with copper. Protect container from physical damage, sun and heat. Attacks some plastics, rubber or coatings.[6]
Metal fittings containing copper, silver, mercury, or magnesium should not be used in ethylene oxide service, since traces of acetylene could produce explosive acetylides capable of detonating ethylene oxide vapor.[6]
Incompatibilities: Because OF HIGH chemical reactivity ... IT reacts WITH MANY pharmaceutical substances & WITH vitamins, amino acids, & other FOOD constituents. ...[6]
Accidental contamination of a large ethylene oxide feed-cylinder by reaction liquor containing trimethylamine caused the cylinder to explode 18 hr later. Contamination was possible because of a faulty pressure gauge and suck-back of froth above the liquid level.[6]

Safety data sheets on the supplier’s page: TCI (Tokyo Chemical Industry), CATO Research Chemicals Inc., SynQuest Laboratories.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[8]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[9]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[10]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[11]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[12]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[13]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[14]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[15]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[16]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.