Ethylene Oxide

1Identification

Name

Ethylene Oxide

IUPAC name

oxirane

CAS number

75-21-8

EC number

200-849-9

Molecular formula

C2H4O

Molecular weight

44.05 g/mol

InChIKey

IAYPIBMASNFSPL-UHFFFAOYSA-N

SMILES

C1CO1

PubChem CID

6354

Synonyms

Oxirane, ETHYLENE OXIDE, Epoxyethane, 1,2-Epoxyethane, Oxacyclopropane, Dihydrooxirene, Anprolene, Oxidoethane, Oxyfume, Ethene oxide, Dimethylene oxide, Amprolene, Anproline, Aethylenoxid

Recommended uses

• Ethylene oxide is used mainly as a chemical intermediate in the manufacture of ethylene glycol (antifreeze), textiles, detergents, polyurethane foam, solvents, medicine, adhesives, and other products. Relatively small amounts of ethylene oxide are used as a fumigant, as a sterilant for food (spices) and cosmetics, and in hospital sterilization of surgical equipment and plastic devices that cannot be sterilized by steam.
  EPA Hazardous Air Pollutants
• Ethylene oxide sterilizers are used by medical and dental staff to sterilize heat-sensitive instruments. [p. 736, Harber] Occupational asthma from ethylene oxide has been reported in a nurse. [Malo]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Sterilizing Equipment [Category: Clean]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Monomers Intermediate
  EPA Chemical Data Reporting (CDR)
• Other Monomers Intermediate
  EPA Chemical Data Reporting (CDR)

Use categories: Food Additives -> PRESERVATIVE -> JECFA Functional Classes

Description

• Ethylene oxide is a flammable gas with a somewhat sweet odor. It dissolves easily in water. Ethylene oxide is a man-made chemical that is used primarily to make ethylene glycol (a chemical used to make antifreeze and polyester). A small amount (less than 1%) is used to control insects in some stored agricultural products and a very small amount is used in hospitals to sterilize medical equipment and supplies.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Ethylene Oxide can cause cancer, developmental toxicity, female reproductive toxicity and male reproductive toxicity according to state or federal government labeling requirements.
  California Office of Environmental Health Hazard Assessment (OEHHA)
• 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.
  CAMEO Chemicals

2Hazard identification

Signal word

Danger

Pictograms

GHS02, GHS05, GHS06, GHS08

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

7 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

NFPA 704 rating

• 3 - Materials that, under emergency conditions, can cause serious or permanent injury.
  Hazardous Substances Data Bank (HSDB)
• 4 - Materials that rapidly or completely vaporize at atmospheric pressure and normal ambient temperature or that are readily dispersed in air and burn readily.
  Hazardous Substances Data Bank (HSDB)
• 3 - Materials that in themselves are capable of detonation or explosive decomposition or explosive reaction but that require a strong initiating source or must be heated under confinement before initiation.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• It can cause death. Lowest inhalation concentration causing toxic effects is 12500 ppm/10 seconds. It is a strong skin irritant. Neurological disorders and even death have been reported. (EPA, 1998)
  CAMEO Chemicals
• · TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and eye damage. · Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. · Fire will produce irritating, corrosive and/or toxic gases. · Runoff from fire control or dilution water may cause environmental contamination.
  Emergency Response Guidebook (ERG)

Fire hazards

• Severe explosion hazard when exposed to heat or flame. Irritating vapors are generated when heated. Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back. Vapor forms explosive mixtures with air over a wide range. Liquid is not detonable but the vapor may be readily initiated into explosive decomposition. Avoid metal fittings containing copper, silver, mercury or magnesium; ammonia, oxidizing agents; acids, organic bases; amines; certain salts; alcohols; mercaptans, ferric chloride; magnesium perchlorate; m-nitroaniline; trimethylamine, potassium, tin chlorides; alkanethiols; bromoethane; aluminum chloride; aluminum oxide; iron chlorides;
  CAMEO Chemicals
• · Flammable; may be ignited by heat, sparks or flames. · May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the absence of air. · Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. · Vapors from liquefied gas are initially heavier than air and spread along ground. · Vapors may travel to source of ignition and flash back. · Some of these materials may react violently with water. · Cylinders exposed to fire may vent and release toxic and flammable gas through pressure relief devices. · Containers may explode when heated. · Ruptured cylinders may rocket. · Runoff may create fire or explosion hazard.
  Emergency Response Guidebook (ERG)
• Extremely flammable. Gas/air mixtures are explosive. Risk of fire and explosion as a result of decomposition when heated.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• Ethylene oxide is a flammable gas with a somewhat sweet odor. It dissolves easily in water. Ethylene oxide is a man-made chemical that is used primarily to make ethylene glycol (a chemical used to make antifreeze and polyester). A small amount (less than 1%) is used to control insects in some stored agricultural products and a very small amount is used in hospitals to sterilize medical equipment and supplies.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• The major use of ethylene oxide is as a chemical intermediate in the manufacture of ethylene glycol. Ethylene oxide is also used as a sterilizing agent for medical equipment and a fumigating agent for spices. The acute (short-term) effects of ethylene oxide in humans consist mainly of central nervous system depression and irritation of the eyes and mucous membranes. Chronic (long-term) exposure to ethylene oxide in humans can cause irritation of the eyes, skin, nose, throat, and lungs, and damage to the brain and nervous system. There also is some evidence linking ethylene oxide exposure to reproductive effects.
  EPA Hazardous Air Pollutants

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• 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. Ethylene oxide may severely irritate or burn mucous membranes and moist skin.
  CAMEO Chemicals
• 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 with a one-way valve or other device).
  Emergency Response Guidebook (ERG)
• (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)
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Cough. Drowsiness. Headache. Nausea. Sore throat. Vomiting. Weakness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• MAY BE ABSORBED! Frostbite. Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain. Blurred vision.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• GAS: Poisonous gases are produced in fire. Do not estinguish the fire unless the flow of gas can be stopped and any remaining gas is out of the line. Specially trained personnel may use fog lines to cool exposures and let the fire burn itself out. Vapors are heavier than air and will collect in low areas. Vapors may travel long distances to ignition sources and flashback. Vapors in confined area may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions. If materials or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies.
  Hazardous Substances Data Bank (HSDB)
• Fire extinguishing agents: water.
  Hazardous Substances Data Bank (HSDB)
• Stop flow of gas if possible. Combat fires from behind barrier, with unmanned hose holder or monitor nozzle. Flood discharge area with water. Cool exposed containers and protect men effecting shut off with water.
  Hazardous Substances Data Bank (HSDB)

Hazardous combustion products

• Incomplete combustion releases carbon monoxide ... .
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 119 [Gases - Toxic - Flammable; polymerization hazard]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions. SPILL: See ERG Tables 1 and 3 - Initial Isolation and Protective Action Distances on the UN/NA 1040 datasheet. FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals
• Immediate precautionary measure · Isolate spill or leak area for at least 100 meters (330 feet) in all directions. Spill · For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances. · For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary. Fire · If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions.
  Emergency Response Guidebook (ERG)

Spill cleanup

• Evacuate danger area! Consult an expert! Personal protection: gas-tight chemical protection suit including self-contained breathing apparatus. Ventilation. Do NOT wash away into sewer. NEVER direct water jet on liquid. Remove gas with fine water spray.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• GAS: Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Establish forced ventilation to keep levels below explosive limit. Stop the flow of gas if it can be done safely. If source of leak us a cylinder and the leak cannot be stopped in place, remove leaking cylinder to a safe place in the open air, and repair leak or allow cylinder to empty. Keep this chemical out of a confined space, such as a sewer, because of the possibility of an explosion, unless the sewer is designed to prevent the build-up of explosive concentrations. LIQUID: For small spills flush area with flooding amounts of water.
  Hazardous Substances Data Bank (HSDB)
• Shut off ignition sources and call fire dept. Stop /flow/ if possible. Stay upwind and use water spray to "knock down" vapor. Isolate and remove discharged material. Notify local health and pollution control agencies.
  Hazardous Substances Data Bank (HSDB)
• PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal ... The plastic bag should be sealed immediately ... The sealed bag should be labelled properly ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Cool.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• 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;
  Hazardous Substances Data Bank (HSDB)
• Store EtO in tightly closed cylinders or tanks in a cool, shaded, well-ventilated, explosion-proof area.
  Hazardous Substances Data Bank (HSDB)
• Temperature: ambient
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Ethylene oxide: Skin: PREVENT SKIN CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate personal protective clothing to prevent skin contact. Eyes: PREVENT EYE CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate eye protection to prevent eye contact. Wash skin: WHEN CONTAMINATED (LIQUID) - If this chemical is in liquid form, the worker should immediately wash the skin when it becomes contaminated. Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F).
  CAMEO Chemicals
• NIOSH: 5 ppm: GMFS+ (any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern); or SCBAF (any self-contained breathing apparatus with a full facepiece); or SAF (any supplied-air respirator with a full facepiece). Emergency or planned entry into unknown concentrations or IDLH conditions: SCBAF:PD,PP (any self-breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode);
  Hazardous Substances Data Bank (HSDB)
• AIR-SUPPLIED MASK; GOGGLES OR FACE SHIELD; RUBBER SHOES & COVERALLS.
  Hazardous Substances Data Bank (HSDB)
• Wear neoprene gloves, safety glasses, plastic protective clothing and self-contained breathing apparatus.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• (See OSHA respirator requirements for selected chemicals) NIOSH Up to 5 ppm: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern† (APF = 50) Any self-contained breathing apparatus with a full facepiece (APF = 50) Any supplied-air respirator with a full facepiece Emergency or planned entry into unknown concentrations or IDLH conditions: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode (APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pres…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• Colorless gas at room temperature (b.p. 11 °C), confirmed carcinogen. Highly flammable, severe explosion hazard when exposed to flame. The autoignition temperature may be as low as 140 °C in presence of rust. Rapid compression of the vapor with air causes explosion. Ethylene oxide vapor may be initiated into explosive decomposition in absence of air [Hess, L. G., et al., Ind. Eng. Chem., 1950, 42, p. 1251]. Metal fittings containing magnesium, copper or silver should be avoided, since traces of acetylene in ethylene oxide may produce metal acetylides capable of detonating the vapor [MCA SD-38, 1971].
  CAMEO Chemicals
• Highly flammable. Flammable over a wide vapor-air concentration range. Must be diluted on the order of 24 to 1 with water to lose flammability. Soluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• 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.
  Hazardous Substances Data Bank (HSDB)
• 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.
  Hazardous Substances Data Bank (HSDB)
• INCOMPATIBILITIES: BECAUSE OF HIGH CHEMICAL REACTIVITY ... IT REACTS WITH MANY PHARMACEUTICAL SUBSTANCES & WITH VITAMINS, AMINO ACIDS, & OTHER FOOD CONSTITUENTS. ...
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• HYDROLYZES SLOWLY IN AQ SOLN
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Cancer, Developmental (effects during periods when organs are developing) , Endocrine (Glands and Hormones), Hematological (Blood Forming), Neurological (Nervous System), Reproductive (Producing Children), Respiratory (From the Nose to the Lungs)
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Eyes, skin, respiratory system, liver, central nervous system, blood, kidneys, reproductive system
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The vapour is irritating to the eyes, skin and respiratory tract. Water solutions may cause skin blisters. Rapid evaporation of the liquid may cause frostbite.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• Repeated or prolonged contact may cause skin sensitization. Repeated or prolonged inhalation may cause asthma. The substance may have effects on the nervous system. This substance is carcinogenic to humans. May cause heritable genetic damage to human germ cells.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• [40 CFR 240-280, 300-306, 702-799 (7/1/2006)] Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U115, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
  Hazardous Substances Data Bank (HSDB)
• Concentrated waste containing no peroxides-discharge liquid at a controlled rate near a pilot flame. Concentrated waste containing peroxides-perforation of a container of the waste from a safe distance followed by open burning.
  Hazardous Substances Data Bank (HSDB)
• A good candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A good candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1040

Shipping name

• UN 1040; Ethylene oxide
  Hazardous Substances Data Bank (HSDB)
• IMO 2.3; Ethylene oxide
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Ethylene oxide or Ethylene oxide with nitrogen up to a total pressure of 1 MPa (10 bar) at 50 degrees C
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1040
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Div 2.3 Poisonous gas (49 eCFR § 173.115)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Poison Gas Flammable Gas
  CAMEO Chemicals

UN classification

• UN Hazard Class: 2.3; UN Subsidiary Risks: 2.1
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 1040 119P
  Emergency Response Guidebook (ERG)

How DOT hazard classes work →

15Regulatory information

• This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Ethylene oxide is produced, as an intermediate or a final product, by process units covered under this subpart.
  Hazardous Substances Data Bank (HSDB)
• Tolerances are established for residues of the antimicrobial agent and insecticide ethylene oxide, when used as a postharvest fumigant in or on the following food commodities: [Table#606]
  Hazardous Substances Data Bank (HSDB)
• Ethylene oxide may be safely used as a fumigant for the control of microorganisms and insect infestation in ground spices and other processed natural seasoning materials, except mixtures to which salt has been added, in accordance with the following prescribed conditions: (i) Ethylene oxide, either alone or admixed with carbon dioxide or dichlorodifluoromethane, shall be used in amounts not to exceed that required to accomplish the intended technical effects. If used with dichlorodifluoromethane, the dichlorodifluoromethane shall conform with the requirements prescribed by 21 CFR 173.355 of this chapter.
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
  Hazardous Substances Data Bank (HSDB)
• Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Oxirane is included on this list. Effective date: 10/4/82; Sunset date: 10/4/92.
  Hazardous Substances Data Bank (HSDB)
• U115; As stipulated in 40 CFR 261.33, when ethylene oxide, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 6354 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.