Propylene Oxide

1Identification

Name

Propylene Oxide

IUPAC name

2-methyloxirane

CAS number

75-56-9

EC number

200-879-2

Molecular formula

C3H6O

Molecular weight

58.08 g/mol

InChIKey

GOOHAUXETOMSMM-UHFFFAOYSA-N

SMILES

CC1CO1

PubChem CID

6378

Synonyms

Propylene oxide, 1,2-Epoxypropane, Methyloxirane, Propene oxide, Epoxypropane, Propyleneoxide, Oxirane, methyl-, 1,2-PROPYLENE OXIDE, Propylene epoxide, Methyl oxirane, 2,3-Epoxypropane, Methyloxacyclopropane, Methyl ethylene oxide, Propane, epoxy-

Recommended uses

• The major use of propylene oxide is in the production of polyethers (the primary component of polyurethane foams) and propylene glycol.
  EPA Hazardous Air Pollutants
• Used mainly as a chemical intermediate; it has been used as a food fumigant (dried fruit and bulk), but use was restricted in 1996 by the EPA. [ACGIH] Used to prepare slides for electron microscopy and to disinfect the skin; [Kanerva, p. 1831]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Restricted use as a food fumigant by EPA in 1996 because of Delaney clause (animal carcinogen); [ACGIH]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Sealant (barrier) Not Known or Reasonably Ascertainable Flame retardant Intermediate Other Lubricating agent Monomers Surfactant (surface active agent)
  EPA Chemical Data Reporting (CDR)

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

Description

• Propylene Oxide can cause cancer according to an independent committee of scientific and health experts.
  California Office of Environmental Health Hazard Assessment (OEHHA)
• Propylene oxide appears as a clear colorless volatile liquid with an ethereal odor. Flash point -35 °F. Boiling point 95 °F. Density 6.9 lb./gal. Flammable over a wide range of vapor-air concentrations. If contaminated, may polymerize with evolution of heat and possible rupture of container. Vapors irritate eyes, skin, and respiratory system. Prolonged contact with skin may result in delayed burns. Vapors heavier than air. Used as a fumigant, in making detergents and lubricants, and to make other chemicals.
  CAMEO Chemicals
• 1,2-epoxypropane is an epoxide that is oxirane substituted by a methyl group at position 2. It is functionally related to an oxirane.
  ChEBI

2Hazard identification

Signal word

Danger

Pictograms

GHS02, GHS06, GHS08

Classification source

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

Precautionary statements

Other reported classifications

5 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)
• 2 - Materials that readily undergo violent chemical changes at elevated temperatures and pressures.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• This material is moderately toxic by inhalation and ingestion. It may cause irreversible and reversible changes. Skin contact with the material or solutions of the material cause irritation; diluted solutions are more irritating than undiluted materials. Exposure may cause mild depression of the central nervous system and eye, nasal, and lung irritation. Contact with the liquid can cause blindness and death. Pulmonary edema may recur up to 2 weeks after exposure. (EPA, 1998)
  CAMEO Chemicals
• · Inhalation or contact with material may irritate or burn skin and eyes. · Fire may produce irritating, corrosive and/or toxic gases. · Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. · Runoff from fire control or dilution water may cause environmental contamination.
  Emergency Response Guidebook (ERG)

Fire hazards

• Vapor is heavier than air and may travel considerable distance to source of ignition and flash back. Vapors form explosive mixture with air. If polymerization takes place in container, there may be a violent rupture of container. Explosion hazard is severe when exposed to flame. Violently reacts with acetylide- forming metals such as copper or copper alloys, ammonium hydroxide; chlorosulfonic acid; hydrochloric acid; hydrofluoric acid; nitric acid; oleum and sulfuric acid. Hazardous polymerization may occur. Avoid active catalytic surfaces such as anhydrous chlorides of iron, tin, and aluminum; peroxides of iron and aluminum; and alkali metal hydroxides, high temperatures; alkalies;
  CAMEO Chemicals
• · HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. CAUTION: Ethanol (UN1170) can burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) · Vapors may form explosive mixtures with air. · Vapors may travel to source of ignition and flash back. · Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.). · Vapor explosion hazard indoors, outdoors or in sewers. · Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. · Runoff to sewer may create fire or explosion hazard.
  Emergency Response Guidebook (ERG)
• Extremely flammable. Heating will cause rise in pressure with risk of bursting. Vapour/air mixtures are explosive.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• Propylene oxide is used in the production of polyethers (the primary component of polyurethane foams) and propylene glycol. Acute (short-term) exposure of humans and animals to propylene oxide has caused eye and respiratory tract irritation. Dermal contact, even with dilute solutions, has caused skin irritation and necrosis in humans. Propylene oxide is also a mild central nervous system (CNS) depressant in humans. Inflammatory lesions of the nasal cavity, trachea, and lungs and neurological effects have been observed in animals chronically (long-term) exposed to propylene oxide by inhalation.
  EPA Hazardous Air Pollutants
• Liquid causes first degree burns on short exposure. [CHRIS] Allergic contact dermatitis reported in a worker swabbing skin with a disinfectant; [Kanerva, p. 1831] Can cause CNS depression and severe eye injuries; A respiratory irritant that may cause pulmonary edema; [CAMEO] Causes mild CNS depression in animals after inhalation of high concentrations; A nasal carcinogen in rodents at concentrations causing irritation; NOAEL is 50 ppm; Detoxified more rapidly than ethylene oxide, and this is one of the reasons for the lower carcinogenic potency of propylene oxide; A dermal sensitizer; [ACGIH] Propylene oxide (UN1280) has warning of explosive polymerization; [ERG 2016]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

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

• Signs and Symptoms of Acute Propylene Oxide Exposure: Propylene oxide may irritate or burn the skin, eyes, and respiratory tract. Pulmonary edema may occur up to 2 weeks after exposure. Dermatitis (red, inflamed skin) is common. Other signs and symptoms of acute exposure may include headache, nausea, vomiting, and unconsciousness. Victims may appear as if they are in a drunken stupor. Emergency Life-Support Procedures: Acute exposure to propylene oxide may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination.
  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 - If this chemical has been swallowed, get medical attention immediately.
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Cough. Sore throat.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as a fog. Solid streams of water may be ineffective. Cool all effective containers with flooding quantities of water. Apply water from as far away as possible. Use "alcohol" foam, dry chemical or carbon dioxide.
  Hazardous Substances Data Bank (HSDB)
• Evacuation: If fire becomes uncontrollable or container is exposed to direct flame, evacuate for a radius of 1 mile.
  Hazardous Substances Data Bank (HSDB)
• Use flooding quantities of water as fog. May use water spray, dry chemical, "alcohol resistant" foam, or carbon dioxide. Use water spray to keep fire exposed containers cool. Fight fire from protected location or maximum possible distance.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 127 [Flammable Liquids (Water-Miscible); polymerization hazard]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions. LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet). FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals
• Immediate precautionary measure · Isolate spill or leak area for at least 50 meters (150 feet) in all directions. Large Spill · Consider initial downwind evacuation for at least 300 meters (1000 feet). Fire · If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
  Emergency Response Guidebook (ERG)

Spill cleanup

• Evacuate danger area! Consult an expert! Remove all ignition sources. Personal protection: complete protective clothing including self-contained breathing apparatus. Ventilation. Collect leaking liquid in sealable dry containers. Absorb remaining liquid in dry sand or inert absorbent. Then store and dispose of according to local regulations.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Evacuation: If material leaking (not on fire) consider evacuation from downwind area based on amount of material spilled, location and weather conditions.
  Hazardous Substances Data Bank (HSDB)
• 1. REMOVE ALL IGNITION SOURCES. 2. VENTILATE AREA OF SPILL OR LEAK. 3. FOR SMALL QUANTITIES, ABSORB ON PAPER TOWELS. EVAPORATE IN A SAFE PLACE (SUCH AS A FUME HOOD). ALLOW SUFFICIENT TIME FOR EVAPORATING VAPORS TO COMPLETELY CLEAR THE HOOD DUCTWORK. BURN THE PAPER IN A SUITABLE LOCATION AWAY FROM COMBUSTIBLE MATERIALS. LARGE QUANTITIES MAY BE COLLECTED, DISSOLVED IN ALC OF GREATER MOL WT THAN BUTYL ALC, & ATOMIZED IN A SUITABLE COMBUSTION CHAMBER.
  Hazardous Substances Data Bank (HSDB)
• Land spill: Dig a pit, pond, lagoon, or holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, sawdust, or commercial sorbents. Apply "universal" gelling agent to immobilize spill.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Separated from acids, bases and strong oxidants. Dry. Cool. Well closed. Keep in the dark.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Use glass or metal containers sealed with nitrogen.
  Hazardous Substances Data Bank (HSDB)
• PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
  Hazardous Substances Data Bank (HSDB)
• Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Separate from acids, alkalies, salts, combustible material, clay-based absorbents.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Propylene oxide: Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact. Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact. Wash skin: WHEN CONTAMINATED - 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). Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.
  CAMEO Chemicals
• /When handling/ wear rubber gloves, large & heavy face shields (body shields are also recommendable) & self-contained breathing apparatus.
  Hazardous Substances Data Bank (HSDB)
• PRECAUTIONS FOR "CARCINOGENS": ... Dispensers of liq detergent /should be available./ ... Safety pipettes should be used for all pipetting. ... In animal laboratory, personnel should ... wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. ... Gowns ...
  Hazardous Substances Data Bank (HSDB)
• Wear appropriate personal protective clothing to prevent skin contact.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• NIOSH At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration: (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 pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus Escape: (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 Any appropriate escape-type, self-contained…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• PROPYLENE OXIDE react with oxidizing agents and strong acids (NTP, 1992). Reacts with Grignard reagents and organolithium compounds. An explosion occurred when propylene oxide was added to an epoxy resin. It was concluded that polymerization was catalyzed by an amine accelerator in the resin [Bretherick, 5th Ed., 1995]. Underwent polymerization when mixed with sodium hydroxide causing ignition and explosion of a drum of the crude product. [Combust Sci. Technol., 1983].
  CAMEO Chemicals
• Highly flammable. Soluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• No acetylide-forming metals such as copper or copper alloys should be in contact with propylene oxide.
  Hazardous Substances Data Bank (HSDB)
• A polyether-alcohol, prepared by co-condensation of ethylene oxide and propylene oxide with a polyhydric alcohol, was stored at above 100 °C and exposed to air via a vent line. After 10-15 hr, violent decompostion occurred, rupturing the vessel.
  Hazardous Substances Data Bank (HSDB)
• ... PROPYLENE OXIDE MAY REACT WITH INORG CHLORIDES PRESENT IN FOODSTUFFS TO FORM TOXIC CHLOROHYDRINS.
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• It polymerizes exothermically.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Respiratory
  EPA Integrated Risk Information System (IRIS)
• Eyes, skin, respiratory system
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The substance is irritating to the eyes, skin and respiratory tract. If swallowed the substance may cause vomiting and could result in aspiration pneumonitis.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• Repeated or prolonged contact with skin may cause dermatitis. This substance is possibly carcinogenic to humans.
  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

• SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
  Hazardous Substances Data Bank (HSDB)
• Propylene oxide is a waste chemical stream constituent which may be subjected to ultimate disposal by controlled incineration. Concentrated waste containing no peroxides; discharge liquid at a controlled rate near a pilot flame. Concentrated waste containing peroxides; perforation of a container of waste from a safe distance followed by open burning.
  Hazardous Substances Data Bank (HSDB)
• PROPYLENE OXIDE MAY BE DISPOSED OF BY DISSOLVING IN PENTYL OR HIGHER CARBON NUMBER ALC & ATOMIZING IN A SUITABLE COMBUSTION CHAMBER.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1280

Shipping name

• IMO 3.1; Propylene oxide
  Hazardous Substances Data Bank (HSDB)
• UN 1280; Propylene oxide
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Propylene oxide
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1280
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Class 3 Flammable and combustible liquid (49 eCFR § 173.120)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Flammable Liquid
  CAMEO Chemicals

UN classification

• UN Hazard Class: 3; UN Pack Group: I
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 1280 127P
  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. Propylene oxide is produced, as an intermediate or a final product, by process units covered under this subpart.
  Hazardous Substances Data Bank (HSDB)
• As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996.
  Hazardous Substances Data Bank (HSDB)
• Propylene oxide is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
  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 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. 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, methyl is included on this list.
  Hazardous Substances Data Bank (HSDB)

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

16Other information

Compiled from PubChem CID 6378 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.