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Chemical Datasheet
PROPYLENE OXIDE |
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Chemical Identifiers
CAS Number |
UN/NA Number |
DOT Hazard Label |
USCG CHRIS Code |
- 75-56-9
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NIOSH Pocket Guide |
International Chem Safety Card |
Propylene oxide
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NFPA 704
General Description
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.
Hazards
Reactivity Alerts
- Highly Flammable
- Polymerizable
Air & Water Reactions
Highly flammable. Soluble in water.
Fire Hazard
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; aqueous acids; amines and acidic alcohols. (EPA, 1998)
Health Hazard
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)
Reactivity Profile
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].
Belongs to the Following Reactive Group(s)
- Epoxides
- Polymerizable Compounds
Potentially Incompatible Absorbents
Use caution: Liquids with this reactive group classification have been
known to react with the
absorbents
listed below.
- Mineral-Based & Clay-Based Absorbents
- Dirt/Earth
Response Recommendations
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)
Firefighting
Firefighting should be done from a safe distance or from a protected location. Wear self-contained (positive pressure if available) breathing apparatus and full protective clothing. Isolate for 1/2 mile in all directions if tank car or truck is involved in fire. Move container from area if you can do so without risk. Spray cooling water on containers that are exposed to flames until well after fire is out. For massive fire in cargo area, use unmanned hose holder or monitor nozzles; if this is impossible, withdraw from area and let fire burn. Withdraw immediately in case of rising sound from venting safety device or any discoloration of tank due to fire.
Extinguish with dry chemical, carbon dioxide, water spray, fog or foam. (EPA, 1998)
Non-Fire Response
Excerpt from ERG Guide 127

[Flammable Liquids (Water-Miscible); polymerization hazard]:
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean, non-sparking tools to collect absorbed material.
LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2024)
Protective Clothing
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.
Provide: QUICK DRENCH - Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2024)
DuPont Tychem® Suit Fabrics
Normalized Breakthrough Times (in Minutes)
Chemical |
CAS Number |
State |
QS |
QC |
SL |
C3 |
TF |
TP |
RC |
TK |
RF |
Epoxy propane, 1,2- |
75-56-9 |
Liquid |
|
|
|
47 |
43 |
13*/20 |
>480 |
>480 |
>480 |
Propylene oxide, 1,2- |
75-56-9 |
Liquid |
|
|
|
47 |
43 |
13*/20 |
>480 |
>480 |
>480 |
Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be
used around heat, flames, sparks or in potentially flammable or
explosive environments. Only...
(DuPont, 2024)
First Aid
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. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.
Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to propylene oxide.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Transport to a health care facility.
Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self- exposure to propylene oxide.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas THOROUGHLY with soap and water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. Transport to a health care facility.
Ingestion Exposure:
1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
2. DO NOT induce vomiting or attempt to neutralize!
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children, 50 to 100 g (1-3/4 to 3-1/2 oz) for adults, with 125 to 250 mL (1/2 to 1 cup) of water.
5. Promote excretion by administering a saline cathartic or sorbitol to conscious and alert victims. Children require 15 to 30 g (1/2 to 1 oz) of cathartic; 50 to 100 g (1-3/4 to 3-1/2 oz) is recommended for adults.
6. Transport to a health care facility. (EPA, 1998)
Physical Properties
Flash Point:
-35°F
(EPA, 1998)
Lower Explosive Limit (LEL):
2.8 %
(EPA, 1998)
Upper Explosive Limit (UEL):
37 %
(EPA, 1998)
Autoignition Temperature:
869°F
(USCG, 1999)
Melting Point:
-169.83°F
(EPA, 1998)
Vapor Pressure:
445 mmHg
at 68°F
(EPA, 1998)
Vapor Density (Relative to Air):
2
(EPA, 1998)
- Heavier than air; will sink
Specific Gravity:
0.859
at 32°F
(EPA, 1998)
- Less dense than water; will float
Boiling Point:
93.61°F
at 760 mmHg
(EPA, 1998)
Molecular Weight:
58.08
(EPA, 1998)
Water Solubility:
greater than or equal to 100 mg/mL
at 66°F
(NTP, 1992)
Ionization Energy/Potential:
9.81 eV
(NIOSH, 2024)
IDLH:
400 ppm
; A potential occupational carcinogen.
(NIOSH, 2024)
AEGLs (Acute Exposure Guideline Levels)
Final AEGLs for Propylene oxide (75-56-9)
Exposure Period |
AEGL-1 |
AEGL-2 |
AEGL-3 |
10 minutes |
73 ppm |
440 ppm |
1300 ppm |
30 minutes |
73 ppm |
440 ppm |
1300 ppm |
60 minutes |
73 ppm |
290 ppm |
870 ppm |
4 hours |
73 ppm |
130 ppm |
390 ppm |
8 hours |
73 ppm |
86 ppm |
260 ppm |
(NAC/NRC, 2024)
ERPGs (Emergency Response Planning Guidelines)
Chemical |
ERPG-1 |
ERPG-2 |
ERPG-3 |
Propylene Oxide (75-56-9)
|
50 ppm  |
250 ppm |
750 ppm |
(AIHA, 2022)
PACs (Protective Action Criteria)
Chemical |
PAC-1 |
PAC-2 |
PAC-3 |
|
Propylene oxide; (Methyl ethylene oxide) (75-56-9)
|
73 ppm |
290 ppm |
870 ppm |
LEL = 23000 ppm |
(DOE, 2024)
Regulatory Information
EPA Consolidated List of Lists
Regulatory Name |
CAS Number/ 313 Category Code |
EPCRA 302 EHS TPQ |
EPCRA 304 EHS RQ |
CERCLA RQ |
EPCRA 313 TRI |
RCRA Code |
CAA 112(r) RMP TQ |
Oxirane, methyl- |
75-56-9 |
10000 pounds |
100 pounds |
100 pounds |
X |
|
10000 pounds |
Propylene oxide |
75-56-9 |
10000 pounds |
100 pounds |
100 pounds |
313 |
|
10000 pounds |
(EPA List of Lists, 2024)
CISA Chemical Facility Anti-Terrorism Standards (CFATS)
|
RELEASE |
THEFT |
SABOTAGE |
Chemical of Interest |
CAS Number |
Min Conc |
STQ |
Security Issue |
Min Conc |
STQ |
Security Issue |
Min Conc |
STQ |
Security Issue |
Propylene oxide; [Oxirane, methyl-] |
75-56-9 |
1.00 % |
10000 pounds |
flammable |
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(CISA, 2007)
OSHA Process Safety Management (PSM) Standard List
No regulatory information available.
Alternate Chemical Names
- AD 6
- AD 6 (SUSPENDING AGENT)
- DL-1,2-EPOXYPROPANE
- DL-PROPYLENE OXIDE
- EPIHYDRIN
- 1,2-EPOXY PROPANE
- EPOXYPROPANE
- (.+-.)-EPOXYPROPANE
- (.+-.)-1,2-EPOXYPROPANE
- 1,2-EPOXYPROPANE
- 2,3-EPOXYPROPANE
- ETHYLENE OXIDE, METHYL-
- METHYL ETHYLENE OXIDE
- METHYL OXIRANE
- METHYLOXACYCLOPROPANE
- METHYLOXIRANE
- (.+-.)-METHYLOXIRANE
- (.+-.)-2-METHYLOXIRANE
- NCI-C50099
- OXIRANE, METHYL-
- OXYPROPYLENE
- PROPANE, 1,2-EPOXY-
- PROPANE, EPOXY
- PROPENE OXIDE
- PROPENEOXIDE
- PROPYLENE EPOXIDE
- PROPYLENE OXIDE
- (.+-.)-PROPYLENE OXIDE
- 1,2-PROPYLENE OXIDE
- PROPYLENEOXIDE