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Chemical Datasheet
METHACRYLONITRILE, STABILIZED |
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Chemical Identifiers
CAS Number |
UN/NA Number |
DOT Hazard Label |
USCG CHRIS Code |
- 126-98-7
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- Poison Inhalation Hazard
- Flammable Liquid
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NIOSH Pocket Guide |
International Chem Safety Card |
Methylacrylonitrile
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NFPA 704
General Description
A clear colorless liquid. Less dense than water. Flash point 55°F. Boiling point 195°F. Very be toxic by ingestion, inhalation and skin absorption. Used to make plastics and coatings.
Hazards
Reactivity Alerts
- Highly Flammable
- Polymerizable
Air & Water Reactions
Highly flammable. Soluble in water.
Fire Hazard
Methacrylonitrile evolves flammable concentrations of vapor at temperatures down to 55.04F. Thus, at room temperatures, flammable concentrations are liable to be present. Toxic fumes of nitrogen oxides are released when the material burns. Also, the chemical will explode due to its tendency to polymerize violently. Avoid heat. Hazardous polymerization may occur. (EPA, 1998)
Health Hazard
A lacrimator (causes tearing); an insidious poison which causes delayed skin reactions. Very readily absorbed through skin. Highly toxic. (EPA, 1998)
Reactivity Profile
METHACRYLONITRILE is a colorless, flammable, toxic liquid. Explosive in the form of vapor when exposed to heat, flame or sparks. When heated to decomposition it emits toxic fumes of nitrile and oxides of nitrogen [Lewis, 3rd ed., 1993, p. 829].
Belongs to the Following Reactive Group(s)
- Nitriles
- Acrylates and Acrylic Acids
- Polymerizable Compounds
Potentially Incompatible Absorbents
Use caution: Liquids with this reactive group classification have been
known to react with the
absorbents
listed below.
- Cellulose-Based Absorbents
- Mineral-Based & Clay-Based Absorbents
- Dirt/Earth
Response Recommendations
Isolation and Evacuation
Excerpt from ERG Guide 131

[Flammable Liquids - Toxic; polymerization hazard]:
IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.
SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 3079 datasheet.
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
Usual precautions for flammable liquid should be applied. (EPA, 1998)
Non-Fire Response
Excerpt from ERG Guide 131

[Flammable Liquids - Toxic; 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.
SMALL SPILL: Absorb with earth, sand or other non-combustible material and transfer to containers for later disposal. 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 Methylacrylonitrile:
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. (NIOSH, 2024)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
Warning: Effects, including skin reactions, may be delayed. Caution is advised. Vital signs should be monitored closely. Heart palpitation may begin within minutes after exposure.
Note: Methylacrylonitrile is very readily absorbed through the skin.
Signs and Symptoms of Acute Methylacrylonitrile Exposure: Signs and symptoms of acute exposure to methylacrylonitrile may include hypertension (high blood pressure) and tachycardia (rapid heart rate), followed by hypotension (low blood pressure) and bradycardia (slow heart rate). Cherry-red mucous membranes and blood, cardiac arrhythmias, and other cardiac abnormalities are common. Cyanosis (blue tint to the skin and mucous membranes) is not a consistent finding. Tachypnea (rapid respiratory rate) may be followed by respiratory depression. Lung hemorrhage and pulmonary edema may also occur. Headache, vertigo (dizziness), agitation, and giddiness may be followed by combative behavior, convulsions, paralysis, protruding eyeballs, dilated and unreactive pupils, and coma. Methylacrylonitrile is irritating to the skin and mucous membranes. Lacrimation (tearing) and a burning sensation of the mouth and throat are common. Excessive salivation, nausea, and vomiting may also occur.
Emergency Life-Support Procedures: Acute exposure to methylacrylonitrile may require decontamination and life support for the victims. All exposed persons should be transported to a health care facility as quickly as possible. 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 methylacrylonitrile.
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. IMMEDIATELY begin administering 100% oxygen to all victims. Monitor victims for respiratory distress.Warning: To prevent self-poisoning, avoid mouth-to-mouth breathing; use a forced-oxygen mask. Direct oral contact with methylacrylonitrile- contaminated persons or their gastric contents may result in self- poisoning.
3. RUSH to a health care facility!
4. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self- exposure to methylacrylonitrile.
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. IMMEDIATELY begin administering 100% oxygen to all victims. Monitor victims for respiratory distress.Warning: To prevent self-poisoning, avoid mouth-to-mouth breathing; use a forced-oxygen mask. Direct oral contact with methylacrylonitrile- contaminated persons or their gastric contents may result in self- poisoning.
3. RUSH to a health care facility!
4. Remove contaminated clothing as soon as possible.
5. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
6. Wash exposed skin areas twice with soap and water.
7. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
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. IMMEDIATELY begin administering 100% oxygen to all victims. Monitor victims for respiratory distress.Warning: To prevent self-poisoning, avoid mouth-to-mouth breathing; use a forced-oxygen mask. Direct oral contact with methylacrylonitrile- contaminated persons or their gastric contents may result in self- poisoning.
2. RUSH to a health care facility!
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. DO NOT induce vomiting or attempt to neutralize!
5. 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.
6. Give the victims water or milk: children up to 1 year old, 125 mL (4 oz or 1/2 cup); children 1 to 12 years old, 200 mL (6 oz or 3/4 cup); adults, 250 mL (8 oz or 1 cup). Water or milk should be given only if victims are conscious and alert. (EPA, 1998)
Physical Properties
Flash Point:
55°F
(EPA, 1998)
Lower Explosive Limit (LEL):
2 %
(NTP, 1992)
Upper Explosive Limit (UEL):
6.8 %
(NTP, 1992)
Autoignition Temperature: data unavailable
Melting Point:
-32.4°F
(EPA, 1998)
Vapor Pressure:
40 mmHg
at 55.04°F
(EPA, 1998)
Vapor Density (Relative to Air):
2.31
(EPA, 1998)
- Heavier than air; will sink
Specific Gravity:
0.8001
at 68°F
(EPA, 1998)
- Less dense than water; will float
Boiling Point:
194°F
at 760 mmHg
(EPA, 1998)
Molecular Weight:
67.1
(EPA, 1998)
Water Solubility:
10 to 50 mg/mL
at 72°F
(NTP, 1992)
Ionization Energy/Potential: data unavailable
IDLH:
4 ppm
(NIOSH, 2024)
AEGLs (Acute Exposure Guideline Levels)
Final AEGLs for Methacrylonitrile (126-98-7)
Exposure Period |
AEGL-1 |
AEGL-2 |
AEGL-3 |
10 minutes |
NR |
1.3 ppm |
3.9 ppm |
30 minutes |
NR |
1.3 ppm |
3.9 ppm |
60 minutes |
NR |
1 ppm |
3.1 ppm |
4 hours |
NR |
0.67 ppm |
2 ppm |
8 hours |
NR |
0.33 ppm |
0.99 ppm |
(NAC/NRC, 2024)
ERPGs (Emergency Response Planning Guidelines)
No ERPG information available.
PACs (Protective Action Criteria)
Chemical |
PAC-1 |
PAC-2 |
PAC-3 |
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Methacrylonitrile; (Methylacrylonitrile) (126-98-7)
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0.091 ppm |
1 ppm |
3.1 ppm |
LEL = 20000 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 |
2-Propenenitrile, 2-methyl- |
126-98-7 |
500 pounds |
1000 pounds |
1000 pounds |
X |
U152 |
10000 pounds |
Methacrylonitrile |
126-98-7 |
500 pounds |
1000 pounds |
1000 pounds |
313 |
U152 |
10000 pounds |
(EPA List of Lists, 2024)
CISA Chemical Facility Anti-Terrorism Standards (CFATS)
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RELEASE |
THEFT |
SABOTAGE |
Chemical of Interest |
CAS Number |
Min Conc |
STQ |
Security Issue |
Min Conc |
STQ |
Security Issue |
Min Conc |
STQ |
Security Issue |
Methacrylonitrile; [2-Propenenitrile, 2-methyl-] |
126-98-7 |
1.00 % |
10000 pounds |
toxic |
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(CISA, 2007)
OSHA Process Safety Management (PSM) Standard List
Chemical Name |
CAS Number |
Threshold Quantity (TQ) |
Methyl Acrylonitrile |
126-98-7 |
250 pounds |
(OSHA, 2019)
Alternate Chemical Names
- ALPHA-METHACRYLONITRILE
- ALPHA-METHYLACRYLONITRILE
- 2-CYANO-1-PROPENE
- 2-CYANOPROPENE-1
- 2-CYANOPROPENE
- ISOPRENE CYANIDE
- ISOPROPENE CYANIDE
- ISOPROPENYLNITRILE
- MAN
- METHACRYLNITRILE
- METHACRYLONITRILE
- METHACRYLONITRILE, STABILIZED
- 2-METHYL-2- PROPENENITRILE
- 2-METHYL-2-PROPENENITRILE
- METHYLACRYLONITRILE
- 2-METHYLACRYLONITRILE
- 1-METHYLETHENYL CYANIDE
- 2-METHYLPROPENENITRILE
- 2-PROPENE- NITRILE, 2-METHYL-
- 2-PROPENENITRILE, 2-METHYL-
- 2-PROPENENITRILE, 2-METHYL
- USAF ST-40
- USAF ST40