NIOSH logo and tagline

Methyl acetate

Synonyms & Trade Names
Methyl ester of acetic acid, Methyl ethanoate
CAS No.
79-20-9
RTECS No.
DOT ID & Guide
1231 129
Formula
CH₃COOCH₃
Conversion
1 ppm = 3.03 mg/m3
IDLH
3100 ppm [10%LEL]
See: 79209
Exposure Limits
NIOSH REL
TWA 200 ppm (610 mg/m3) ST 250 ppm (760 mg/m3)
OSHA PEL
TWA 200 ppm (610 mg/m3) See Appendix G
Measurement Methods
NIOSH 1458;
OSHA 7
See: NMAM or OSHA Methods
Physical Description
Colorless liquid with a fragrant, fruity odor.
Molecular Weight
74.1
Boiling Point
135°F
Freezing Point
-145°F
Solubility
25%
Vapor Pressure
173 mmHg
Ionization Potential
10.27 eV
Specific Gravity
0.93
Flash Point
14°F
Upper Explosive Limit
16%
Lower Explosive Limit
3.1%
Class IB Flammable Liquid: Fl.P. below 73°F and BP at or above 100°F.
Incompatibilities & Reactivities
Nitrates; strong oxidizers, alkalis & acids; water [Note: Reacts slowly with water to form acetic acid & methanol.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, nose, throat; headache, drowsiness; optic nerve atrophy; chest tightness; In Animals: narcosis
Target Organs
Eyes, skin, respiratory system, central nervous system
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet (flammable)
Change:No recommendation
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush promptly
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH/OSHA

Up to 2000 ppm:
(APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)*
(APF = 10) Any supplied-air respirator*

Up to 3100 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*
(APF = 50) Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s)
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)*
(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 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 organic vapor canister
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0507
Page last reviewed: October 30, 2019