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Methyl acetylene

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Synonyms & Trade Names
Allylene, Propine, Propyne, 1-Propyne
CAS No.
74-99-7
RTECS No.
UK4250000
DOT ID & Guide
Formula
C₃H₄
Conversion
1 ppm = 1.64 mg/m3
IDLH
1700 ppm [10%LEL]
See: 74997
Exposure Limits
NIOSH REL
TWA 1000 ppm (1650 mg/m3)
OSHA PEL
TWA 1000 ppm (1650 mg/m3)
Measurement Methods
NIOSH S84 (II-5)
See: NMAM or OSHA Methods
Physical Description
Colorless gas with a sweet odor. [Note: A fuel that is shipped as a liquefied compressed gas.]
Molecular Weight
40.1
Boiling Point
-10°F
Freezing Point
-153°F
Solubility
Insoluble
Vapor Pressure
5.2 atm
Ionization Potential
10.36 eV
Flash Point
NA (Gas)
Upper Explosive Limit
?
Lower Explosive Limit
1.7%
Relative Gas Density
1.41
Flammable Gas
Incompatibilities & Reactivities
Strong oxidizers (such as chlorine), copper alloys [Note: Can decompose explosively at 4.5 to 5.6 atmospheres of pressure.]
Exposure Routes
inhalation, skin and/or eye contact (liquid)
Symptoms
irritation respiratory system; tremor, hyperexcitability, anesthesia; liquid: frostbite
Target Organs
respiratory system, central nervous system
Personal Protection/Sanitation
(See protection codes)
Skin:Frostbite
Eyes:Frostbite
Wash skin:No recommendation
Remove:When wet (flammable)
Change:No recommendation
Provide:Frostbite wash
First Aid
(See procedures)
Eye:Frostbite
Skin:Frostbite
Breathing:Respiratory support
Respirator Recommendations

NIOSH/OSHA

Up to 1700 ppm:
(APF = 10) Any supplied-air respirator
(APF = 50) Any self-contained breathing apparatus 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: 0560
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health