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Methyl bromide

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Synonyms & Trade Names
Bromomethane, Monobromomethane
CAS No.
74-83-9
RTECS No.
PA4900000
DOT ID & Guide
1062 123
Formula
CH₃Br
Conversion
1 ppm = 3.89 mg/m3
IDLH
Ca [250 ppm]
See: 74839
Exposure Limits
NIOSH REL
Ca See Appendix A
OSHA PEL
C 20 ppm (80 mg/m3) [skin] See Appendix G
Measurement Methods
NIOSH 2520;
OSHA PV2040
See: NMAM or OSHA Methods
Physical Description
Colorless gas with a chloroform-like odor at high concentrations. [Note: A liquid below 38°F. Shipped as a liquefied compressed gas.]
Molecular Weight
95.0
Boiling Point
38°F
Freezing Point
-137°F
Solubility
2%
Vapor Pressure
1.9 atm
Ionization Potential
10.54 eV
Specific Gravity
1.73 (Liquid at 32°F)
Flash Point
NA (Gas)
Upper Explosive Limit
16.0%
Lower Explosive Limit
10%
Relative Gas Density
3.36
Flammable Gas, but only in presence of a high energy ignition source.
Incompatibilities & Reactivities
Aluminum, magnesium, strong oxidizers [Note: Attacks aluminum to form aluminum trimethyl, which is SPONTANEOUSLY flammable.]
Exposure Routes
inhalation, skin absorption (liquid), skin and/or eye contact (liquid)
Symptoms
irritation eyes, skin, respiratory system; muscle weak, incoordination, visual disturbance, dizziness; nausea, vomiting, headache; malaise (vague feeling of discomfort); hand tremor; convulsions; dyspnea (breathing difficulty); skin vesiculation; liquid: frostbite; [potential occupational carcinogen]
Target Organs
Eyes, skin, respiratory system, central nervous system
Cancer Site
[in animals: lung, kidney & forestomach tumors]
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact (liquid)
Eyes:Prevent eye contact (liquid)
Wash skin:When contaminated (liquid)
Remove:When wet (flammable)
Change:No recommendation
Provide:Quick drench (liquid)
First Aid
(See procedures)
Eye:Irrigate immediately (liquid)
Skin:Water flush immediately (liquid)
Breathing:Respiratory support
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 organic vapor canister
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0109   MEDICAL TESTS: 0138
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health