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Methyl isocyanate

Synonyms & Trade Names
Methyl ester of isocyanic acid, MIC
CAS No.
624-83-9
RTECS No.
NQ9450000
DOT ID & Guide
2480 155
Formula
CH3NCO
Conversion
1 ppm = 2.34 mg/m3
IDLH
3 ppm
See: 624839
Exposure Limits
NIOSH REL
TWA 0.02 ppm (0.05 mg/m3) [skin]
OSHA PEL
TWA 0.02 ppm (0.05 mg/m3) [skin]
Measurement Methods
OSHA 54
See: NMAM or OSHA Methods
Physical Description
Colorless liquid with a sharp, pungent odor.
Molecular Weight
57.1
Boiling Point
102-104°F
Freezing Point
-49°F
Solubility
(59°F): 10%
Vapor Pressure
348 mmHg
Ionization Potential
10.67 eV
Specific Gravity
0.96
Flash Point
19°F
Upper Exposive Limit
26%
Lower Explosive Limit
5.3%
Class IB Flammable Liquid: Fl.P. below 73°F and BP at or above 100°F.
Incompatibilities & Reactivities
Water, oxidizers, acids, alkalis, amines, iron, tin, copper [Note: Usually contains inhibitors to prevent polymerization.]
Exposure Routes
inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, nose, throat; resp sensitization, cough, pulmonary secretions, chest pain, dyspnea (breathing difficulty); asthma; eye, skin damage; In Animals: pulmonary edema
Target Organs
Eyes, skin, respiratory 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
Provide:Eyewash, Quick drench
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH/OSHA

Up to 0.2 ppm:
(APF = 10) Any supplied-air respirator*

Up to 0.5 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*

Up to 1 ppm:
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 3 ppm:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

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: 0004   MEDICAL TESTS: 0143
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