NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Methyl hydrazine



Synonyms & Trade Names

MMH, Monomethylhydrazine
DOT ID & Guide
1244 / 131


NIOSH REL: Ca C 0.04 ppm (0.08 mg/m3) [2-hr] See Appendix A
OSHA PEL: C 0.2 ppm (0.35 mg/m3) [skin]
Ca [20 ppm] See: 60344
1 ppm = 1.89 mg/m3
Physical Description
Fuming, colorless liquid with an ammonia-like odor.
MW: 46.1
BP: 190°F
FRZ: -62°F
Sol: Miscible
VP: 38 mmHg
IP: 8.00 eV

Sp.Gr(77°F): 0.87
Fl.P: 17°F
UEL: 92%
LEL: 2.5%

Class IB Flammable Liquid: Fl.P. below 73F and BP at or above 100F.
Incompatibilities & Reactivities

Oxides of iron; copper; manganese; lead; copper alloys; porous materials such as earth, asbestos, wood & cloth; strong oxidizers such as fluorine & chlorine; nitric acid; hydrogen peroxide
Measurement Methods
NIOSH 3510
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
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
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: Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, skin absorption, ingestion, skin and/or eye contact
Irritation eyes, skin, respiratory system; vomiting, diarrhea, tremor, ataxia; anoxia, cyanosis; convulsions; [potential occupational carcinogen]
Target Organs
Eyes, skin, respiratory system, central nervous system, liver, blood, cardiovascular system

Cancer Site
[in animals: lung, liver, blood vessel & intestine tumors]
See also: INTRODUCTION   See ICSC CARD: 0180   See MEDICAL TESTS: 0142