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May 1994
 

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)


Methyl hydrazine

CAS number: 60–34–4

NIOSH REL: 0.04 ppm (0.08 mg/m3) 2-hour CEILING; NIOSH considers methyl hydrazine to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 0.2 ppm (0.35 mg/m3) CEILING [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.2 ppm (0.38 mg/m3) CEILING [skin], A2

Description of substance: Fuming, colorless liquid with an ammonia-like odor.

LEL: . . . 2.5% (10% LEL, 2,500 ppm)

Original (SCP) IDLH: 50 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the report by Jacobson et al. [1955] of a mouse LC50 of 56 ppm.

Short-term exposure guidelines: National Research Council [NRC 1985] Short-term Public Emergency Guidance Levels (SPEGLs):

1-hour SPEGL: 0.24 ppm

2-hour SPEGL: 0.12 ppm

4-hour SPEGL: 0.06 ppm

8-hour SPEGL: 0.03 ppm

16-hour SPEGL: 0.015 ppm

24-hour SPEGL: 0.01 ppm

ACUTE TOXICITY DATA:

Lethal concentration data:

 

SpeciesReferenceLC50 (ppm)LCLo (ppm)TimeAdjusted 0.5-hr

LC (CF)

Derived value
Rat

Rat

Monkey

Dog

Monkey

Mouse

Rat

Mouse

Hamster

Fairchild 1967

Haun et al. 1969

Haun et al. 1969

Haun et al. 1970

Haun et al. 1970

Haun et al. 1970

Haun et al. 1970

Jacobson et al. 1955

Jacobson et al. 1955

34

74

162

195

145

272

427

56

143

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4 hr

4 hr

1 hr

30 min

30 min

30 min

30 min

4 hr

4 hr

68 ppm (2.0)

148 ppm (2.0)

203 ppm (1.25)

195 ppm (1.0)

145 ppm (1.0)

272 ppm (1.0)

427 ppm (1.0)

112 ppm (2.0)

286 ppm (2.0)

6.8 ppm

15 ppm

20 ppm

20 ppm

15 ppm

27 ppm

43 ppm

11 ppm

29 ppm

Human data: None relevant for use in determining the revised IDLH.

 

Revised IDLH: 20 ppm

Basis for revised IDLH: The revised IDLH for methyl hydrazine is 20 ppm based on acute inhalation toxicity data in animals [Haun et al. 1969, 1970]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for methyl hydrazine at concentrations above 0.04 ppm.]

REFERENCES:

1. Fairchild EJ II [1967]. Toxic Hazards Research Unit annual technical report: 1967. Wright-Patterson Air Force Base, OH: Aerospace Medical Research Laboratory, Report No. AMRL-TR-67-137, pp. 1-58.

2. Haun CC, MacEwen JD, Vermont EH, Egan GF [1969]. The acute inhalation toxicity of monomethyl hydrazine vapor. Wright-Patterson Air Force Base, OH: Aerospace Medical Research Laboratory Report No. AMRL-TR-68-169.

3. Haun CC, MacEwen JD, Vernot EH, Egan GF [1970]. Acute inhalation toxicity of monomethylhydrazine vapor. Am Ind Hyg Assoc J 31:667-677.

4. Jacobson KH, Clem JH, Wheelwright HJ, Rinehart WE, Mayes N [1955]. The acute toxicity of the vapors of some methylated hydrazine derivatives. AMA Arch Ind Health 12:609-616.

5. NRC [1985]. Emergency and continuous exposure guidance levels for selected airborne contaminants. Vol. 5. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 23-35.

 
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