1,1-Dimethylhydrazine

CAS number: 57–14–7

NIOSH REL: 0.06 ppm (0.15 mg/m³) 2-hour CEILING; NIOSH considers 1,1-dimethylhydrazine to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 0.5 ppm (1 mg/m³) TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.5 ppm (1.2 mg/m³) TWA [skin], A2

Description of Substance: Colorless liquid with an ammonia- or fish-like odor.

LEL:. . 2% (10% LEL, 2,000 ppm)

Original (SCP) IDLH: 50 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that 1 of 3 dogs died following a 4-hour exposure to 52 ppm [Jacobson et al. 1955]. Concentrations above 50 ppm may cause permanent eye damage.

Existing short-term exposure guidelines: American Industrial Hygiene Association [AIHA 1964] Emergency Exposure Limits (EELs):

5-minute EEL: 600 ppm

10-minute EEL: 200 ppm

30-minute EEL: 100 ppm

60-minute EEL: 50 ppm

National Research Council [NRC 1985] Emergency Exposure Guidance Levels (EEGLs):

1-hour EEGL: 0.24 ppm

2-hour EEGL: 0.12 ppm

4-hour EEGL: 0.06 ppm

8-hour EEGL: 0.03 ppm

16-hour EEGL: 0.015 ppm

24-hour EEGL: 0.01 ppm

ACUTE TOXICITY DATA

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat Mouse Hamster Dog Dog Dog Rat Dog	Jacobson et al. 1955 Jacobson et al. 1955 Jacobson et al. 1955 Jacobson et al. 1955 Jacobson et al. 1955 Weeks et al. 1963 Weeks et al. 1963 Weeks et al. 1963	252 172 392 LC100: 111 LC33: 52 3,580 1,410 981	----- ----- ----- ----- ----- ----- ----- -----	4 hr 4 hr 4 hr 4 hr 4 hr 15 min 1 hr 1 hr	504 ppm (2.0) 344 ppm (2.0) 784 ppm (2.0) 222 ppm (2.0) 104 ppm (2.0) 2,828 ppm (0.79) 1,763 ppm (1.25) 1,226 ppm (1.25)	50 ppm 34 ppm 78 ppm 22 ppm 10 ppm 283 ppm 176 ppm 123 ppm

Other animal data: No adverse effects were noted in dogs exposed at 50, 200, and 600 ppm for 60, 15, and 5 minutes, respectively; only mild toxic responses were noted at 100, 400, and 1,200 ppm for 60, 15, and 5 minutes, respectively [Weeks et al. 1963].

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

Revised IDLH: 15 ppm Basis for revised IDLH: The revised IDLH for 1,1-dimethylhydrazine is 15 ppm based on acute toxicity data in animals [Jacobson et al. 1955]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for 1,1-dimethylhydrazine at concentrations above 0.06 ppm.]

REFERENCES:

1. American Industrial Hygiene Association, Toxicology Committee [1964]. Emergency exposure limits. Am Ind Hyg Assoc J 25:578-586.

2. Jacobson KH, Clem JH, Wheelwright HJ, Rinehart WF, Mayer N [1955]. The acute toxicity of the vapors of some methylated hydrazine derivatives. AMA Arch Ind Health 12:609-619.

3. 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. 37-46.

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 2226.

5. Weeks MH, Maxey GC, Sicks ME, Greene EA [1963]. Vapor toxicity of UDMH in rats and dogs from short exposures. Am Ind Hyg Assoc J 24:137-143.