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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 79–24–3

NIOSH REL: 100 ppm (310 mg/m3) TWA

Current OSHA PEL: 100 ppm (310 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 100 ppm (307 mg/m3) TWA

Description of substance: Colorless, oily liquid with a mild, fruity odor.

LEL: . 3.4% (10% LEL, 3,400 ppm)

Original (SCP) IDLH: 1,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Patty [1963] that exposure to 5,000 ppm for 2 hours was lethal to 1 of 2 rabbits and to 0 of 2 guinea pigs; exposure to the same concentration for 3 hours was fatal to 2 of 2 rabbits and to 0 of 2 guinea pigs [Machle et al. 1940].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value
Rat IMCC 1979 LC100: 13,000 ----- 6 hr 29,900 ppm (2.3) 2,990 ppm
Mouse Izmerov et al. 1982 ----- 6,250 2 hr 10,000 ppm (1.6) 1,000 ppm
Rabbit Machle et al. 1940 5,000 ----- 2 hr 8,000 ppm (1.6) 800 ppm
Rabbit Machle et al. 1940 LC100: 5,000 ----- 3 hr 9,000 ppm (1.8) 900 ppm

Other animal data: Guinea pigs survived both a 2-hour and a 3-hour exposure to 5,000 ppm [Machle et al. 1940]. Rats exposed to 2,200 ppm for 6 hours had no noticeable difficulty [IMCC 1979].

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

Revised IDLH: 1,000 ppm [Unchanged]

Basis for revised IDLH: Based on acute inhalation toxicity data in animals [Izmerov et al. 1982; Machle et al. 1940], the original IDLH for nitroethane (1,000 ppm) is not being revised at this time.


1. IMCC [1979]. Technical data sheet no. 21: nitromethane. Des Plaines, IL: International Minerals and Chemical Corporation, Inc., NP Division.

2. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 93.

3. Machle W, Scott EW, Treon J [1940]. The physiological response of animals to some simple mononitroparaffins and to certain derivatives of these compounds. J Ind Hyg Toxicol 22(8):315-332.

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 2077.