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May 1994

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


CAS number: 110–54–3

NIOSH REL: 50 ppm (180 mg/m3) TWA

Current OSHA PEL: 500 ppm (1,800 mg/m3) TWA

1989 OSHA PEL: 50 ppm (180 mg/m3) TWA

1993-1994 ACGIH TLV: 50 ppm (176 mg/m3) TWA

Description of Substance: Colorless liquid with a gasoline-like odor.

LEL:. . 1.1% (10% LEL, 1,100 ppm)

Original (SCP) IDLH: 5,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that a 10-minute exposure to 5,000 ppm caused dizziness and a sensation of giddiness [Patty and Yant 1929]. Because these symptoms could impede escape, 5,000 ppm is judged to be the IDLH.

Short-term exposure guidelines: None developed


Lethal dose data:








Adjusted LD

Derived value
RatKimura et al. 1971oral28,71056,1375,614 ppm-----

Human data: It has been reported that a 10-minute exposure to 5,000 ppm caused dizziness and a sensation of giddiness [Patty and Yant 1929].


Revised IDLH: 1,100 ppm [LEL]

Basis for revised IDLH: Based on health considerations and acute toxicity data in humans [Patty and Yant 1929], a value of about 2,500 ppm would have been appropriate. However, the revised IDLH for n-hexane is 1,100 ppm based strictly on safety considerations (i.e., being 10% of the lower exposure limit of 1.1%).


1. Kimura ET, Ebert DM, Dodge PW [1971]. Acute toxicity and limits of solvent residue for sixteen organic solvents. Toxicol Appl Pharmacol 19:699-704.

2. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1198.

3. Patty FA, Yant WP [1929]. Odor intensity and symptoms produced by commercial propane, butane, pentane, hexane, and heptane vapor. Pittsburgh, PA: Department of Commerce, U.S. Bureau of Mines, Report of Investigations, No. 2979, pp. 1-10.

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