Isoamyl alcohol (primary & secondary)

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

CAS number: 123-51-3 (primary), 528–75–4 (secondary)

NIOSH REL: 100 ppm (360 mg/m3) TWA, 125 ppm (450 mg/m3) STEL

Current OSHA PEL: 100 ppm (360 mg/m3) TWA

1989 OSHA PEL: 100 ppm (360 mg/m3) TWA, 125 ppm (450 mg/m3) STEL

1993-1994 ACGIH TLV: 100 ppm (361 mg/m3) TWA, 125 ppm (452 mg/m3) STEL

Description of substance: Colorless liquids with a disagreeable odor.

LEL(primary): 1.2% (10% LEL, 1,200 ppm)

LEL (secondary): Unknown

Original (SCP) IDLH: 10,000 ppm [LEL]

Basis for original (SCP) IDLH: The chosen IDLH is based on the lower explosive limit (LEL) of 12,000 ppm and the statement in Patty [1963] attributed to Smyth [1956] that rats survived 8,000 ppm.

Short-term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value


Munch 1972

Purchase 1969







6,557 ppm

2,480 ppm

656 ppm

248 ppm

Other animal data: RD50 (mouse), 4,452 ppm [Alarie 1981].

Human data: An oral dose of 24.3 grams has been lethal for adults [Gosselin et al. 1984]. [Note: An oral dose of 24.3 grams is equivalent to a worker being exposed to 4,000 ppm for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

Revised IDLH: 500 ppm

Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for isoamyl alcohol. Therefore, the revised IDLH for isoamyl alcohol (primary & secondary) is 500 ppm based on acute oral toxicity data in humans [Gosselin et al. 1984] and animals [Munch 1972]. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers.


1. Alarie Y [1981]. Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.

2. Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th ed. Section II. Ingredients Index. Baltimore, MD: Williams & Wilkins Company, p. 175.

3. Munch JC [1972]. Aliphatic alcohols and alkyl esters: narcotic and lethal potencies to tadpoles and to rabbits. Ind Med Surg 41:31-33.

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1454.

5. Purchase IFH [1969]. Studies in kaffircorn malting and brewing. XXII. The acute toxicity of some fusel oils found in Bantu beer. S Afr Med J 43:795-798.

6. Smyth HF Jr [1956]. Improved communication: hygienic standards for daily inhalation. Am Ind Hyg Assoc Q 17(2):129-185.

Page last reviewed: December 4, 2014