Isopropyl alcohol

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

CAS number: 67–63–0

NIOSH REL: 400 ppm (980 mg/m3) TWA, 500 ppm (1,225 mg/m3) STEL

Current OSHA PEL: 400 ppm (980 mg/m3) TWA

1989 OSHA PEL: 400 ppm (980 mg/m3) TWA, 500 ppm (1,225 mg/m3) STEL

1993-1994 ACGIH TLV: 400 ppm (983 mg/m3) TWA, 500 ppm (1,230 mg/m3) STEL

Description of substance: Colorless liquid with the odor of rubbing alcohol.

LEL: . 2.0% (10% LEL, 2,000 ppm)

Original (SCP) IDLH: 12,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that rats survived when exposed for 4 hours to 12,000 ppm but exposure for 8 hours to 12,000 ppm resulted in death among one half of the group [Smyth 1956].

Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):

1-hour EEGL: 400 ppm

24-hour EEGL: 200 ppm


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value



Carpenter et al. 1949

NCI 1974

Smyth 1956







4 hr

3 hr

8 hr

32,000 ppm (2.0)

23,040 ppm (1.8)

24,000 ppm (2.0)

3,200 ppm

2,304 ppm

2,400 ppm

Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value



Antonova & Salmina 1978

Antonova & Salmina 1978

WHO 1970










14,126 ppm

10,080 ppm

17,948 ppm

1,413 ppm

1,008 ppm

1,795 ppm

Other animal data: RD50 (mouse), 17,693 ppm [Alarie 1981]. It has been reported that rats survived when exposed to 12,000 ppm for 4 hours [Smyth 1956].

Human data: Ten volunteers exposed for 3 to 5 minutes to 200, 400, or 800 ppm reported mild to moderate irritation of the eyes, nose, and throat at the two higher concentrations [Nelson et al. 1943]. The probable lethal oral dose has been reported to be 190 grams [Gosselin et al. 1984]. [Note: An oral dose of 190 grams is equivalent to a worker being exposed to about 50,700 ppm for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

Revised IDLH: 2,000 ppm [LEL]

Basis for revised IDLH: Based on health considerations and acute toxicity data in humans [Gosselin et al. 1984; Nelson et al. 1943] and animals [NCI 1974; Smyth 1956], a value of about 2,400 ppm would have been appropriate for isopropyl alcohol. However, the revised IDLH for isopropyl alcohol is 2,000 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 2%).


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

2. Antonova VI, Salmina ZA [1978]. The maximal permissible concentration of isopropyl alcohol in water bodies with due regard for its action on the gonads and the progeny. Gig Sanit 43(1):8-11 (in Russian).

3. Carpenter CP, Smyth HF Jr, Pozzani UC [1949]. The assay of acute vapor toxicity, and the grading. J Ind Hyg Toxicol 31:343-346.

4. Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th ed. Baltimore, MD: Williams & Wilkins Company, pp. III-217 to II-219.

5. NCI [1974]. Interagency Collaborative Group on Environmental Carcinogenesis, National Cancer Institute Memorandum, June 17, 1974.

6. Nelson KW, Ege JF Jr, Ross M, Woodman LE, Silverman L [1943]. Sensory response to certain industrial solvent vapors. J Ind Hyg Toxicol 25(7):282-285.

7. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 2. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 56-68.

8. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1438.

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

10. WHO [1970]. Propan-2-ol: biological data. In: Toxicological evaluation of some extraction solvents and certain other substances. Food and Agriculture Organization Nutrition Meetings Report Series 48A. Geneva, Switzerland: United Nations, World Health Organization, pp. 114-120.

Page last reviewed: December 4, 2014