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

CAS number: 75-07-0

NIOSH REL: None established; NIOSH considers acetaldehyde to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 200 ppm (360 mg/m3) TWA

1989 OSHA PEL: 100 ppm (180 mg/m3) TWA, 150 ppm (270 mg/m3) STEL

1993-1994 ACGIH TLV: 25 ppm (45 mg/m3) CEILING, A3

Description of substance: Colorless liquid or gas (above 69øF) with a pungent, fruity odor.

LEL: 4.0% (10% LEL, 4,000 ppm)

Original (SCP) IDLH: 10,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Patty [1963] and ACGIH [1971] that all rats survived a 4-hour exposure to 8,000 ppm, but all rats died from a 16,000 ppm exposure [Smyth 1956].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hr LC (CF) Derived Value
Rat Appelman et al. 1982 13,000 —– 4 hr 26,000 ppm (2.0) 2,600 ppm
Hamster Feron 1979 17,000 —– 4 hr 34,000 ppm (2.0) 3,400 ppm
Rat Skog 1950 20,000 —– 30 min 20,000 ppm (1.0) 2,000 ppm
Rat Skog 1950 20,536 —– 30 min 26,536 ppm (1.0) 2,054 ppm

Other animal data: RD50 (mouse), 4,946 ppm [Alarie 1981].

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


  1. ACGIH [1971]. Acetaldehyde. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 1-2.
  2. Alarie Y [1981]. Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.
  3. Appelman LM, Woutersen RA, Feron VJ [1982]. Inhalation toxicity of acetaldehyde in rats. I. Acute and subchronic studies. Toxicology 23(4):293-307.
  4. Feron VS [1979]. Effects of exposure to acetaldehyde in Syrian hamsters simultaneously treated with benzo(a)pyrene or diethylnitrosamine. Prog Exp Tumor Res 24:162-176.
  5. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1967.
  6. Skog E [1950]. A toxicological investigation of lower aliphatic aldehydes. I. Toxicity of formaldehyde, acetaldehyde, and butryaldehyde; as well as acrolein and crotonaldehyde. Acta Pharmacol Toxicol 6(4):299-318.
  7. 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