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

CAS number: 62-53-3

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

Current OSHA PEL: 5 ppm (19 mg/m3) TWA [skin]

1989 OSHA PEL: 2 ppm (8 mg/m3) TWA [skin]

1993-1994 ACGIH TLV: 2 ppm (7.6 mg/m3) TWA [skin]

Description of substance: Colorless to brown, oily liquid with an aromatic amine-like odor.

LEL: 1.3% (10% LEL, 1,300 ppm)

Original (SCP) IDLH: 100 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Henderson and Haggard [1943] that 100 to 160 ppm is the maximum concentration that can be inhaled for 1 hour without serious disturbance. AIHA [1955] reported that 50 to 100 ppm can probably be tolerated for 60 minutes.

Short-term exposure guidelines: None developed


Lethal concentration data:

LC50 LCLo 0.5-hr Derived
Species Reference (ppm) (ppm) Time LC (CF) Value
Mouse Back et al. 1972 175 ----- 7 hr 420 ppm (2.4) 42 ppm
Rat Carpenter et al. 1949 ----- 250 4 hr 500 ppm (2.0) 50 ppm
Cat von Oettingen 1941 ----- 180 8 hr 450 ppm (2.5) 45 ppm

Lethal dose data:
LD50 LDLo Derived
Species Reference Route (Mg/kg) (mg/kg) Adjusted LD Value
Dog Back et al. 1972 oral ----- 195 353 ppm 35 ppm
Rat Dieke et al. 1947 oral ----- 250 452 ppm 45 ppm
Mouse Gig Tr Prof Zabol oral ----- 464 839 ppm 84 ppm
Rat Jacobsen 1972 oral ----- 440 796 ppm 80 ppm
G. pig Kodak 1984 oral ----- 400 724 ppm 72 ppm

Human data: Volunteers tolerated 1-hour exposures ranging from 100-160 ppm with only moderate adverse health effects (undefined) [von Oettingen 1941]. It has also been reported that 100 to 160 ppm is the maximum concentration that can be inhaled for 1 hour without serious consequence [Henderson and Haggard 1943] and that 50 to 100 ppm can probably be tolerated for 60 minutes [AIHA 1955].

Revised IDLH: 100 ppm [Unchanged]

Basis for revised IDLH: Based on acute inhalation toxicity data in humans [AIHA 1955; Henderson and Haggard 1943; von Oettingen 1941], the original IDLH for aniline of 100 ppm is not being revised at this time. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for aniline at any detectable concentration.]


  1. AIHA [1955]. Aniline. In: Hygienic guide series. Am Ind Hyg Assoc Q 16:331-332.
  2. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-8 to A-9.
  3. Carpenter CP, Smyth HF Jr, Pozzani UC [1949]. The assay of acute vapor toxicity, and the grading and interpretation of results on 96 chemical compounds. J Ind Hyg Toxicol 31:343-346.
  4. Dieke SH, Allen GS, Richter CP [1947]. The acute toxicity of thioureas and related compounds to wild and domestic Norway rats. J Pharmacol Exp Ther 90:260-270.
  5. Gig Tr Prof Zabol [1969]; 13(5):29-32 (in Russian).
  6. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 228.
  7. Jacobsen KH [1972]. Acute oral toxicity of mono- and di-alkyl ring-substituted derivatives of aniline. Toxicol Appl Pharmacol 22:153-154.
  8. Kodak [1984]. Aniline. In: TSCA 8d submission to U.S. Environmental Protection Agency (OTS 206512). Rochester, NY: Eastman Kodak Company.
  9. von Oettingen WF [1941]. The aromatic amines and nitro compounds, their toxicity and potential dangers. Washington, DC: Government Printing Office, U.S. Public Health Service, Public Health Bulletin 271:1-15.
Page last reviewed: December 4, 2014