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

CAS number: 104-94-9

NIOSH REL: 0.5 mg/m3 TWA [skin]

Current OSHA PEL: 0.5 mg/m3 TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.1 ppm (0.5 mg/m3) TWA [skin]

Description of substance: Yellow to brown, crystalline solid with an amine-like odor.

LEL: Unknown

Original (SCP) IDLH: 50 mg/m3

Basis for original (SCP) IDLH: Because no data on acute inhalation toxicity are available for anisidine (o-, p-isomers), the chosen IDLH is based on chronic data. ACGIH [1971] reported that mice survived exposures to 10 to 30 mg/m3 for 2 hours/day, 6 days/week for 1 month; a decrease in the excitability of nerves was noted [Zaeva and Fedorova 1962]. Because mice survived 30 mg/m3, 2 hours/day, 6 days/week for 1 month, a worker should be able to escape from 50 mg/m3 without injury or irreversible health effects.

Short-term exposure guidelines: None developed


Lethal dose data:

LD50 LDLo Derived
Species Reference Route (Mg/kg) (mg/kg) Adjusted LD Value
Rabbit IARC 1982 oral 2,900 ----- 20,300 mg/m3 2,030 mg/m3
Mouse IARC 1982 oral 1,300 ----- 9,100 mg/m3 910 mg/m3
Mouse Nippon 1956 oral ----- 1,000 7,000 mg/m3 700 mg/m3
Rat Sziza and Podragyai 1957 oral 1,400 ----- 9,800 mg/m3 980 mg/m3

Other animal data: Mice have survived exposures to concentrations of 10 to 30 mg/m3 for 2 hours/day, 6 days/week for 1 month with a only decrease in the excitability of nerves noted [Zaeva and Fedorova 1962].

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

Revised IDLH: 50 mg/m3 [Unchanged]

Basis for revised IDLH: Based on subchronic inhalation toxicity data in animals [Zaeva and Fedorova 1962], the original IDLH for p-anisidine of 50 mg/m3 is not being revised at this time.


  1. ACGIH [1971]. Anisidine (o-, p-isomers). In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 14.
  2. IARC [1982]. IARC monographs on the evaluation of carcinogenic risk of chemicals to humans. Vol. 27. Lyon, France: World Health Organization, International Agency for Research on Cancer, p. 63.
  3. Nippon Yakurigaku Zasshi (Japanese Journal of Pharmacology) [1956]; 52:215-221 (in Japanese).
  4. Sziza M, Podragyai L [1957]. Toxikologische untersuchung einiger in der ungarischen industrie zur anwendung gelangenden aromatischen amidoverbindungen. Arch Gewerbepath Gewerbehyg 15:447-456 (in German).
  5. Zaeva GN, Fedorova VI [1962]. Toxsikol Nov Prom Khim Vesh 4:91 (in Russian).
Page last reviewed: December 4, 2014