Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 95–53–4
NIOSH REL: None established; NIOSH considers o-toluidine to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990] that may be absorbed through the skin.
Current OSHA PEL: 5 ppm (22 mg/m3) TWA [skin]
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 2 ppm (8.8 mg/m3) TWA [skin], A2
Description of substance: Colorless to pale-yellow liquid with an aromatic, aniline-like odor.
LEL: . . Unknown
Original (SCP) IDLH: 100 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Sax  that 100 ppm is the maximum concentration endurable for 1 hour without serious consequences. No other data are available on which to base the IDLH.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal dose data:
|Species||Reference||Route||LD50(mg/kg)||LDLo(mg/kg)||Adjusted LD||Derived value|
|IARC 1982IARC 1982
|1,052 ppm816 ppm
|105 ppm82 ppm
Other animal data: Rats have survived an 8-hour exposure to saturated vapors of o-toluidine [Smyth et al. 1962].
Human data: It has been reported that a 60-minute exposure to 40 ppm produces severe toxic effects [Goldblatt 1955]. It has been reported that 100 ppm is the maximum concentration endurable for 1 hour without serious consequences [Sax 1975].
|Revised IDLH: 50 ppmBasis for revised IDLH: The revised IDLH for o-toluidine is 50 ppm based on acute inhalation toxicity data in humans [Goldblatt 1955; Sax 1975]. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for o-toluidine at any detectable concentration.]|
1. Goldblatt MW . Research in industrial health in the chemical industry. Brit J Ind Med 12:1-20.
2. IARC . ortho-Toluidine and its hydrochloride. In: IARC monographs on the evaluation of carcinogenic risk of chemicals to humans. Vol. 27. Some aromatic amines, anthraquinones and nitroso compounds, and inorganic fluorides used in drinking-water and dental preparations, pp. 155-175.
3. Jacobsen KH . Short communication: acute oral toxicity of mono- and di-alkyl ring-substituted derivatives of aniline. Toxicol Appl Pharmacol 22:153-154.
4. Sax NI . o-Toluidine. In: Dangerous properties of industrial materials. 4th ed. New York, NY: Van Nostrand Reinhold Company, pp. 1173-1176.
5. Smyth HF, Carpenter CP, Weil CS, Pozzani UC, Striegel JA . Range-finding toxicity data: list VI. Am Ind Hyg Assoc J 23:95-107.