o-Anisidine

CAS number . . . . . . . . . . . 90-04-0
NIOSH REL. . . . . . . . . . . . 0.5 mg/m3 TWA [skin]; NIOSH considers
                                 o-anisidine to be a potential occupational
                                 carcinogen as defined by the OSHA
                                 carcinogen policy [29 CFR 1990].
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 . . . . Red or yellow, oily liquid 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

ACUTE TOXICITY DATA

Lethal dose data:

                                                                              
                                   LD50    LDLo                      Derived
Species     Reference     Route   (mg/kg) (mg/kg)    Adjusted LD      Value
______________________________________________________________________________
Rat      IARC 1982        oral     2,000   -----    14,000 mg/m3   1,400 mg/m3
Mouse    IARC 1982        oral     1,400   -----     9,800 mg/m3     980 mg/m3
Rabbit   IARC 1982        oral       870   -----     6,090 mg/m3     609 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
                                 only a 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 o-anisidine (50 mg/m3) is not being revised at this time. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for o-anisidine at concentrations above 0.5 mg/m3.]

REFERENCES:

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. Zaeva GN, Fedorova VI [1962]. Toxsikol Nov Prom Khim Vesh 4:91 (in Russian).