CAS number . . . . . . . . . . . 86-50-0
NIOSH REL. . . . . . . . . . . . 0.2 mg/m3 TWA [skin]
Current OSHA PEL . . . . . . . . 0.2 mg/m3 TWA [skin]
1989 OSHA PEL. . . . . . . . . . Same as current PEL
1993-1994 ACGIH TLV. . . . . . . 0.2 mg/m3 TWA [skin]
Description of substance . . . . Colorless crystals or a brown, waxy solid.
LEL. . . . . . . . . . . . . . . Noncombustible Solid
Original (SCP) IDLH. . . . . . . 20 mg/m3 
Basis for original (SCP) IDLH. . Because no useful data on acute inhalation
                                 toxicity are available concerning the toxic
                                 effects produced by azinphos-methyl, the
                                 chosen IDLH has been based on an analogy with
                                 parathion, which has an IDLH of 20 mg/m3.
Short-term exposure guidelines . None developed

ACUTE TOXICITY DATA

Lethal concentration data:

                                                       Adjusted               
                                                        0.5-hr         Derived
Species     Reference         LC50    LCLo   Time       LC (CF)         Value
______________________________________________________________________________
Rat      Newell and Dilley  69 mg/m3  -----  1 hr   86 mg/m3 (1.25)  8.6 mg/m3
         1978
Rat      Sanderson 1961     79 mg/m3  -----  1 hr   99 mg/m3 (1.25)  9.9 mg/m3

Lethal dose data:


                                                                              
                                     LD50    LDLo                      Derived
Species     Reference        Route  (mg/kg) (mg/kg)   Adjusted LD       Value
______________________________________________________________________________
Rat      Dubois et al. 1957   oral   16      -----     115 mg/m3    12   mg/m3
G. pig   Dubois et al. 1957   oral   80      -----     560 mg/m3    56   mg/m3
Rat      Gaines 1960          oral   11      -----      77 mg/m3     7.7 mg/m3
Rat      Gaines 1960          oral   13      -----      91 mg/m3     9.1 mg/m3
Mouse    Murphy et al. 1976   oral    8.6    -----      60 mg/m3     6.0 mg/m3
Rat      Sanderson 1961       oral    7      -----      49 mg/m3     4.9 mg/m3
Mouse    Sato 1959            oral    8      -----      56 mg/m3     5.6 mg/m3
Dog      Worthing 1991        oral   10      -----      70 mg/m3     7.0 mg/m3

Human data . . . . . . . . . . . Eight workers exposed to concentrations as
                                 high as 9.6 mg/m3 (no time period given)
                                 showed no signs or symptoms of illness
                                 [Jegler 1964].

Revised IDLH: 10 mg/m3
Basis for revised IDLH: The revised IDLH for azinphos-methyl is 10 mg/m3 based on acute inhalation toxicity data in humans [Jegler 1964] and animals [Newell and Dilley 1978; Sanderson 1961]. This may be a conservative value due to the lack of acute toxicity data for workers exposed to concentrations above 10 mg/m3.

REFERENCES:

1. DuBois KP, Thursh DR, Murphy SD [1957]. Studies on the toxicity and pharmacologic actions of the dimethoxyl ester of benzotriazine dithiophosphoric acid. J Pharmacol Exp Ther 119:208-218.
2. Gaines TB [1960]. Acute toxicity of pesticides in rats. Toxicol Appl Pharmacol 2:88-99.
3. Jegler Z [1964]. Exposure to guthion during spraying and formulating. Arch Environ Health 8:565-569.
4. Murphy SD, Cheever KL, Chow AYK, Brewster M [1976]. Organophosphate insecticide potentiation by carboxylesterase inhibitors. Proc Eur Soc Toxicol 17:292-300.
5. Newell GW, Dilley JV [1978]. Teratology and acute toxicology of selected chemical pesticides administered by inhalation. Menlo Park, CA: Stanford Research Institute, p. 18. Prepared for Health Effects Research Laboratory, U.S. EPA, EPA-60011-78-003.
6. Sanderson DM [1961]. Treatment of poisoning by anticholinesterase insecticides in the rat. J Pharm Pharmacol 13:435-442.
7. Sato I [1959]. Studies on organic phosphorus gusathion and phosdrin. I. The toxicity of gusathion and phosdrin. Kuma Med J 12(1):312-317.
8. Worthing CR, ed. [1991]. Azinphos-methyl. In: The pesticide manual: a world compendium. 9th ed. Old Woking, Surrey, England: Unwin Brothers Limited, p. 46.