CAS number: 1910425
NIOSH REL: 0.1 mg/m3 (respirable dust) TWA [skin]
Current OSHA PEL: 0.5 mg/m3 (respirable dust) TWA [skin]
1989 OSHA PEL: 0.1 mg/m3 (respirable dust) TWA [skin]
1993-1994 ACGIH TLV: 0.1 mg/m3 (respirable dust) TWA,
0.5 mg/m3 (total dust) TWA
Description of substance: Yellow solid with a faint, ammonialike odor.
LEL: . Noncombustible Solid
Original (SCP) IDLH: 1.5 mg/m3
Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Gage [1968] that "after single exposures the LC50 appears to be a function of the duration and of the concentration; in the rat the lethal concentrationtime product is about 6 micrograms/literhour. Guinea pigs and male mice are about as sensitive as rats. Female mice are less sensitive. The dog can tolerate a concentrationtime product of 25 micrograms/literhour without ill effects."
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
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| Respirable dust G. pig | Gage 1968 | |||||
| Respirable dust Mouse | Gage 1968 | |||||
| Respirable dust Rat | Gage 1968 | |||||
| Nonrespirable dust Rat | Palazzolo 1965 |
Lethal dose data:
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| Rat
Mouse Dog G. pig | Bailey & White 1965 Barabas et al. 1981 Iyakuhin 1979 Murray &Gibson 1972 |
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Human data: It has been stated that the high acute inhalation
toxicity of paraquat is dependent wholly on the size of the particulate,
with respirable sizes (i.e., <5 micrometer mass median
diameter) found to be 5 to 6 times more toxic than nonrespirable
dusts [McElligo 1965]. It has been reported that under paraquat
spraying conditions particle sizes appear to be nonrespirable
[Swan 1969].
| Revised IDLH: 1 mg/m3
Basis for revised IDLH: The revised IDLH for paraquat is 1 mg/m3 based on the acute inhalation toxicity data for respirable particulate in animals [Gage 1968]. This is a conservative value if the occupational exposure is totally to nonrespirable size particles of paraquat since respirable aerosols are much more toxic [McElligo 1965; Swan 1969]. |
REFERENCES:
1. Bailey GW, White JL [1965]. Herbicides: a compilation of their physical, chemical, and biological properties. Residue Reviews 10:97102.
2. Barabas K, Vigh L, Horvath I, Szabo L, Matkovics B [1981]. Effects of paraquat in vivo on fatty acids of mouse and guinea pig tissues. Gen Pharmacol 12:225227.
3. Gage JC [1968]. Toxicity of paraquat and diquat aerosols generated by a sizeselective cyclone: effect of particle size distribution. Br J Ind Med 25:304314.
4. Iyakuhin Kenkyu (Study of Medical Supplies) [1979]; 10:520522 (in Japanese).
5. McElligo TF [1965]. Industrial hygiene research lab report IHR/172. Alderly Park, Macclesfield, Cheshire, England: Imperial Chemicals Industries, Ltd. [From ACGIH [1991]. Paraquat. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 11591161.]
6. Murray RE, Gibson JE [1972]. A comparative study of paraquat intoxication in rats, guinea pigs and monkeys. Exp Molec Pathol 17:317325.
7. Palazzolo RF [1965]. Report to Imperial Chemical Industries, Ltd. Alderly Park, Macclesfield, Cheshire, England. [From ACGIH [1991]. Paraquat. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 11591161.]
8. Swan AAB [1969]. Exposure of spray operators to paraquat. Br J Ind Med 26:322329.
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