Parathion

CAS RN:56-38-2

Threshold Limit Values

8 hr Time Weighted Avg (TWA): 0.05 mg/cu m, skin. /Inhalable fraction and vapor/
Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.
A4; Not classifiable as a human carcinogen.
Biological Exposure Index (BEI): Determinant: total p-nitrophenol in urine; Sampling Time: end of shift; BEI: 0.5 mg/g creatinine. The determinant is nonspecific, since it is also observed after exposure to other chemicals.
Biological Exposure Index (BEI): Determinant: cholinesterase activity in red cells; Sampling Time: discretionary; BEI: 70% of individual's baseline. The determinant may be present in biological specimens collected from subjects who have not been occupationally exposed, at a concentration which could affect interpretation of the result. Such background concentrations are incorporated in the BEI value. The determinant is nonspecific, since it is also observed after exposure to other chemicals. The biological determinant is an indicator of exposure to the chemical, but the quantitative interpretation of the measurement is ambiguous. These determinants should be used as a screening test if a quantitative test is not practical or as a confirmatory test if the quantitative test is not specific and the origin of the determinant is in question.
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