Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 62–73–7
NIOSH REL: 1 mg/m3 TWA [skin]
Current OSHA PEL: 1 mg/m3 TWA [skin]
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 0.90 mg/m3 (0.1 ppm) TWA [skin]
Description of Substance: Colorless to amber liquid with a mild, chemical odor.
LEL:. . Unknown
Original (SCP) IDLH: 200 mg/m3
Basis for original (SCP) IDLH: No useful data on acute inhalation toxicity are available on which to base the IDLH for dichlorvos. If the IDLH were estimated from the female rat oral LD50 of 55 mg/kg [Mattson et al. 1955 cited by Patty 1963], an IDLH of 400 mg/m3 would be chosen. On the basis of an analogy with parathion, however, which has an OSHA PEL of 0.1 mg/m3 and an IDLH of 20 mg/m3, an IDLH of 200 mg/m3 has been chosen for dichlorvos which has an OSHA PEL of 1 mg/m3.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
|Species||Reference||LC50||LCLo||Time||Adjusted 0.5-hrLC (CF)||Derivedvalue|
|RatMouse||Gig Sanit 1968Gig Sanit 1968||15 mg/m313 mg/m3||———-||4 hr4 hr||30 mg/m3 (2.0)16 mg/m3 (2.0)||3.0 mg/m32.6 mg/m3|
Lethal dose data:
|Species||Reference||Route||LD50(mg/kg)||LDLo(mg/kg)||Adjusted LD||Derived value|
|Hartley and Kidd 1984Ikuzawa et al. 1966
Kokshareva et al. 1977
Technical News 1972
|700 mg/m3427 mg/m3
|70 mg/m343 mg/m3
Human data: Exposure to a concentration of 1 mg/m3 for 7.5 to 8.5 hours resulted in a plasma cholinesterase depression of 20 to 25% [Hunter 1964].
|Revised IDLH: 100 mg/m3Basis for revised IDLH: The revised IDLH for dichlorvos is 100 mg/m3 based on an analogy to parathion. Since the toxicity of dichlorvos is about 10 times lower than parathion (based on acute oral toxicity data in animals), the revised IDLH for dichlorvos is 10 times the revised IDLH for parathion (10 mg/m3).|
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