Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 79-34-5
NIOSH REL: 1 ppm (7 mg/m3) TWA [skin]; NIOSH considers 1,1,2,2-tetrachloroethane to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].
Current OSHA PEL: 5 ppm (35 mg/m3) TWA [skin]
1989 OSHA PEL: 1 ppm (7 mg/m3) TWA [skin]
1993-1994 ACGIH TLV: 1 ppm (6.9 mg/m3) TWA [skin]
Description of substance: Colorless to pale-yellow liquid with a pungent, chloroform-like odor.
LEL: . . Noncombustible Liquid
Original (SCP) IDLH: 150 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Negherbon  that a 30-minute exposure to 146 ppm caused vertigo (along with irritation of the mucous membranes, sense of pressure in the head, and fatigue) in humans; the same effects were noted after a 10-minute exposure to 335 ppm [Lehmann et al. 1936].
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
|Species||Reference||LC50(ppm)||LCLo(ppm)||Time||Adjusted 0.5-hrLC (CF)||Derived value|
|Carpenter et al. 1949Izmerov et al. 1982
Lehmann et al. 1936
|4 hr2 hr
|2,000 ppm (2.0)1,029 ppm (1.6)
3,094 ppm (1.14)
2,000 ppm (2.0)
|200 ppm103 ppm
Human data: A 30-minute exposure to 146 ppm has caused vertigo, irritation of the mucous membranes, sense of pressure in the head, and fatigue; the same effects were noted after a 10-minute exposure to 335 ppm [Lehmann et al. 1936; Negherbon 1959].
|Revised IDLH: 100 ppmBasis for revised IDLH: The revised IDLH for 1,1,2,2-tetrachloroethane is 100 ppm based on acute inhalation toxicity data in humans [Lehmann et al. 1936; Negherbon 1959] and animals [Izmerov et al. 1982]. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for 1,1,2,2-tetrachloroethane at concentrations above 1 ppm.]|
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