Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content


May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 79–00–5

NIOSH REL: 10 ppm (45 mg/m3) TWA [skin]; NIOSH considers 1,1,2-trichloroethane to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 10 ppm (45 mg/m3) TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 10 ppm (55 mg/m3) TWA [skin]

Description of substance: Colorless liquid with a sweet, chloroform-like odor.

LEL: . . 6% (10% LEL, 6,000 ppm)

Original (SCP) IDLH: 500 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the UCC [1972] report that 500 ppm killed 1 of 6 rats in 4 hours, and 4 of 6 rats in 8 hours.

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50 LCLo Time Adjusted 0.5-hrLC (CF) Derived value
Cat Arch Hyg Bakteriol 1936 —– 13,100 mg/m3 4.5 hr 4,957 ppm (2.1) 496 ppm
Rat Carpenter et al. 1949 —– 2,000 ppm 4 hr 4,000 ppm (2.0) 400 ppm
Rat UCC 1972 LC17: 500 ppm —– 4 hr 1,000 ppm (2.0) 100 ppm
Rat UCC 1972 LC67: 500 ppm —– 8 hr 1,250 ppm (2.5) 125 ppm

Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 100 ppmBasis for revised IDLH: The revised IDLH for 1,1,2-trichloroethane is 100 ppm based on acute inhalation toxicity data in animals [UCC 1972]. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for 1,1,2-trichloroethane at concentrations above 10 ppm.]


1. Arch Hyg Bakteriol [1936]; 116:131 (in German).

2. Carpenter CP, Smyth HF Jr, Pozzani UC [1949]. The assay of acute vapor toxicity and the grading and interpretation of results on 96 chemical compounds. J Ind Hyg Toxicol 31(6):343-346.

3. UCC [1972]. Toxicology studies: 1,1,2-trichloroethane. New York, NY: Union Carbide Corporation.