May 1994

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)

1,1,2-Trichloroethane

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

ACUTE TOXICITY DATA:

Lethal concentration data:

Species	Reference	LC₅₀	LC_Lo	Time	Adjusted 0.5-hr LC (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 ppm

Basis 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.]

REFERENCES:

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.