Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)
CAS number: 76–12–0
NIOSH REL: 500 ppm (4,170 mg/m3) TWA
Current OSHA PEL: 500 ppm (4,170 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 500 ppm (4,170 mg/m3) TWA
Description of substance: Colorless solid or liquid (above 77°F) with a slight, ether-like odor.
LEL: . . Noncombustible Solid/Noncombustible Liquid
Original (SCP) IDLH: 15,000 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by ACGIH  that exposure to 10,000 ppm for 1.5 to 2 hours produced slight intoxication in rats but no loss of reflexes [Greenberg and Lester 1950], and on the report that a 4-hour exposure to 15,000 ppm was fatal to rats [Clayton et al. 1966].
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
|Clark & Tinston 1982
Clayton et al. 1966
Izmerov et al. 1982
|15,800 ppm (0.79)|
30,000 ppm (2.0)
23,235 ppm (1.6)
Other animal data: Rats exposed to 10,000 ppm for 1.5 to 2 hours showed slight signs of intoxication but no loss of reflexes, while 20,000 to 30,000 ppm was fatal in 1.0 to 2.5 hours [Greenberg and Lester 1950].
Human data: None relevant for use in determining the revised
|Revised IDLH: 2,000 ppm
Basis for revised IDLH: The revised IDLH for 1,1,2,2-tetrachloro-1,2-difluoroethane is 2,000 ppm based on acute inhalation toxicity data in animals [Greenberg and Lester 1950] and to be consistent with the revised IDLH for the similar chlorofluorocarbon 1,1,1,2-tetrachloro-2,2-difluoroethane which has a revised IDLH of 2,000 ppm. This may be a conservative value due to the lack of relevant acute toxicity data for workers.
1. ACGIH . 1,1,2,2-Tetrachloro 1,2-difluoroethane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 249.
2. Clark DG, Tinston DJ . Acute inhalation toxicity of some halogenated and non-halogenated hydrocarbons. Hum Toxicol 1:239-247.
3. Clayton JW Jr, Sherman H, Morrison SD, Barnes JR, Hood DB . Toxicity studies on 1,1,2,2-tetrachloro-1,2-difluoroethane and 1,1,1,2-tetrachloro-2,2-difluoroethane. Am Ind Hyg Assoc J 27(4):332-340.
4. Greenberg LA, Lester D . Toxicity of the tetrachlorodifluoroethanes. AMA Arch Ind Hyg Occup Med 2:345-347.
5. Izmerov NF, Sanotsky IV, Sidorov KK . Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 54.
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