1,1,2,2-Tetrachloro-1,2-difluoroethane

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 [1971] 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:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat Rat Mouse	Clark & Tinston 1982 Clayton et al. 1966 Izmerov et al. 1982	20,000 15,000 14,522	----- ----- -----	15 min 4 hr 2 hr	15,800 ppm (0.79) 30,000 ppm (2.0) 23,235 ppm (1.6)	1,580 ppm 3,000 ppm 2,324 ppm

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 IDLH.

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.

REFERENCES:

1. ACGIH [1971]. 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 [1982]. 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 [1966]. 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 [1950]. Toxicity of the tetrachlorodifluoroethanes. AMA Arch Ind Hyg Occup Med 2:345-347.

5. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 54.