1,1,2,2­Tetrachloro­1,2­difluoroethane

IDLH Documentation
CAS number: 76­12­0

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

1993­1994 ACGIH TLV: 500 ppm (4,170 mg/m3) TWA

Description of substance: Colorless solid or liquid (above 77°F) with a slight, ether­like 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 4­hour exposure to 15,000 ppm was fatal to rats [Clayton et al. 1966].

Short­term 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 1,1,2,2­tetrachloro­1,2­difluoroethane 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 1,1,1,2­tetrachloro­2,2­difluoroethane 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]. 1,1,2,2­Tetrachloro 1,2­difluoroethane. 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 non­halogenated hydrocarbons. Hum Toxicol 1:239­247.

3. Clayton JW Jr, Sherman H, Morrison SD, Barnes JR, Hood DB [1966]. Toxicity studies on 1,1,2,2­tetrachloro­1,2­difluoroethane and 1,1,1,2­tetrachloro­2,2­difluoroethane. Am Ind Hyg Assoc J 27(4):332­340.

4. Greenberg LA, Lester D [1950]. Toxicity of the tetrachlorodifluoroethanes. AMA Arch Ind Hyg Occup Med 2:345­347.

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. Go back to the Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)