Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home
Share
Compartir
May 1994
 

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


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

CAS number: 76–11–9

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

LEL :. . Noncombustible solid

Description of substance: Colorless solid with a slight, ether-like odor.

Original (SCP) IDLH: 15,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that rats became slightly intoxicated after being exposed for 1.5 hours to 15,000 ppm [Greenburg and Lester 1950] and on the statement by ACGIH [1971] that rats died following a 4-hour exposure to 15,000 ppm [Clayton et al. 1966].

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal concentration data:

 

SpeciesReferenceLC50

(ppm)

LCLo

(ppm)

TimeAdjusted 0.5-hr

LC (CF)

Derived value
Rat

Rat

Clayton et al. 1966

Torkelson et al. 1971

15,000

20,000

-----

-----

4 hr

30 min

30,000 ppm (2.0)

20,000 ppm (1.0)

3,000 ppm

2,000 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 a concentration of 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 1,1,1,2-tetrachloro-2,2-difluoroethane is 2,000 ppm based on acute inhalation toxicity data in animals [Torkelson et al. 1971] and to be consistent with the revised IDLH for the similar chlorofluorocarbon 1,1,2,2-tetrachloro-1,2-difluoroethane which has a revised IDLH of 2,000 ppm. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers.

REFERENCES:

1. ACGIH [1971]. 1,1,1,2-Tetrachloro-2,2-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. 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.

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

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1331.

5. Torkelson TR, Kary CD, Chenoweth MB, Larsen ER [1971]. Single exposure of rats to the vapors of trace substances in methoxyflurane. Toxicol Appl Pharmacol 19:1-9.

 
Contact Us:
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO