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May 1994

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


CAS number: 76–14–2

NIOSH REL: 1,000 ppm (7,000 mg/m3) TWA

Current OSHA PEL: 1,000 ppm (7,000 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 1,000 ppm (6,990 mg/m3) TWA

Description of Substance: Colorless gas with a faint, ether-like odor at high concentrations.

LEL:. . Nonflammable Gas

Original (SCP) IDLH: 50,000 ppm

Basis for original (SCP) IDLH: Dichlorotetrafluoroethane is known to be a narcotic in high concentrations, but no human exposure data are available concerning its narcotic effects. Based on an analogy with dichlorodifluoromethane, a related compound that produces dizziness in humans at 50,000 ppm [ILO 1971], an IDLH of 50,000 ppm is assumed for this draft technical standard.

Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):

1-hr EEGL: 10,000 ppm

24-hr EEGL: 1,000 ppm


Lethal concentration data:







Adjusted 0.5-hr







Paulet 1976

Paulet 1976

Paulet 1976







30 min

30 min

30 min

720,000 ppm (1.0)

700,000 ppm (1.0)

750,000 ppm (1.0)

72,000 ppm

70,000 ppm

75,000 ppm

Other animal data: Evidence of serious arrhythmia was noted in 1 of 12 dogs exposed for 5 minutes to 25,000 ppm plus intravenous epinephrine [Reinhardt et al. 1971]. Cardiac sensitization has been induced with endogenous epinephrine at 50,000 to 800,000 ppm [Mullin et al. 1972; Reinhardt et al. 1971].

Human data: Significant reduction in ventilatory lung capacity, bradycardia, and increased variability in heart rate have been reported following exposures to 2,300 to 21,400 ppm for 15, 45, or 60 seconds [IPCS 1990].


Revised IDLH: 15,000 ppm

Basis for revised IDLH: The revised IDLH for dichlorotetrafluoroethane is 15,000 ppm based on acute inhalation toxicity data in animals [Reinhardt et al. 1971] and an analogy to dichlorodifluoroethane, another closely related halogenated hydrocarbon, which has a revised IDLH of 15,000 ppm.


1. ILO [1971]. Fluorocarbons. In: Encyclopaedia of occupational health and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour Office, pp. 560-562.

2. IPCS [1990]. Environmental criteria 13. Fully halogenated chlorofluorocarbons. Geneva, Switzerland: World Health Organization, International Programme on Chemical Safety.

3. Mullin LS, Azar A, Reinhardt CF, Smith PE Jr, Fabryka EF [1972]. Halogenated hydrocarbon-induced cardiac arrhythmias with release of endogenous epinephrine. Am Ind Hyg Assoc J 33:389-396.

4. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 1. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 51-55.

5. Paulet G [1976]. Les fluorocarbones en question. J Eur Toxicol (Supplement) 9(7):385-407 (in French).

6. Reinhardt CF, Azar A, Maxfield ME, et al. [1971]. Cardiac arrhythmias and aerosol sniffing. Arch Environ Health 22:265-279.

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