Emergency and Continuous Exposure Limits for Selected Airborne Contaminants: Volume 2 (1984)

Fluorocarbon 113 (FC-113) has been used principally as a dry-cleaning solvent, refrigerant, and blowing agent. It is also used as a cleaning solvent for sensitive electronic parts and in the maintenance of hydraulic piping systems in submarines.

Exposure of the skin of human subjects to FC-113 resulted in localized numbness followed by transient erythema after exposure stopped (Reinhardt and Schultze, 1968). End-tidal air samples demonstrated that some solvent had been absorbed through the skin.

Human exposure at 1,500 ppm produced no effects after 2.75 h (Stopps and McLaughlin, 1967). Signs indicative of CNS involvement were seen after 30 min of exposure at 2,500 ppm. These slight decreases in psychomotor performance were reversible and disappeared by 15 min after exposure stopped.

Human volunteers were exposed at 500 or 1,000 ppm for 6 h/d, 5 d/wk, during a 2-wk period. No adverse changes were seen in performance of complex mental tasks, clinical status, or results of biochemical tests. Breath analysis did not reveal a significant buildup of FC-113 (Reinhardt et al., 1971).

FC-113 has very low acute oral toxicity, with an LD₅₀ in rats of 43 g/kg (Michaelson and Huntsman, 1964). Its lethal dose after application to the skin of rabbits is greater than 11 g/kg, the largest feasible dose. Mild irritation results from contact with the skin and eyes (Haskell Laboratory, 1963; Reinke, 1962).

Exposure to FC-113 at 50,000–60,000 ppm has proved lethal to rats after 4 h. Signs of toxicity indicative of CNS involvement were incoordination, tremors, irregular respiration, and convulsions (Bodganowicz, 1973; Dashiell, 1971; Sarver, 1971).

Rats were exposed at an average concentration of 2,520 ppm, 7 h/d, 5 d/wk, for 6 wk (Limperos, 1954). No signs of toxicity were seen throughout the experiment.

Other groups of laboratory animals were similarly exposed at up to 5,100 ppm without effect (Carter et al., 1970; Philadelphia Naval Shipyard, 1952; Steinberg et al., 1969). In a limited study involving six rats exposed at 12,000 ppm for up to 24 mo, a slight sleepiness was observed and disappeared immediately after daily exposure stopped (Desoille et al., 1968). Rats were exposed by inhalation for 6 hr a day, 5 d/wk, for 104 wk. Exposures were at 0, 2,000, 10,000, and 20,000 ppm (v/v). No significant toxic effects were observed, and no evidence of carcinogenicity was seen (C.F.Reinhardt, personal communication).

FC-113, like other chlorofluorocarbons and hydrocarbons, is capable of sensitizing the beagle heart to exogenous epinephrine in standard 5-min cardiac-sensitization screening studies. A concentration of 5,000 ppm can sensitize 25–35% of exposed dogs; 2,500 ppm is ineffective (Clark and Tinston, 1973; Reinhardt et al., 1973). However, dogs exposed while running on a treadmill (to increase their own epinephrine concentration) were not sensitized at concentrations up to 20,000 ppm (Mullin et al., 1971; Trochimowicz et al., 1974).

FC-113 is analogous to FC-11 with regard to its pharmacokinetics and metabolism. It has a short half-life in the body, is not metabolized to any significant extent, and is rapidly expelled through the lungs upon removal from exposure (C.F.Reinhardt, personal communication).

The ACGIH TLV-TWA and the OSHA federal standard (ACGIH, 1983; OSHA, 1983) for FC-113 are both 1,000 ppm. ACGIH recommended a TLV-STEL for 15-min excursions of 1,250 ppm (ACGIH, 1980). The TLV-TWA was recommended on the basis of a belief that it would provide a margin of safety for systemic effects and an adequate margin against cardiac sensitization.

The previous EELs and CEL were established by the Committee in 1969. On the basis of 5-min cardiac-sensitization screening tests with dogs (which showed no effects at 2,500 ppm and positive findings at 5,000 ppm), an absence of effects in unexcited humans exposed at 1,500 ppm for 1.5 h, but changes in manual dexterity at 2,500 ppm for 1.5 h, the

Committee suggests a 60-min EEL of 1,500 ppm. The Committee recommends a 24-h EEL of 500 ppm on the basis of an absence of adverse health effects in unexcitead humans exposed at 500 ppm or 1,0 h/d, 5 d/wk, for 2 wk. In view of absence of adverse effects in rats exposed to 20,000 ppm (v/v) for two years, its short half-life, little metabolism, and rapid removal from the body, the Committee recommends a 90-day CEL of 100 ppm.

The present Committee’s recommended EELs and CEL for FC-113 and the limits proposed in 1969 are shown below.

American Conference of Governmental Industrial Hygienists. 1983. 1,1,2-Trichloro-1,2,2-trifluoroethane. Documentation of the Threshold Limit Values. 4th ed. Cincinnati, Ohio: American Conference of Governmental Industrial Hygienists. p. 411–412.

American Conference of Governmental Industrial Hygienists. 1983. TLVs(^R): Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment with Intended Changes for 1983–1984. Cincinnati, Ohio: American Conference of Governmental Industrial Hygienists. 93 p.

Bodganowicz, T.K. 1973. Acute inhalation toxicity. Report No. 179–73. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [1] p. [Unpublished]

Carter, V.L., Chikos, P.M., MacEwen, J.D., and Back, K.C. 1970. Effects of inhalation of Freon 113 on laboratory animals. Pp. 309–314 in Proceedings of the 1st Annual Conference on Environmental Toxicology. Report No. AMRL-TR-70–102, Paper No. 20. Wright-Patterson Air Force Base, Ohio. [Also issued as NTIS AD-727 524]

Clark, D.G., and Tinston, D.J. 1973. Correlation of the cardiac sensitizing potential of halogenated hydrocarbons with their physicochemical properties. Br. J.Pharmacol. 49:355–357.

Dashiell, O.L. 1971. Acute inhalation toxicity. Report No. 46–71. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [2] p. [Unpublished]

Desoille, H., Truffert, L., Bourguignon, A., Delavierre, P., Philbert, M., and Girard-Wallon, C. 1968. Etude experimentale de la toxicite du trichlorotrifluoroethane (freon 113). Arch. Mal. Prof. Med. Trav. Secur. Soc. 29:381–388.

Haskell Laboratory for Toxicology and Industrial Medicine. 1963. Acute skin absorption of Freon 113, trifluorotrichloroethane. Newark, Delaware: E.I.du Pont de Nemours & Co. [Unpublished]

Limperos, G. 1954. Inhalation toxicity of “Freon 113” (1,1,2-trichlorotrifluoroethane). Report No. 3–54. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [9] p. [Unpublished]

Michaelson, J.B., and Huntsman, D.J. 1964. Oral toxicity study of 1,2,2-trichloro-1,1,2-trifluoroethane. J. Med. Pharm. Chem. 7:378–379.

Mullin, L.S., Azar, A., Reinhardt, C.F., Smith, P.E., Jr., and Fabryka, E.F. 1971. Halogenated hydrocarbon induced cardiac arrhythmias associated with release of endogenous epinephrine. Report No. 279–71. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [21] p. [Unpublished]

Occupational Safety and Health Administration. 1983. Toxic and Hazardous Substances. Air contaminants. 29 CFR 1910.1000.

Philadelphia Naval Shipyard. 1952. Non-inflammable solvent cleaner for insulated electrical motor parts; toxicity tests of. (ITL Test No. 2335; Progress Report NS 041 001). Philadelphia, Pennsylvania: Philadelphia Naval Shipyard, Industrial Test Laboratory. 8 p.

Reinhardt, C.F., McLaughlin, M., Maxfield, M.E., Mullin, L.S., and Smith, P.E., Jr. 1971. Human exposures to fluorocarbon 113 (1,1,2-trichloro-1,2,2-trifluoroethane). Am. Ind. Hyg. Assoc. J. 32:143–152.

Reinhardt, C.F., Mullin, L.S. and Maxfield, M.E. 1973. Epinephrine-induced cardiac arrhythmia potential of some common industrial solvents. J. Occup. Med. 15:953–955.

Reinhardt, C.F., and Schultze, L.R. 1968. Human skin absorption studies with trichlorotrifluoroethane, F-113. Report No. 84–68. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [7] p. [Unpublished]

Reinke, R.E. 1962. “Freon 113” (1,1,2-trichlorotrifluoroethane). [Eye irritation experiment]. Report No. 39–62. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [1] p. [Unpublished]

Sarver, J.W. 1971. Four-hour inhalation toxicity. Report No. 104–71. Newark, Delaware: E.I.du Pont de Nemours & Co., Haskell Laboratory for Toxicology and Industrial Medicine. [2] p. [Unpublished]

Steinberg, M., Boldt, R.E., Renne, R.A., and Weeks, M.H. 1969. Inhalation toxicity of 1,1,2-trichloro-1,2,2-trifluoroethane (TCTFE). Study number 33–18–68/69. Edgewood Arsenal, Maryland: U.S. Army Environmental Hygiene Agency. 20 p.

Stopps, G.J., and McLaughlin, M. 1967. Psychophysiological testing of human subjects exposed to solvent vapors. Am. Ind. Hyg. Assoc. J. 28:43–50.

Trochimowicz, H.J., Azar, A., Terrill, J.B., and Mullin, L.S. 1974. Blood levels of fluorocarbon related to cardiac sensitization: Part II. Am. Ind. Hyg. Assoc. J. 35:632–639.