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Dichlorodifluoromethane
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 75–71–8
NIOSH REL: 1,000 ppm (4,950 mg/m3) TWA
Current OSHA PEL: 1,000 ppm (4,950 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 1,000 ppm (4,950 mg/m3) TWA
Description of Substance: Colorless gas with an ether-like odor at extremely high concentrations.
LEL:. . Nonflammable Gas
Original (SCP) IDLH: 50,000 ppm
Basis for original (SCP) IDLH: Based on the statement by ILO [1971] that 50,000 ppm induces dizziness in humans, an IDLH of 50,000 ppm is chosen for this draft technical standard.
Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):
1-hour EEGL: 10,000 ppm
24-hour EEGL: 1,000 ppm
ACUTE TOXICITY DATA
Lethal concentration data:
| Species | Reference | LC50(ppm) | LCLo(ppm) | Time | Adjusted 0.5-hrLC (CF) | Derivedvalue |
|---|---|---|---|---|---|---|
| MouseRabbit
G. pig Rat |
Paulet 1976Paulet 1976
Paulet 1976 Scholz 1962 |
760,000800,000
800,000 600,000 |
———-
—– —– |
30 min30 min
30 min 2 hr |
760,000 ppm (1.0)800,000 ppm (1.0)
800,000 ppm (1.0) 960,000 ppm (1.6) |
76,000 ppm80,000 ppm
80,000 ppm 96,000 ppm |
Other animal data: Serious cardiac arrhythmia was found in 5 of 12 dogs exposed to 50,000 ppm for 5 minutes and injected with epinephrine [Reinhardt et al. 1971]. In another study, respiratory-circulatory effects that included bronchoconstriction and tachycardia were found at 50,000 to 100,000 ppm [Aviado and Smith 1975].
Human data: Exposure up to 60,000 ppm was tolerated for 80 minutes by 1 volunteer [NRC 1984]; when exposed at 40,000 ppm for 14 minutes and then at 20,000 ppm for 66 minutes, another volunteer developed EEG changes and had slurred speech and decreased psychologic test scores [NRC 1984]. It has been stated that 50,000 ppm induces dizziness [ILO 1971]. Volunteers exposed for 2.5 hours to 10,000 ppm showed a 7% reduction in a standardized psychomotor test [Azar et al. 1972].
| Revised IDLH: 15,000 ppmBasis for revised IDLH: The revised IDLH for dichlorodifluoromethane is 15,000 ppm based on acute inhalation toxicity data in humans [Azar et al. 1972; ILO 1971] and animals [Aviado and Smith 1975; Reinhardt et al. 1971]. |
REFERENCES:
1. Aviado DM, Smith DG [1975]. Toxicity of aerosol propellants in the respiratory and circulatory systems. Toxicology 3:241-252.
2. Azar A, Reinhardt CF, Maxfield ME, et al. [1972]. Experimental human exposure to fluorocarbon 12 (dichlorodifluoromethane). Am Ind Hyg Assoc J 3:207-216.
3. ILO [1971]. Fluorocarbons. In: Encyclopaedia of occupational health and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour Office, pp. 560-562.
4. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 2. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 34-40.
5. Paulet G [1976]. Les fluorocarbones en question. J Eur Toxicol (Supplement) 9:385-407 (in French).
6. Reinhardt CF, Azar A, Maxfield ME, Smith PE Jr, Mullin LS [1971]. Cardiac arrhythmias and aerosol “sniffing.” Arch Environ Health 22:265-279.
7. Scholz J [1962]. New toxicological investigations on certain types of freon used as propellants. Fortschr Biol Aerosol-forsch 1957-61 (in German). Ber Aerosol Kongr 4:420-429. [From ACGIH [1991]. Dichlorodifluoromethane. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 420-422.]