Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 75–43–4
NIOSH REL: 10 ppm (40 mg/m3) TWA
Current OSHA PEL: 1,000 ppm (4,200 mg/m3) TWA
1989 OSHA PEL: 10 ppm (40 mg/m3) TWA
1993-1994 ACGIH TLV: 10 ppm (42 mg/m3) TWA
Description of Substance: Colorless gas with a slight, ether-like odor.
LEL:. . Nonflammable Gas
Original (SCP) IDLH: 50,000 ppm
Basis for original (SCP) IDLH: ACGIH  reported that 52,000 ppm produced incoordination, irregular breathing, and tremors in guinea pigs [Underwriters’ Laboratory 1935]. Scheel (member of the Standards Completion Program Respirator Committee), in evaluating the work of Aviado and Belej , indicated cardiac toxicity at 100,000 ppm. Based on the above data, an IDLH of 50,000 ppm has been chosen.
Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):
1-hour EEGL: 100 ppm
24-hour EEGL: 3 ppm
ACUTE TOXICITY DATA
Lethal concentration data:
Tappan and Waritz 1964
von Weigand 1971
von Weigand 1971
|>373,832 ppm (2.0)
99,800 ppm (2.0)
<125,000 ppm (1.25)
<125,000 ppm (1.25)
Other animal data: In 5-minute cardiac sensitization screening tests, 2 of 12 unanesthetized dogs exposed to 10,000 ppm of dichloromonofluoromethane plus intravenous epinephrine showed evidence of serious arrhythmia; no response was noted at 5,000 ppm [Mullin 1975].
Human data: None relevant for use in determining the revised IDLH.
|Revised IDLH: 5,000 ppm
Basis for revised IDLH: The revised IDLH for dichloromonofluoromethane is 5,000 ppm based on acute inhalation toxicity data in animals [Mullin 1975; Tappan and Waritz 1964; von Weigand 1971]. This may be a conservative value due to the lack of relevant acute toxicity data for workers.
1. ACGIH . Dichloromonofluoromethane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 81-82.
2. Aviado DM, Belej MA . Toxicity of aerosol propellants on the respiratory and circulatory systems. I. Cardiac arrythmia in the mouse. Toxicology 2:31-42.
3. Kozbakova AE . Comparative toxicity of chlorinated and fluorinated methane and ethane derivatives. Gig Tr Prof Zabol 20(11):38-41 (in Russian).
4. Mullin LS . Unpublished data. Newark, DE: Haskell Laboratory, E.I. DuPont de Nemours and Company, November 1975. [From ACGIH . Dichlorofluoromethane. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 434-435.]
5. NRC . 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. 41-45.
6. Tappan CH, Waritz RS . Unpublished data: acute inhalation toxicity of Freon-21® (fluorodichloromethane). Report No. 128-64. Newark, DE: E.I. DuPont de Nemours and Company, Haskell Laboratory for Toxicology and Industrial Medicine, November 1964.
7. Underwriters’ Laboratory . The comparative life, fire, and explosion hazards of dichloromonofluoromethane (F21). Miscellaneous Hazard Report No. 2630. [From ACGIH . Dichloromonofluoromethane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 81-82.]
8. von Weigand W . Investigations on the inhalation toxicity of fluorine derivatives of methane, ethane, and cyclobutane. Zentralbl Arbeitsmed Arbeitsschutz 21:149-156 (in German).