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Dichlorodifluoromethane																				Related Pages
										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-hr** **LC (CF)**
    **Derived** **value**Mouse RabbitG. pigRat
    Paulet 1976 Paulet 1976Paulet 1976Scholz 1962
    760,000 800,000800,000600,000
    ----- ---------------
    30 min 30 min30 min2 hr
    760,000 ppm (1.0) 800,000 ppm (1.0)800,000 ppm (1.0)960,000 ppm (1.6)
    76,000 ppm 80,000 ppm80,000 ppm96,000 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 ppm **Basis 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.]

			
							
								Page last reviewed:  December 4, 2014						Content
							source: 	National Institute for Occupational Safety and Health NIOSH Publications & Products
Immediately Dangerous To Life or Health (IDLH) Values
Table of IDLH Values
Criteria for Determining IDLH Values
Historical Documentation
Original (SCP) Values
Abbreviations for IDLH Documentation
Abbreviations for Journal Titles Follow NIOSH Facebook
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