Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 7782–50–5
NIOSH REL: 0.5 ppm (1.45 mg/m3) 15-minute CEILING
Current OSHA PEL: 1 ppm (3 mg/m3) CEILING
1989 OSHA PEL: 0.5 ppm (1.5 mg/m3) TWA, 1 ppm (3 mg/m3) STEL
1993-1994 ACGIH TLV: 0.5 ppm (1.5 mg/m3) TWA, 1 ppm (2.9 mg/m3) STEL
Description of Substance: Greenish-yellow gas with a pungent, irritating odor.
LEL: . . Nonflammable Gas
Original (SCP) IDLH: 30 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by ILO  that exposure to 30 ppm will cause intense coughing fits, and exposure to 40 to 60 ppm for 30 to 60 minutes or more may cause serious damage.
Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):
1-hour EEGL: 3 ppm
24-hour EEGL: 0.5 ppm
ACUTE TOXICITY DATA
Lethal concentration data:
|Adjusted 0.5-hr |
|Back et al. 1972 |
Back et al. 1972
Tab Biol Per 1933
|1 hr |
|357 ppm (1.22) |
167 ppm (1.22)
5,342 ppm (1.67)
858 ppm (1.0)
330 ppm (0.60)
|36 ppm |
*Note: Conversion factor (CF) was determined with "n" = 3.5 [ten Berge et al. 1986].
Other animal data: RD50 (mouse), 9.34 ppm [Alarie 1981].
Other human data: Exposures to 30 ppm have been reported to cause intense coughing fits and exposure to 40 to 60 ppm for 30 to 60 minutes or more may cause serious damage [ILO 1971]. A concentration of 34 to 51 ppm has been reported to be lethal in 1 to 1.5 hours [Freitag 1941] while 14 to 21 ppm has been suggested as being dangerous within 0.5 to 1 hour [NPIRI 1983].
|Revised IDLH: 10 ppm |
Basis for revised IDLH: The revised IDLH for chlorine is 10 ppm based on acute inhalation toxicity data in humans [Freitag 1941; ILO 1971; NPIRI 1983].
1. Alarie Y . Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.
2. Back KC, Thomas AA, MacEwen JD . Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report no. TSA-20-72-3, pp. A-182 to A-183.
3. Freitag . Danger of chlorine gas. Z. Gesamte Schiess Sprengstoffwes.
4. ILO . Chlorine and compounds. In: Encyclopaedia of occupational health and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour Office, pp. 287-288.
5. Lehmann KB . Experimentelle studien uber den einfluss technisch und hygienisch wichtiger gase und dampfe auf den organismus. Thiel III und IV: Chlor und brom. Arch Hyg 7:231-285 (in German).
6. NPIRI . Raw materials data handbook, physical and chemical properties, fire hazard and health hazard data. Vol. II. 2nd ed. Organic solvents. Bethlehem, PA: National Printing Ink Research Institute, pp. 831-857.
7. 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. 5-11.
8. Prentiss AM . Chemicals in war. A treatise on chemical warfare. New York, NY: McGraw-Hill Book Company, Inc., p. 150.
9. Tab Biol Per ; 3:231 (in German).
10. ten Berge WF, Zwart A, Appelman LM . Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301-309.
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