CAS number: 7446-09-5
NIOSH REL: 2 ppm (5 mg/m3) TWA, 5 ppm (13 mg/m3) STEL
Current OSHA PEL: 5 ppm (13 mg/m3) TWA
1989 OSHA PEL: 2 ppm (5 mg/m3) TWA, 5 ppm (13 mg/m3) STEL
1993-1994 ACGIH TLV: 2 ppm (5.2 mg/m3) TWA, 5 ppm (13 mg/m3) STEL
Description of substance: Colorless gas with a characteristic, irritating, pungent odor.
LEL: . . . Nonflammable Gas
Original (SCP) IDLH: 100 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by AIHA [1955] that 50 to 100 ppm is considered the maximum concentration for exposures of 0.5 to 1 hour [Henderson and Haggard 1943]. With regard to the atmospheric concentration immediately hazardous to life, AIHA [1955] reported that 400 to 500 ppm is considered dangerous for even short periods of exposure [Henderson and Haggard 1943] and that exposure to unendurable concentrations is not necessarily hazardous if escape is made within a few minutes.
Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):
10-minute EEGL: 30 ppm
30-minute EEGL: 20 ppm
60-minute EEGL: 10 ppm
24-hour EEGL: 5 ppm
ACUTE TOXICITY DATA:
Lethal concentration data:
Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derived value Rat Flury & Zernik 1935 —- 993 20 min 864 ppm (0.87) 86 ppm Rat Flury &Zernik 1935 —- 611 5 hr 1,314 ppm (2.15) 131 ppm Mouse Flury &Zernik 1935 —- 764 20 min 665 ppm (0.87) 67 ppm Mouse Hilado &Machado 1977 3,000 —- 30 min 3,000 ppm (1.0) 300 ppm Rat Kinkead & Einhaus 1984 2,520 —- 1 hr 3,150 ppm (1.25) 315 ppm Human Shupe et al. 1972 —- 1,000 10 min 690 ppm (0.69) 69 ppm Human Tab Biol Per 1933 —- 3,000 5 min 1,500 ppm (0.5) 150 ppm
Other animal data: RD50 (mouse), 117 ppm [Alarie 1981].
Other human data: The maximum concentration for exposures of 0.5 to 1 hour is considered to be 50 to 100 ppm [Henderson and Haggard 1943]. It has been reported that 400 to 500 ppm is considered dangerous for even short periods of exposure [Henderson and Haggard 1943].
Revised IDLH: 100 ppm [Unchanged]Basis for revised IDLH: Based on acute inhalation toxicity data in humans [Henderson and Haggard 1943; Shupe et al. 1972; Tab Biol Per 1933], the original IDLH for sulfur dioxide (100 ppm) is not being revised at this time.
REFERENCES:
1. AIHA [1955]. Sulfur dioxide. In: Hygienic guide series. Am Ind Hyg Assoc Q 16:332-333.
2. Alarie Y [1981]. Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.
3. Flury F, Zernik F [1935]. Zusammenstellung der toxischen und letalen dosen für die gebräuchlichsten gifte und versuchstiere. Abder Hand Biol Arbeitsmethod 4:1289-1422 (in German). [From Back KC, Thomas AA, MacEwen JD [1972]. 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. A250 to A251.]
4. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 131.
5. Hilado CJ, Machado AM [1977]. Effect of sulfur dioxide on Swiss albino mice. J Combustion Toxicol 4:236-244.
6. Kinkead ER, Einhaus RL [1984]. Acute toxicity of thionyl chloride vapor for rats. Wright-Patterson Air Force Base, OH: Air Force Systems Command, Air Force Aerospace Medical Division, Aerospace Medical Research Laboratory, Technical Report AFAMRL-TR-84-069.
7. 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. 95-102.
8. Shupe JL, Olson AE, Sharma RP [1972]. Fluoride toxicity in domestic and wild animals. Clin Toxicol 5:195-213.
9. Tab Biol Per [1933]; 3:231 (in German).
