| Agent Name |
Sulfur dioxide |
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| CAS Number |
7446-09-5 |
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| Formula |
O2-S |
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| Major Category |
Toxic Gases & Vapors |
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| Synonyms |
Sulfurous acid anhydride; Sulfurous oxide; Sulfur oxide; [NIOSH] |
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| Category |
Corrosive Gases |
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| Description |
Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14 degrees F. Shipped as a liquefied compressed gas.] [NIOSH] |
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| Sources/Uses |
Formed as a byproduct of burning sulfur-containing materials; used for bleaching, disinfecting, and fumigating; [ACGIH] Used to preserve fruits and other foods; manufacture molasses, wine, and beer; bleach textile fibers; tan leather; pulp wood; manufacture lithium batteries and glass; treat water; and refine oil and metal; [HSDB] |
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| Comments |
Listed as one of "major irritant airborne toxicants"; [LaDou, p. 523] Possible frostbite from contact with liquid; [NIOSH] In the presence of water and acid, metabisulfite, a preservative, can generate toxic amounts of SO2. [ATSDR Med. Manage. Guidelines] The following chemicals can release SO2 when spilled in water: Sulfur chlorides; Sodium, Calcium & Zinc hydrosulfite; and Thionyl chloride. [ERG 2008] See the Process, "Toxic Gas from Spilling Chemical in Water." Sulfur dioxide is fibrogenic to the lungs in the context of an acute inhalation exposure complicated by bronchiolitis obliterans. [LaDou, p. 330] |
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| Reference Link |
ATSDR Medical Management - Sulfur dioxide |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
No |
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| TIH |
Yes |
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| TLV (ACGIH) |
2 ppm |
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| STEL (ACGIH) |
5 ppm |
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| PEL (OSHA) |
5 ppm |
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| MAK |
0.5 ppm |
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| IDLH (NIOSH) |
100 ppm |
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| Excerpts from Documentation for IDLHs |
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]. |
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| Odor Threshold Low |
0.33 ppm |
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| Odor Threshold High |
5 ppm |
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| RD50 |
117 ppm |
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| Lethal Concentration |
LC50 (rats) = 2,520 ppm/1H |
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| Explanatory Notes |
Detection odor threshold from AIHA (mean = 2.7); Boiling point = -10 deg C; [ICSC] See 2008 Notice of Intended Changes. [ACGIH] |
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| Half Life |
No reports found; [TDR, p. 1098] |
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| Reference Link |
International Chemical Safety Cards (WHO/IPCS/ILO) |
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| Flammability (NFPA) |
0: will not burn |
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| Adverse Effects |
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| Toxic Pneumonitis |
Yes |
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| Fibrogenic |
Yes |
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| IARC Carcinogen |
Not Classifiable |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: SULFUR DIOXIDE
|
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