Agent Name

Sulfur dioxide

CAS Number

7446-09-5

Formula

O2-S

Major Category

Toxic Gases & Vapors

Synonyms

Sulfurous acid anhydride; Sulfurous oxide; Sulfur oxide; [NIOSH]

Category

Corrosive Gases

Description

Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14 degrees F. Shipped as a liquefied compressed gas.] [NIOSH]

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]

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 2012] 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]

Reference Link

ATSDR Medical Management - Sulfur dioxide

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

TIH

Yes

STEL (ACGIH)

0.25 ppm

PEL (OSHA)

5 ppm

MAK

1 ppm

IDLH (NIOSH)

100 ppm

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].

Odor Threshold Low

0.33 ppm

Odor Threshold High

5 ppm

RD50

117 ppm

Lethal Concentration

LC50 (rat) = 2,520 ppm/1H

Explanatory Notes

Detection odor threshold from AIHA (mean = 2.7); Boiling point = -10 deg C; [ICSC]

Half Life

No reports found; [TDR, p. 1098]

Reference Link

ICSC: Sulphur dioxide

Adverse Effects
Chronic Bronchitis

Yes

Toxic Pneumonitis

Yes

Fibrogenic

Yes

IARC Carcinogen

Not Classifiable

ACGIH Carcinogen

Not Classifiable

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

Chemical Information

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Biomedical References

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent:

Processes

Industrial Processes with risk of exposure:

Activities

Activities with risk of exposure: