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Chemical Sampling Information (CSI)
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General Description

Synonyms: Sulphur dioxide; Sulfurous acid anhydride; Sulfurous oxide; Sulfur oxide

OSHA IMIS Code Number: 2290

Chemical Abstracts Service (CAS) Registry Number: 7446-09-5

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: WS4550000

Department of Transportation Regulation Number (49 CFR 172.101) and 2012 Emergency Response Guidebook [4 MB PDF, 392 pages]: 1079 125

NIOSH Pocket Guide to Chemical Hazards - Sulfur Dioxide: Physical description, chemical properties, potentially hazardous incompatibilities, and more




Exposure Limits and Health Effects

Exposure Limit

Limit Values

HE Codes

Health Factors and Target Organs

OSHA Permissible Exposure Limit (PEL) - General Industry
See 29 CFR 1910.1000 Table Z-1

5 ppm
(13 mg/m3) TWA

HE14

Upper respiratory irritation, nosebleeds

OSHA PEL - Construction Industry
See 29 CFR 1926.55 Appendix A

5 ppm
(13 mg/m3) TWA

HE14

Upper respiratory irritation, nosebleeds

OSHA PEL - Shipyard Employment
See 29 CFR 1915.1000 Table Z-Shipyards

5 ppm
(13 mg/m3) TWA

HE14

Upper respiratory irritation, nosebleeds

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL)

2 ppm
(5 mg/m3) TWA

5 ppm
(13 mg/m3) STEL

HE4

Blindness

HE9

Bronchoconstriction

HE11

Breathing difficulties

HE14

Eye and respiratory irritation, eye and skin burning

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) (2009)

0.25 ppm
(0.65 mg/m3) STEL

A4

HE9

Bronchoconstriction, exacerbation of asthma

HE10

Decreased lung function, chronic respiratory symptoms

HE11

Lower respiratory irritation and symptoms

HE14

Upper respiratory irritation

CAL/OSHA PELs

2 ppm
(5 mg/m3) TWA

5 ppm
(10 mg/m3) STEL

 

 

National Toxicology Program (NTP) carcinogenic classification: Not listed

International Agency for Research on Cancer (IARC) carcinogenic classification: Class 3 [4 MB PDF, 58 pages] (not classifiable as to its carcinogenicity to humans)

U.S. Environmental Protection Agency (EPA) carcinogenic classification: Not listed

EPA Inhalation Reference Concentration (RfC): Not established

Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Level (MRL): 0.01 ppm (acute)

NIOSH Immediately Dangerous to Life or Health (IDLH) concentration: 100 ppm

Notes on Other Potential Health Effects and Hazards

  1. Contact with liquid sulfur dioxide can cause frostbite on the skin (NIOSH/IPCS 2006).
  2. Some evidence indicates an association between environmental exposure to sulfur dioxide during pregnancy and low birth weight (ATSDR 1998).

Date Last Revised: 9/6/2012

Literature Basis

  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Sulfur Dioxide. 2009.
  • ATSDR: Toxicological Profile - Sulfur Dioxide [4 MB PDF, 23 pages]. US Health and Human Services (US HHS), 1998.
  • NIOSH: Occupational Health Guideline - Sulfur Dioxide, 1978.
  • NIOSH/IPCS: International Chemical Safety Cards - Sulphur Dioxide. October 10, 2006.
Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

  • sampling media: MCE filter followed by a cellulose filter coated with sodium carbonate (SKC No. 225-9005, or equivalent
    maximum volume: 200 Liters
    maximum flow rate: 1.5 L/min (TWA)
    maximum volume: 23 Liters
    maximum flow rate: 1.5 L/min (STEL)
    current analytical method: Ion Chromatography; IC
    method reference: NIOSH Analytical Method (NIOSH 6004 [29 KB PDF, 4 pages])
    method classification: Partially Validated
    note: Sulfur trioxide can cause a positive interference.

  • sampling media: Special sampling tube containing an uncoated glass fiber filter, followed by a sodium carbonate coated glass fiber filter, followed by two beds of silver nitrate coated silica gel (200/200 mg). (SKC No. 226-177, or equivalent)
    maximum volume: 12 Liters
    maximum flow rate: 0.05 L/min (TWA)
    maximum volume: 7.5 Liters
    maximum flow rate: 0.5 L/min (Ceiling)
    current analytical method: Chromatography; IC/Cond
    method reference: OSHA Analytical Method (OSHA 1011)
    method classification: Fully Validated
    note: The sampling pump must be capable of maintaining a constant flow of 0.5 L/min with a back pressure of approximately 20 inches of water.
    note: Use this method when sampling for both hydrogen sulfide and sulfur dioxide. Sulfur trioxide and gaseous elemental sulfur can cause a positive interference. OSHA personnel can obtain samplers from SLTC.

  • sampling media: Impregnated Activated Beaded Carbon (100/50 mg sections) (SKC No. 226-80, or equivalent)
    maximum volume: 12 Liters
    maximum flow rate: 0.1 L/min (TWA)
    maximum volume: 1.5 Liters
    maximum flow rate: 0.1 L/min (STEL)
    current analytical method: Ion Chromatography; IC
    method reference: OSHA Analytical Method (OSHA ID-200)
    method classification: Fully Validated
    note: Sulfur trioxide can cause a positive interference. Hydrogen sulfide is a positive interference. Use NIOSH Method 6004 if the presence of hydrogen sulfide is suspected.

  • sampling media: Mixed Cellulose Ester Filter in series with Midget Fritted Glass Bubbler (MFGB) containing 15 mL 0.3N hydrogen peroxide.
    maximum volume: 60 Liters
    maximum flow rate: 1.0 L/min (TWA)
    maximum volume: 15 Liters
    maximum flow rate: 1.0 L/min (STEL)
    current analytical method: Ion Chromatography; IC
    method reference: OSHA Analytical Method (OSHA ID-104)
    method classification: Validated
    note: Sulfur trioxide can cause a positive interference.

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