SULFUR DIOXIDE†
| Chemical Identification | |
|---|---|
| CAS # | 7446-09-5 |
| Formula |
SO₂ |
| Synonyms |
sulfurous acid anhydride; sulfurous oxide; sulfur oxide |
| Physical Properties | |||
|---|---|---|---|
| Physical description | Colorless gas with a characteristic, irritating, pungent odor. | ||
| Boiling point | 14°F | Molecular weight | 64.1 |
| Freezing point/melting point | -104°F | Vapor pressure | 3.2 atm |
| Flash point | Vapor density | 2.26 | |
| Specific gravity | 1.434 | Ionization potential | 12.30 eV |
| Lower explosive limit (LEL) | Upper explosive limit (UEL) | ||
| NFPA health rating | 3 | NFPA fire rating | 0 |
| NFPA reactivity rating | 0 | NFPA special instruction | |
| Vapor hazard ratio (VHR) | |||
| Historical exceedance percentage | |||
| Target organs | |||
| Monitoring Methods Used by OSHA | ||||||
|---|---|---|---|---|---|---|
| Analyte code (IMIS no.) | 2290 | |||||
| Sampling group | ||||||
| Sampler/Sampling media | Silica gel coated with silver nitrate and a glass fiber filter treated with sodium carbonate/glycerol, 2, (200/200 mg) [SKC 226-177] | |||||
| Sampling time* | 240 min |
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| Sampling volume (TWA)* | 12 L |
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| Sampling flow rate (TWA)* | 0.05 L/min |
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| Sampling volume (STEL/Peak/C)* | 7.5 L |
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| Sampling flow rate (STEL/Peak/C)* | 0.5 L/min |
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| Analytical method instruments | IC | |||||
| Method reference | OSHA 1011 (fully validated) | |||||
| Notes | Use this method when sampling for both hydrogen sulfide and sulfur dioxide. Sulfur trioxide and gaseous elemental sulfur can cause a positive interference. 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. |
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| Special requirements | ||||||
* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.
| Wipe Method | |
|---|---|
| Sampler/Sampling media | |
| Bulk Method |
|---|
| On-Site Screening Techniques | ||||||
|---|---|---|---|---|---|---|
| Device | CMS Chip | CMS Chip | ||||
| Model/Type | Sulfur dioxide, 0.4-10 ppm range | Sulfur dioxide, 5-150 ppm range | ||||
|
Sampling information (see manufacturer instructions) |
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| Exposure Limits | |||||||
|---|---|---|---|---|---|---|---|
|
OSHA PEL
8-hour TWA (ST) STEL (C) Ceiling Peak |
NIOSH REL
Up to 10-hour TWA (ST) STEL (C) Ceiling |
ACGIH TLV©
8-hour TWA (ST) STEL (C) Ceiling |
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| PEL-TWA |
5 ppm (13 mg/m³) |
REL-TWA |
2 ppm (5 mg/m³) |
TLV-TWA | PEL-TWA |
2 ppm (5 mg/m³) |
|
| PEL-STEL | REL-STEL |
5 ppm (13 mg/m³) |
TLV-STEL |
0.25 ppm [2008] |
PEL-STEL |
5 ppm (10 mg/m³) |
|
| PEL-C | REL-C | TLV-C | PEL-C | ||||
| Skin notation |
N |
Skin notation |
N |
Skin notation |
N |
Skin notation |
N |
| Notes: | Notes: | Notes: | Notes: | ||||
| Health factors: See NIH-NLM PubChem. | IDLH |
100 ppm |
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| Carcinogenic classifications: TLV-A4, IARC-3 | Notes: | ||||||
|
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
0.3 ppm/3 ppm/25 ppm |
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| Additional Resources and Literature References |
|---|
|
NOAA: CAMEO Chemicals - Sulfur dioxide NIOSH: Pocket Guide to Chemical Hazards - Sulfur dioxide Literature References
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Last Updated Date : 01/12/2021