Sulfur Dioxide (SO2)
Quick Reference
What is SO2?
A colorless strong-smelling gas used primarily in the production of sulfuric acid and winemaking. The sulfite pulp production process does use SO2, but no pulp mills in BC currently use this process. It is acidic and highly soluble in water. Also produced in small concentrations as a byproduct of combustion of sulfur containing compounds, such as diesel fuel. May be transported as a compressed gas or generated on-site.
Crew Safety
- Staging/Perimeter
- Small tank: 100 m initially then refer to ERG
- Large tank: 1000 m initially then refer to ERG
- Large tank involved in a fire: 1600 m
- Additional Resources
- If rescue required a industrial response team or fire department with SCBAs is required.
- PPE requirements
- Large spills require SCBA with chemical protective clothing if direct exposure to SO2.
- Routine industrial exposure, such as in winemaking, requires use of a respirator with an acid-gas cartridge.
- Safely initiating patient contact
- Patient should be brought to the crew in a safe location. Crew can decontaminate the patient.
Effect on the Patient
It is an acidic gas that is highly soluble in water and, when it contacts moisture, it converts to sulfurous acid. Thus, it is highly irritating to mucous membranes and the eyes. This usually limits exposure times, however prolonged exposure is possible if a patient is trapped. This may cause irritation or burns to a patient’s eyes, or irritation/burns/edema in the upper airway. Prolonged exposure may lead to delayed onset of pulmonary edema.
Patient Decontamination
* Remove clothing without pulling over the head. Contaminated clothing not to accompany patient.
* If eye irritation is present continuously flush eyes.
* Skin irritation not usually present, but if it is, flush skin with warm water for 15 minutes.
Patient Treatment
* Decontamination as above.
* Treat respiratory distress and other symptoms as per BCEHS CPGs.
* Transport for assessment and observation due to risk of delayed onset pulmonary edema.
Safe Transfer of Care
No risk of secondary contamination once patient has been removed from source and initial decontamination has occurred.
Paramedic and Equipment Decontamination
If patient was decontaminated and paramedics staged in a safe location no special decontamination is required. If patient compartment has foul odour ventilate for 20 minutes.
Quick Access Resources
DPIC Monograph
No DPIC monograph available.
Paramedic Specialist Safety Data Sheet
Emergency Response Guidebook
WorkSafe BC Bulletin on SO2 in Winemaking
Revision History
| Version | Date | Changes | Author |
|---|---|---|---|
| 1.0 | 2026-05-01 | Initial version | Clinical Hub |