Registration Dossier

Administrative data

Description of key information

The acute toxic action of sulfur dioxide is characterized by rapid onset of depression of the respiratory rate and by tissue changes in the upper respiratory tract that penetrate to deeper regions as concentrations rise. In persons exposed to high sulfur dioxide concentrations either accidentally or in former times at workplaces, burning of eyes, nose and throat, rhinorrhea, tearing of eyes, dyspnoea, chest tightness, cough, and injury of the cornea have been observed.

Key value for chemical safety assessment

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
Value:
2 528.5 mg/m³

Additional information

There are no acute inhalation studies available according to OECD Guideline 403. However, sufficient information on acute toxicity can be derived from some older studies. For rats the 4-hour LC50 is between 965 and 1,168 ppm, for mice the 30-min LC50 is 3,400 ppm. In hamsters 5-hour exposures to 400 ppm were lethal for all exposed animals, whereas 200 ppm were tolerated without deaths. Animals died from respiratory distress and asphyxia. The acute toxic action of sulfur dioxide is characterized by rapid onset of depression of the respiratory rate and by tissue changes in the upper respiratory tract that penetrate to deeper regions as concentrations rise. In persons exposed to high sulfur dioxide concentrations either accidentally or in former times at workplaces, burning of eyes, nose and throat, rhinorrhea, tearing of eyes, dyspnoea, chest tightness, cough, and injury of the cornea have been observed. Entry adopted from the OECD SIAR on sulfur dioxide without modification.

Justification for classification or non-classification

Sulfur dioxide is already legally classified as acute toxic via inhalation category 3 according to annex VI of regulation (EC) 1272/2008. This has been confirmed in animal tests and human case reports. Sulfur dioxide will be classified as acute toxic via inhalation category 3 (H331).