Sulfurous acid anhydride, sulfurous oxide, sulfur dioxide, SO2

2.1 Classification of the substance or mixture

Health Physical Environmental Acute Toxicity, Oral – Does not meet criteria Gas Under Pressure – Aquatic Toxicity – Acute Toxicity (Inhalation) – Category 3 Liquefied Gas Short Term/Long Term Skin Corrosion/Irritation – Category 1 – Does not meet criteria Eye Damage/Eye Irritation – Category 1 Respiratory or Skin Sensitization – Does not meet criteria Mutagenicity – Does not meet criteria Carcinogenicity – Does not meet criteria Reproductive Toxicity – Does not meet criteria Specific Target Organ Toxicity Acute Exposure – Category 3 Chronic Exposure – Does not meet criteria LABEL:

Signal word

DANGER

Precautionary statements

DANGER! Contains gas under pressure. May explode if heated. Avoid breathing gas. Toxic if inhaled. Use only outdoors or in a well-ventilated area. Causes severe skin burns and serious eye damage Store in a well-ventilated place. Keep container tightly (Liquid SO2) closed. May cause respiratory irritation. Wear protective gloves, protective clothing, and eye and face protection when handling liquid SO2. Dispose of containers/contents according to local waste disposal regulations. IF INHALED: Remove person to fresh air and keep comfortable for breathing. Call a poison centre/doctor. IF IN EYES: Rinse continuously with water for several minutes. Immediately call poison centre/doctor. SPECIAL TREATMENT: (For Liquid SO2 ON SKIN): Gently take off immediately all contaminated clothing. Rinse skin with lukewarm water. DO not rub area or apply dry heat in attempt to rewarm area. Transport immediately to emergency care facility. Emergency Overview: A colourless gas or liquefied compressed gas with a pungent, irritating odour and taste. Sulphur dioxide does not burn but cylinders or tanks may rupture and explode if heated, releasing clouds of irritating and toxic SO2 gas. Contact with liquid SO2 can cause freezing of tissue and frostbite. Wear full protective clothing and a positive pressure full face-piece SCBA in emergency situations involving SO2.

Potential health effects

Irritating to the eyes and upper respiratory tract, becoming a severe irritant at high concentrations. Most inhaled SO2 only penetrates as far as the nose and throat because it dissolves so rapidly in the moist tissues of the upper airways. In severe cases at very high concentrations serious respiratory effects have been reported. Direct skin or eye contact with liquid SO2 may cause frostbite and burns. Sulphur dioxide is not listed as a carcinogen by OSHA, NTP, IARC, ACGIH or the EU. (See Toxicological Information, Section 11.)

Environmental effects

Sulphur dioxide is a common air contaminant in most industrialized areas; it is also the chemical precursor to acid rain. At elevated concentrations, many plants are sensitive to atmospheric sulphur dioxide. Release of this product to the environment should be avoided (see Ecological Information, Section 12).