Sulfur Dioxide - SO2
Hazard: Flammable Will not explode
Classification: Health Extremely toxic
Oxidizing agent
Synonyms: Sulfurous acid anhydride, sulfurous oxide, and sulfur oxide
Exposure limits: (OSHA) PEL\TWA: 5 ppm
(ACGIH) STEL: 0.25 ppm/ 15 min
(OSHA) IDLH: 100 ppm / 30 min
Industries: Pulp and paper mills, and coal fired generating stations
Sulfur dioxide is a colorless gas with a characteristic, irritating, pungent odor. Sulfur dioxide is released when compounds containing sulfur, such as fossil fuels like coal are burned.
Sulfur dioxide is a highly toxic gas which poisons its victims via inhalation through the lungs. SO2 combines with water to form sulfuric acid (H2SO4). It is for this reason sulfur dioxide can burn the respiratory tract upon inhalation. High doses of sulfur dioxide can cause death quite rapidly.
Effects of Various SO2 Levels
Sulfur OxideLevel in PPM Resulting Conditions on Humans
.3-1 Sulfur Dioxide initially detected by taste
5 Permissible Exposure Level (OSHA)
3 Odor becomes easily detected
6-12 Irritation of the nose and throat
20 Irritation of the eyes
50-100 Maximum exposure for a 30 minute period
400-500 Dangerous concentration can cause edema of the lungs and glottis and death from prolonged exposure |