Sulfur Dioxide


  • Ore Refining
  • Mining
  • Portland Cement Manufacturing
  • Industrial Exposure: accidental release of sulfur dioxide gas
  • Sulfur Treatment of Fruit
  • Pulp Paper Processing: acute releases may occur on a background of low-level chronic exposure
  • Refrigerant: sulfur dioxide was used in the past


  • Sulfur Dioxide Inhalation
    • High Water Solubility -> immediately affect upper airways and conjunctiva
  • Sulfur Dioxide Increases Airway Epithelial Permeability: may allow direct stimulation of airway smooth muscle or stimulate parasympathetics (with resulting bronchoconstriction)
  • Chronic bronchitis: may be seen in dogs after exposure to SO2


  • FOB: may be necessary to rule out airway injury

Clinical Manifestations

Pulmonary Manifestations

Bronchiolitis Obliterans (BO) (see Bronchiolitis Obliterans, [[Bronchiolitis Obliterans]])

  • Epidemiology
    • Reports of US soldiers from Iraq/Afghanistan with BO who were in proximity to a fire in a sulfur mine in 2003 (that produced high ambient air levels of sulfur dioxide, a known cause of BO), exposure to dust storms, exposure to incinerated solid/human waste, and/or exposure to combat smoke [MEDLINE]

(delayed onset of pulmonary injury is unusual)


  • Steroids: may be benficial in acute lung injury, but unproven


  • Constrictive bronchiolitis in soldiers returning from Iraq and Afghanistan. N Engl J Med. 2011 Jul 21;365(3):222-30. doi: 10.1056/NEJMoa1101388 [MEDLINE]