What is the pathophysiology of smoke inhalation caused by sulfur trioxide?

Updated: Oct 15, 2021
  • Author: Keith A Lafferty, MD; Chief Editor: Joe Alcock, MD, MS  more...
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The smoke-producing agent FS, also known as sulfuric oxide, chlorosulfonic acid, or sulfuric anhydride, is typically a colorless liquid, which can exist as ice, fiberlike crystals, or gas. When it is exposed to air, it rapidly takes up water and forms white fumes. The smoke consists of 50% sulfur trioxide and 50% chlorosulfonic acid.

FS usually is dispersed by spray atomization. The sulfur trioxide evaporates from spray particles, reacts with surrounding moisture, and forms sulfur acid. The sulfur acid condenses into droplets that produce a dense white cloud. FS is extremely corrosive, which led to its disuse in by the military. However, it has industrial use as an intermediate in the production of sulfuric acid, as well as other chemicals and explosives. [24]

Toxicity from FS is that of an acidic irritation to mucosal membranes and even skin. The corrosive effect of acid on mucosa and keratinized skin causes significant irritations and chemical burns.

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