Methyl isocyanate

Background

• Compound that is intermediate chemical in formulation of many carbamate pesticides
• Highly toxic if inhaled, contacted, or ingested
• Odorless, clear liquid
• Principle toxicant in Bhopal disaster

Clinical Features

• Potent lachrymal agent
• Symptom onset may be immediate after exposure or delayed 1-2 days
• Mucosal irritation of eyes, nose, pharynx, skin
• Cough, chest pain, SOB
• At high levels: pulmonary edema, severe reactive airway disease, bronchial/alveolar hemorrhage

Differential Diagnosis

Chemical weapons

• Blister chemical agents (Vesicants)
  • Lewisite (L)
  • Sulfur mustard (H)
  • Phosgene oxime (CX)
• Pulmonary chemical agents (Choking agents)
  • Ammonia toxicity
  • Methyl isocyanate
  • Methyl bromide
  • Hydrochloric acid
  • Chlorine gas
  • Phosgene
• Incendiary agents
  • Agent orange
  • White phosphorus
• Cyanide chemical weapon agents (Blood agents)
  • Prussic acid (AKA hydrogen cyanide, hydrocyanic acid, or formonitrile)
• Nerve Agents (organophosphates)
  • Acetylcholinesterase inhibitors
  • Household and commercial pesticides (diazinon and parathion)
  • G-series (sarin, tabun, soman)
  • V-series (VX)
• Lacrimating or riot-control agents
  • Pepper spray
  • Chloroacetophenone
  • CS

Evaluation

• Clinical diagnosis, evaluate for alternatives and complications

Management

• Decontaminate
• Supportive

References

• Agency for Toxic Substances & Disease Registry https://www.atsdr.cdc.gov/toxfaqs/tfacts182.pdf