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Formic acid


Key Points


  • Flammable on heating
  • Reacts with alkalis and oxidising materials such as peroxides, nitric acid and chromic acid. Formic acid forms explosive reactions
  • Emits toxic fumes of carbon monoxide when heated to decomposition or on contact with strong acids
  • In the event of a fire involving formic acid, alcohol resistant foam or fine water spray and liquid tight chemical protective kit with breathing apparatus


  • Toxic by all routes of exposure
  • CHIP classification: corrosive
  • Inhalation causes irritation of the eyes and nose with sore throat, cough, chest tightness, headache and confusion
  • Ingestion causes immediate burning of the mouth and throat, difficulty swallowing, vomiting and stomach pain
  • Exposure to skin can cause burns to the skin layers 
  • Eye exposure causes pain, lacrimation and increased sensitivity to light


  • Avoid release into the envionment
  • Inform the Environment Agency of substantial releases


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Version 1

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Compendium of Chemical Hazards