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MDI or TDI: First Aid Guidance

Julianne Ogden
Consult the Manufacturer’s Safety Data Sheet (SDS) for specific first aid instructions. Take the SDS when seeking medical attention.

The following is only general guidance on first aid procedures1 in the event of an accidental over exposure to MDI or TDI and the person overexposed experiences any of the following:

  • Difficulty breathing;
  • Eye contact;
  • Skin contact; or
  • Ingestion.
Difficulty Breathing
  • The person affected should be moved from risk of further exposure and made to rest.
  • Obtain medical attention immediately.
  • The onset of symptoms may occur several hours after exposure has taken place if the person has been sensitized to the substance.
Eye Contact
  • Flush the eyes immediately with the contents of several sterile eye wash bottles or copious amounts of tap water. Then remove contact lenses, if present and easily removable, and continue eye irrigation for not less than 15 minutes.
  • Obtain medical attention.
Skin Contact

MDI and TDI may be difficult to wash off with just water or soap and water. Refer to the Manufacturer’s SDS for assistance in determining which of the following methods is most appropriate.

  • Remove contaminated clothing and shoes
  • Wash off thoroughly with large amounts of water and then wash well with soap and water.


  • Wash off with soap and water. After washing, cover affected area with polyethylene glycol (300-500 molecular weight) and wash again with soap and water to thoroughly remove polyethylene glycol and residual isocyanate. Repeat if necessary.
  • If material has hardened, soak affected area with polyethylene glycol or corn oil and carefully remove so as not to damage skin.

For severe exposures, obtain medical attention immediately. Get under safety shower and begin rinsing off.

  • Do not induce vomiting.
  • Wash out the mouth with water. Do not administer liquids.
  • The person affected should be made to rest.
  • Obtain medical attention.
Additional Information for Medical Personnel
  • MDI and TDI are respiratory irritants and potential respiratory sensitizers. There are no specific antidotes and treatment is essentially symptomatic for primary irritation or bronchospasm.
  • MDI and TDI have very low oral toxicity.
  • Post-incident follow-up checks are recommended.

1 First aid guidance reference source: MDI & TDI Safety Health and the Environment: A Source Book and Practical Guide, published by John Wiley & Sons, Ltd., copyright 2003, edited by: D. C. Allport, D. S. Gilbert and S. M .Outterside. https://www.diisocyanates.org/institute-sponsored-book

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