Where It Comes From
Two-part polyurethane coatings and hardeners; HDI monomer and HDI-based polyisocyanates in automotive refinish and industrial paints [2][3].
How You Are Exposed
Breathing vapors and fine spray droplets during mixing, spraying, and sanding/cleanup; skin and eye contact with liquid or overspray [1][2].
Why It Matters
Can cause sensitization and occupational asthma; once sensitized, even tiny exposures can trigger severe symptoms. Also irritates eyes, nose, throat, and skin [1][2].
Who Is at Risk
Auto refinishers, industrial painters, coating applicators, and anyone working in poorly ventilated areas; workers with asthma or allergies [2][3].
How to Lower Your Exposure
Use enclosed spray booths and local exhaust; choose non-isocyanate products when feasible; wear proper PPE—supplied-air respirator for spraying, chemical-resistant gloves/coveralls, eye protection; keep others out until coatings cure; report symptoms early and get medical evaluation [1][2][3].
References
- [1]CDC/NIOSH Pocket Guide to Chemical Hazards: Hexamethylene diisocyanate (HDI). https://www.cdc.gov/niosh/npg/
- [2]CDC/NIOSH Alert: Preventing Asthma and Death from Diisocyanate Exposure. DHHS (NIOSH) 96-111. https://www.cdc.gov/niosh/docs/96-111/
- [3]U.S. EPA. Diisocyanates Action Plan (TSCA), 2011. https://www.epa.gov/assessing-and-managing-chemicals-under-tsca/action-plans#diisocyanates