Contact allergy to trimethylolpropane triacrylate (TMPTA) in an aziridine plastic hardener

4 workers developed hand and face dermatitis when exposed to a floor top coat. This contained a polyurethane and a polyfunctional aziridine hardener and additives. The aziridine hardener was made by reacting propyleneimine with a polyfunctional acrylate, trimethylolpropane triacrylate (TMPTA). All 4 reacted to the hardener and to TMPTA, which is present in excess. 2 of them also reacted to pentaerythritol triacrylate (PETA), which can be used in the production of aziridine hardeners. TMPTA and PETA cross-react, and are known sensitizers in UV-hardening acrylates. The present finding shows that well-known sensitizers can be found in hidden sources when used in a quite different chemical process.