They know from experience that the material they work with could be dangerous. Sometimes they have burnt themselves or seen others hurt by the acids, dyes, caustic soda, and other chemicals they handle. The material they work with, the reactions involved, the consequences all this, they know nothing of. They work mechanically, following the orders of their bosses.
Accidents are common.
He got no treatment other than first aid. No case was registered. No compensation paid. He was back to work in a few days. A few children, who work at boiling ingredients, are given rubber gloves to wear.