Sensitizer

A substance which on first exposure causes little or no reaction in man or test animals, but which on repeated exposure may cause a marked response not necessarily limited to the contact site. Skin sensitization is the most common form of sensitization in the industrial setting, although respiratory sensitization to a few chemicals is also know to occur.

Importance: Knowing that a substance is a sensitizer allows you to be aware of the signs and symptoms of overexposure.