430 ILCS 35/2-9

"Strong sensitizer" means any substance which will cause on normal living tissue through an allergic or photodynamic process a hypersensitivity which becomes evident on reapplication of the same substance and which is designated as such by the Director. Before designating any substance as a strong sensitizer, the Director shall find that the frequency of occurrence and severity of the reaction indicate a significant potential for causing hypersensitivity.