| nickel and nickel salts | thiuram sulfides | hexamethylenediisocyanate |
| chromium salts | p-phenylenediamine | p-tertiary butyl phenol |
| cobalt salts | diphenylquanidine | formaldehyde |
| organomercurials | resorcinol monobenzoate | neomycin |
| mercaptobenzthiazole | methyl methacrylate | benzocaine |