HC Red No. 7 functions as a semipermanent (direct) hair colorant in one cosmetic product at 1%. Analytical studies found the relative purity of HC Red No. 7 to be > 98.5%. Impurities may include 2-nitro-benzene-1,4-diamine; 3-(4-amino-3-nitro-phenyl)-oxazolin-2-one; 2-chloroethyl