An emulsion hair bleach composition prepared by combining an aqueous oxidizing agent composition, a persulfate composition, and, optionally, a bleach oil composition, in amounts sufficient to provide a mixture containing an active oxygen concentration of about 3 to 5% by weight of the total mixture, a total alkalinity concentration of about 0.7 1.2 meq/gm., and 0.5 20% by weight of the total mixture of an oil having a solubility parameter of 5 12 (cal/cm.sup.3).sup.1/2; an emulsion hair bleach composition capable of lightening hair in 10 to 30 minutes, and a kit for use in bleaching hair.