Hydrogen peroxide is the primary ingredient in hair bleach. Most hair bleach contains between 6 percent and 10 percent hydrogen peroxide. Other ingredients include ammonium persulfate, potassium persulfate and sodium persulfate.
Hydrogen peroxide is the bleaching agent that reacts with hair to remove color. Persulfates are added to hair bleach to increase the rate of the chemical reaction. Care must be taken when using hair bleach containing hydrogen peroxide. Small concentrations of hydrogen peroxide can cause the skin to tighten and whiten. After using hair bleach, the skin should be rinsed with running water. Skin burns are possible when bleaches containing higher concentrations of hydrogen peroxide are used. Accidentally ingesting hair bleach containing hydrogen peroxide may cause stomach upset and vomiting. Ingesting large amounts of hydrogen peroxide can irritate and burn the stomach and usually requires a trip to the emergency room.
According to the Australian Department of Health, persulfates can have detrimental physical effects when they come into contact with skin. An acute allergic reaction might cause swelling, itching and reddening of the skin, and repeated exposure can lead to dermatitis, a skin disorder that causes large, scaly and itchy rashes to appear. It is important to exercise caution when using products containing hydrogen peroxide or persulfates.