Most of the Hair coloring products contain potentially harmful ingredients. These chemical ingredients may cause skin, eye, and throat and lung irritation and could also lead to the cancer of the bladder.

Some of the dangerous chemicals used in hair dying are:

  1. Hydrogen Peroxide: the chemical is used to strip away the natural color of the hair before dying. The chemical is said to change the hair structure and makes the hair brittle which removes the natural luster of the hair.
  2. Ammonia: this chemical is used to open the hair’s cuticle i.e. the outer layer of the hair in order to allow the dye to reach the inside of the hair i.e. the shaft. This can cause caustic burns or irritation to the skin
  3. PPD or Para-phenylenediamine: this is another agent used as a dye to darken the hair shades. This is a petroleum-derived chemical and research states that PPD, when combined with Hydrogen Peroxide, is very toxic and the long term usage can cause cancer.
  4. Parabens: Parabens are a class of widely used preservatives in cosmetic Methyl parabens and Propyl parabens are common paraben preservatives that are widely used in hair care products and can produce severe allergies and skin irritation.
  5. Lead Acetate: may cause neurological problems and can also cause anemia. The chemical is used as a color additive to add a darker shade.
  6. Resorcinol is another chemical that is used in hair dyes and can cause scalp irritation and this allergen can also affect the endocrine system.
  7. DMDM hydantoin: they are usually used as preservatives and can increase the risk of cosmetic dermatitis in consumers allergic to formaldehyde

Consumers need to decide whether or not to use permanent dyes, but do note that pregnant women are strongly advised not to color their hair, and the Environmental Working Group found that 69% of hair-dye products they tested for their Skin Deep database may pose cancerous risks. A 1994 National Cancer Institute report states dark dyes used over long periods of time seem to increase the risk of cancers such as non-Hodgkin’s lymphoma and multiple myelomas. You should be aware that all permanent colors will have some chemicals. Choosing the one that has the least chemical or no chemical would be an appropriate choice.

http://www.dailymail.co.uk/health/article-18662/Hair-dye-cause-cancer–brunettes-greater-risk.html