Many popular sunscreens contain the chemical ingredient Benzophenone (or its derivatives Benzophenone-3 or Oxybenzone) since it is one of the best of the chemical sunscreens in protecting against both UVA and UVB rays. However, sunscreens containing these chemicals are NOT a good choice. Here is an instance in which the protection may create more harm than good and actually cause the disease it's trying to prevent. Benzophenone is a powerful free radical generator activated by ultraviolet light. These free radicals could initiate a reaction that may ultimately lead to melanoma and other skin cancers.
Studies show that some of the chemicals in sunscreens are absorbed into the bloodstream in significant amounts. The longer sunscreen chemicals are left on the skin, the greater the absorption into the body. One study notes "it would be prudent not to apply oxybenzone to large surface areas of skin for extended and repeated periods of time, unless no alternative protection is available. There may be an additional concern for young children who have less well-developed processes of elimination, and have a larger surface area per body weight than adults."
Many sunscreen products contain triethanolamine (TEA). This ingredient may combine with nitrite (used as a preservative or may be present as an environmental contaminant) to cause formation of cancer-causing nitrosamines. Nitrites are not disclosed on cosmetic labels so there's no way of telling which products are contaminated with nitrosamines. Particularly disturbing is that up to 35 percent of TEA applied to the skin can enter the bloodstream.
The Environmental Working Group and other toxicology experts believe that oxybenzone is linked to hormone disruption and potentially to cell damage that may lead to skin cancer.