Here is some more information I found recently.
There are also signs that retinyl palmitate (topical vitamin A), an ingredient in 41 percent of sunscreens, potentially becomes photocarcinogenic, or tumor-producing, when exposed to the sun. That's right. The sunscreen could actually make you more likely to develop tumors -- when you spend time in the sun.
For decades, irresponsible cosmetic companies and a small group of very vocal, publicity-seeking dermatologists have strongly advocated that chemical sunscreens should be heavily applied before any exposure to sunlight, even on young children. They insisted that such sunscreen use would prevent skin cancer and protect your health. This was despite of a lack of any adequate safety testing of these chemicals. (It should be emphasized that most dermatologists are much more cautious and careful.)
On the other hand, over the past decade, many scientists studying cancer have come to virtually the opposite conclusion; that is, the use of sunscreen chemicals may be increasing the incidence of cancer and that sunlight exposure may actually decrease human cancer rates and improve your health.
It now appears that many heavily-used chemical sunscreens may actually increase cancers by virtue of their free radical generating properties. And more insidiously, many commonly used sunscreen chemicals have strong estrogenic actions that may cause serious problems in sexual development and adult sexual function, and may further increase cancer risks.
It is not that these compounds were ever viewed as benign substances. Organic chemists have been long aware of the dangers of compounds in chemical sunscreens. Such chemicals are widely used to start free radical reactions during chemical synthesis. These chemicals are the dangerous types that one carefully keeps away from your skin while working in a laboratory. To use them, you mix them into a combination of other chemicals, then flash the mixture with an ultraviolet light. The ultraviolet absorbing chemicals then generate copious amounts of free radicals that initiated the desired chemical reactions.
Despite the medical establishment's near unanimity on the issue of sunlight exposure, on other health issues in the past, serious errors been promoted to the public.
1. No proof that sunscreen prevents skin cancer.
The FDA’s 2007 draft sunscreen safety regulations say: “FDA is not aware of data demonstrating that sunscreen use alone helps prevent skin cancer.” The International Agency for Research on Cancer (IARC) agrees. IARC recommends clothing, hats and shade as primary barriers to UV radiation and writes that “sunscreens should not be the first choice for skin cancer prevention and should not be used as the sole agent for protection against the sun.
2. There’s some evidence that sunscreens might increase the risk of the deadliest form of skin cancer for some people.
Some researchers have detected an increased risk of melanoma among sunscreen users. Scientists speculate that sunscreen users stay out in the sun longer and absorb more radiation overall, or that free radicals released as sunscreen chemicals break down in sunlight may play a role. One other hunch: Inferior sunscreens with poor UVA protection that have dominated the market for 30 years may have led to this surprising outcome. All major public health agencies still advise using sunscreens, but they also stress the importance of shade, clothing and timing.
3. There are more high SPF products than ever before, but no proof that they’re better.
In 2007 the FDA published draft regulations that would prohibit companies from labeling sunscreens with an SPF (sun protection factor) higher than SPF 50+. The agency wrote that higher values were “inherently misleading,” given that “there is no assurance that the specific values themselves are in fact truthful.” Scientists are also worried that high-SPF products may tempt people to stay in the sun too long, suppressing sunburns (a late, key warning of overexposure) while upping the risks of other kinds of skin damage.
4. Too little sun might be harmful, reducing the body’s vitamin D levels.
Sunshine serves a critical function in the body that sunscreen appears to inhibit: the production of vitamin D. The main source of vitamin D in the body is sunshine, and the compound is enormously important to health–it strengthens bones and the immune system, reduces the risk of various cancers (including breast, colon, kidney, and ovarian cancers) and regulates at least 1,000 different genes governing virtually every tissue in the body. Over the last two decades, vitamin D levels in the U.S. population have been decreasing steadily, creating a “growing epidemic of vitamin D insufficiency.”
5. The common sunscreen ingredient vitamin A may speed the development of cancer.
Recently available data from an FDA study indicate that a form of vitamin A, retinyl palmitate, when applied to the skin in the presence of sunlight, may speed the development of skin tumors and lesions. This evidence is troubling because the sunscreen industry adds vitamin A to 41 percent of all sunscreens.
The industry puts vitamin A in its formulations because it is an anti-oxidant that slows skin aging. That may be true for lotions and night creams used indoors, but FDA recently conducted a study of vitamin A’s photocarcinogenic properties, the possibility that it results in cancerous tumors when used on skin exposed to sunlight. Scientists have known for some time that vitamin A can spur excess skin growth (hyperplasia), and that in sunlight it can form free radicals that damage DNA.
6. Pick your sunscreen: nanomaterials or potential hormone disruptors.
The ideal sunscreen would completely block the UV rays that cause sunburn, immune suppression and damaging free radicals. It would remain effective on the skin for several hours and not form harmful ingredients when degraded by UV light. It would smell and feel pleasant so that people use it in the right amount and frequency.
Unsurprisingly, there is currently no sunscreen that meets all of these criteria. The major choice in the U.S. is between “chemical” sunscreens, which have inferior stability, penetrate the skin and may disrupt the body’s hormone systems, and “mineral” sunscreens (zinc and titanium), which often contain micronized–or nano-scale particles of those minerals. After reviewing the evidence, EWG determined that mineral sunscreens have the best safety profile of today’s choices.
7. Europe has better sunscreens.
Sunscreen makers and users in Europe have more options than in the United States. In Europe, sunscreen makers can select from among 27 chemicals for their formulations, compared to 17 in the U.S. Companies selling in Europe can add any of seven UVA filters to their products, but have a choice of only three when they market in the U.S. European sunscreens could earn FDA’s proposed four-star top rating for UVA protection, while the best U.S. products would earn only three stars. Sunscreen chemicals approved in Europe but not by the FDA provide up to five times more UVA protection; U.S. companies have been waiting five years for FDA approval to use the same compounds. Last but not least, Europeans will find many sunscreens with strong (mandatory) UVA protection if proposed regulations in Europe are finalized. Under FDA’s current proposal, Americans will not.
8. This will be the 33rd consecutive summer without final U.S. sunscreen safety regulations.
In the United States, consumer protection has stalled because of the FDA’s 32-year effort to set enforceable guidelines for consumer protection. EWG has found a number of serious problems with existing products, including overstated claims about their perfomance and inadequate UVA protection. Many of these will be remedied when the FDA’s proposed sunscreen rule takes effect. But even after the rule is enacted, gaps will remain. FDA does not consider serious toxicity concerns such as hormone disruption when approving new sun filters, and the new rules would fail to measure sunscreen stability despite ample evidence that many products break down quickly in sunlight.