Summer’s here at last, and Americans from coast to balmy coast are off to the beach, the pool, the yard, the game, the park, and every destination in between. No matter where your family is heading, one thing is certain: you’ll be packing plenty of sunscreen to protect everyone from the sun’s damaging UV radiation. But as we slap it on to soak in the rays, what are we ourselves soaking in as a result? The answer may have you reaching for the shade instead.

Whether it’s a day’s outing or a two-week vacation, next to a cold drink and a trashy novel the one thing we’re most likely to pack is a tube of sunscreen. In an era of thinning ozone layers and increased public awareness of the hazards of overcooked skin, sunscreens have become an industry all their own, one that’s risen from a mere $18 million in annual sales in 1972 to over half a billion dollars a year by some estimates.

What’s behind this precipitous rise in sunscreen sales? In a word or two, the answer is skin cancer. Malignant melanoma as it’s formally called is the most common cancer in the U.S. The National Cancer Institute reports 1.3 million cases of malignant melanoma each year. It estimates that 40-50% of all Americans living to an age 65 or more will have at least one brush with the disease. And according to Mother Jones magazine, this rate is increasing 6% each year. The good news is that with early detection skin cancer remains one of the most curable kinds. Indeed, despite these big scary numbers, skin cancer is responsible for less than 1% of all cancer deaths.

Though there are several different kinds of malignant melanoma, what they all have in common is that exposure to the ultraviolet (UV) radiation found in sunlight is a major risk factor. And cancer is not the only condition that can be triggered by UV rays. They’re also associated with eye cataracts and suppression of the immune system. The Centers for Disease Control says that as much as 90% of all visible signs of aging can be traced to sun exposure.

Enter sunscreen, the seemingly simple solution everyone reaches for when the clouds part and the beach beckons. There are two kinds of sunscreens that correspond to the two types of damaging UV radiation found in sunshine, UVA and UVB. All sunscreens protect against UVB exposure. Their UVB protection is rated by their Sun Protection Factor (SPF), which is an FDA-regulated term describing how much longer you can stay in the sun before burning. It’s meant to be a simple multiplier that gives you some idea of the protection a particular product provides. Say, for example, that your skin typically starts to burn after 10 minutes of unprotected sun exposure. Apply SPF-20 sunscreen and your skin won’t start to burn for 200 minutes. That is, you can stay in the sun 20 times longer before damage begins to occur. (Readers should note that the SPF system is only meant to provide a ballpark figure. Actual protection times can vary considerably based on a variety of factors from skin type and amount of sunscreen used, to the time of day and the conditions under which your exposure occurs.)

In addition to UVB, most sunscreens today also protect against UVA radiation. Sunscreens that provide this protection will generally say so prominently on the label. Look for this claim or for sunscreens that say they offer “broad-spectrum protection”.

To provide protection against UVA & UVB radiation, sunscreens can employ any number of different chemicals. Some of these chemicals absorb the UV rays so your skin doesn’t have to. Others simply block the radiation outright like a shield.

The most common UVA-protecting chemicals are benzophone, which is also called oxybenzone, dioxybenzophone, or benzophenome-3; and avobenzone, a.k.a. Parsol-1789. There are more options when it comes to UVB rays. UVB protectants include PABA, or para-aminobenzoioc acid; PABA esters, which include padimate O, padimate A, and glyceryl aminobenzoate; and cinnamates, which, as their name suggests, are derived from cinnamon and include the chemicals octyl methoxycinnamate and cinoxate. Ingredients that block sun altogether and therefore protect against both forms of UV radiation include titanium dioxide and zinc oxide.

Unfortunately (and we all knew there was an “unfortunately” in here somewhere didn’t we?), these chemicals may not be much safer than the sunshine they’re meant to protect us from. That’s the verdict of a growing body of evidence. Here’s the rundown on common sunscreen chemicals and the unexpected problems they may be causing.

• Benzophone has been found to cause rashes in the occasional user. More importantly, it appears to mimic the hormone estrogen. In test-tube studies, breast cancer cells multiplied in the presence of benzophone, a fact that indicated estrogenic activity was occurring. In another study, scientists at the University of California at Riverside found that two-thirds of male turbot and sole fish living near a sewage outlet three miles from Huntington Beach, California, were growing ovarian tissue in their testes. Researchers said that the only cause they could “exclusively identify” was oxybenzone, which washed off sunbathers’ bodies in the shower, survived sewage treatment, and settled to the sea floor where it was consumed by the bottom-feeding fish. Such preliminary research suggests that benzophone has the potential to disrupt the human endocrine system. This is a worrisome finding because this chemical is more readily absorbed into the body than most other active sunscreen ingredients. In the environment, benzophone is also increasingly found in surface and groundwater. Scientists fear it may affect the liver and bone marrow of animals that ingest large amounts of benzophone-contaminated water.

• Avobenzone can also be absorbed by the body. According to research conducted at Oxford University, sunlight striking avobenzone becomes excited and reactive. In this state, its increased chemical energy results in the release of free radicals that can damage cellular DNA. Avobenzone has the additional disadvantage of degrading in sunlight and becoming ineffective after about an hour, meaning more must be applied.

• PABA and PABA esters are getting harder and harder to find in sunscreens. That’s a good thing because some 40% of the population is sensitive to PABA and experiences red itchy skin after contact. Research has also found that PABA and related compounds, like avobenzone, break down in the presence of sunlight to form free radicals that can harm DNA in the body’s cells. PABA has also been found to promote the creation of something called thymine dimers, a DNA defect that some of us lack the ability to repair. Ironically, people who cannot repair DNA dimers are more susceptible to skin cancer.

• Cinnamates may cause a host of problems. Octyl methoxycinnamate (OMC) is a suspected endocrine disruptor. According to the Green Guide, exposure to OMC has affected the development of the brain and reproductive organs in tests on laboratory rats. Some people may develop rashes after contact. And Norwegian researchers found that small concentrations of OMC added to an ethyl alcohol solution containing live mouse cells caused 40-50% of those cells to perish. When the solution was placed under a sun lamp to simulate the effects of sunshine, cell mortality increased further.

• Titanium dioxide and the familiar zinc oxide (remember all those lifeguards with white noses?), were once thought fairly safe. Although titanium dioxide has shown some phototoxicity (i.e. the ability to damage cells upon exposure to light), most formulations containing it coat this ingredient with materials that greatly reduce this potential. When used as a sunscreen under normal conditions, titanium dioxide has not displayed phototoxicity. Further, researchers say it’s much less likely than other active ingredients to be absorbed by the skin. Zinc oxide does not irritate the skin and has generally been considered quite safe. However, sunscreen manufacturers are increasingly replacing traditional forms of zinc oxide and titanium dioxide in their products with nanoparticles of these substances. These nanoparticles are just one of the many new technologies emerging from the nascent field of nanotechnology, the science of making incredibly small things. A nano-meter is a billionth of a meter. Just how small is that? A human hair is 80,000 nanometers wide. DNA is about 3.5 nanometers across. When things get that small, they start to behave unpredictably. In fact, a 2004 report from the British Royal Society concluded that nanotech materials are notably different from anything that has ever been made before, and called for a precautionary approach to their use. And therein lies the point: since nanotechnology is still very much in its infancy, no one really yet knows how nanotech substances behave in the human body or in the environment. Their increasing use in consumer products like sunscreens essentially amounts to a nationwide experiment with unsuspecting users as guinea pigs. Because the FDA doesn’t require labeling for nanotech ingredients it can be difficult to know which sunscreens contain them (see below). This means that titanium dioxide and zinc oxide, once generally safe ingredients, can no longer automatically be considered so.

• Other ingredients used in sunscreens may produce unhealthy effects as well. For example, Diethanolamine and triethanolamine can combine with any nitrites present as preservatives or contaminants to form carcinogenic nitrosamines. Diethanolamine has also been found in tests of waterways around the country, which means it survives water treatment to become a pollutant. Paraben preservatives, which are present in virtually every sunscreen formula, have been implicated as potential endocrine disruptors.

It should be said that most if not all of the research conducted into sunscreen active ingredient safety has been conducted on animal cell cultures and lab specimens. (Seventh Generation does not condone nor conduct animal testing, but we will report on certain studies if they’re potentially relevant to human health.) The results of such tests are not always applicable to humans. However, a proper precautionary approach demands that whenever preliminary research suggests the possibility of harm, protective measures should be taken until safety can be proven. This outcome applies in the case of sunscreen research.

In addition to concerns about the ingredients in sunscreens, many believe the use of sunscreen products is unhealthy in other ways as well. Because most sunscreen active ingredients appear unaffected by traditional water treatment methods, many in the public health community believe we’re getting a double dose of exposure: once when we use a sunscreen product and again when we eat fish or drink water that contains its escaped ingredients.

There is also the issue of Vitamin D. In people, this crucial vitamin protects against up to 16 different kinds of cancer, yet the body can only manufacture it when skin is exposed to direct sunlight. Some fear the use of sunscreens is preventing people from getting the sun exposure required for the body to manufacture proper amounts of this nutrient.

Then there’s the theory of human sunscreen psychology. This idea says that the use of sunscreens makes us think we can safely stay out in the sun far longer than we really can. We put a handful or two on in the morning, repeat this in the afternoon, and think we’re invincible until sundown. Yet in order to work properly sunscreen must be slathered on in copious quantities every couple of hours. That generally means using a bottle per person per day, an amount few if any sunbathers ever apply. In the view of many, the outcome of wearing too little sunscreen for too long in the sun can be seen in the rising incidence of skin cancer discussed earlier.

None of these points, however, mean that we can’t have fun in the sun. Here are some tips to keep you safe from both potentially toxic sunscreens and the sunburn they’re meant to prevent:

• Seek old-fashioned non-nanotech zinc oxide and don’t worry about the white look. Avoid formulas that claim to offer “transparent” zinc oxide protection, micro-encapsulated zinc oxide, or use any form of the terms “micro” or “nano” on their labels. These are all indications of nanotech at work. When in doubt, call the manufacturer and ask whether their product uses nanotech ingredients.

• Don’t use any sunscreen on a child younger than six months. The risks are just too great. Instead, keep infants out of the sun entirely. Similarly, keep any exposures experienced by young children to a minimum

• Minimize older children’s sun exposure between the hours of 10:00 am and 3:00 pm, when sunlight is at its strongest and the radiation is most direct. Adults should seek frequent shade during these hours as well.

• Use your shadow as an indicator of the sun's intensity. If your shadow appears shorter than you are that means the sun is at its peak strength. Use the American Academy of Dermatology’s Shadow Rule: No Shadow? Seek Shade!

• Remember that your daily sun exposure is cumulative. Taking a shade break after some time in the
sun does not reset your day’s exposure to zero.

• UV rays reflect off of things like sand, tile, water, snow, and even buildings. So limit your exposure to these kinds of reflective surfaces whenever you can, and be aware of any that are nearby. Even if you’re in the shade, reflective surfaces can be exposing you to UV radiation.

• Carry and use an umbrella. Take a big one to the beach for shade, and use a smaller parasol for walking around.

• Instead of using sunscreens, wear a wide-brimmed hat, long-sleeved shirts, long pants, caftans, etc. made from light but tightly woven fabric. If you can see through the fabrics to any degree, that’s your hint they won’t offer enough sun protection.

• Consider UV-protective fabric clothing. This special material is airy, cool, and designed to block UV radiation. It’s become particularly popular in Australia, a nation at great risk to sun exposure due to the Earth’s thinning ozone layer, and is carried by many outdoor gear retailers here in the U.S.

• Note: you may also have heard of a laundry product called SunGuard that treats laundered clothes with a material called Tinosorb. A product of Ciba-Geigy Corporation, Tinosorb is, in essence, a repackaged version of their optical brightener, Tinopal. In addition to the fact that Tinosorb is intentionally designed to leave chemical residues on clothing, it faces the same issues of non-biodegradability and aquatic toxicity that optical brighteners face. Although Ciba-Geigy says Tinosorb particles are too large to be absorbed by the skin and are therefore safe, it’s not a product we recommend.

This article originally appeared in "The Non-Toxic Times," an e-newsletter published by Seventh Generation. Each month, Seventh Generation researches their extensive library and network of experts to bring you important tips, resources and news about the issues that affect the health of your home, family and the environment.

Seventh Generation offers a full selection of non-toxic household products for a clean home, a healthy family, and a safer world. They are committed to providing products that perform as well as conventional products, and are also safe and environmentally responsible. For valuable coupons and to subscribe to their e-newsletter, "The Non-Toxic Times," visit www.seventhgeneration.com