The peaches-and-cream charm of famous faces notwithstanding—think of Cate Blanchett, Nicole Kidman, Keira Knightley—Americans’ love affair with the suntan is still going strong. But evidence has been mounting for years that ultraviolet (UV) exposure, including exposure from tanning beds, significantly ups the risk of skin cancer and other skin damage.

And the incidence of skin cancer has been going up. According to the World Health Organization, the rate of skin cancer in the United States has doubled in the last 30 years. The Food and Drug Administration, the American Cancer Society and other organizations caution against indoor tanning. Health advocates have pushed for laws limiting indoor tanning, especially for teens. Yet in spite of all these warnings, tanning salons are doing a lively business.

In 2009 the World Health Organization’s International Agency for Research on Cancer (IARC) added UV exposure, including tanning beds, to its list of known human carcinogens, based a review of scientific studies on tanning from the last 25 years. The IARC concluded that indoor tanning is associated with two types of skin cancer, cancer of the eye, and DNA damage, which has led to skin cancer in laboratory animals and humans.

The evidence also showed that UV exposure is most harmful to young people. The IARC found that the risk of melanoma, the deadliest form of skin cancer, increases by 75 percent when people start using tanning beds before age 30. This is an especially striking figure considering the popularity of tanning among teenagers.

Based on these conclusions, UV exposure is now classified as posing the same level of cancer risk as tobacco, arsenic and mustard gas (it is important to remember that these findings apply equally to natural sun exposure).

What are the benefits of indoor tanning? The website of the Indoor Tanning Association (ITA), the industry’s trade group, states that many people use tanning beds to “enjoy the positive psychological and physiological effects of regular exposure to ultraviolet light.”

“The majority of us in the Northeast are Vitamin D deficient” in the winter, said Alex Fiorey, the owner of Solar Express tanning salon in Greenfield. Ten to 15 minutes of full-body UV exposure is needed to produce the recommended amount of Vitamin D, he said, which can be difficult to achieve during the short days of winter when we are bundled up in coats, hats and scarves. He also said that many of his customers come in to treat their seasonal depression “without taking a pill,” or simply for the “look good, feel good” benefit. Many tan to treat their eczema or psoriasis, he added, which would cost hundreds of dollars more to treat at a dermatologist’s office. While the American Cancer Society and other health organizations recognize these benefits, they recommend getting them by other means, such as vitamin D supplements, to minimize UV exposure.

In the debate about tanning, the pro-tanning bloc describes a tan as the body’s natural protection against sunburn, saying that the increased melanin in the skin acts as a natural sunscreen. The other side, including the American Cancer Society, says any tan is a sign of skin damage. The FDA also advises that a tan only provides a sun protection factor (SPF) of 2 to 4, far below what you get from slapping on some Coppertone.

Fiorey, however, pointed out that the chemicals in sunscreen have been shown to cause cancer. While it is beneficial to wear as sun protection occasionally, “It’s not a good idea to be wearing it every day,” he said.

If you are going to tan, is indoors really better than outdoors? According to Fiorey, tanning indoors is “smarter” because of the control tanning beds offer. UV exposure from the sun can vary greatly depending on the time of day, cloud cover and other factors. In a tanning bed the UV intensity is consistent, offering the user more control over how much exposure she receives. Florey says indoor tanning is a smart option as long as tanners follow the recommended exposure times for their skin type and the specific tanning bed they are using. “It’s a controlled, gradual process,” he said. “You’re not going to walk out with a tan in one day.”

In Massachusetts, minors under 14 must be accompanied by a parent or guardian to use tanning salons, and those aged 14 to 17 must have written parental consent. Tanning salons must provide each customer with advice on safe tanning, and the use of protective goggles is mandatory for all tanning bed users. Fiorey said that all his staff are trained to prevent sunburn, “which is what causes disease.”

While tanning beds may be a safer choice than out door tanning for those who want to bronze, any UV exposure is still a health risk, no matter what the source. It may be too early to truly compare the risks of indoor vs. outdoor tanning, but what is clear is that either one should be done in moderation.