Whether sun ecposure is good or bad has the indoor tanning industry and dermatologists flinging very personal charges.

First came the Dunce of the Month award.

Dr. Rex Amonette was aghast when he saw himself pictured in a national magazine wearing a dunce cap. The past president of the American Academy of Dermatology, an authority on skin cancer, roasted as a dunce?

But that was just the start. Next, his house was pelted with eggs.

The soft-spoken Memphis, Tenn., doctor blamed local agitators and laughed it off. "I'm not a very adversarial person," he says. "I never planned to get myself involved in something like this."

What Amonette has become involved in is a vituperative war raging for the past few years between dermatologists like himself and the indoor tanning industry. It's a war pitting the mostly mom-and-pop tanning salons against what they portray as a sinister cabal of doctors and drug companies out to terrify sun-lovers and take away their livelihood.

Professional courtesy? Solid data? Scientific detachment? Forget it.

So far, this war is more heat than light, perhaps not surprising when the battle means billions of dollars to both sides. The charges and countercharges -- some substantiated, some not -- have flown freely over the basic disagreement: whether any sort of tanning is good or bad for your skin and health.

You won't find the answer here. Nor will you find it with any certainty in any of the many studies and articles published by both sides over the past few years. Despite the fact that by now, in mid-summer 1997, we know that sunburn can cause melanomas, and untanned skin is back in vogue for the first time since the 1920s, there apparently is no hard and fast evidence about tanning.

The dermatologists don't have data to buttress claims that tanning beds are partly at fault for escalating skin cancer problems they see in their offices, though they are rushing to compile it. The tanning industry has taken advantage of that vacuum to claim that tanning, indoor or out, actually reduces the risk of cancer.

No kidding. A recent press release by the International Smart Tan Network, the trade group representing the country's 25,000 free-standing tanning salons, says tanning can prevent the blistering sunburn associated with deadly forms of skin cancer.

Less likely to burn

According to the May release, titled, "Tanning Salons Preventing Sunburn, which may prevent cancer," indoor tanners are 57 percent less likely to sunburn than non-tanners.

Earlier this year, when the American Academy of Dermatology made public a study showing a 9 percent increase in people who reported sunburns, the tanning industry used it as evidence that the doctors' crusade to woo people out of the sun had failed.

"Professional tanning facilities are teaching people to live practical lives by avoiding sunburn," Smart Tan executive director Joseph Levy says. "The dermatology industry's leaders, on the other hand, are telling people to avoid sun exposure -- impractical advice that doesn't take into account today's active lifestyles."

It's like telling a teen-ager to abstain from sex, he says. Non-tanners out on weekends or holidays burn easily because they aren't in the know about smart tanning methods, he says.

To Amonette and colleagues, this logic is absurd. Any light source, whether natural or artificial, can create change in the skin that leads to aging and skin cancer, Amonette says.

He agrees that some exposure to light is good. "I firmly believe that. It is necessary to have good metabolical systems," he says. But he says the tanning industry goes too far when it alleges regular tanning could help reduce cancer deaths by 30,000 a year.

That claim in industry press releases is based on a California professor's 1993 study linking Vitamin D in sunlight and lower incidence of colon, breast, prostate and ovarian cancers. There is little backup research to support his theory, however; critics note that the body gets what Vitamin D it needs from many sources, including milk.

Amonette talks with his patients about trying to avoid tanning or sunburn by using sunscreen and clothing to protect themselves. "Most of us take that approach, rather than [advocate] total avoidance of light," he says.

A big point of contention between the two sides is just how much sunlight is too much.

"To them, it means blisters," Amonette says. "To us, it's slight reddening of skin. Everybody gets it [first] to get tan."

The University of Tennessee professor, who describes himself as "No. 1 on [the tanning industry] hit list," can't say tanning beds are more unsafe than the sun itself.

"I only know that people get more intense light. This is shown by the fact the skin reddens and darkens more than it would outside in a short time in the beds. And we know that when we take small biopsies, we can see that damage to the skin from indoor tanning is different from outdoor [sun] in that it is deeper."

Started in 1979