It's outright insane if you stop to think about it: In order to "protect" air passengers, the U.S. government is blasting them all with dangerous levels of radiation from full-body X-ray scanners.

Not exactly how I like my "protection" -- especially since the feds won't provide any honest-to-goodness safety data on these machines.

It seemed like we were finally getting somewhere earlier this year when the TSA told Sen. Susan Collins it would authorize an independent safety study. You'd think they would have done that before they installed these machines at every airport -- but better late than never, right?

Well, it might be "never" after all -- because TSA administrator John Pistole recently told Congress that the study is off.

The question has to be asked: What are they so afraid of?

I think it's pretty obvious: Radiation exposure -- even the small amounts used in these machines -- can cause DNA damage and cellular changes. Over time, that can lead to cancer.

These machines use backscatter radiation, which goes beneath the clothes and concentrates on the skin itself -- so TSA agents can view a "naked" picture of you and see what you might be hiding without having to look at your bones, liver, guts, etc.

But since that radiation focuses on the skin, it can build up there and boost the risk of skin cancers, especially among those most often exposed, like regular air travelers.

And who knows what kind of risks these machines will pose to pregnant women, children, and infants.

One expert says he thinks X-ray scanners will cause 100 cancer cases each year -- and while that may sound like a small number, why put even a single life on the line in the name of security?

Even if you agree that the government should get a look at everyone's naked body before boarding an airplane -- and I don't -- there are machines that can do it without using a drop of radiation.

The feds even have the machines, and are using them in some airports -- but they insist on using the X-ray machines right along with them.

Even Europe has said they'll only use the radiation-free machines -- and they've actually banned the X-ray scanners from their airports until they see some actual scientific data proving they're safe.

I hope they're not holding their breath.