The latest threat to America’s skies — explosive surgical implants that authorities have dubbed “belly bombs” — poses a security challenge so bizarre that air travelers learning of the new danger Wednesday could only scratch their heads and wonder what’s next.

If those fliers had collagen injections or dental implants, what’s next may mean having their heads examined. Literally.

The Transportation Security Administration advised airlines that terror groups are believed to be experimenting with explosives that could be implanted in buttocks and breasts, allowing suicide bombers to pass through airport body scanners undetected. This raised the specter of a surgically altered world in which it must be asked: If Pamela Anderson has to undergo an MRI to get on an airplane, have the terrorists won?

Because airport body scans don’t show the blood and bones beneath the skin, this new threat is at once so sophisticated and medieval that security officials may resort to trace detection swabs to detect bombs under the skin — a procedure rarely used in this country.

“It’s already so difficult with all the screening devices, maybe they should just spray everybody with those swabs,” said Marilu Nieto, who brought her grandson to Mineta San Jose International Airport on Wednesday. “That’s what it’s coming to. Just hose them all down.”

A spokesman for the TSA acknowledged that current scanning devices wouldn’t necessarily catch explosive compounds such as pentaerythritol tetranitrate implanted under a person’s skin. “As a precaution, passengers flying from international locations to U.S. destinations may notice additional security measures in place,” a statement from the TSA said.

Mastermind at work

The TSA said it had no evidence of a specific plot, but intelligence sources indicated this new threat to international air travel was likely the handiwork of Ibrahim Asiri, the al-Qaida mastermind behind the Christmas Day 2009 attempt to bring down a Northwest Airlines plane by the so-called “underwear bomber.”

Few Americans could have imagined when the first airport metal detectors were installed more than four decades ago that travelers would one day be expected to nearly disrobe before boarding their flights. The idea of implanting explosives in the same places plastic surgeons use to “enhance” many Americans does not strike Zoltan Prokay as far-fetched.

“If they do it properly, like a breast implant where the skin is stretched to accommodate the device, it could work,” said Prokay, who spent 2½ years in Iraq working to detect improvised explosive devices as a member of a U.S. Special Forces team. He was flying out of San Jose as a pilot for a private airline, which he declined to identify, when word of the TSA advisory began to spread. “It could be set to go off at a certain altitude. If you get an altimeter implanted in your other breast though, maybe you would set off the metal detector.”

Prokay sees it as a natural — if horrifying — progression from the shoe bomber and the underwear bomber. “This would be the bosom bomber,” he said. “It’s not funny. And yet it is kind of funny. The bosom bomber.”

“If (terrorists) really want to attack, there is always a way,” Renata Boudon, 47, said in French after arriving at San Francisco International Airport for a two-week vacation in the western United States. “It doesn’t scare me much.” She and her two sons, 18-year-old Eric and 12-year-old Marc, live in Brazil and said they won’t change anything about their travel habits because of the new information. “If it happens, it happens,” she said. “There is nothing you can do.”

Passengers’ views

In San Jose, visiting Mount Holyoke College history professor Holly Hanson said that instead of increased technology, airport security should focus on psychological profiling, a practice she said is used effectively at Israel’s airports. “It’s much more effective to search for anxiety in passengers than to search by technology,” she said. “You use social psychology to find people who are morally conflicted about something they’re planning to do.”

Kimberly Merenz struck a more defiant note while waiting to fly home to New York state from SFO. “I’m not going to live my life in fear,” she said. “It’s my way of spitting in their faces.”

Assuming those really are their faces.

Contact Bruce Newman at 408-920-5004.