The Obama administration and the United Kingdom's Cameron-led Coalition government are embroiled in a growing battle over controversial scanners that digitally disrobe passengers in the name of security.

Pilots Boycott Scanners

Over the last week two of the world's largest pilots' unions -- the U.S. Airline Pilots Association, representing about 5,000 U.S. Airways pilots, and the Allied Pilots Association, representing about 11,500 American Airlines pilots -- announced boycotts of the full body scanners, following a pair of reports that claim the U.S. Transportation Safety Administration underestimated the health risks of scans on frequent fliers.

Captain Sam Mayer, who is the APA's communications committee chairman explained the boycott, in an interview with The Register, commenting, "We are already subjected to larger amounts of radiation by flying long distances at high altitudes.  While the TSA is telling us it's completely safe, that may be true for the occasional user, but we haven't seen any data yet talking about the long term cumulative effects of this over time."

Now that the two largest pilot unions say that the scanners are too dangerous for them, the question becomes how the public will react to being told that they have to risk their health when pilots don't.

Experts Say TSA Erred in Health Risk Assessment

The boycotts are based primarily on a Congressional report delivered by Dr. David Brenner, head of Columbia University's Center for Radiological Research.  In his report, Dr. Brenner, a foremost expert in the field of radiation's effects on the human body, concluded that the Transportation Security Administration underestimated backscatter wave scanners' cancer risk nearly 20-fold.

Backscatter scanners are one of the two types of scanners deployed across the U.S. and at various locations abroad.  There were 189 backscatter units and 152 millimeter-wave machines deployed at 65 U.S. airports at the end of October.  Next year that number is expected to double, thanks to new installations -- including many new backscatter scanning machines.

In an interview with CNN, Dr. Brenner concludes, "If you think of the entire population of, shall we say a billion people per year going through these scanners, it's very likely that some number of those will develop cancer from the radiation from these scanners."

The TSA says that the scans are safe, citing tests from the Food and Drug Administration's Center for Devices and Radiological Health, the National Institute of Standards and Technology and the Johns Hopkins University Applied Physics Laboratory.  An agency spokesperson comments, "TSA sets strict standards for all of its technology to include detection capabilities, operational capabilities and health and safety standards. The two approved technologies that meet all of those standards are backscatter and millimeter wave."

The agency previously claimed that being scanned exposes the body to about two minutes worth of cosmic radiation at altitude -- or about 1/1000th of the radiation received from a standard chest X-ray.  

Both Dr. Brenner's study and a separate study by Peter Rez, a professor of physics at Arizona State University, claim that those estimates were 5 to 20 times too low, and that the actual risk was probably close to 10 to 20 minutes worth of high altitude cosmic radiation exposure -- about a 1/50th to 1/100th of a chest X-ray's radiation dosage.  Both experts agree that children and frequent fliers are at the greatest risk, and that the cancer risk is concentrated on the skin.

The TSA has not outright denied these claims by two of the field's top experts.

Professor Rez says for the average passenger, the risk of dying from body-scanner induced cancer is about equal to the risk of dying from a terrorist attack -- 1 in 30 million.  He states, "They're both incredibly unlikely events. These are still a factor of 10 lower than the probability of dying in any one year from being struck by lightning in the United States."

Despite Ethical Concerns, the Expensive Scanning Show Goes On

Even if passengers are content to take their chances with the health risk, or travel at airports that use the safer millimeter wave technology, significant other concerns exist.  Recent reports revealed that the scanners may be able to save images of naked passengers.  The U.S. Marshals Service, in an ongoing court battle, recently admitted to storing thousands of nude images of passengers.  The TSA has long claimed such images are never stored.

Other reports revealed that TSA employees joked about their coworkers' genitals raising questions about whether passengers are subject to similar mockery.

And perhaps most troubling is the subject of children.  In the U.S., at many airports children must be digitally undressed if they want to fly.  While scanners are designed to blur the crotch region and certain other features, they still show rough outlines of genitalia.  Many people are uncomfortable with TSA employees digitally undressing their children.  

In the UK scans of children were likened to child pornography and banned.  In the U.S., scans of children are mandatory.  Nude images of children were likely among those stored by the Federal Marshals.

Further, studies have shown the scanners to be very ineffective at detecting many types of low-density chemicals or plastic weapons which could be used in a terrorist attack.

Those who defy the Obama and Cameron administrations' scanner edicts will likely be unable to fly, and/or be subjected to intense searches.  And pilots who follow the proposed boycott may find themselves out of a jobs, as a pilot who refused a scan in Memphis, Tennessee reportedly did.

The Obama administration hopes to deploy 1,000 more scanners by the end of 2011.  The UK has deployed scanners to two of its busiest airports -- Heathrow and Manchester and may expand deployment next year as well.  Taxpayers in both nations get to foot the bill for the expensive "security" devices.