How X-Ray Scanners Became Mandatory In US Airports

OverTheGeicoE writes "ProPublica has a story on how x-ray scanners became the controversial yet mandatory security fixtures we in the US must now endure. The story title, 'U.S. Government Glossed Over Cancer Concerns As It Rolled Out Airport X-Ray Scanners,' summarizes a substantial part of the article, but not all of it. The story also describes how government attitudes about the scanners went from overwhelmingly negative in the early 1990s to the naive optimism we see today. How did this change occur? The government weakened its regulatory structure for radiation safety in electronic devices, and left defining safety standards to an ANSI committee dominated by scanner producers and users (prison and customs officials). Even after 9/11 there was still great mistrust of x-ray scanners, but nine years of lobbying from scanner manufacturers, panic over failed terrorist attacks, and pressure from legislators advancing businesses in their own districts eventually forced the devices into the airports. The article estimates that 6 to 100 cancers per year will be caused by the x-ray scanners."

Comments

Broken window fallacy

[Compaqt]

...pressure from legislators advancing businesses in their own districts eventually forced the devices into the airports.

The idea is that you create "make-work" for people to do, and then there'll be more jobs.

http://en.wikipedia.org/wiki/Parable_of_the_broken_window

The problem is the money you're spending is coming out of taxes, which is reducing the amount that would have been invested in other productivity-enhancing or job-producing activities in the economy.

Re:Broken window fallacy

[grumling]

Like the Hoover Dam was pretty much busy work to get the economy going again (jobs, money flow, pride, etc) and when it was complete it became a large source of electricity.

Bad example. The Hoover Dam was planned and sent through Congress during the Harding and Coolidge administrations. It was a happy accident that it was built during the 1930s, and Six Companies made out like bandits because they got labor at a much better price than estimated, and lots of it. In fact, the reason it is called the Hoover Dam and not Boulder Dam is because Hoover got the states together to sign the Colorado River Pact in the late teens and early 1920s. And the benefit to the US (and the world) is easily calculated in irrigated land in the southern US and the massive increase in food production that resulted.

A make work project would be about 1/2 the various epidemiological studies that look at cancer rates and power lines. Or locking up drug offenders for life.

Re:That's a good tradeoff

[heypete]

X-rays are ionizing radiation.

Re:That's a good tradeoff

[mbone]

There has been a long debate on this, most of which you can easily find by search engine. These devices do a raster scan with a fairly intense spot beam (most of this radiation goes right through you; the spot beam has to be strong as the signal is actually the fraction scattered off of your skin). The spot beam would be a problem if it was to sit on one location for any length of time, so you are totally reliant on the software to not get a serious dose. That alone is a real worry, as most medical Xray radiation problems are due to software errors. That also means that any repeated glints out of the device (say, by people's metal buttons) are likely to cause problems for nearby agents (as they tend to stand in the same place, and so could get repeated exposures). It also means that just wearing a dosimeter is pretty worthless. The agent's chest might get no glint exposure and their feet or crotch might get a serious one.

The above is pretty much the conventional wisdom. As a physicist, I also worry about the way that they calculated dosage (whole body versus surface exposure) may seriously underestimate the risk, but that worry is not very conventional. If I am right, look for skin cancers to start appearing in frequent flyers in areas normally covered by clothing. Of course, that will take a few years; Michael Chertoff is likely to have retired with his loot by then.

Re:That's a good tradeoff

[ChumpusRex2003]

Nice post. Just one correction, at the beam energies used in these devices (50 kVp - 120 kVp), most X-ray photons certainly do not go straight through you. At about 120 kVp, about 75% will get absorbed through the torso - and in the case of 50 kVp, essentially 100% will be absorbed (with only a fraction of a percent getting scattered, as 50 kVp is below the optimal range for Compton scattering in body tissues).

In fact, it was widely stated in the marketing information and propaganda for these scanners that the X-ray beam does not penetrate skin. This statement is patently false at all energies in commercial use. If they can get away with deliberate lies as basic as that, how can you reasonably believe any more difficult claims?