Sen. Susan Collins (R-Maine) and several of her Democratic and Republican colleagues on a panel that oversees the Department of Homeland Security (DHS) yesterday introduced a bill requiring the department to launch an independent study of the health effects on people who use backscatter X-ray body imagers at airport security checkpoints in the United States.

The legislation is aimed specifically at Advanced Imaging Technology (AIT) machines made by OSI Systems [OSIS], which rely on ionizing radiation to obtain an image of a person who is scanned by the system, and operated by the Transportation Security Administration at some airport security checkpoints.

Concerns about the health effects of the backscatter-based AIT systems have been brought to the attention of Congress from time to time, by their constituents as well as scientists. In 2010, several researchers at the Univ. of California-San Francisco asked the White House to create an independent panel of experts to review data around the effects on people of radiation emitted by these machines.

TSA has steadfastly refuted any health concerns from the X-ray imagers, citing a number of studies that show the radiation exposure to be minimal, especially compared to the dosage passengers receive from the sun on airline flights.

Last year, two other UCSF researchers, separate from the others whose research is ongoing, issued their own paper in the Archives of Internal Medicine saying the risk of getting cancer from the backscatter-based AIT machines is miniscule and that there is no cause for alarm (Defense Daily, March 30, 2011).

Still, Collins, who is the ranking member on the Senate Homeland Security and Governmental Affairs Committee, has not been assuaged. Last fall, she pressed TSA Administrator John Pistole for a study on the health effects of the X-ray scanners and he at first agreed but then backed off a week later (Defense Daily, Nov. 29, 2011).

Pistole has said the matter will be addressed in a forthcoming DHS Inspector General report.

The new legislation asks the DHS Science and Technology Directorate to sponsor the independent study and wants the National Science Foundation to consult with whatever laboratory does the work. The bill also wants a report on the findings. In addition to the health effects on people going through the machines, the report should also look at the effects of radiation on frequent air travelers, TSA employees, flight crews, children and pregnant women and other people with a greater sensitivity to radiation, and other people that work at an airport.

The legislation also wants signage related to the backscatter machines at the front of passenger checkpoint lines to notify people who may be sensitive to radiation exposure of alternative screening methods.

The bill was co-sponsored by Sens. Daniel Akaka (D-Hawaii), Scott Brown (R-Mass.), Tom Coburn (R-Okla.), and Carl Levin (D-Mich.).

At some airport checkpoints, TSA also operates AIT machines supplied by L-3 Communications [LLL], although these are based on millimeter wave technology and are not the subject of health concerns on passengers.