Scientists can’t check TSA’s scanner-safety claims

Seattle Times

If you believe the government, you have little to worry about from the radiation beam flitting over the front and back of your body in airport watchdogs’ search for explosives and other hidden implements of terror this holiday season.

The Transportation Security Administration (TSA) says 464 body-scanning machines are in place at 75 U.S. airports. The more controversial of these units is the so-called backscatter device, which allows agents to see through clothes by scattering low-dose X-rays at a passenger’s front and back. A less-controversial model is the “millimeter wave” scanner, which produces a body image but doesn’t use X-rays.

When working properly, TSA says, backscatter scanners, 14 of which are in use at Seattle-Tacoma International Airport, emit an infinitesimal, virtually harmless amount of radiation.

The problem: TSA offers no proof that anyone is checking that those machines are “working properly.”

TSA ticks off a litany of groups that it says are involved with determining and ensuring the safety of the devices, including:

  • The Food and Drug Administration (FDA)
  • The U.S. Army Public Health Command
  • Johns Hopkins Applied Physics Laboratory
  • The Health Physics Society

However, those organizations say they have no responsibility for the safety of TSA’s machines. Further, the Department of Homeland Security agency refuses to release exposure data to top non-TSA safety experts.

The questioning of TSA’s “working properly” assurances becomes even more significant with numerous reports that screeners sometimes missed as many as seven of every 10 guns, knives and mock explosive devices that government testers tried to sneak through airport checkpoints.

People each year are subjected to hundreds of millions of diagnostic X-rays, virtually all without incident. So why the angst over TSA’s backscatter scanners that, when working properly, emit far lower doses of radiation?

To ensure the doses are as low as billed, it is imperative to calibrate the machines accurately and monitor their performance carefully.

A spike in the intensity of the scanning beam, or a slowdown or pause in the timing of its sweep across a body, could cause significant radiation damage, according to a radiologist and two radiological health physicists.

The FDA and many state radiation-safety offices license, inspect and monitor almost all medical radiation devices. But even identical X-ray machines used in nonmedical government venues fall outside FDA scrutiny, the agency said last week.

Nevertheless, TSA maintains that, when it comes to the safety of full-body scanners, “everything is working fine,” an agency spokesman said.

“The safety of our scanning systems are routinely and thoroughly tested by the manufacturer, FDA, the U.S. Army, the Health Physics Society, Johns Hopkins Applied Physics Laboratory and others,” the spokesman said.

TSA does do some of its own inspections, said Sarah Horowitz, another TSA press officer.

“Preventive maintenance checks, including radiation safety surveys, are performed at least once every 12 months,” she said.

TSA sounds reassuring when it lists the organizations as the guardians of the safety of the public passing between the two radiation-emitting walls of scanners.

But interviews with those safety sentinels reveal none of them was doing routine testing of operating airport scanners. Further, all said they have no responsibility to monitor the safety of those passing through airport scanners.

For example, the FDA says it doesn’t do routine inspections of any nonmedical X-ray unit, including ones operated by TSA.

The FDA has not field-tested these scanners and hasn’t inspected the manufacturer. It has no legal authority to require owners of these devices — in this case, TSA — to provide access for routine testing on these products once sold, FDA press officer Karen Riley said.

She added, however, that the FDA has received no reports of radiation safety-related problems with these products.

TSA boasts about the Army’s involvement in its safety program. Statements suggest radiological health experts from the respected U.S. Army Public Health Command routinely check the 464 units in use, both backscatter and millimeter-wave.

But that’s not the case, said Fran Szrom, a certified health physicist with the Army Health Command. Two-person teams from the Army unit this year performed surveys of scanners at only three airports — in Boston, Los Angeles and Cincinnati, she said. That was all TSA asked the Army to do.

TSA also frequently cites a study it commissioned by the noted Johns Hopkins Applied Physics Laboratory (APL). But the Hopkins work did nothing to ensure consistent safety of those exposed to radiation from the scanners.

“APL’s role was to measure radiation coming off the body scanners to verify that it fell within [accepted] standards. We were testing equipment and in no way determined its safety to humans,” said Helen Worth, the lab’s head of public affairs. “Many news articles have said we declared the equipment to be safe, but that was not what we were tasked to do.”

Moreover, the study said APL scientists were unable to test a ready-for-TSA scanner because the manufacturer would not supply one. Instead, tests were performed on a scanner cobbled together from spare parts in manufacturer Rapiscan Systems’ California warehouse.

“The system evaluated may be configured different than the system deployed to the operational environment,” the report said. APL found two areas in the mock-up where escaping radiation could cause exposure to the public that exceeded annual safe limits.

TSA also cited the 6,000-member, nonprofit Health Physics Society as endorsing the safety of its scanners. The society long has said “that intentionally exposing people to low levels of ionizing radiation for security screening is justified” if nationally accepted exposure standards are monitored routinely and met.

However, the group says it did not and does not monitor the safety of TSA devices — only that, if the devices operate as promised, safety should not be an issue, said Howard Dickson, the society’s immediate past president.

“The dose rates are so low that you would expect [the scanners] would have to be grossly out of performance with the national standard to create much of a hazard,” Dickson said. “… I’m not saying it’s foolproof by any means, but it would be a very unusual condition that would create a hazardous condition.”

Many members work for the nuclear industry, but the society often has served as an honest broker of information on hot-button and emotional radiation issues.

Despite that reputation, TSA has refused the society’s requests for data that the agency collects on radiation exposure in and around its scanners.

“If the public had and understood this information, all of these calibrations, all of the dose rates measured [for] people going through [the scanners] and those operating them, we wouldn’t have all the months of media frenzy,” said Kelly Classic, a certified health physicist and member of the society. Instead, she said, “all they do is assure us that everything is safe.”

TSA’s response: “The report is completed but being fine-tuned and thus can’t be released.”

The amount of radiation generated by a properly calibrated full-body device in a typical 15-second scan is equal to about an hour of normal background radiation, TSA says.

But physicians and most radiation health specialists say there is no “safe” dose of radiation, so any planned exposure must be justified.

John Sedat, a biochemistry professor emeritus at the University of California, San Francisco, and three of his colleagues attempted to verify TSA claims that the full-body scanners were safe.

They studied all available information on the new system and tried to determine the wavelength of the X-rays, the intensity of energy released in the design and safeguards.

“We found that essentially none of this information was known or made public, and more interestingly, it looked like this technology had not been independently vetted by the scientific community, published, peer-reviewed or even discussed openly,” Sedat said. “Essentially, all the information was coming from companies that were making the devices, and it looked like it was being parroted by the FDA and the TSA, which didn’t seem reasonable.”

Sedat and his colleagues in April sent a lengthy letter outlining their safety concerns to the White House science adviser, John Holdren, asking that several areas — especially an impartial review — be considered. The White House didn’t reply until November, seven months later.

Sedat says he and his colleagues have “some heavily redacted reports which basically just raise more [danger] flags, because it’s very far from an independent, outside review.”

Bottom line: The university group isn’t any closer to assessing whether there are health hazards from the scanners.

“We just don’t have access to the needed information,” Sedat said. “We’ve got 5 percent of the population that might be sensitive to X-rays. Are older people, myself included, at greater risk? What about pregnant women and children? These issues need to be addressed.”

One point that Sedat challenges in TSA’s statement is that, if there’s any danger, it’s only to the top layer of skin.

“Not so,” Sedat said. Radiation “penetrates the skin, and then as it goes deeper into the tissue it diminishes. But the skin and adjacent tissue is at risk. There is no question about that.”

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