Enlarge By J. Scott Applewhite, AP Rep. Ed Markey, D-Mass., asked Department of Homeland Security's inspector general to investigate the effectiveness of the TSA's X-ray inspection program for full-body scanners. RADIATION EXPOSURE RADIATION EXPOSURE Americans typically are exposed to 300 millirem of radiation each year from natural sources. How airport security devices compare with other exposures to radiation: • One full-body airport X-ray scan: Less than 0.01 millirem • Regulatory limit for emissions from airport baggage X-ray machines: Less than 0.5 millirem per hour • Panoramic dental X-ray: 1 millirem • Flight from New York to Los Angeles: 4 millirem • Chest X-ray: 10 millirem • Mammogram: 36 millirem • CT chest scan: 700 millirem Sources: Department of Homeland Security, Health Physics Society Members of Congress are calling on the Transportation Security Administration to release inspection reports that would show whether airport X-ray machines that screen passengers and bags are regularly meeting requirements to emit only low levels of radiation. The calls by lawmakers came after the TSA didn't respond to USA TODAY's repeated requests since Nov. 26 to review equipment records that would show whether the X-ray machines are properly monitored and maintained. In the past, the agency has failed to identify problems with its X-ray machines, records show, and the USA TODAY request came in the wake of concerns by travelers and some experts about possible health risks if new full-body scanners malfunction. X-RAYS: Malfunctioning equipment concerns experts In addition, Rep. Ed Markey, D-Mass., asked the Department of Homeland Security's inspector general to investigate the effectiveness of the TSA's X-ray inspection program for full-body scanners. "I am concerned that TSA's past history in this area … could lead to unintentional exposures to radiation of both TSA employees and members of the public," Markey wrote in a letter Monday to the inspector general. Proper maintenance and monitoring are important, experts said. "Mechanical things break down," said Peter Rez, a physics professor at Arizona State University. He worries about what could happen if the machine used on passengers malfunctions and the X-ray scanning beam stops on one part of the body for an extended time. "It's a serious issue," Rez said. "This might have consequences like a radiation burn." CDC: X-ray exposure CDC: Response to worker concerns CDC: San Juan disease cluster unlikely CDC: Boston cancer cluster unlikely Travelers rely on the TSA to ensure that the full-body X-ray machines don't deliver more than the small radiation dose necessary to see through clothing. TSA spokesman Nicholas Kimball offered this reassurance: "All radiation surveys conducted to date have found radiation emissions to be below the applicable national standard." Based on a 2008 report by the Centers for Disease Control and Prevention, the TSA and its maintenance contractors failed in the past to detect when some X-ray machines used on baggage emitted radiation beyond what regulations allow. The report shows some machines were missing protective lead curtains or had safety features disabled by TSA employees with duct tape, paper towels and other materials. MARKEY: Requests records from TSA MARKEY: Requests IG investigation Jill Segraves, the TSA's director of occupational safety, said the agency has made significant changes in how it monitors and maintains X-ray equipment since the CDC study, which tested machines at 12 airports in 2003 and 2004. The TSA uses a different maintenance contractor, services machines monthly and trains employees to identify and report potential safety problems, she said. "There's more eyes on these machines than there ever were," Segraves said. "We have an excellent safety program." Lawmakers want to make sure. After inquiries from congressional staff Friday, Kimball said the TSA will try to make recent inspection reports available to USA TODAY but they will first need to be reviewed for sensitive security information. He could not say how long that would take. Rep. Jason Chaffetz of Utah, the top Republican on a House Oversight and Government Reform subcommittee over federal workforce issues, said he'll pursue release of the TSA's radiation inspection records when his party takes control of the committee in January. "It should send some flashing red lights when they won't allow the public to review that data," said Chaffetz, who has sponsored legislation that would limit the use of full-body scans. Chaffetz said he's concerned about potential radiation exposure, including to TSA employees. "I think it's a very legitimate question with long-term implications," he said. Rep. John Dingell, D-Mich., wrote the TSA on Nov. 18, seeking answers about the safety effects of the full-body X-ray scanners. "I hope that TSA will recognize that it's in the agency's best interest to open (full-body scanner) units to a more thorough review and inspection process," Dingell told USA TODAY. 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