Airport X-ray machines are safe for passengers, report says

— -- Full-body X-ray scanning machines at airport security checkpoints use an "extremely low dose" of radiation that's safe for passengers, the Homeland Security Department's inspector general reported Tuesday.

In drawing his conclusion, Carlton Mann, an assistant inspector general, cited previous scientific findings.

They include a Johns Hopkins University assessment in August 2010 that said a passenger would have to be screened 47 times a day for a year to exceed yearly limits of radiation set by the American National Standards Institute.

The Transporation Security Administration has maintained that the X-ray, or "backscatter," machines are safe since it began deploying them in March 2010.

Currently, there are 247 backscatter machines at 39 airports. The rest of the 630 full-body scanners at 150 airports use millimeter-wave technology, which isn't under scrutiny.

"We believe this report fully endorses TSA's extensive efforts to keep the traveling public safe, which is our agency's ultimate priority," TSA Administrator John Pistole wrote in response to the report.

Despite its repeated guarantees, the agency has been dogged by health and safety concerns over the use of the devices.

In November, the European Union banned the use of X-ray machines because of health concerns. Sen. Susan Collins, R-Maine, has asked for an additional public-health study to ensure the machines aren't a risk.

Among concerns is whether the TSA properly inspects and calibrates the machines to ensure that passengers aren't exposed to higher levels of radiation.

The inspector general's report said it didn't identify any improperly calibrated machines. However, it urged the TSA to routinely check the machines to make sure they're safe.

Rep. Ed Markey, D-Mass., says the report confirms the need for the TSA to provide additional training for its officers on calibrating the machines — something the agency agreed with in responding to the report.

The TSA deployed full-body scanning machines because metal detectors didn't find explosives on the so-called underwear bomber, Umar Farouk Abdulmutallab, on Christmas Day 2009.