After years of rebuffing health concerns over airport scanners, the Transportation Security Administration plans to conduct new tests on the potential radiation exposure from the machines at more than 100 airports nationwide.

But the TSA does not plan to retest the machines or passengers. Instead, the agency plans to test its airport security officers to see if they are being exposed to dangerous levels of radiation while working with the scanners.

News of the test leaked out after the TSA issued a request last month to government vendors to provide wearable, personal dosimeters, devices that measure exposure to radiation.

“TSA is dedicated to the health and safety of its employees,” TSA spokesman Nico Melendez said. “We continuously test our technology to ensure it is safe for both passengers and our officers and post all results to our website.”

Critics of the TSA support the idea of testing TSA workers. But they continue to call on the TSA to perform independent studies of the full-body scanners to ensure that airline passengers are not being exposed to dangerous levels of radiation.

“We still have no idea how much radiation is being imposed on travelers by a properly functioning machine,” said James Babb, co-founder of We Won’t Fly, a consumer advocacy group. “A malfunctioning machine could be particularly nasty.”

Melendez said the scanners have been tested and approved by the National Institute of Occupational Safety and Health and the U.S. Army Public Health Command.

In fact, TSA Administrator John Pistole backed away from plans for new testing in November because he said he received a draft report from the inspector general of the Homeland Security Department that confirmed the conclusion of previous independent studies that the scanners are safe for all passengers.