(CNN) -- The Transportation Security Administration may back off a plan to conduct an independent study of the health effects of airport body scanners, saying a soon-to-be-released inspector general's report validates earlier conclusions that the machines are not harmful.
TSA Administrator John Pistole testified November 2 at a Senate hearing that he would conduct an independent study of backscatter machines, which use radiation to detect any objects that may be under clothing.
But on Tuesday, he told CNN a draft report by the inspector general of the Department of Homeland Security likely will eliminate the need for a new study.
"I have no concerns about the safety of the machines," Pistole said. He said independent scientific organizations say the backscatter machines emit the same amount of radiation that passengers are exposed to during three minutes in flight.
"But there are those who continue to express concerns, and so I want to do everything that I can to reassure those people that these machines are as safe as possible," Pistole said.
"That being said, I just learned about an inspector general report that is in draft form that validates those prior studies, so that may suffice," he said. "We'll work with Congress to see whether that addresses their concerns."
But Sen. Susan Collins, R-Maine, who asked for the independent study, said Wednesday she does not believe the inspector general's report will address her concerns.
"I hope the Obama administration is not backing away from an independent study," Collins said in a written statement. "What I asked for -- and what the administrator committed to -- was an independent study on the health effects of AIT (advanced imaging technology) machines, not just a study on whether TSA is doing an adequate job of inspecting, maintaining and operating AIT machines, which I understand is the approach" of the inspector general's report.
"Travelers are concerned that the radiation emitted from these machines may be damaging to passengers' health," Collins said.
This year, she added, TSA found calculation errors, missing data and anomalies in some test results regarding radiation emitted from screening equipment. "Such reports undermine public confidence that this technology is safe," she said. "We need an independent review of the technology to ensure it does not adversely affect the health of passengers and TSA employees."
The TSA has deployed about 250 backscatter machines, which use X-rays, and about 260 millimeter-wave machines, which use radio waves and do not emit X-rays. It has also purchased another 300 millimeter-wave machines. X-rays can damage DNA and cause cancer; the radio waves cannot.
Collins' remarks came two days after the European Commission announced that, "in order not to risk jeopardizing citizens' health and safety, only security scanners which do not use X-ray technology are added to the list of authorized methods for passenger screening at EU airports."
The use of such scanners has increased since the Christmas Day 2009 attempt by a passenger to blow up a plane en route from Amsterdam to Detroit by detonating plastic explosives he had hidden in his underwear. Umar Farouk AbdulMutallab pleaded guilty to all charges in the case on October 12.