Ralph Nader and a coalition of consumer, privacy and civil rights groups today urged the Chairmen of the House and Senate Homeland Security Committees to demand that the Department of Homeland Security (DHS) stop the deployment of full-body scanning security devices in US airports until an independent review of the devices’ health effects, effectiveness and privacy safeguards is completed.

In a letter sent today to Senator Joseph Lieberman and Rep. Bennie Thompson, the groups state that two out of every three passengers will be directed to enter one of these machines for a head-to-toe body scan by the end of next year. A large number of these devices will be the ‘backscatter’ scanner which use low-dose x-rays to scan passengers.

Scientists and radiation experts have come forward to dispute DHS claims that the x-ray doses pose negligible health risks to passengers. Scientists are concerned about the potential for skin cancers, and harm to pregnant women and those with compromised immune systems.

The groups’ letter comes one month after a broad coalition of organizations petitioned DHS to suspend the body scanner program, stating that the “uniquely intrusive search” is unreasonable and violates the U.S. Constitution.

Security experts have also concluded that the scanning devices can be easily defeated by concealing explosives in body cavities.

“The potential public health risks, privacy concerns, taxpayer costs and questionable effectiveness of body scanners demand that the DHS stop the deployment of body scanners to the nation’s airports until an impartial panel can be convened to study these issues,” the letter states.