How will we know if airport scanners malfunction? Safety data does NOT exist???

Eh,  a scientist is raising something really awful about the scanners at the airport, those machines that will be proliferating all across the country in numerous airports. There's concern about the efficacy of the scanners, including 

• who will check their accuracy? 
• How will we know if they're malfunctioning? 
• What happens if they fail and no one knows it? 
• How will this radiation affect children? 
• What is some folks are susceptible to cancer genetically? How will these machines react to those people?

This is from the scientist's blog found here, which I can't pronounce. These concerns were sent from a group of scientists to the TSA; their concerns are unresolved:

• Our overriding concern is the extent to which the safety of this scanning device has been adequately demonstrated. This can only be determined by a meeting of an impartial panel of experts that would include medical physicists and radiation biologists at which all of the available relevant data is reviewed."
• "The X-ray dose from these devices has often been compared in the media to the cosmic ray exposure inherent to airplane travel or that of a chest X-ray. However, this comparison is very misleading: both the air travel cosmic ray exposure and chest X-rays have much higher X-ray energies and the health consequences are appropriately understood in terms of the whole body volume dose. In contrast, these new airport scanners are largely depositing their energy into the skin and immediately adjacent tissue, and since this is such a small fraction of body weight/vol, possibly by one to two orders of magnitude, the real dose to the skin is now high."
• "In addition, it appears that real independent safety data do not exist."
• "There is good reason to believe that these scanners will increase the risk of cancer to children and other vulnerable populations. We are unanimous in believing that the potential health consequences need to be rigorously studied before these scanners are adopted."

  You can say, "Oh, but the machines have been tested. The government would never allow something like this to happen under their watch. That's what we have all our government watchdogs for, like the FDA, et al."
  May I remind you of the Tuskegee experiment, in which many men went untreated for syphilis because they trusted the government? Read at Wikipedia:

The Public Health Service, working with the Tuskegee Institute, began the study in 1932. Investigators enrolled in the study 399 impoverished African-American sharecroppers from Macon County, Ala., infected with syphilis. For participating in the study, the men were given free medical exams, free meals and free burial insurance. They were never told they had syphilis, nor were they ever treated for it. According to the Centers for Disease Control, the men were told they were being treated for "bad blood," a local term used to describe several illnesses, including syphilis, anemia and fatigue.