I went through security at the Dayton airport last year. I refused the L3 "body scanner" (backscatter) machine. The TSA worker asked me why. I told him I thought it was an unnecessary risk. He laughed and basically told me that I was wrong, and that the machine poses no safety risk. But I still opted for the pat-down. Shortly thereafter, the TSA issued a recommendation that backscatter workers wear "radiation badges" to monitor their exposure. Never trust manufacturers of security products (like L3) on their word alone...