Tell the TSA agents that they need to tell their doctors to aggressively screen for cancer. Standing next to these things for 40 hours a week for months has NOT been proven safe.
Hopefully, the cost of supporting this useless security theater will make it infeasible eventually.
The TSA got rid of all the backscatter x-ray machines, so the body scanners aren't using ionizing radiation anymore. This was the biggest health concern with the old devices, and I was really glad to see those gone.
The newer scanners use millimeter wave RF, which is non-ionizing and much safer. The primary concern with RF is classic thermal effects, which shouldn't be significant at low power levels.
There's still plenty of room for research on the topic, but no direct causal link to any health effects have been found with these systems at present.
(That said, the TSA agents are also standing next to the baggage x-ray machines all day. And I do still see backscatter x-ray body scanners in use in other countries.)
Hopefully, the cost of supporting this useless security theater will make it infeasible eventually.