I'd say start with the companies who make full body scanners (millimeter wave, which uses ionizing radiation and causes cancer (ref: http://en.m.wikipedia.org/wiki/Backscatter_X-ray ), but that's a whole other can of worms.)
Small correction: millimeter wavelengths are non-ionizing. X-rays are much smaller (0.01 to 10nm - Wikipedia).
Small correction: millimeter wavelengths are non-ionizing. X-rays are much smaller (0.01 to 10nm - Wikipedia).