I deal with Voltage in my line of work anywhere from 12VDC to 480VAC using a 5KVDC Megger to test the 4160VAC motors the plant produces I work at steps up from 13.8KV to 220KV for transmission and our peaker produces 18KV stepped up to 66KV for local substation use. The breakers I work on are tested for low resistance using a DLRO which reads in the MicroOhm range μΩ 1x10−6. Every meter reading the line voltage and current are ratio-ed down to safe levels at the control boards in either 120V or 5Amps so yes I'm fluent in the SI system.
If you did not hear it these readings were taken at least one meter from the ground not at ground level And Yes I believe anything above normal background is bad for you especially if you live with it 24-7 or eat & drink the food and water contaminated by it! And so far the Japanese solution to most of the high readings has been to raise the acceptable levels of exposure!
Oh yes one other thing I was trained at what was formerly the US Army Nuke school so having been in the building that housed the first nuke plant in the country to synch with the commercial grid I do know a thing or two about it and have seen the effects of radiation exposure to workers.