The ARRL has some good writing on RF exposure. Basically everything I've read comes down to treating radiated RF energy as thermal risk. So it's not magic stuff that will give you cancer or cause your cells to turn inside out or something, it's just going to raise the temperature of whatever region of your body the signal is going to interact with. Could be 0.003 degrees C, could be 30 degrees C -- all that depends on the energy involved.

But that's at HF frequencies and above, not this VLF stuff which is somewhat of a different beast. Risks there are probably similar to AC mains power distribution, I would guess: touch it and get a nasty shock, don't touch it and you're fine.