We already know now much more than we apply. Global warming is the most obvious example. It's true, the hypothetical people in 50 years will consider the current and earlier generations barbarian in their approach to the use of the fossil fuels. But we actually even now know fantastically good the exact effects the electromagnetic waves, and that at least since 1905 work of Einstein for which he received Nobel prize. So there was a lot of time already to check if we got that wrong. Don't worry about a few watts your phone produces, worry about the Sun and anything that produces that kind of radiation (or worse, but in that direction), the one which is on the opposite side of the radio waves and visible light and the one for which we know exactly how damaging it is:

https://en.wikipedia.org/wiki/Thymine_dimers

https://en.wikipedia.org/wiki/Ultraviolet_index

Regarding lead poisoning, it was since forever known that lead is poisonous, the "safe level" was something that was better established in last 50 years and enforced by better policies. There's no parallel for infrared and radio waves (that is, lower frequencies and energies of photons) but there is for UV or gamma rays (that is, higher frequencies and energies of photons).