Is technological advancement poisoning our environment?

This is not the first time that we've heard about the potential risk involved with transmitters. Why is it that we do not err on the side of caution? Now there is testing on 4G/LTE happening in Johannesburg with possibly negative impact on the environment. Those running the tests claim that there is no conclusive evidence that the cellphone telephony is linked to cancer. However, those close to cellphone masts have experienced discomfort and unusual symptoms. Surely, something is causing the blackening of trees if not the 4G testings. It was in 2011 that I first heard about electrosensitivity. Clearly we are releasing things in our environment that does not agree with some individuals.

Having said this, it is true though that the same fear was expressed with the initial use of microwave ovens. The difference here though is that in spite of the lack of scientific evidence there appears to be clear reporting of unusual occurrences by both humans and nature. Is it wise to simply ignore these clues and forge ahead with implementation plans without first investigating these reported cases? Is global warming not enough of a wake-up call (no pun intended) on the risk of ignoring the signs around us, or have we become so blinded by our relentless drive for technological advancement.