Is wi-fi bad for your health?

There's an interesting news report currently on the BBC news website about Canada's Lakehead University,where there's a restiction in the use of wi-fi because of health concerns. If you look around various physiotherapy disussion forums you will see that discussions regulary come up about the safety of electromagnetic energy sources ( in the mainly shortwave spectrum) used within physiotherapy. I'd really like to know if there's a health risk from those things we've all been told are safe. There's probably not been any specific testing of physiotherapy equipment for it's effect on human tissue and definitely no long term studies on it. And what about the other things which are readily practiced in physiotherapy-things like TENS, acupuncture , manipulation ? Has anyone looked at potential for long term harm with these treatments? We're not talking about the immediate effects such as adverse clinical events associated with a neck manipulation or pneumothorax associated with acupuncture but the long term adverse health consequences, such as increased risk of developing certain health problems a long time after the event. Could having repeated acupuncture increase the risk of devloping cancer? Could neck manipulation increase the risk of stroke years after the event?