of course it`s bad for your lungs if you SMOKE it.
if you vapoourize it, your lungs do not inhale anything bad like plant matter.
they have done long term studies (25 year study) on the effects of vapourized thc inhilation, and guess what, they found no permanent ill effects.
but as for smoking it, it`s been proven to cause certain lung ailments and permanent damage to the lungs, not from the thc but the burning of the plant material and the papers, blunts are the worst when it comes to lung damage as they are comprised of tobacco and weed.
tobacco has been proven to cause lung cancer and heart disease.as for weed alone, in a water pipe, has not. dont get me wrong, it does damage the lung tissue somewhat, but not even close to tobacco.