A new study finds no evidence that marijuana smoking causes lung cancer:
The largest study of its kind has unexpectedly concluded that smoking marijuana, even regularly and heavily, does not lead to lung cancer.
The new findings "were against our expectations," said Donald Tashkin of the University of California at Los Angeles, a pulmonologist who has studied marijuana for 30 years.
These results are interesting and presumably welcome to marijuana smokers. They also undermine one of the standard arguments for prohibiting marijuana.
But the possibility of negative health effects should never have been a reason to prohibit marijuana: alcohol, tobacco, saturated fat, chains saws, and automobiles are all legal products.
And even if smoking marijuana does increase the risk of lung cancer, users can avoid this risk with alternative consumption methods. One is vaporization, which heats marijuana enough to release the THC without combustion. Another is cooking the marijuana into brownies. In a legal market these methods would be readily available if the evidence suggested a risk from smoking. So, even if there is a lung cancer risk, prohibition increases rather than decreases this risk.