(2015)   Savage argues that marijuana is more dangerous than tobacco, citing claims that marijuana smoke contains much higher levels of ammonia and other carcinogenic chemicals than tobacco smoke and that users may inhale heavy metals such as mercury He contends THC is fat-soluble and lingers in the body, criticizes "medical marijuana" rationales, and says vaporizers reduce toxins but still harm the brain and performance. He explains how marijuana impairs focus, skills, and life outcomes.