When one burns any plant matter (leaves, stems, etc.), carcinogenic organic compounds result. Marijuana smoke contains most of the carcinogens of tobacco smoke, yet this fact is almost never mentioned in medical or lay publications. Why not? A decades-long study shows a two-fold increase in lung cancer in heavy marijuana smokers. Did you read about that in the media? Why not?

Meanwhile, the crusade against vaping continues unabated. Many things are dangerous to some degree. Intelligent people concern themselves with greater dangers first. It makes no sense to go into a panic over tobacco and vaping, while being apathetic about marijuana or alcohol, and remaining somnolent about fentanyl.

Ref.: Callaghan RC, Allebeck P, Sidorchuk A. Marijuana use and risk of lung cancer: a 40-year cohort study. Cancer Causes and Control 2013;24:1811-20.