Carcinogens, toxic chemicals, mutagens etc. Tobacco smoke contains over fifty known carcinogens, including nitrosamines and polycyclic aromatic hydrocarbons. Sidestream smoke contains more than 4,000 chemicals, including 69 known carcinogens. Gasoline contains benzene and other known carcinogens. Mutagens are not necessarily carcinogens, and vice versa. It contains several substances that are also listed individually as human carcinogens by the IARC. This releases carcinogens and neurotoxins into the air, contributing to an acrid, lingering smog. Other carcinogens include asbestos and radioactive materials. These substances are called "carcinogens". Cannabis smoke contains many of the same carcinogens as tar from tobacco smoke. All six asbestos mineral types are known to be human carcinogens. One mechanism of action for genotoxic carcinogens includes the formation of DNA adducts. Another effort decreased the precursors of likely carcinogens in tobacco plants. Over fifty known carcinogens have been identified in cannabis smoke. Some are carcinogens per IARC, possibly including breast cancer.