Cigarette butts are the most common toxic waste found in beach and waterway cleanups and the number one item found on California highways. This is dangerous for many reasons, including, 1)cigarette butts are poisonous when ingested by children or animals; 2) the toxic chemicals in cigarette butts are a threat to our aquatic ecosystems; and 3) the substances that leach out are highly toxic to freshwater micro-organisms.

Smoking also poses a direct threat to our forests, homes, and parks. Discarded cigarette butts have been linked to large wildfires, resulting in the destruction of wildlife, vegetation, and property. Cigarette-induced fires can burn hundreds of acres of land and have done so all over the state.

(https://www.undo.org/environmental-impact/cigarette-butts-are-toxic-waste)