Fewer cigarette butts means a less toxic environment.

While most people know that exposure to tobacco smoke—both active and passive—is life-threatening, many do not realize that the dangers from smoking don’t end once a cigarette is extinguished. A growing body of research is documenting the impact of tobacco litter on the environment. In the US alone, a large number of the 280 billion cigarettes purchased each year end up littering sidewalks, waterways, parks, beaches and public roads.

But the environmental impact of tobacco goes far beyond litter. Cigarette butts leach toxic chemicals —including arsenic, cadmium, lead and polycyclic aromatic hydrocarbons—that could pollute the environment and harm its ecosystems. They are mostly made of plastic and are only biodegradable under ideal conditions, making them a long-lasting threat to the environment.

And like many aspects of tobacco, the impact of cigarettes on the environment has economic implications as well. Cities, towns and other municipalities must pay clean-up costs for tobacco litter; in 2009, in the city of San Francisco alone, these costs were estimated to be more than $10 million each year.