Why Smoking Bans Lead to More Fires

Freakonomics explains:

Death by fire has declined significantly over the past 100 years, but there’s one surprising policy that may actually increase the prevalence of fires: smoking restrictions and bans. A new paper by Emory economist Sara Markowitz finds that “laws regulating indoor smoking are associated with increases in some types of fires. Specifically, workplace restrictions and bans are associated with increases in fires in all locations and in residential units. Restaurant and bar bans are associated with increases in fires in restaurants and all eating/drinking establishments.” Markowitz explains the counterintuitive results: “Even when bans are effective in reducing smoking, if the reduction is mostly among the safe smokers and the remaining smokers act more carelessly, then we could easily see an increase in fires.” For example, “In the case of restaurants and bars, it is easy to imagine a person going outside to smoke and then improperly disposing of the cigarette in flammable material such as mulch or shrubbery.”

Note: It is not that smokers act more carelessly, it's that smokers are thrust outdoors into generally public areas, where there is less supervision over what they are doing.

In a bar, for example, ash trays will be provided and bar owners have a lot of incentive to keep flammables away from where smokers smoke. Outside, not so much.