The tobacco industry's role in the 16 Cities Study of secondhand tobacco smoke: do the data support the stated conclusions?

backgroundSince 1996, the tobacco industry has used the 16 Cities Study conclusions that workplace secondhand tobacco smoke (SHS) exposures are lower than home exposures to argue that workplace and other smoking restrictions are unnecessary.

objectivesOur goal was to determine the origins and objectives of the 16 Cities Study through analysis of internal tobacco industry documents and regulatory agency and court records, and to evaluate the validity of the study's conclusions.

resultsThe tobacco industry's purpose in conducting the 16 Cities Study was to develop data showing that workplace SHS exposures were negligible, using these data to stop smoking restrictions by the U.S. Occupational Safety and Health Administration. The extensive involvement of R.J. Reynolds Tobacco Company and the tobacco industry's Center for Indoor Air Research in controlling the study was not fully disclosed. The study's definition of "smoking workplace" included workplaces where smoking was restricted to designated areas or where no smoking was observed. This definition substantially reduced the study's reported average SHS concentrations in "smoking workplaces" because SHS levels in unrestricted smoking workplaces are much greater than in workplaces with designated smoking areas or where no smoking occurred. Stratifying the data by home smoking status and comparing exposures by workplace smoking status, however, indicates that smoke-free workplaces would halve the total SHS exposure of those living with smokers and virtually eliminate SHS exposure for most others.

conclusionsData in the 16 Cities Study reveal that smoke-free workplaces would dramatically reduce total SHS exposure, providing significant worker and public health benefits.