The conclusion of the United States Surgeon General's Advisory Committee on Smoking and Health in 1964 that excessive cigarette smoking causes lung cancer is cited as the major turning point for public health action against cigarettes. But the surgeon general and US Public Health Service (PHS) scientists had concluded as early as 1957 that smoking was a cause of lung cancer, indeed, "the principal etiologic factor in the increased incidence of lung cancer." Throughout the 1950s, however, the PHS rejected further tobacco-related public health actions, such as placing warning labels on cigarettes or creating educational programs for schools. Instead, the agency continued to gather information and provided occasional assessments of the evidence as it came available. It was not until pressure mounted from outside the PHS in the early 1960s that more substantive action was taken. Earlier action was not taken because of the way in which PHS scientists (particularly those within the National Institutes of Health) and administrators viewed their roles in relation to science and public health.