Tobacco companies privately agreed that cigarettes caused cancer by the mid-1950s.

In public, cigarette companies released a statement in 1954 claiming there was no proof smoking caused lung cancer. But behind closed doors, their own scientists knew the truth. By 1958, three top scientists from British American Tobacco visited the US. They found that almost every expert they met, inside and outside the industry, believed the cancer link was already proven. They chose to keep this quiet to protect their profits.