What Was the Year When America Found out Smoking Was Bad for You?

I'm sure Americans have known for years and years… and years about the health risks of smoking, but the most documented account of admission, to me, was made by the Surgeon General of the United States.
This is part of the quote from the Office of the Surgeon General in 1965 -

The Federal Cigarette Labeling and Advertising Act of 1965 (Public Law 89–92) required that the warning "Caution: Cigarette Smoking May Be Hazardous to Your Health" be placed in small print on one of the side panels of each cigarette package. The act prohibited additional labeling requirements at the federal, state, or local levels.
In June 1967 the Federal Trade Commission (FTC) issued its first report to Congress recommending that the warning label be changed to "Warning: Cigarette Smoking Is Dangerous to Health and May Cause Death from Cancer and Other Diseases."
In 1969 Congress passed the Public Health Cigarette Smoking Act (Public Law 91–222), which prohibited cigarette advertising on television and radio and required that each cigarette package contain the label "Warning: The Surgeon General Has Determined That Cigarette Smoking Is Dangerous to Your Health."

Suggestion:

Not that many people smoked prior to the 1900s. Ready made cigarettes were for the rich and most of the poor chewed their tobacco. Starting around the beginning of WWI (1914) governments started handing out free cigarettes to their soldiers in the trenches to keep them alert. The soldiers became addicted to smoking and when they returned to the homefront the demand for ready mades increased tremendously. Also women started to smoke in the 1920s. In the 1930s doctors noticed a huge increase in the number of people with lung cancer. At that time lung cancer was a very very rare disease and lots of doctors had never seen it. At that time the medical profession deducted that the increase in smoking had brought on the increase in lung cancers. However by this time cigarette making was a multi million dollar industry and they paid to shut everyone up. This continued until the 1960s when people really began to question how healthy tobacco was. The cigarette industry still denied it and it wasn't until the late 1970s and early 1980s that most people accepted that use of tobacco causes cancer.