According to some people, this is OTL with chemtrails and whatever they put in the water, so better buy only certain brands of bottled water and make sure you buy orgone generators to get rid of chemtrails over your house.
More seriously (and this is pretty over the top), get Big Tobacco/predecessors of Big Tobacco an even greater say in the government and culture of the West in the early 20th century. Get a totalitarian United States which happens to give the tobacco industry a major say in how things are ran. Get them to promote the idea that smoking is as natural and necessary as drinking water and eating food. We have to remember that cigarettes were popular enough that the military demanded every soldier get some cigarettes, since they were necessary for fighting a war. So using that logic, cigarettes could be made "necessary" for everyday life. Even little kids need cigarettes to get through the schoolday! Science can be tampered with to support this. Totalitarian United States goes with this logic, and makes damn sure everyone gets their cancer sticks. Of course, you still have to pay for them, although for the poor, elderly, etc., the government will cover the price, and soup kitchens and such hand them out with every meal. Further, anyone who doesn't smoke is viewed as abherrant, odd, and anti-patriotic, amidst other insults. The very act of not smoking puts you on a watchlist in the same way being a communist in the 1950s did.
If/when a rebellion breaks out, the government makes sure no tobacco gets through to the rebellious area. Strikes and other conflicts are often broken in this manner. Prisoners sentenced to solitary confinement, or other dangerous prisoners, are denied cigarettes (which prisoners are normally given). The government thus uses nicotine addiction to control the population. And as tobacco companies are closely associated with the government, anything linking cigarettes to lung cancer, heart disease, etc. are considered anti-American propaganda and pseudoscience, and are not allowed to be published or spread. Any American scientist or researcher working on that line of science will disappear in the night, and those who flee abroad will be certain they are persona non-grata. The government will fund plenty of efforts globally to make damn sure that they can discredit and destroy anyone, anywhere in the world, who thinks that smoking is dangerous. And in general, the government doesn't particularly care if some people get that from smoking anyway, since after all, not everyone does, right?