If you can merely cast doubt upon them. The same tactic is being employed, to great effect, by mostly the same people, today, in the Great Climate Change "debate."
Btw: I am a fierce opponent of tobacco consumption in any form other than soup. I smoked like a fucking chimney for 35 years. Both my parents succumbed to COPD (too young), which was the consequence of their life-long addictions. Some such fate probably awaits me, even though it has been 17 years since my last cigaret/cigar.
I would cheerfully strangle ANY tobacco executive I met.