I think it was Sir Richard Doll (the scientist that first proved the link between tobacco smoking and cancer), that, after a lifetime of research, claimed being

I think it was Sir Richard Doll (the scientist that first proved the link between tobacco smoking and cancer), that, after a lifetime of research, claimed being around smokers didn't concern him in the slightest. Spending significant amounts of time in confined, smoke-filled spaces might be a different story though.