Has there been a documented case of second hand smoke killing anyone? Then again, Living in most major cities will do the same things to your lungs and that doesn't seem to stop people.

Leaving aside a bunch of bad things like asthma and emphysema, let's take something pretty pathologically objective like squamous cell lung cancer (that is very closely tied to smoking in our world).

Secondhand smoke-wise, you can always find someone who contracted SCLC (or asthma or emphysema or something ) who never smoked or who was not exposed to secondhand smoke. Likewise you can find folks who contracted those bad things and who *were* exposed to tobacco.

It's the old bell-curve thing, though. It isn't what happens in any single case. It is about what the risk is for an overall population in what epidemiologists (I used to be one) call "relative risk"

It is in the interest of tobacco companies to poke holes in causative implications based in the same old "My Uncle Charlie smoked until he was 110!" basis, but it belies the really nasty [censored] that befalls their customers when you look across the whole population of their customers.

Anyhow, the overall bad effects of secondhand smoke are decently well established (look here for starters), are becoming even more well established, and I think I can safely say that most flight attendants are *really* glad you can no longer smoke on their airplanes!