Or you could make an argument about the debatable efficacy of secondhand smoke. (I have heard people claiming that secondhand smoke is not as bad as people make it out to be. I do not have sources for this, nor am I particularly arguing it.)

Also, what about all the E&M radiation? If you want to go out on a limb, it's a little less tenuous than finger-cancer...

Now you're just making Max Planck cry.