Forgive me if I postpone testing this theory. On my current 5-person shift, the only 2 smokers are the supervisor and senior officer (also technically a supervisor).

Smokers aren't evil, other than the arrogant "I'll smoke wherever I damn well please and if that's two feet from your dinner table, too bad" types. Smoking is evil. Those who made billions of dollars while people died horrible deaths from smoking-related diseases the tobacco companies knew about and refused to acknowledge are evil. And so on. Don't take anything I say personally. My take on smoking is accurate - it has horrific effects and people, clothes, homes, and vehicles reek because of it - but having never smoked, it's easier for me to be objective. And never having had an addiction, I can only imagine how frustrating it is to want to quit and not be able to.

Since it fits the thread, let me share a story. The first airline I worked for was by coincidence the nation's first non-smoking airline, Muse Air. It flew from 1980-85, at which point Southwest bought it. Southwest's leader is a big smoker so the non-smoking policy went out the window.

One of our mechanics told me they were puzzled at first when butterfly-type air return valves in the aircraft a/c systems started sticking closed. Investigation revealed a thick brownish gunk on the valves - yep, from the newly-permitted smoking on board. Know what it took to clean smoking's byproducts off the valves?

Carburetor cleaner.