No it hasn't. There was a study that came out after that episode which confirmed secondhand smoke, and caused them to issue a retraction.

www.youtube.com/watch?v=3s8yqj3EL7A

Two points:

1) From your link, "The study doesn’t cover the many other ill effects of breathing somebody else’s cigarette smoke, of course, which include asthma and possibly cardio-pulmonary disease." So not debunked exactly.

2) Penn & Teller are entertainers (and illusionists). They present controversial opinions for the sake of a TV show. It is not journalism and shouldn't be accepted at face value.

ETA: https://en.m.wikipedia.org/wiki/Penn_%26_Teller:_Bullshit!

Penn says, "right now, as I sit here, there probably is danger in secondhand smoke".

Your link only says it doesn't cause cancer, not that it is harmless.

Asthma sufferers, for example, have all sorts of additional breathing difficulties when forced to breathe smoke (of any kind).

P&T's Bullshit is a really bad source of information.