Can you fail a hair follicle test from second hand smoke?

Next to impossible.

I agree with Lucky.

Nope.

When the lab gets the hair they run it through a chemical wash that washes all external contaminants off. As far as ingesting it, it would be almost impossible to show up on a hair drug test. I wouldn't worry.

Except you don't ingest it, you inhale it. And I guess that all depends on how much you inhaled. Outside very unlikely, inside in a small poorly ventilated room where a lot of people were smoking it... maybe, enough to worry if you were at enough of those parties.

I'm guessing unlikely... but I remember parties in my youth, there was smoke so thick I had to leave out of fear of the remote possibility of causing a problem. ( Job related random testing) And people that weren't smoking at the party that stayed actually got a high from it.