Second-hand 'toke' could lead to failure of workplace drug test

Researchers in Calgary say employees should be aware they could fail workplace drug tests due to second-hand smoke from marijuana.   

A new research study from the University of Calgary says THC _ the active ingredient in marijuana _ is detectable in the body after as little as 15 minutes of exposure even if the person is not actively smoking it.   

The study is published online in Canadian Medical Association Journal Open.  

Findings suggest anyone exposed to second-hand smoke in a poorly ventilated room including a kitchen, basement, or living room with the windows closed, will test positive after 15 minutes.  

It can take between 24 and 48 hours for the THC to clear from the system.  

The study says that could prove problematic for workers at businesses that have a zero tolerance drug policy.