Can You Fail a Drug Test from Secondhand Smoke?

Can You Fail a Drug Test from Secondhand Smoke?

Have you ever wondered if you can fail a drug test from secondhand marijuana smoke or from being in a car someone has "hot boxed" or "clam baked"? Maybe you're curious, maybe you've been around people smoking and are concerned you'll fail a drug test or maybe you're hoping it could be a convenient excuse for why you failed your drug test?

The answer is probably not. I remember years ago my probation officer had a sign hanging in her office. The sign stated something to the affect that you would need to be in a 10x10 room with no ventilation and something like 300 joints would need to be smoked in order for you to fail the test. As you can imagine probably highly unlikely to happen. 

The reason for this is when you exhale marijuana smoke very little THC is exhaled. This is why it's very unlikely someone would be able to get high from or fail a drug test because of second hand smoke. 

Research has shown that when someone smokes marijuana and exhales, very little THC is emitted. A study back in 2010 went a little but firther and researchers measured the effects of secondhand smoke on non-marijuana smokers. The non-smokers were put in a well ventilated space with people casually smoking pot for 3 hours. The researchers then took blood and urine samples from the non-smokers. They discovered that THC was present, but the amount was well below the level needed to fail a drug test. Another study had similar results. 

The long and short of it is that it would be highly unlikely for you to fail a drug test due to second hand smoke. If you're having to take a drug test and have been at a concert with or in a car with people smoking pot you likely don't have anything to worry about. And if you've failed a drug test and are planning to use the "I was in a car with someone" excuse, skip it because it's not very likely.