Can You Fail a Drug Test From Second Hand Marijuana Smoke?

If you are a veteran marijuana consumer, you have heard of the term ‘contact high’, also known as secondhand cannabis smoke, I’m sure.
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Maybe you had a friend that was hanging out with you while you were smoking, and they were certain that they had a ‘contact high’ from being around you while you were puffing. Many are worried about this and hurting their chances to pass a drug test.

Or maybe you knew someone that failed a drug test, and swore that they had never smoked marijuana themselves, but were around people that were. That was the case with NFL player Josh Gordon, who was suspended from the NFL for barely failing a chemical test for marijuana.

For a long time marijuana consumers, and non-marijuana consumers for that matter, were left to wonder if those scenarios were even possible. I know I have hung out with people before that didn’t smoke marijuana, and although they felt like there were getting a contact high, I was pretty sure they were just lame and trying to over embellish. I have heard of many people that have failed drug tests and swore that they didn’t smoke, and I have always wanted to see the science behind what it would take to fail a drug test due to being around second hand marijuana smoke.

Being around enough second hand marijuana smoke to ‘get high’ is a different question than how much marijuana smoke someone would need to be around to fail a drug test. Being ‘high’ is subjective, while the amount of THC in ones system is quantifiable with a chemical test. Just because I have above a threshold for THC in my system doesn’t mean that I’m high at the time of the test because marijuana can stay in someone’s system for a long time, which is something that is common knowledge to anyone who knows anything about marijuana.

Can someone fail a drug test for marijuana when they are around secondhand marijuana smoke, but don’t actually take puffs themselves? According to the results of a study that were published last month, the answer is yes. Below is the abstract from the study:

Exposure to secondhand cannabis smoke results in absorption of cannabinoids.
Secondhand exposure can produce mild subjective and behavioral/cognitive effects.
Room ventilation ameliorates the effects of secondhand cannabis smoke exposure.


Cannabis is the most widely used illicit drug. Many individuals are incidentally exposed to secondhand cannabis smoke, but little is known about the effects of this exposure. This report examines the physiological, subjective, and behavioral/cognitive effects of secondhand cannabis exposure, and the influence of room ventilation on these effects.

Non-cannabis-using individuals were exposed to secondhand cannabis smoke from six individuals smoking cannabis (11.3% THC) ad libitum in a specially constructed chamber for 1 h. Chamber ventilation was experimentally manipulated so that participants were exposed under unventilated conditions or with ventilation at a rate of 11 air exchanges/h. Physiological, subjective and behavioral/cognitive measures of cannabis exposure assessed after exposure sessions were compared to baseline measures.

Exposure to secondhand cannabis smoke under unventilated conditions produced detectable cannabinoid levels in blood and urine, minor increases in heart rate, mild to moderate self-reported sedative drug effects, and impaired performance on the digit symbol substitution task (DSST). One urine specimen tested positive at using a 50 ng/ml cut-off and several specimens were positive at 20 ng/ml. Exposure under ventilated conditions resulted in much lower blood cannabinoid levels, and did not produce sedative drug effects, impairments in performance, or positive urine screen results.

Room ventilation has a pronounced effect on exposure to secondhand cannabis smoke. Under extreme, unventilated conditions, secondhand cannabis smoke exposure can produce detectable levels of THC in blood and urine, minor physiological and subjective drug effects, and minor impairment on a task requiring psychomotor ability and working memory.

So according to researchers, yes you can fail a drug test for being around secondhand marijuana smoke. With the case of NFL player Josh Gordon, he tested positive for 16 ng/ml of THC, which was above the 15 ng/ml threshold that the NFL considers to be a failed test. In his appeal he stated that he was just around other people that were smoking marijuana, and based off of this study, I would be inclined to believe him.

So can people get high from being around secondhand marijuana smoke? It’s a subjective question, but yes, I suppose someone could, especially if they had a very low tolerance. If someone is sitting across the room while someone else is on the other side of the room blowing pipe hits out the window in a well ventilated area, then I would probably say no. But if people are sitting in a cramped space, hotboxing like crazy, then I think it’s definitely possible. Especially if the hotbox session includes joints and blunts, where the smoke billows out of the joint/blunt and isn’t the exhale of the hotbox participants. You have to assume that the smoke can accumulate, and even though a person may be in the session area but isn’t puffing, they are going to inhale that ‘non-lung filtered’ smoke.

Moral of the story is, if you are in a position to where you know you are going to have to submit to a drug test in the near future, it’s best to stay upwind of any marijuana smoke. Also, if you don’t want to get high from secondhand marijuana smoke, you probably shouldn’t volunteer to sit in a confined space with poor ventilation while others are puffing away. Do you have any secondhand marijuana smoke stories? They could be personal, or just a story that you heard. If so, make sure to post them in the comments.