Can I Test Positive from Secondhand Smoke?
Is it possible for your body and mind to be affected by prolonged contact with someone else who’s smoking marijuana? For the most part, as long as you’re careful to keep the room well-ventilated, and avoid too much prolonged exposure, your contact high should be nothing to worry about.
You’re supposed to take a drug test tomorrow. You haven’t done any drugs recently, so you should be in the clear, right? But maybe you live with someone who smokes weed. Maybe your friends do it while you’re in the same room. If you’re inhaling their secondhand smoke, can you get drugs into your system? Will you test positive on a drug test? Here’s what you need to know.
For years, people have debated the concept of a contact high. Is it possible for your body and mind to be affected by prolonged contact with someone else who’s smoking marijuana? Well, science has weighed in, and… it depends on the circumstances.
In one experiment, twelve people were put into a room together for an hour. Six smoked marijuana, while the other six didn’t. When the experiment was conducted in a closed, unventilated room, the six who didn’t smoke found that they still obtained a slight buzz. Their heartbeats were faster than normal, and they didn’t perform as well on cognitive tests.
When the experiment was conducted in an open, ventilated room, however, the participants who didn’t smoke showed no signs at all of impairment. So essentially, a contact high is possible, even if you don’t smoke, but it’s also fairly easy to avoid: simply open up the windows and you’ll be fine.
Impairment is one thing, but even in well-ventilated areas, trace amounts of marijuana will still get into your system when you spend time in close proximity to people who are smoking. Is prolonged exposure enough to cause you to test positive on a drug test?
Tests have been conducted into this issue as well, and the answer is… probably not. Non-smokers were given drug tests after several hours of exposure to secondhand marijuana smoke, and though trace amounts of THC were found by the most sensitive tests, it wasn’t enough to trigger most standard drug tests.
Subjects were also tested after prolonged exposure in an unventilated room—the ones who got a contact high. In this case, there were a very small number of positive tests, but the occurrence was very rare. Only those who were tested within just a couple of hours of exposure triggered a positive result for THC.
So if you were hanging out with your roommate while they were smoking last night, whether or not the windows were open, it’s doubtful you have anything to worry about on your drug test. However, if the test is going to be a lab test, with gas chromatography/mass spectrometry, rather than a standard, over the counter, immunoassay test, it will be more sensitive and may be enough to trigger a positive result. Likewise if you’re being tested literally within hours of your secondhand exposure, there’s a possibility that there’s enough THC in your system to fail the test.
Still, these are both worst case scenarios. For the most part, as long as you’re careful to keep the room well-ventilated, and avoid too much prolonged exposure, your contact high should be nothing to worry about.