Does Secondhand Marijuana Smoke Show on a Drug Test?

It’s estimated that nearly 100 million Americans have used marijuana, and 14 million do so on a regular basis. While you may not be one of them, a friend, family member or significant other may be. If this is the case and you are scheduled to take a drug test for a job, you may be worried about whether or not you will pass. People in this scenario often ask, ‘can you test positive for marijuana from second hand smoke?’

Can You Test Positive for Marijuana from Second Hand Smoke?

In the U.S. 90% of drug tests are urinalysis tests. This means that a urine sample is tested to detect drug metabolites. In the instance of marijuana the metabolite is tetrahydrocannabinol, more commonly referred to as THC. If a subject has 50 nanograms per milliliter (ng/ml) or more of THC in their sample, then they will be considered positive for use. Tests verified that even after significant, long exposure to second hand marijuana smoke, a person is highly unlikely to reach 50ng/ml, therefore it was deemed an appropriate floor for determining use.

In most cases, you will not test positive for marijuana from second hand smoke. To put it in perspective, a recent study conducted by the Legal Institute of Medicine in Germany examined eight people who were exposed to second hand marijuana smoke in a well-trafficked cannabis shop for three hours. None of the subjects reached a urine THC level higher than 25ng/ml.  Only in instances where the area was so smoke-filled that it irritated the eyes would there be a potential for you to test positive for marijuana from second hand smoke.

Second Hand Smoke Facts

• While traces of THC will stay in the urine for up to 21 days if you smoke marijuana regularly, typically trace signs of THC will only show up for a day or two if you get second hand smoke from the drug.
• Being in a small, enclosed area will make marijuana second hand smoke exposure more severe.
• Absorption of THC in plasma depends on puff duration, depth of inhalation, and breath hold. This means that there will be an extremely low absorption rate from second hand smoke.
• THC is stored in fat cells. Those that are more heavy set will likely show higher concentrations of THC from second hand smoke than those with less fat.

Accuracy of Drug Tests

Quite possibly your concern is with the accuracy of the drug test more so than how much THC may be in your system from second hand smoke. With today’s technology, companies like MedicalDisposables Corp are able to produce highly accurate drug tests. These tests are designed to avoid false positives that can slow down the hiring process and even eliminate candidates that are actually drug-free.

If the staffing agency or hiring company is using a test provider that has the most up-to-date testing techniques, traces of the second hand smoke from marijuana will likely show up. However, the test can discern between use and second hand exposure. Results will show that the amount is so negligible that it isn’t a positive for actual use. Rest assured that if you have been exposed to second hand marijuana smoke you should still be able to pass a drug test, even within a day or two from the exposure.