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Can You Fail A Drug Test From Second Hand Smoke?

New research reveals that passive marijuana smokers may even feel high, but the presence of marijuana is detected in the blood or urine of the second-hand users only when they smoke in unventilated places.

Second-Hand Smoke

Marijuana is the most popular drug all over the world and people often smoke it in enclosed spaces, which are poorly ventilated or have no ventilation at all. In such conditions even those who do not actually smoke pot, but just stay near smokers can inhale quite a lot of smoke. The studies that were conducted in 1980s revealed that such passive marijuana use can cause positive result in urine test for TetraHydroCannabinol (THC), the main psychoactive substance of cannabis. But these studies used low potency weed and did not consider the levels of room ventilation. Also, they did not track the mental and behavioral characteristics of people after the exposure. That’s why new research was conducted to study the possibility to get high and fail drug test after the second-hand smoke.

The Study

The team of Evan S. Herrmann, a postdoctoral researcher in behavioral sciences and psychiatry at Johns Hopkins School of Medicine, conducted research on a group of twenty marijuana smokers and non-smokers. The team took samples of blood and urine as well as saliva and hair from participants for signs of THC. After that, those who smoked and those who did not were made to sit together and undergo two separate 1-hour sessions in a dorm size aluminum Plexiglas smoke chamber.

second hand marijuana smoke

The smokers were instructed to smoke ten high-potency cigarettes with one gram of marijuana while the non-smokers were asked to just sit there. After every session, participants completed different tasks and surveys. Some of them were biological, some cognitive and some subjective.

The Result

In the first session, the room was ventilated to allow bi-directional airflow at a standard rate that was set for an office building. Here the non-smokers had THC but in low levels. They were able to work normally and their urine samples did not test positive for THC.

In the second session, the airflow was restricted in the chamber (“hot-box” condition). Here significant levels of THC were reported in the urine as well as blood samples of the non-smokers even after 22 hours. Moreover, some of them even claimed to feel high.

Herrmann affirmed that the results were consistent with the expectations and thereby it could be stated that passive smoking can lead to a positive result in THC test, but only in an extreme scenario. The researchers stated that the unventilated chamber is the worst possible situation, which is rarely observed in real life.

Yet, the study has confirmed that yes, you can fail drug test from second hand smoke, although such conditions are hardly achievable in reality. So, if you were present in unventilated room with heavy pot smokers before drug test, you should consider some of the urine cleansing methods of passing drug test to guarantee yourself negative result.