Drugs Education

Can You Test Positive in a Drug Test for Marijuana Because of Second-Hand Smoke?

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If you know the story of Josh Gordon and how he was suspended several times from the NFL for failing substance abuse tests and how his legal team blamed the failed test of August 2014 on second-hand marijuana smoke, then you probably also know that the second-hand smoke angle is a card that is commonly played by people that fail a drug test.

In the 1980s, studies suggested that ‘social exposure’ to marijuana could result in a non-user registering positive in a drug test for tetrahydrocannabinol (THC), cannabis’ main psychoactive ingredient. Further studies over the years have also come to the same conclusion.

Second-hand marijuana smoke exposure:

  • Leads to cannabinoids absorption.
  • Can influence cognition and behaviour.
  • Under unventilated conditions produce:
  • Cannabinoid levels that are detectable in urine and blood.
  • Minor to reasonable sedative drug effects.
  • Mild heart rate increases.
  • Impaired cognitive performance.
  • Under proper room ventilation, will have reduced effects.

Scenarios Under Which You Can Test Positive Due to Second-Hand Smoke

Apart from the fact that being in a poorly ventilated room increases the chances of a non-user testing positive to a drug test due to second-hand smoke, there are other instances that can influence those chances.

  • The Second-Hand Smoke Is from the Use of a More Potent Strain of Marijuana

Tetrahydrocannabinol (THC) is the chemical that inflicts most of the psychological effects that accompany marijuana use. It behaves like the body’s natural cannabinoid chemicals. Since cannabinoid receptors reside in the part of the brain associated with memory, pleasure, thinking, time perception, and coordination, THC affects those functions of the brain when it attaches to and activates the receptors.

Like in every other product, producers always try to find out what motivates consumers to purchase their products and then highlight that aspect of the product to make it more attractive.

In the case of marijuana, THC is the chemical that triggers the ‘high’ that comes with using it. Hence, it’s not uncommon for producers to seek and breed more potent strains like Satori and Bruce Banner, which have 28% and 29% high THC. Compared with strains like Red Dragon (22.7% high THC), Satori and Bruce Banner will produce more intense psychoactive effects and have higher chances of producing positive drug test results in second-hand smokers.

  • Recent Exposure to Second-Hand Smoke


There is no simple answer to how long marijuana can be detectable in the body. It all depends on the drug testing method employed, the potency of the strain exposed to, and how heavily and frequently the user smokes marijuana.

For non-users exposed to second-hand marijuana smoke, the answer only gets a tad simpler, but not completely simple. Depending on whether your exposure happened in a ventilated or unventilated place, you can expect up to 50ng/ml, although most second-handed smoking scenarios yield 20ng/ml, which is most detectable within a day after exposure. Then much of the THC begins to filter away after the first 24hours.

  • Length of Exposure and Amount of Marijuana Being Smoked

The amount of exposure a second-hand smoker can expect will obviously be higher with more people smoking marijuana around him or her or with a larger amount of marijuana being smoked. This only gets worse if the non-smoker remains in that environment for a longer period. These instances could very well affect the person’s drug test result.

How to Minimise Your Chances of Testing Positive When You Don’t Use


The answer is simple. Avoid being in a closed quarter (especially a car or room) with people smoking marijuana. In short, stay away from people smoking illegal substances, whether in a ventilated or unventilated place.

Article Submitted on behalf of drugrehab-bristol.uk and alcoholrehab-bristol.uk

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