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Could Second-Hand Smoke Make You Fail a Cannabis Drug Test?

Could Second-Hand Smoke Make You Fail a Cannabis Drug Test?

Introduction

A question we are often asked concerns the effects of second-hand cannabis smoke and whether being in and around weed smokers could cause a positive drugs test for cannabis for somebody that has not actually smoked the drug.

Cannabis Drug Tests are often incorporated into Single Drug Tests, Multi Drug Tests or Saliva Drug Tests.

Key Question: Can passive exposure to cannabis smoke produce a positive result on a drug test? This is an important concern for employees, parents, and anyone subject to drug testing.

Will Second-Hand Cannabis Smoke Influence The Results Of A Urine Drug Test?

Most drug testing at work is based on urine drug testing. A sample of urine is provided by the donor and analysed for the presence of drugs of abuse.

The general scientific consensus until now has been that second-hand cannabis smoke will not influence the results of a urine drug test. However, cannabis as a drug has changed in recent years. Many of the newer strains of the drug are much more potent and stronger than ever before. Because of this, new studies have been commissioned to look at the issue of second-hand smoke and its affects on a non-cannabis user.

A urine drug test for cannabis will detect the metabolite THC which is the product of the drug that causes many of the drug’s psychoactive effects. Some newer strains of cannabis are stronger and can contain more THC than older variants of the drug.

What Are Drug Test Cut-Off Levels? Understanding cannabis drug test cut-off levels helps explain why second-hand exposure is unlikely to trigger a positive result. These thresholds are set to distinguish genuine use from incidental exposure.

New Study Into Second-Hand Cannabis Smoke

Researchers from the University School of Medicine, Baltimore put together 12 couples. Each couple consisted of a regular cannabis smoker and a non-cannabis smoker. Together they were seated in a sealed compartment for 60 minutes whilst the cannabis user smoked on a strong joint.

After the hour was over, the 12 non-smokers were asked to urinate in a cup at regular intervals and their pee was tested for the presence of THC.

The Journal of Analytical Toxicology published the results of the study in October 2014. They concluded that the urine levels of THC only passed the typical drug test cut-off of 50 nanogram per millilitre in one individual for one very brief instance. (4-6 hours after exposure).

📊 Study Finding: Only 1 out of 12 non-smokers showed THC levels above the standard 50 ng/ml threshold, and this was only briefly after intensive exposure.

Positive Drug Tests From Cannabis Smoke Are “Likely To Be Rare”

The authors of the report concluded that instances of positive drug tests from second-hand cannabis smoke are “likely to be rare”. This remote possibility would only occur in the first few hours after intensive exposure to second-hand smoke, such as after being in a car with a cannabis user for a number of hours.

When air was passed into the smoking chamber, making the smoke less concentrated, the levels of THC recorded in urine did not come anywhere near the threshold of 50 ng/ml required to effect a drugs test.

Reassuring Conclusion: Typical environmental exposure to second-hand cannabis smoke is highly unlikely to result in a failed drug test. You would need to be in an extremely smoke-saturated environment for an extended period.

Cannabis Edibles And Second-Hand Exposure

While the study focused on second-hand smoke exposure, it’s worth noting that consuming cannabis edibles does not produce the same kind of second-hand exposure risk. The THC in edibles is metabolised differently in the body compared to inhaled smoke. So being around someone who has eaten a cannabis edible is highly unlikely to cause a positive drug test result for bystanders. However, it’s still wise to avoid any potential cannabis exposure if you need to undergo drug testing.

Photo by frankie cordoba on Unsplash

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