Whenever people ask, “can you fail a drug test from second hand smoke” I always replay that it has a lot to do with the type of drug test being performed. Most commonly there are two major types of drug tests, the hair follicle drug test and the urine drug test.

Hair Follicle Test for Marijuana

In the case of a hair follicle drug test, there are two factors that should be considered:

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Does second hand smoke deposit onto the hair?

Can a contact high lead to a positive hair follicle test result?

These are two very different questions because what drug testing labs test for is the presence of something called a metabolite of THC. Metabolite is a fancy way of saying the byproduct of your body having ingested and metabolized a drug. The metabolite a different drug from the drug you ingested since your body has processed it and turned it into a different chemical.

In the case of marijuana, THC is the drug that would get you high and THC-COOH is the drug that is the result of your body processing the THC.

So, in theory, one could rub marijuana all over their head seconds before taking a hair follicle test and pass with flying colors since the drug testing lab isn’t looking for THC, they’re looking for THC-COOH. Since the raw marijuana contains only THC, the drug testing lab wouldn’t find any.

Urine Test for Marijuana

The second part of the hair follicle test question is whether or not being around others who are smoking marijuana, casing you to involuntarily inject the drug, could cause you to fail a drug test.

The short answer is: It’s possible but highly, highly unlikely.

Hair follicle drug tests for marijuana are highly inaccurate for very low exposure to THC. It’s generally accepted that you would need to smoke at least three times within the last 90 days to even be at risk of failing a hair follicle drug test for marijuana. That’s actual smoking and getting high. Most people who are exposed to second hand marijuana smoke might feel some minor effects from the drug but they certainly aren’t on par with the person (or people) actually doing the smoking.

So, in order to fail a hair follicle test for marijuana one would need to not only have gotten a contact high (and a pretty good high at that) but have gotten contact highs many multiples of times over a relatively short period of time (90 days).

For the average person, that seems like a fringe scenario. Unless you work at a “Coffee Shop” in Amsterdam or live with someone who smokes marijuana like a chimney on a daily basis, contact exposure to marijuana smoke is highly unlikely to cause you to test positive for drugs on a hair follicle drug test.

Unfortunately, the same can not be said for urine tests. Urine tests are popular in many drug testing scenarios because they are fairly accurate for marijuana usage within a fairly short range of time. They may not be able to show if you smoked a joint 60 days ago but they’re fairly accurate in determining if you smoked one 60 minutes ago.

When you ingest THC, your body will metabolize the drug and eliminate it from your system through various means. When your body attempts to deposit THC metabolites in your hair, there are some complicating factors involved with that. First off, your body only attempts to rid itself of THC-COOH through the hair follicles at a limited rate. Second, THC-COOH has to adhere or bind with your hair shaft so that the deposits don’t become unstable (i.e. break down into other drugs). Lastly, certain realities of life, UV exposure, heat, etc, promote THC-COOH breaking down naturally which lessens the overall concentration of THC-COOH in your hair.

Obviously if you smoke frequently and-or in high doses, these factors become less and less important.

However, when your body attempts to eliminate THC-COOH via other methods, for example through your urine, the rate of elimination is more predictable, and is, for the most part, not as influenced by factors.

Your body also deposits the THC-COOH metabolite into your fat cells which is why you can still test positive for weeks after ingesting THC if you are a heavy smoker who has accumulated large amounts of THC-COOH in your fat cells. As your body naturally burns fat cells, the THC is released into your system and eliminated via urine (and sweat and other means).

That said, the typical urine testing cutoff is 50 ng/mL which would be very difficult to achieve from a single exposure to second hand smoke. And the window of detection would be only about 3 – 4 days since there isn’t a history of constant exposure to second hand smoke.

In other words, if you work in an Amsterdam “Coffee House” exposed to marijuana smoke 8 hours a day every day, it’s highly likely that you would test positive for THC-COOH. On the other hand, if you went to a Phish concert last night, your body would eliminate the relatively small amounts of THC-COOH from your system pretty rapidly and you would be unlikely to have a high enough concentration of THC-COOH in your urine to test positive.

Can You Fail a Drug Test From Second Hand Smoke?

It’s possible. It’s unlikely for the vast majority of people but it is possible.

Get the facts about hair follicle drug tests

If you would like to learn more about hair follicle drug tests and a proven method that will help you pass a hair follicle drug test, check out my eBook, How to Pass a Hair Follicle Drug Test.

Pass a Hair Follicle Drug Test