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In the CBD community, we’ve all heard horror stories of grandmother’s being arrested for having a CBD tincture, or CBD store-owners having their stores raided and their products seized by police. But what’s behind these arrests?

These stories typically follow a familiar thrust: the police suspect that a product is marijuana, send a sample to the lab, and it comes back positive for THC. But a study has revealed that one of the most common types of tests that police forensic labs use struggles to distinguish between THC and CBD. 

In fact, this test, which is also used by drug testers hired by employers and courts determining custody battles, can actually mistake the CBD levels in a product for THC and result in a false-positive. And this isn’t conjecture: products that were lab-tested by the vendor for less than 0.3% THC have come back positive from police tests.

What exactly is happening here? We investigate. 

CBD’s hazy legal status 

The confusion about CBD stems from it’s contradictory legal status; or, rather, it stems from the very controversial status of hemp, the plant from which CBD and cannabis (AKA conventional marijuana) is extracted. Until 2018, all parts of the hemp plant were illegal, but that changed with the 2018 Farm Bill, which formally declared hemp and CBD legal at a federal level. 

But the story doesn’t end there: far from it. Because, while CBD is now federally legal, it’s still formally illegal in many states. While you probably won’t get prosecuted just for using CBD (though there are a number of prominent cases of this, see below), selling CBD is still treacherous and risky in many parts of the US. 

 Further complicating things, the FDA has formally banned the inclusion of CBD-infused food and drink, two of the most common ways that people consume CBD. Some states, like California and New York, have followed suit and banned any state businesses from selling CBD-infused food and drink.

Legality all comes down to the THC content

So, CBD is legal federally, but not in some states, and it’s also extracted from the same plant as cannabis: the hemp plant.  This raises the question: in states where CBD is illegal, how do the authorities distinguish between CBD products and marijuana products? It’s all about the THC.

The 2018 Farm Bill set the standard: any product (whether it’s flower, oil, powder, tincture, capsules, anything) with a THC level below 0.3% is considered hemp/CBD, while any product with MORE than 0.3% THC is legally considered marijuana. 

This is where CBD labelling comes in: some products that claim to have less than 0.3% THC actually contain more, and you are still legally responsible if you get busted with a product that contains more than 0.3% THC. 

Now, in states where CBD is legal you aren’t likely to get any hassle for purchasing/using CBD products, but in states trying to crack down on CBD (like Texas, Florida, or Louisiana) this is exactly how they get people: when authorities catch people with CBD (whether sellers or users), they test it and find there’s more than 0.3% THC in the product, and then declare it marijuana.

How do police test hemp to determine if it’s marijuana?

Police forensic labs most often test cannabis with a machine called a gas-chromatography mass-spectrometry, or GC-MS, machine. The lab adds a chemical to to the sample in question and uses the machine to identify trace amounts of THC. 

Here’s the rub: the tests police use to determine the presence of THC are highly inaccurate

The big problem with police using a GC-MS machine to test for the presence of THC was revealed in a 2012 study, which found that, with the use of a chemical agent called trifluoroacetic anhydride, or TFAA often used by police in marijuana field tests, the GC-MS machine was often unable to distinguish between CBD and THC.

That’s right:  the test would actually confuse the CBD levels in a product for THC levels, and report that the product is marijuana. 

This isn’t just a problem with police tests: often, drug testing services hired by employers use the same tests to determine THC levels in the urine of employees. As a result, there are many stories of people being fired for drug tests that came back positive for THC when they had only used CBD products. The New York Times even published an article recounting many such stories. 

And it gets worse: it’s not just the fancy forensic lab-tests that can result in false-positives: the cheap, disposable field tests that police in many states use to determine on the spot whether a suspected substance contains anything illicit are also inaccurate

So, police can take a sample of a CBD product, field-test it and determine that it contains THC, and then ANOTHER sample can be sent to a forensic lab that comes back positive for THC, when in reality all these tests are identifying is CBD. 

People can be (and have been) charged with crimes, employees have lost their jobs, sellers have had their businesses raided and their products seized, parents have lost custody of their children: all because of essentially fraudulent tests that falsely convict people of marijuana use. 

New police drug test being developed

There is at least a bit of hope for the future: a test developed by Swiss chemists is being demoed in Virginia which purportedly can accurately distinguish between CBD and THC levels. Traditional police field kits use chemicals that will turn the sample purple if cannabinoids are detected, but this new test will turn the product purple-pink if the product contains CBD and blue if it contains THC. 


WATCH YOUR BACK! If you’re only a CBD user you’re unlikely to get hassled, but it’s especially risky if you’re a seller living in an CBD-unfriendly state. Check out this state-by-state guide to CBD legality, and make sure that any products that you sell are lab-tested before you sell them (and have the documents on hand in case the police come poking around).