The Wyoming Division of Criminal Investigation is warning people that it's illegal to possess CBD oil in Wyoming that contains measurable amounts of THC without a Hemp Extract Registration Card.

Those cards are issued through the Wyoming Department of Health and Matt Waldock of DCI says only a limited number of those cards have been issued. CBD oil is extracted from hemp plants and is legal for treatment of certain medical conditions in Wyoming for registration cardholders.

But Matt Waldock of DCI says CBD oil is being sold over the counter in the state at pet stores, convenience stores, and other retail outlets. He says that while the sellers usually claim the oil has little or no THC content, testing on some of the oils has shown that to be untrue in many cases.

THC is the active ingredient in marijuana. While possession of the oil is not illegal if it does not contain THC, it may be difficult for the average person to know for sure whether the drug is present in many cases.