Senate Bill 1257, which took effect November 1, moved THC from Schedule III to Schedule I. The shift aligns THC with marijuana, which was already classified as Schedule I under state law.

Critics say the reclassification creates a legal trap because THC and its metabolites can remain detectable in the body for days, weeks, or even months after use, long after any impairment has faded.

"Just to be clear, we're not advocating for impaired driving on any substance, especially marijuana. But the fact is, this is not something that's checking for impairment. They are literally just saying detection now equals evidence for conviction," said Joshua Graston, a chemist and lead formulator for a medical marijuana processor who is also a patient.

John Dungan, a medical marijuana patient, said the law effectively makes it impossible to use a card legally. "Literally you cannot have a medical marijuana card and actually use it and be legal because anytime after it's staying in your system for a month because it's stored in the fat cells. So you literally can't use it anytime they can pull you over they could just arbitrarily give you a DUI at any point now," Dungan said.

Criminal defense attorney Frank Urbanic said a driver could perform perfectly on field sobriety tests and still face a DUI conviction based solely on a positive chemical test.

"Somebody could be driving perfectly and they could do the field sobriety tests, pass them with flying colors. But if for whatever reason the officer wants to do a chemical test on that person and they test positive for THC or metabolite, that evidence alone can be used against them to find them guilty of DUI," Urbanic said.

Urbanic also warned that refusing a chemical test carries its own consequences, including license revocation, a requirement to install an ignition interlock device, and the prosecutor's use of the refusal as evidence of a "consciousness of guilt."

"So this thing is just a complete mess," he said.

The House author of the bill, State Rep. Tim Turner, R-Kinta, said the intent was to crack down on THC trafficking, not to target medical marijuana patients.

"Before marijuana was a Schedule I, THC was a Schedule III. It's all the same now. So again, if you possessed flower before, which is marijuana, you possess the Schedule I. THC was a Schedule III. So it's no different. Don't be driving a vehicle intoxicated and you won't have a problem. Period," Turner said.

Turner dismissed claims that the change was designed to generate DUI cases or undermine the state's medical marijuana program.

"Your impairment is your impairment. If you want to use your medical marijuana and get behind a wheel and you're impaired, you're gonna be DUI, no matter if it's a one or a three. So, you know, this craziness that we're hearing that, well, we changed it because we want to DUI people and we want to take medical marijuana out of Oklahoma is a farce," he said.

The debate comes as Oklahoma's medical marijuana industry remains one of the largest in the country, with hundreds of thousands of licensed patients. For patients who rely on cannabis for conditions such as chronic pain, epilepsy, or post-traumatic stress, the new classification raises questions about how they can legally use their medicine and drive without risking prosecution.

Defense attorneys say the practical effect is that any patient who uses cannabis could be charged with DUI based on a positive test alone, regardless of whether they show signs of impairment. They are urging lawmakers to consider legislation that would require proof of impairment rather than mere detection.

Turner said he believes the concerns are based on misinformation and that the law simply treats THC the same as marijuana. The change took effect November 1.