Patients and advocates around the state cried foul earlier this year when introduced to Colorado HB 1261, which set a 5-nanogram/mL limit on THC in drivers’ blood. Now, it’s becoming clear just how problematic this bill is. Patients who were not stoned while driving–which is what this bill attempts to prevent–might be put in jail for having THC in their systems.

The problem here is that the blood testing the state uses returns numbers for THC-COOH, or THC that’s stored in fatty tissue. It’s not active, meaning you can fail this blood test even if you haven’t smoked in a week (or more, depending on your body.) Of course, many smokers already knew this, which is partly why the bill was so hated in the community.

But prosecutors might not be aware, says attorney M. Colin Bresee. Bresee thinks that law enforcement doesn’t know the difference between THC-COOH and THC (the active bits,) which is causing confusion and putting innocent people behind bars. He also says that patients are pleading guilty because they don’t know the difference, either.

Obviously this creates a bit of a problem. That’s why Dr. Alan Shackelford, who wrote regulations for the Department of Revenue concerned medical marijuana safety, is opposed to this bill in its current form. He also plans to further study THC blood levels. William Breathes, for Denver Westword, is having his blood tested by Quest Diagnostics, thanks to a recommendation by Shackelford, to obtain an accurate reading of THC-COOH vs. THC in his blood.

The bill goes into debate in the Senate on Monday. With any luck, it will at least be revised to specify active THC levels to prevent confusion. But when even Representative Claire Levy, who sponsored the bill, feels the 5-nanogram limit is too low, perhaps it’s safe to say that HB 1261 needs more work.