I’m not familiar with the CO Constitution but have to agree with comments regarding drawing a distinction between the right to use medical marijuana by prescription vs. the employment discrimination issues. And that distinction is what makes it sticky. While CA and CO have different laws, there’s a CA case that may be an interesting read for your analysis. It is highly criticized for the result and the court was accused of skirting the real issue. (Subsequent attempts to reverse the decision via legislation were vetoed by the Governor.) But it’s worth being familiar nonetheless.
In Ross v. Ragingwire Telecommunications, the California supreme court found in favor of an er that fired an ee who failed a drug test. The ee had a prescription for marijuana and was not claiming the right to use it or be under the influence of it at work. Rather, he challenged his firing based on failing the drug test. He sued for wrongful term (public policy) and failure to accommodate (for failing the drug test) under state non-discrimination laws.
Under CA’s Compassionate Use statute, the ee could not be charged with certain crimes, such as possession. But the court ruled that nothing in the Compassionate Use Act required an employer under our state discrimination laws to accommodate the use of illegal drugs. The court also reinforced that regardless of state law, marijuana is still illegal under federal law, a la the USSC decision in Gonzales.