Law.com write by way of introduction.

In 1996, California voters passed Proposition 215, known as the California Compassionate Use Act, making California the first state to legalize marijuana for medicinal use. In the succeeding 13 years, 32 states followed with full legalization for medicinal purposes, and 14 states passed laws allowing for low THC/high CBD forms of medical marijuana. Today, only three states (Idaho, South Dakota and Nebraska) prohibit all forms of medical marijuana. As an employment law attorney representing companies, when my clients call with questions about medical marijuana, they want to know how it affects their drug testing and safety policies and what accommodations, if any, they have to make for employees who are using medical marijuana. With the majority of the United States on board with medicinal cannabis use and 13 years of progressive legalization, one would think that we would have clear guidance on these topics. Well, one would be wrong. The legal landscape for employers grappling with the impact of medical marijuana on their workplaces remains quite hazy (pun intended).

The first layer of haze is created by the federal treatment of medical marijuana. Despite broad legalization across the country, cannabis remains a Schedule I drug under the Controlled Substances Act, which ironically means it has no medical use. Moreover, because federal regulations often govern how drug tests are performed and verified, medical use of marijuana (even in the states where it is legal) does not constitute a legitimate medical reason for testing positive for cannabis metabolites. What does this mean? The medical marijuana user who tests positive for cannabis will have his test certified as positive, despite his status as a legal user under state law. Conversely, the Adderall user who tests positive for amphetamines will have his test certified as negative as long as he can produce his prescription!

The second layer of haze is created by differences in the state acts. No two acts are exactly alike. Accounting for some of the differences is the method by which the states achieved legalization. Approximately half the states legalized medical marijuana by voter initiative, while the other half legalized through carefully crafted and debated legislation. Not surprisingly then, the level of detail provided across state acts varies. Some acts discuss workplace accommodations, others remain silent on the subject. Some states, like Pennsylvania, include anti-discrimination language, while its neighbor state, New Jersey, does not. Some acts provide great detail about what the act does and does not protect, while others are bare bones measures designed only to protect medicinal users from criminal prosecution.

The final layer of haze comes from judicial interpretation. For approximately 10 years, we felt like we had some clarity. The courts’ rulings were consistently employer-friendly.

Full article at https://www.law.com/thelegalintelligencer/2019/05/24/legal-guidance-for-medical-marijuana-in-the-workplace-remains-hazy/