Not long ago, a workplace drug screening that turned up marijuana use was a fireable offense. These days, employers face a confusing patchwork of federal, state, and local laws regarding the drug and the consequences of a positive test aren't always so clear.
At the federal level, marijuana is still illegal. The Controlled Substances Act lists the drug as a Schedule I controlled substance. While the Americans with Disabilities Act requires employers to make reasonable accommodations for qualified workers with disabilities, possessing and using marijuana for any purpose is still a federal crime, regardless of state law. That means under the ADA, employers don't need to accommodate marijuana use, even for approved medical reasons. Read more https://www.forbes.com/sites/alonzomartinez/2019/10/01/marijuana-accommodations-in-the-workplace-your-employees-are-smoking-pot-now-what/#26e93e08507d