In the recent article Marijuana Is Changing the Workplace. Here’s How Employers Should Deal With It., Slate.com's headline is curious---how should employers respond to employees' use of legal medical marijuana?---as though there are a myriad of options. The source of the article, Inc.com, takes more of a proactive approach with its headline: Why You Need a Workplace Marijuana Policy.
In any case, not knowing or understanding the law doesn't mean an employer can choose whether to follow it. Thank heavens for lawyers who get paid to explain to client the state of the law and recommend sound policies and courses of action.
The article begins with "be familiar with the laws that have been passed in their states...."
You could try to find your state's laws on the subject; that might be sufficient to create a policy for any of your clients that employ people. Why not do that and track trends for your clients? Consider figuring out how every state handles this issue as a way to forecast the nation's feelings on marijuana law. Daunting? Of course. That's why you should see if someone (usually a law librarian) has done it for you!
Fifty-state surveys can be found in a number of places: Westlaw, Lexis, BloombergLaw, HeinOnline, the National Conference of State Legislators to name a few. And in this case, BloombergLaw (which you can access with the password you received when you started law school) offers a specific survey on medical marijuana laws in the employment context. Bloomberg Law's state
surveys can be found under the Practice Centers tab. Just pick the practice area
in which you are interested, then choose "BNA State Comparison
Charts" on the left, and you'll see what Bloomberg has to offer.