As we all know, a growing number of states have legalized marijuana use to varying degrees. In some states, medical marijuana is permitted, but not recreational. In some states, anything goes. In some states, including New Jersey and New York, even testing for marijuana is illegal in most circumstances. And we still have states where use of marijuana is illegal. (As of today, marijuana is still an illegal drug under federal law. Legislation to legalize it at the federal level is pending, but its fate is not clear.)

If an employer has operations in multiple states, chances are good that its obligations will be different in different locations.

(One of the downsides to federalism -- a founding principle of our nation that I respect -- is that it is a nightmare for employers who have operations across different states, and marijuana is nowhere near the only issue. I'm going to take this opportunity to propose that Congress enact a "Uniform Multi-State Employment Law Act," which would allow employers in multiple states to follow the same rules in all states in which they operate. The UMSELA would preempt any state or local employment laws to the contrary, but only with respect to multi-state employers. Single-state employers would have the option of following the UMSELA or, if they prefer, the laws that apply in their individual states.)

Anyway, back to reality. There is no UMSELA (at least, not yet), and it may not even be constitutional. So what are the options for an employer who operates in "legal-marijuana" and "illegal-marijuana" states, and in addition may have to comply with federal law?

Option One: Lowest common denominator. Even in states where marijuana is illegal, employers are not required to test for marijuana or to prohibit recreational use. So one option would be to simply stop testing for marijuana anywhere unless there is reason to believe an employee is under the influence while at work. (This is allowed -- at least in theory -- even in the states where testing for marijuana is generally illegal.) In other words, treat marijuana use the same way you treat alcohol use. Exceptions would have to be made for employees who must be tested under federal law, including the regulations of the U.S. Department of Transportation that apply to holders of Commercial Drivers' Licenses.

Option Two: Keep it complicated so you can be as weed-free as possible. The other option is to allow marijuana use only to the extent permitted by applicable law. A lot of employers are choosing to do this. I'd flat-out say in the policy that the company does not condone the use of marijuana but intends to comply with applicable law in the jurisdictions where it does business. As a result, the company's substance abuse policies will be different depending on where the employee works. At this point (I think), there should be four categories of marijuana states:

Where marijuana is illegal, continue to test as you see fit. Pre-employment, reasonable cause, post-accident*, random for all or random only for safety-sensitive positions, post-rehab. As long as you are consistent and keep an eye on the latest from your state legislatures, you should be fine.

*Reasonable minds (and the laws in the various states) differ, but I do not favor post-accident testing unless there is reason to believe that the employee you are testing may have been at fault in the accident. 

Where medical use only is legal, same as above. But be sure that the medical history taken by the testing vendor or Medical Review Officer asks the individual to disclose whether he or she is using marijuana legally because of a medical condition. If an individual in a medical marijuana state tests positive for this reason (and presents appropriate documentation), then begin the "interactive process" required by the Americans with Disabilities Act* to determine whether the individual can safely perform the job and, if not, whether there are reasonable accommodations that can be made to allow him or her to perform the job. And, of course, if accommodations can be made, then make them.

*The ADA does not apply to "current" users of illegal drugs, which includes marijuana because it is illegal under federal law. But in a state where medical marijuana is legal, I'd still follow the ADA interactive process in determining whether the individual can safely and competently perform the job -- or another vacant job. Failure to do so could result in liability under the applicable state disability discrimination law.

Where all marijuana use is legal, follow the "Lowest Common Denominator" approach described above. OR, if your employees are not in a state that prohibits marijuana testing, take a hard line on recreational use while following the "medical marijuana" option described above for anyone who is legally using marijuana for a medical condition.

Where all marijuana use is legal and testing for marijuana is against the law, follow the "Lowest Common Denominator" approach in all cases.

And, of course, employers who adopt the "complicated" approach would still have to follow any marijuana-related requirements -- including prohibitions -- that apply under federal law, including DOT regs.

Oh! And one other thing. What about new hires or employees who test positive for marijuana but fall into one of these categories?

• Live in a "legal-marijuana" state but have been hired for a position in a "illegal-marijuana" state?
• Are transferring within the company from a position in a "legal-marijuana" state to a position in an "illegal-marijuana" state?
• Go on vacation to a "legal-marijuana" state, smoke weed legally while there, and then return to work, only to have the bad luck to be selected for a random test?
• Live in a state where marijuana use is legal but work in a state where it is illegal?

I told you it was complicated!

With the first two, I'd create an "acknowledgement" document saying that the new hire/employee understands that marijuana use is illegal in the "destination" location and ask them to certify that they agree to comply with all applicable marijuana laws upon relocation or transfer. If they won't agree to that, then I would not let them take a position in the "illegal-marijuana" state. But in the case of a current employee who was being considered for transfer, he or she should still be allowed to stay in the current position in the "legal-marijuana" state.

If the new hire or transferring employee is currently in a state where even testing for marijuana is illegal, then I don't know what to tell you. You might be able to fly them in to the "destination" state and do the testing there. But don't wait until they take the job (and actually relocate or transfer) before testing.

With the employee who indulges while on vacation in a legal-pot state, being the nice person I am, I'd be inclined to confirm the vacation plans and the laws in the state where the vacation was taken, let the employee return to work as scheduled unless there is a safety concern, and then re-test in 4-5 weeks. If the re-test is negative, I'd let it go. If the re-test is positive after that much time, then it is likely that the employee is still a current user. In that case, I'd treat the employee the same way as any other employee in the "illegal" state who tests positive for marijuana.

I'm not sure about the employee who lives in a "legal pot" state and works in an "illegal pot" state, assuming the employee uses marijuana only at home, where it's legal. I might go with the Lowest Common Denominator option (let them do their thing at home, but reserve the right to test if required by federal law or if the employee appears to be under the influence while working). I am open to other suggestions.

I have to end with a huge "hat tip" to the excellent Greg Giangrande of the New York Post, who has a weekly Human Resources advice column. One of his questions this week was about employers who have operations in legal-marijuana/no-testing and illegal-marijuana states, which was the inspiration for this blog post.