A year ago, we wrote about employees' and employers' rights when it comes to medical marijuana. And since then, two more states have legalized medical marijuana, and three (along with D.C.) have legalized recreational use. While your right to create and uphold a drug-free policy was clear back then, courts in Colorado and Rhode Island are now considering workplace discrimination lawsuits. What exactly is legalized and protected in each of these states is also different, and sometimes ambiguous. It's getting hazy out there.

Here are five things you need to know as an employer.

1. Federal Law (Still) Says No:

One thing has remained clear: weed is still illegal on a federal level. If your business receives federal funding, that trumps your state's marijuana laws. The same goes if your employees are involved in transportation (from truck drivers to ship captains to aircraft maintenance personnel). Those workers (and their employers) answer to the Department of Transportation - which recently reiterated its no-doobies-for-drivers rules for both medical and recreational marijuana.

2. The Patchwork:

The laws in the twenty-three states - and D.C. - with legalized medical marijuana are all different, ranging from how much an individual can grow at home (four plants in Montana, a dozen in Oregon...) to acceptable ways to imbibe (New Yorkers aren't actually allowed to smoke weed--edibles and vapor only).

When it comes to the workplace, there's just as much variation. While no state says employees can be stoned on the job (we'll come back to that shortly), different laws give employers and employees different rights. In Rhode Island, employers are specifically prohibited from discriminating against an employee for his or her pot prescription. In Massachusetts, employers aren't required to change their drug policies to "accommodate" medical marijuana, while Colorado employers have to tolerate everything except the "use, consumption, possession, transfer, display, transportation, sale or growing of marijuana in the workplace."  

You get the idea. It's vital to make sure you're familiar with the laws in your state, and that any policies your company has is consistent with them - but even that might not be enough.

3. The Challengers:

Currently, medical marijuana is not protected under the Americans with Disabilities Act, meaning an employer can theoretically fire an employee because of his or her prescription. However, that's now being challenged.

In Rhode Island, the ACLU recently filed a suit on behalf of Christine Callaghan, who was turned down for a job after mentioning her prescription for marijuana to deal with debilitating migraines. Rhode Island's law specifically protects pot prescription holders from employment discrimination, but the argument doesn't stop there: the ACLU also argues that discriminating against the treatment is a kind of disability discrimination.

Meanwhile, Colorado's Supreme Court is trying to work out where company policy stands between state and federal law. Dish Network fired customer service rep Brendan Coats after a drug test found inactive THC in his system. On one side, Dish has a strict no-drugs-ever policy, and pot is still illegal on a federal level - but on the other side, marijuana use is legal in Colorado both by prescription and for recreation. Colorado also has a law that says employers can't fire workers for legal activities they do off-the-clock. Adding to all the confusion is the question of what "off-the-clock" even means: Dish's lawyer argues that, even though Coats wasn't high at work, the benefits of his pot use (he's paralyzed from the chest down, and has a prescription to control muscle spasms) still extended into work hours. Not surprisingly, the Colorado court has been mulling this one over since September.

4. Safety First:

With cases like these popping up around the country, what's an employer to do? The Labor Law Center and Forbes

5. We Can Help:

In recent years, marijuana's legal status has been changing rapidly and unevenly around the country. It's important that you keep up with these developments, and make sure that your business' policies are up to date. It's also key that you protect your business if a suit does come up - and that's where Employment Practice Liability Insurance (EPLI) comes in. Talk to us about how best to protect your business - and of course, we'll keep an eye on this as it develops, too. We're here to help you avoid getting dazed and confused.