Employers’ desires for a drug-free workplace have of late been at odds with the permitted use of medical marijuana in many states, and the employers are largely coming out ahead. But what happens when states legalize recreational use? In InsideCounsel’s February issue, we looked at the questions new marijuana laws have raised for employers, and how in-house counsel should proceed. Here we’ve summarized what counsel need to know, to set your minds at ease.

I’m just now crawling out from under the rock I call my home. What exactly happened?

Take a moment to adjust. It’s basically chaos out here, and marijuana legalization is no exception. It seems pretty simple on the surface—at election time in November 2012, voters in Washington state and Colorado voted to legalize the recreational use of marijuana.

But marijuana is still illegal under federal law. The Department of Transportation (DOT) said on Dec. 3, 2012, that these state laws would not count as an excuse for a positive drug test for employees in safety-sensitive positions, such as pilots and school bus drivers.

The Department of Justice has yet to say how these new state laws are going to affect its enforcement efforts, but Littler Mendelson Shareholder Nancy Delogu thinks it will continue to enforce federal law in places that sell or dispense marijuana, but leave individuals largely alone.

What does that mean for company drug policies? Should I panic?

Zero-tolerance drug policies should still be fine. So should drug testing programs. The courts have so far upheld employers’ rights to enforce drug-free workplaces, even if an employee is legally taking medical marijuana.

“Go ahead and enforce your zero-tolerance drug policies regardless of the reason for marijuana use, whether medical or recreational, without regard to the new state laws,” says Richard Meneghello, a partner at Fisher & Phillips.

However, employers in Arizona, Connecticut, Rhode Island and Maine should be careful. These states all have laws that require employers to accommodate medical marijuana, but though federal law may preempt those measures, none has yet faced a court test. Unless you want your company to be the test case, tread cautiously.

What about off-duty use?

In Colorado, employers cannot terminate employees for lawful conduct they engage in outside of the workplace during nonworking hours. It’s possible that employees could use that to argue that employers can’t ban workers from using now-legal recreational marijuana on their own time.

Washington doesn’t have an off-duty conduct law. Plaintiffs lawyers in the state, however, are already chomping at the bit to challenge employers. Fisher & Phillips Partner Richard Meneghello says he’s already seen a Washington plaintiffs lawyer quoted as saying it would be a “miscarriage of justice” to fire someone for legal recreational marijuana use.

Is there anything I should do right now?

In-house counsel of companies with operations in Colorado and Washington might want to revisit their policies and check the wording. Employers can continue to ban illegal drugs, but to avoid confusion among employees, policies might need to clarify that marijuana is still included.

Littler Mendelson Shareholder Nancy Delogu recommends saying something to the effect that all drugs “made illegal as a matter of federal, state or local law, including marijuana,” are banned.

As for drug-testing policies, employers should make clear that any amount of marijuana in a person’s system is unacceptable, as opposed to state Driving While Intoxicated laws, which may consider the presence of a low level of the substance as “unimpaired.”