As of this writing, marijuana is legal in 30 states. The District of Columbia, California, Colorado, Massachusetts, Nevada, Oregon, Vermont and Washington now permit adults over 21 to buy marijuana, no prescription * needed. A number of states have also decriminalized the possession of small amounts of marijuana.

Recreational pot became legal in California on Jan. 1. Frank Polizzi, public information officer for California’s Division of Occupational Safety and Health, says “Landscape contractors in California are required to prevent intoxicated employees from placing themselves or others at risk. This is pursuant to workplace safety regulations, regardless of the legal status of drugs or other intoxicants.”

Jennifer Grady is an employment and immigration attorney at The Grady Firm P.C., with offices in Southern California. She is also a partner attorney and member of the board of California Employers Association. (The opinions expressed are hers alone.) She advises updating your written drug and alcohol policies annually to comply with updates in the law and having them reviewed by a lawyer before they are distributed.

Rather than simply stating your drug and alcohol policy in a job application or employee handbook, Grady recommends having employees sign a standalone document that outlines the policies, expectations and circumstances under which they may be tested, along with potential consequences for policy violations. Always get an employee’s informed written consent before proceeding with drug or alcohol testing.

As an employer, you need to know exactly what the law in your state specifies and not make assumptions about what you think it says. For additional guidance, contact the National Association of Landscape Professionals, your state contractors’ association or your legal advisor.

* Since marijuana remains illegal under federal law, doctors can’t prescribe it. All they can do is write a recommendation.