(AP Photo/Jeff Chiu, File)

If you live in the District or one of the 23 states that have legalized marijuana, think twice before lighting a joint if you work for the federal government:

Pot is still illegal for you.

New guidance from the Office of Personnel Management on Wednesday is unambiguous and stern. Federal workforce rules remain unchanged for the roughly 4.1 million federal employees and military personnel across the U.S. The feds still consider marijuana an illegal drug, and possessing or using it is a crime.

“Heads of agencies are expected to advise their workforce that legislative changes by some states and the District of Columbia do not alter federal law, existing suitability criteria or Executive Branch policies regarding marijuana,” OPM Director Katherine Archuleta wrote in a memo posted on the agency Web site.

Read OPM’s guidance on marijuana use for federal employees

The District and 23 states have authorized adult use of medical marijuana. Of those, four states — Colorado, Washington, Alaska and Oregon — and D.C. also allow recreational use.

[In Washington state, a 10-person team toils for the government — selling pot]

Archuleta said these changes, a mix of ballot measures and laws passed by legislatures, have “raised questions” about whether federal employees in these areas are safe to smoke, although it is unclear what prompted her memorandum to executive departments and agencies now.

Marijuana became legal in the District, for example, in February, allowing anyone 21 and older to possess up to 2 ounces of pot, although the drug is still prohibited on federally administered properties such as the National Mall, Rock Creek Park and even public housing.

In other words, the 1986 executive order from President Ronald Reagan requiring the federal workplace and workforce to be drug-free remains in place, applying to medicinal as well as recreational use of marijuana.

The law makes “knowing or intentional” marijuana possession illegal for federal employees, even if they do not intend to manufacture, distribute or dispense it. Here’s a relevant part of the order:

“Executive Order 12564, Drug-Free Federal Workplace, mandates that (a) Federal employees are required to refrain from the use of illegal drugs; (b) the use of illegal drugs by Federal employees, whether on or off duty, is contrary to the efficiency of the service; and (c) persons who use illegal drugs are not suitable for Federal employment.  The Executive Order emphasizes, however, that discipline is not required for employees who voluntarily seek counseling or rehabilitation and thereafter refrain from using illegal drugs.”

Marijuana use also can be a basis for firing in some situations, Archuleta wrote.

The order requires the federal workplace and workforce to be drug-free. It includes especially strict rules for personnel who either hold security clearances or apply for them.

The 1986 directive “expressly states that use of illegal drugs on or off duty by federal employees in positions with access to sensitive information may pose a serious risk to national security and is inconsistent with the trust placed in such employees as servants of the public.”

Most random and routine drug testing within the federal workforce occurs with jobs related to national security and law enforcement, while other employees are generally tested only when supervisors have reasonable suspicion that they’re using drugs at work.

Practically, the government may have a hard time enforcing its rules for other employees, since many agencies do not give them regular drug-tests.

Even outside the federal workforce, the U.S. government has refused to relax its marijuana regulations. For instance, medical pot has been legal in the District of Columbia and several states for years, but the Department of Veterans Affairs will not prescribe the drug or complete paperwork for patients to enroll in state marijuana programs, despite heavy lobbying from veterans suffering from post-traumatic stress and physical pain.

Archuleta’s memo does note that the federal government offers prevention, treatment and rehabilitation programs for civilian employees with drug problems.