Veterans Affairs employees can still be fired for using marijuana even in states where the drug is legal, department officials said in a new message sent out to employees this week.

The memo, described as a “self-explanatory, simple reminder” by VA leadership, applies to all department staffers and was signed by VA Secretary Robert Wilkie. It specifies that employment with the department requires that workers “refrain from using illegal drugs on and off duty,” including marijuana.

“There is no legitimate medical explanation for a marijuana positive test result, other than a verified prescription of certain FDA-approved drugs,” the message stated. “A prescription for medical marijuana is not an acceptable medical explanation for a positive drug test.”

VA officials would not comment on the timing of the message and whether they have seen an increase in positive drug tests in recent months. They also did not say if there are planning any changes in drug testing for employees.

The message comes as cannabis advocates continue to push VA officials to broaden testing of the drug for a variety of service-connected injuries and conditions. Currently, 34 states allow cannabis for medicinal uses. Only 10 states have not adopted some legal use of the drug. [Read more at Military Times]