OLYMPIA – Under pressure from the federal government, the state agency trying to develop regulations for legal marijuana stores is again changing a rule regarding how far they must be from schools and playgrounds.

Stores selling recreational marijuana to adults must be at least 1,000 feet away from those and some other locations that attract children, as measured in a straight line between the boundaries of the two properties.

Last week, in announcing the latest round of rule changes that put limitations on businesses that would grow, process or sell marijuana, the state Liquor Control Board tentatively approved a rule that would measure that 1,000 feet along “the most common path of travel.” It was the system the board used for liquor store licenses, and could have resulted in stores being closer to schools.

U.S. attorneys for Eastern and Western Washington earlier this week warned Gov. Jay Inslee that they would enforce the straight-line standard, sometimes called “as the crow flies.” A recent memo from the U.S. Justice Department said failing to keep the drug away from minors is one of the things that could cause its agents to enforce federal laws, which still list it as an illegal drug for all uses.

Rick Garza, agency executive director, said the board used the emergency rule process for the change so potential applicants would know about it as they look for locations and prepare to seek licenses, which might be available in mid-November. Stores aren’t likely to be open until next June.