SAN DIEGO—California's second largest city is considering regulating its more than 80 medical marijuana clinics caught in a legal cloud that some say has left the dispensaries vulnerable to raids and arrests. SAN DIEGO—California's second largest city is considering regulating its more than 80 medical marijuana clinics caught in a legal cloud that some say has left the dispensaries vulnerable to raids and arrests.

Under the proposed ordinance taken up by San Diego's City Council on Monday, pot shops—both existing and new—would be required to obtain a permit by the city planning commission and prove they are a nonprofit business.

They also would have their hours limited to between 7 a.m. and 9 p.m. and would be barred from doing business within 1000 feet of places of worship, parks, schools, playgrounds, libraries, child-care and youth facilities and other dispensaries.

Opponents say the proposed law is a de facto-ban on the pot clubs.

Ben Cisneros, of the nonprofit Canvass for a Cause, said the regulations will push clinics out to far-flung industrial zones patrolled by federal agents near the U.S.-Mexico border and other remote areas that are difficult to reach. More than 3,700 people have written to city officials asking for a less restrictive ordinance to ensure AIDS patients, veterans and others have access to medical cannabis, he said.

Cisneros said regulations should allow dispensaries within 600 feet of schools and not require approval by the planning commission if they are in commercial zones and there are no complaints. He also said keeping dispensaries more than 1,000 feet apart from each other limits them because so few landlords want to rent to the clinics because of the stigma.