SAN FRANCISCO (CBS/AP) – The Board Of Supervisors Tuesday unanimously approved a measure raising the legal age to purchase tobacco products within San Francisco’s city limits to 21 years old.

San Francisco now joins Boston, New York City and Hawaii and more than 100 U.S. cities in raising the minimum age to buy cigarettes, e-cigarettes and other tobacco products. The law goes into effect June 1.

A proposal to change the tobacco-buying age from 18 to 21 stalled in the California Assembly last fall.

The issue has gained traction nationally as lawmakers try to discourage young people from starting to smoke, especially the popular e-cigarettes. A report last year by the Institute of Medicine found that 90 percent of daily smokers first tried a cigarette before 19.

Opponents argue that since California law sets a minimum age of 18 for tobacco, that provision prohibits municipalities from setting a higher limit.

Healdsburg has suspended enforcing its new tobacco age limit of 21 after a national tobacco retailer group threatened to sue. Santa Clara County, on the other hand, is enforcing its tobacco ban for those under 21 in unincorporated areas.

Meanwhile, San Francisco’s city attorney called the ordinance legally sound.

Thomas Briant, executive director of the National Association of Tobacco Outlets, has urged San Francisco to hold off on voting until the state attorney general can issue a decision. He said 18-year-olds are adults when it comes to voting, serving in the military or signing a contract — and smoking should be no different.

California residents 18 and older can obtain a medicinal marijuana recommendation from a licensed physician, buy and possess up to a half a pound of marijuana, as well as grow plants for personal consumption.

Attorney General Kamala Harris has no legal opinion pending, a spokeswoman said.

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