San Francisco Mayor Gavin Newsom has signed a bill that bans the sale of tobacco in pharmacies. He says the city is the first in the United States to take this step.

The measure, proposed by Newsom and approved by the city's Board of Supervisors, amends the health code to prohibit tobaccos sales in drug stores of all sizes. However, pharmacies located inside of "big box" retailers or grocery stores are exempt.

Starting Oct. 1, a store that violates the ban is subject to administrative penalties by the city's director of public health. Businesses also can be criminally cited and face fines ranging from $100 to $1,000.

In a statement issued Tuesday, Newsom says, "Pharmacies should be places where people go to get better, not where people go to get cancer."