Security-cost details for the mayor and district attorney, along with visiting dignitaries, may become public knowledge if voters approve a ballot measure in June.

The measure, sponsored by Supervisor Ross Mirkarimi, would require the Police Department to disclose how much money is spent on security for dignitaries and elected officials.

The Board of Supervisors Rules Committee approved the measure for the ballot Thursday and it will be sent to the full board, where it’s expected to be endorsed.

Police Chief George Gascón said he’s concerned that this measure would “handcuff the Police Department” and force it to later justify how much money is spent protecting elected leaders.

“We have elected officials who become the targets of extremist groups,” Gascón told the Rules Committee. “It’s hard for us to predict how much money we spend every year for protection.”

The committee disagreed, saying the ordinance would not cap the money spent on security but instead would provide some transparency when it comes to paying for a security detail.

“This is about principle, about sunshine and transparency,” Mirkarimi said. “Nothing we are talking about compromises dignitary security.”

A second measure, a policy statement sponsored by Mirkarimi and Supervisor David Campos, would ask voters to allow San Francisco to tax and regulate the cultivation of marijuana. The committee also was set to decide on a third measure, requiring a community-based foot beat policing program. But Mirkarimi, who sponsored the legislation, said he was willing to withdraw the measure for the June ballot and instead have further discussions with the police chief and community.

esherbert@sfexaminer.com