San Francisco has imposed a 45-day pause on approvals for new data centers and expansions of existing ones. The Board of Supervisors voted unanimously Tuesday to adopt an urgency ordinance that took effect immediately.

The measure makes San Francisco the first Bay Area county to enact a temporary data-center moratorium. It stops approval of permit applications while the city examines the facilities’ effects.

District 10 Supervisor Shamann Walton proposed the pause amid concerns about energy and water use, noise and possible water contamination. He said the city would study air quality, land use and neighborhood impacts, and work on clearer rules and opportunities for community input. More than a dozen people spoke in favor of the measure at a committee meeting Monday.