SAN FRANCISCO (CBS SF) — A gas main break in the area of McAllister and Scott streets near Alamo Square Park Tuesday forced the evacuation of a half-block area for almost two hours, according to the San Francisco Fire Department.

San Francisco Fire confirms that the four-inch gas line was ruptured when a construction crew was digging into the street at the corner of McAllister and Scott Tuesday afternoon at about 3:07 p.m.

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About a dozen buildings in a half-block evacuation area around the intersection a block north of the northwest corner of Alamo Square Park have been cleared, according to authorities. San Francisco Fire and police personnel were going door to door to inform residents of the evacuation.

Authorities are asking that residents avoid the area.

As of 4:35 p.m., there was one reported exposure and 16 people displaced in the area.

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PG&E spokeswoman Andrea Menniti said PG&E repair crews were able to stop the flow of gas as of about 4:47 p.m. Three PG&E customers will be without gas as repairs are made.

Once the gas line was capped, the residents in the area who had been evacuated were allowed to return to their homes.

The 5-Fulton & 5R-Fulton Rapid San Francisco Municipal Railway bus routes were rerouted while crews worked to stop the leak, according to Muni officials.

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KPIX 5 has a camera headed to this breaking story and will provide more information as it becomes available.