SAN BRUNO (CBS 5) – City construction crews working on a sewer line accidentally damaged a natural gas line in San Bruno Tuesday afternoon, causing a leak that prompted the evacuation of about a half-dozen homes, Mayor Jim Ruane told CBS 5.

The rupture occurred just before 2 p.m., when construction workers digging on Chestnut Avenue near Jenevein Avenue struck a 2-inch steel-low pressure-distribution line, according to PG&E spokesman Andrew Souvall.

Houses in a two-block were evacuated for about 45 minutes as a precaution, the mayor said.

Most residents were not at home at the time of the leak, fire officials indicated.

PG&E crews managed to cap the line about 4 p.m., Ruane said.

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