VALLEJO (CBS SF) — The Vallejo Police Department lobby reopened Thursday afternoon following a carbon monoxide leak earlier in the day.

Police personnel noticed a rotten egg smell in the building around 5:30 a.m. and called the Vallejo Fire Department around 6:30 a.m., fire department spokesman Kevin Brown said.

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Crews determined the smell came from hydrogen and sulfur released by a bank of backup batteries used to maintain electric power until generators kick in. A by-product of the release was a low level of carbon monoxide, Brown said.

The Vallejo Fire Department posted photos of the operation on Twitter.

Five people in the building had low levels of carbon monoxide in their systems but quickly recovered, he said.

The building at 111 Amador St. is not served through a single ventilation system and only some rooms were affected by the smell, Brown said.

Police dispatch services were relocated to the Solano County Sheriff’s Office communications center to handle 911 calls, police said.

A county hazardous materials team was released from the scene at 11:45 a.m. and police reopened the lobby around 1:30 p.m.

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