OAKLAND (CBS SF) — Firefighters will make a final sweep Monday at the scene of the 20-acre East Bay Hills vegetation fire “to make sure we are at 100 percent containment,” a battalion chief said Sunday.

The fire, which was reported at 1:05 p.m. near Grizzly Peak Boulevard and South Park Drive Wednesday, is presently 90 percent contained, Oakland fire Battalion Chief Melinda Drayton said.

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Firefighters from the Oakland Fire Department and the East Bay Regional Park District Fire Department are patrolling the area today, Drayton said.

Half of the fire was on Oakland land in the hills and half of the fire was on land owned by the Lawrence Berkeley National Laboratory that’s mostly in Contra Costa County, fire officials have said.

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University of California at Berkeley police spokeswoman Sgt. Sabrina Reich said on Thursday that the fire is being considered as a possible arson but Drayton has declined to comment on that, saying that Cal Fire is the lead investigative agency looking into the cause and origin of the fire.

Cal Fire Battalion Chief Mike Martin said at the scene late Thursday afternoon that the only thing he can say is that there’s an open investigation into the fire and the probe could take days, weeks or even months.

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