(CNN) -- The wildfire that has scorched thousands of acres and destroyed dozens of homes in Southern California for almost a week apparently was started by a power tool being used to clear brush in the area, fire officials said.
Residents return Saturday to neighborhoods evacauted because of a California wildfire.
The multi-agency group fighting the fires announced Sunday that the fire started near a trail in the Santa Barbara area and appears to have been "related to the use of power tool equipment involved in vegetation clearance."
Authorities are looking for someone who might have been clearing brush this past Monday and Tuesday.
Most of the 50,000 residents and business owners who last week fled the Jesusita Fire had returned by Sunday afternoon, and the blaze was 55 percent contained, fire authorities said. The estimated day of containment is Wednesday, according to Derek Johnson, a spokesman for Santa Barbara County.
The fire has burned nearly 9,000 acres and destroyed or damaged about 80 homes and other buildings since it began Tuesday, according to the team coordinating firefighting efforts. Damages and the cost of the efforts were estimated at $9 million.
Mandatory evacuation orders were downgraded to evacuation warnings, the team said in a news release earlier Sunday. Parts of three roads and Highway 154 remained closed. Watch how residents wait to return to homes »
Twenty-eight firefighters had been injured, according to Johnson. Earlier, when only 18 firefighters were reported hurt, a spokeswoman for the coordinating team had said that most of the injuries weren't serious.
Area temperatures hovered Sunday in the high 60s, with winds from 3 mph to 7 mph, according to the National Weather Service. High temperatures, strong winds and low humidity had made the blaze hard for firefighters to bring under control.
The blaze comes about six months after another wildfire, named the Tea Fire, destroyed about 200 homes in the area.