(CNN) -- The wildfire that scorched thousands of acres and destroyed dozens of homes in Southern California this week apparently was started by a power tool clearing brush in the area, fire officials said Sunday.
Residents return Saturday to neighborhoods evacauted because of a California wildfire.
The fire started near a trail in the Santa Barbara, California, area and appears to have been "related to the use of power tool equipment involved in vegetation clearance," according to the multi-agency group fighting the fires.
Authorities are looking for someone who may have been clearing brush on Monday and Tuesday.
The blaze is 55 percent contained and most of the 50,000 residents and business owners who last week fled the Jesusita Fire near Santa Barbara, California, returned by Sunday afternoon, officials said Sunday.
The Jesusita 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.
Mandatory evacuation orders were downgraded to evacuation warnings, the team said in a news release. Portions of three roads and Highway 154 remained closed.
Eighteen firefighters were injured, a spokeswoman for the team said, but most of the injuries weren't serious.
Area temperatures hovered Sunday in the high 60s with winds between 3 mph and 7 mph, according to the National Weather Service.
"All of those together really gave us the opportunity to get in there and make a difference," Fire Chief Tom Davis of Santa Barbara County said Saturday. Watch how residents wait to return to homes »
The cause of the fire was unknown.
The blaze comes about six months after another wildfire, the Tea Fire, destroyed about 200 homes in the area.