Fire investigators are trying to determine the cause of a brush fire which caused a big scare in Ventura County.
The 20 plus acre fire broke out just after 4 p.m. Wednesday off of Olsen Road in Simi Valley, just west of Wood Ranch Parkway.
It sent a huge plume of smoke into the sky, burning a rugged hillside near the Ronald Reagan Presidential Library.
Some 150 firefighters aided by helicopters and air tankers contained the blaze in a little over two hours. No structures were damaged.
