A vacant mobile home caught fire Wednesday afternoon and the cause is still undetermined. Shortly after noon, Ontario Fire and Rescue responded to a fire at the 700 block of Sugar Avenue, where a mobile home was fully engulfed. No one was inside the trailer home at the time the blaze erupted and no injuries were reported. Ontario Fire and Rescue Chief Terry Leighton said he suspects the cause of the blaze is electrical, though it’s not officially determined.