MASON CITY | Officials believe a block heater sparked a blaze that damaged a semi-tractor parked at a Mason City recycling center on Saturday.
The fire broke out about 9 p.m. in a semi-tractor parked at Alter Metal Recycling, 2200 S. Pierce Ave.
A block heater connected to the vehicle's engine is believed to have started the blaze, said Mason City Fire Department Capt. Richard Paulson.
The tractor appeared to sustain significant damage.
No one was in the vehicle at the time of the fire.
-- Molly Montag