Hawaii County fire investigators are trying to find out what caused a fire that destroyed a makeshift trailer home on a construction site in Keaau early this morning.

Firefighters responded to a 3:32 a.m. alarm and found a 9-foot by 14-foot trailer home fully engulfed in flames when the arrived at the address on Moano Street in the Eden Roc subdivision.

The structure collapsed as firefighters battled the blaze, which was under control at 3:56 a.m.

There were no injuries. Damage is estimated at $1,400.