KERNERSVILLE, N.C. -- A firefighter was hurt while fighting a house fire earlier today (Jan. 14).

Kernersville Fire Chief Walt Summerville said the firefighter suffered back and shoulder injuries when a portion of a house collapsed on him when an explosion occurred. The firefighter was treated at and later released from Forsyth Medical Center.

The fire broke out at 1389 Union Cross Road at 1:52 a.m. Wednesday. The explosion and partial collapse occurred shortly after firefighters entered the burning single-story house to search for people reportedly trapped inside. The seven people living there got out without injuries.

Summerville said the town's fire marshal believes the blaze started in the chimney. The residents had burned a fire in the fireplace Tuesday night. The fire marshal is still trying to determine the cause of the explosion. Summerville said investigators expect to find no "sinister" cause.

Kernersville police closed a portion of Union Cross Road near Old Salem Road/Sedge Garden Road until about 9 a.m. today because water used to fight the fire caused the street to freeze.

Firefighters from the Winston-Salem, Beesons Crossroads and Union Cross fire departments helped fight the fire.