Port Huron Firefighters say a 31-year-old was injured during an apartment fire Sunday morning at about 3:30 along Military. The blaze caused extensive damage to a four unit building at 2430 Military Street. Officials believe he was injured while fighting the fire with a garden hose prior to the fire department arriving. His injuries were described as minor. Investigations into the cause of the fire are continuing. The Marysville Fire Department was called for assistance and stood by at the Port Huron Fire Station.