Firefighters kept busy over the holiday weekend.

The St Joseph Fire Department responded to an apartment fire at 2209 Union Street just after midnight Saturday morning. Authorities say the fire caused extensive damage to the basement and first floor of the structure.

An investigation into the cause of the fire continues. The Red Cross is lending assistance to more than a dozen residents. A St Joseph firefighter was treated and released at Heartland Regional Medical Center for heat exhaustion.

Early Sunday morning, city fire crews were dispatched to an area just south of the city limits to a fire reported in a vacant structure in a mobile home park. Firefighters responded shortly before 2am to 2635 Southwest Kathy Lane, lot #46.