COLUMBIA, MO -- Fires kept Columbia firefighters busy Thursday, especially at two particular locations.

At about 8:40 a.m., crews were called to the Denny’s restaurant on Knipp Street. When they arrived, smoke was inside the building and customers were making their way out.

Investigators determined a malfunction in the gas water heater caused the fire, which did about $10,000 in damage.

And there was a close call in the afternoon at an apartment complex.

Firefighters responded to Broadway Townhomes on Green Valley Drive for a large grass fire.

Flames reaching six feet in the air were making their way toward the apartments, but crews extinguished them within 20 feet of reaching the buildings.

Investigators found used fireworks near the scene. They haven’t determined if that was the cause, and no one saw the start of the fire to help confirm the fireworks were to blame.