ANTIOCH (KRON) — A firefighter was injured while responding to a two-alarm fire in Antioch this morning according to a fire spokesman.

The fire started around 8:40 a.m. at the Mira Vista Hills apartment complex in the 2200 block of San Jose Drive just south of state Highway 4.

By the time fire crews arrived, one apartment was burning and another was threatened by spreading flames, Contra Costa Fire Protection District Fire Marshal Robert Marshall said.

Crews had the fire under control by 9:09 a.m., but not before two apartments were damaged. Two other units sustained water damage, Marshall said.

One firefighter was injured when he either fell off the roof or some roofing materials fell on him, Marshall said.

No other injuries were reported. Investigators still don’t know how the fire started or how many people lost their homes.