Firefighters were called to the fire in an apartment complex at 2301 Sycamore Drive at around 9 p.m., a dispatcher for the Contra Costa County Fire Protection District said.
The fire was under control by 9:37 p.m., but six units were damaged by the blaze and two others sustained heavy smoke damage.
The residents of those units were displaced; the total number of displaced residents was not immediately available.
One person was injured and taken to a hospital by a family member but the extent of their injuries was unknown this morning.
The cause of the fire remains under investigation. The damage to the building is estimated to be around $600,000.