According to the Contra Costa Times, one of the fires occurred at a senior apartment complex equipped with a sprinkler system. By the time firefighters had arrived, sprinklers had doused the flames. The fire alarm and sprinklers "had operated as designed and averted what would have been a certain tragedy," according to a statement by the Contra Costa County Fire Prevention District that was mentioned in a news story on Patch.
The other fire occurred later in the day in an unsprinklered home and injured a resident who was trying to fight the fire before escaping the premises with four other family members. Though the fire was contained to one room, the Contra Costa Times reports that significant smoke damage had occurred.