Contra Costa firefighters were still working a 10-acre fire south of Antioch tonight that damaged six buildings and several cars, and sent two people to the hospital with smoke inhalation, a Contra Costa County Fire Protection District captain said. It was the most significant of several fires near Antioch Saturday, a day when several triple-digit temperatures were recorded in the eastern reaches of the Bay Area. A two-alarm fire in the 4300 block of Deer Hill Lane in southeast Antioch, about a quarter-mile south of the Kaiser Permanente hospital on Deer Valley Road, appears to have started about 5:12 p.m. as a car fire, but by 5:30 flames had started spreading to structures, several vehicles in a nearby salvage yard and "various piles of combustible materials," said Contra Costa County Fire Protection District Capt. Lisa Martinez. Firefighters from the that department, as well as the East Contra Costa Fire. Protection District and CalFire, helped contain that blaze. Martinez said the fire had not been completely extinguished by 8:45 p.m. "They have a tank that will hold 2,000 to 3,000 gallons of water and we are refilling engines with that water that is being trucked in," said Contra Costa County Fire Captain Lisa Martinez. Two people, a man and a woman, were taken to a nearby hospital for treatment of smoke inhalation, Martinez said. No firefighters were injured, but their job was made more challenging not only by dry conditions and 100-degree temperatures, but by a lack of hydrants nearby that forced firefighters to use water tankers.