ANTIOCH (CBS SF) – Contra Costa firefighters were mopping up 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.

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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.

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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.

Earlier Saturday, at about 1:30 p.m., East Contra Costa Fire Protection District and CalFire firefighters responded to a grass fire off Armstrong Road, southwest of Byron Airport and east of Vasco Road.

Thirteen acres of grassland burned before the blaze was contained the East County fire district said. The cause of the fire had not been established by 6:30 p.m.

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Temperatures were expected to go down Sunday, which should make conditions for firefighters less challenging. But almost the entire region will remain under “red flag warning” during which fire danger is extremely high, bolstered by high temperatures, moderate winds and an abundance of dry fuels, including grasses.