BANNING, Calif. -

The four-day-old Silver Fire, which has destroyed 26 homes, injured 10 people and forced hundreds from their residences, grew to 19,000 acres on Saturday morning, but fire crews were able to make good progress containing the blaze while some residents were allowed back into their neighborhoods.

The blaze, which broke out for unknown reasons on Poppet Flats Road south of Banning at 2:05 p.m. Wednesday, was 70 percent contained as of late today.

At 6 p.m., the Riverside County Sheriff's Department lifted evacuation orders for the communities of Snow Creek, Cabazon, Mt. Edna and Poppet Flats. Evacuation orders for Twin Pines and Silent Valley remained in effect, and Highway 243 was closed north of Poppet Flats Road to Wesley Street in Banning.

More than 2,100 firefighters were deployed on the fire lines, along with about 200 engines and eight helicopters.

A civilian injured Wednesday in the area where the fire started was taken by air to a burn center suffering from severe burns, Riverside County Fire Department Chief John Hawkins said.

Two firefighters suffered heat exhaustion and were ordered to be off duty for 72 hours, Hawkins told reporters at a Thursday afternoon news conference in Beaumont. Information on the extent of the injuries to three other firefighters was not specified.

Fire officials said 26 homes, one commercial structure and 21 outbuildings were destroyed and two homes were damaged.

Evacuation centers were set up at Hemet and Beaumont high schools. The San Jacinto Valley Animal Campus was opened for evacuated pets.

Gov. Jerry Brown declared a state of emergency in Riverside County in response to the fire, freeing state resources to aid in the battle.

Hawkins said that on Wednesday, the fire spread rapidly from its point of origin near Wolfskill Truck Trail and Old Idyllwild Road, destroying homes in Twin Pines. The fire marched nine miles from its starting point, and moved east toward Snow Creek in the Cabazon area, he said.

Smoke from the fire was reported in downtown Palm Springs and around the Coachella Valley in the middle of the week. The South Coast Air Quality Management District warned that children, seniors, people with heart or lung disease and other vulnerable groups should minimize outdoor activity in areas where smoke can be seen or smelled.