Ranchers work to evacuate cattle as the Gifford Fire burns nearby on Monday in Los Padres National Forest, Calif. (AP Photo/Noah Berger)

SANTA MARIA, Calif. (AP) — More than 800 structures are threatened by a massive wildfire in central California that left at least three people injured as it burned through Los Padres National Forest.

The Gifford Fire scorched more than 129 square miles of coastal Santa Barbara and San Luis Obispo counties, with 7% containment, according to a U.S. Forest Service update on Tuesday morning.

More than 1,900 personnel are battling the blaze that grew out of at least four smaller fires that erupted Friday along State Route 166 between Santa Maria and Bakersfield. The causes of the fires are under investigation.

The blaze is burning through steep terrain and creating a huge smoke column, said Capt. Scott Safechuck, a spokesperson with the Santa Barbara County Fire Department.

“A lot of it’s in really inaccessible areas where even bulldozers can’t even get into,” Safechuck said, adding that aircraft is being added to the firefight.

The smoke will affect parts of Southwest California, the National Weather Service’s Los Angeles office said, noting that wildfire smoke is a health risk. Smoke was expected to move toward the south and east.

The blaze threatened about 872 structures and forced the closure of the highway in both directions east of Santa Maria, a city of about 110,000 people in Santa Barbara County. About 65 miles northwest of Santa Barbara and 150 miles northwest of Los Angeles, the hilly agricultural region is dotted by sprawling California live oaks and Sycamore trees and is known for its strawberry fields and wine industry.