The 43,400-acre Soberanes Fire, which has destroyed 57 homes in the Big Sur area and killed one person, was caused by an illegal campfire that was not fully put out, authorities said Tuesday.
The fire started the morning of July 22 in Garrapata State Park and is only 18 percent contained after burning more than 67 square miles.
More than 5,400 personnel are responding to the blaze, which is continuing to burn in the steep and rugged terrain of the scenic Central Coast.
Threats remain to Palo Colorado, Bixby, White Rock, Rancho San Carlos, Cachagua, Tassajara, Jamesburg and the communities in the greater Carmel Valley area. Major power lines are also threatened, as are endangered species and area watersheds, Cal Fire said.
At a news conference Tuesday afternoon, Cal Fire officials announced that an illegal, abandoned campfire sparked the massive wildfire.
The fire was left in a pit about 2 1/4 miles up the Soberanes Creek Trail from Highway 1, television station KSBW in Salinas reported.
On Twitter, Cal Fire spokesman Daniel Berlant warned people to always extinguish campfires.