The Skirball Fire in the Bel Air area was caused by an illegal cooking fire at a nearby encampment, the Los Angeles Fire Department said.

Fire officials released a statement on Tuesday, saying investigators have determined that the blaze was caused by an illegal cooking fire at an encampment in a brush area adjacent to where Sepulveda Boulevard crosses under the 405 Freeway.

The Skirball Fire burned 422 acres of grass and brush, destroyed six homes and damaged 12 others in the Bel Air area.

The fire is currently 85 percent contained with 69 fire personnel still working on scene to achieve 100 percent containment, LAFD officials said.