VENTURA, Calif. — Firefighters battled a wildfire Wednesday in chaparral and grasslands on Santa Cruz Island off the coast of Southern California, officials said.

The fire grew to about 250 acres (101 hectares) after escaping Tuesday from a prescribed burn that had been set earlier in the week, Channel Islands National Park spokeswoman Yvonne Menard said from the park’s mainland headquarters in Ventura.

The blaze began in the isle’s central valley near a historic main ranch on property of The Nature Conservancy, which owns most of the island and manages it cooperatively with the national park.

The 96-square-mile (248-square-kilometer) island is the largest in the chain of eight Channel Islands, five of which are in the national park.

The island’s central valley has been the hub of past ranching operations dating back to the mid-1800s. Near the main ranch are other buildings including a historic chapel as well as facilities of a University of California, Santa Barbara field station.

Fire protection measures were in place and no buildings had been damaged, Menard said.

Menard said there have only been four previous fires in the central valley in the past 25 years. Rainfall this season has been less than half the normal amount, like much of Southern California.

The island has a vast array of natural and cultural resources: Santa Cruz was once home to a large population of indigenous people who first met European explorers in the 16th century. It passed through Spanish and Mexican hands before U.S. control.

It also has important fossils and unique plants and animals.

The flames were battled by air tankers from a mainland base and firefighters from the National Park Service, Los Padres National Forest and Santa Barbara County.

More firefighters were being summoned from Sequoia and Sierra national forests, along with the Mesa and Carson hotshot crews from the Southwest, Menard said.