SAN JOSE, Calif. -- A four-alarm fire raced through an historic IBM plant early Saturday, collapsing walls and destroying the two-story structure before it was brought under control by 85 firefighters.

San Jose Capt. Anthony Pianto said the blaze was fire reported at 1:30 a.m. and quickly was escalated to four alarms.

Firefighters pumped water on the blaze and had surrounded the building and its six wings, located on Concord Drive between Cottle Road and Hayes Avenue.

"We have taken a defensive position," Pianto said of the effort.

The fire was controlled at 9:45 a.m. after firefighters fought it for about eight hours, Pianto said.

The 69,000-square-foot building was eligible for the National Register of Historic Places, an attorney who has been trying to preserve the structure said.

"Hopefully they saved part of it," said attorney Susan Brandt-Hawley, who specializes in environmental and preservation law. "There is no dispute about its historic importance."

Building 25 is historic for its association with inventions and advances in information storage technology, association with scientists individually significant for their research and advancements in the field, for its modern architecture, and for its connection with IBM, according to Brandt-Hawley.

In addition to the National Register of Historic Places, the building, which has five wings, also is eligible for the California Register of Historical Resources, and as a city landmark, said Brandt-Hawley, with the Brandt-Hawley Law Group.

IBM occupied Building 25 around 1957 and vacated in 1996, said company spokeswoman Colleen Haikes.

In 1956, construction started on the 190-acre Cottle Road Campus. Building 25 was the fourth to be built. A year after construction started, the modernistic single-story building became home to the San Jose Research and Development Laboratories, according to IBM's Web site.

Modern architect John Bolles collaborated with landscape architect Douglas Baylis as well as several prominent artists in designing the building and the IBM campus, Brandt-Hawley said.

The disk drive was created at one of IBM's buildings in San Jose, however that particular building was not damaged in the fire.

The cause of the fire is unknown and damage estimates have not been released. No injuries were reported.

IBM is headquartered in Armonk, N.Y.