LIVERMORE – A massive fire that destroyed a barn and a cottage at the Washburn-Norlands Living History Center was caused by a lamp used to provide warmth for a litter of newborn piglets, fire investigators said Tuesday.

The fire lit up the night sky and could be seen from miles away, and it took firefighters from 10 communities to quell the blaze after it was reported at 9 p.m. Monday.

The fire swiftly engulfed the entire barn, spread next door to the cottage and threatened the rest of the structure including the mansion, prompting volunteers to scramble to remove family heirlooms, said Mitch Thomas, a trustee and treasurer.

A backhoe that seemed to appear out of nowhere was used to pull the cottage away from the mansion and save it from destruction, Thomas said.

“It was brilliant. I am in awe,” said Thomas. The backhoe operator managed to avoid putting even a scrape on the mansion, he said.

Norlands is the ancestral home of the Washburn family, which included governors, members of Congress, a secretary of state and a Civil War general. The 445-acre property is now a museum and working farm that includes a schoolhouse, church and library.

This wasn’t the first fire to strike Norlands. In 1987, an arsonist set fire to the one-room schoolhouse, which was a total loss. It was rebuilt.

Unlike in 1987, this fire was deemed to be an accident, caused by the lamp used to keep a pig and her piglets warm, said Sgt. Joel Davis, an investigator from the State Fire Marshal’s Office.

In the end, several farm animals, including the pigs and a couple of chickens, were killed and lots of old donated farm equipment was destroyed, along with all of the period pieces in the cottage. But the family heirlooms and artifacts were removed from the mansion, avoiding smoke damage.

The buildings are fully insured, and trustees plan to rebuild the barn, Thomas said. It remains to be seen whether the cottage can be rebuilt to its original specifications because of fire codes, he said.

Thomas said he feared the worst because he could see fire and smoke two miles from Norlands as he raced there Monday night. Without quick-thinking firefighters and the backhoe operator, the fire would have leveled everything in its path, Thomas said.