A four-alarm fire in Durham destroyed a barn and left two first-responders injured, but firefighters spared most of the home from the fire, authorities said.

"It was a hell of a save," Durham Fire Chief Corey Landry said.

Firefighters from more than a dozen communities - including many who fought a fire in Portsmouth only hours before - protected the historic home at 4 Smith Park Lane. The fire destroyed a barn and a large breezeway or addition connected to the home, the chief said.

Landry said a police officer suffered a leg muscle injury that could keep him out of work for weeks.

A firefighter slipped and fell, suffering a back injury and a concussion.

"I think the helmet saved him," said Landry, who expects the firefighter back to work by midweek.

The injured were taken to the hospital and later released.

Landry said one wall of the home was damaged. Landry didn't have a dollar estimate for the damage. He said antiques were stored in the barn, but wasn't aware of any animals that lived there.

Durham firefighters were at another fire scene at 20 Main St., when the call came in about 3:30 p.m. for the barn fire. Firefighters heard exploding propane tanks in the barn, which collapsed in the fire.

The state Fire Marshal's Office and local authorities were working to determine the fire's cause.

The Durham Community Church opened its doors to provide bathrooms and warmth for emergency responders.

Durham and University of New Hampshire police helped with traffic and crowd control.

Fire apparatus and manpower from Dover, Lee, Madbury, Exeter, Portsmouth, Pease, Nottingham, North Hampton, Stratham, Newington, Somersworth, Rochester, Newmarket, Barrington and Rollinsford. South Berwick, Maine, helped with station coverage.