The Fort Wayne Fire Department was called at 2:56 a.m. to the A2Z Mercantile Building, 1835 S. Calhoun St., to a reported building fire. Crews found smoke coming from the front of the building, according to a news release. The first crew forced open the door and found heavy fire in the ceiling on the first floor.

While extinguishing the fire the ceiling collapsed on one firefighter. He was taken by Three Rivers Ambulance Authority to the hospital, where he was treated and released, according to the release.

It took over an hour to bring the fire under control. The cause of the blaze, which caused heavy damage to the building, remains under investigation.

The fire department was also assisted by the Fort Wayne Police Department, Fort Wayne Neighborhood Code Compliance, Fort Wayne Street Department, American Electric Power and Northern Indiana Public Service Co.

A2Z Real Estate Holdings received a commendation from Fort Wayne historic preservation organization ARCH in 2016 for its historic preservation work on the building. A plate on the front of the building says it was established in 1918.