PITTSBURGH >> Authorities say a multistory building on Pittsburgh’s South Side built at least 141 years ago will be demolished on safety grounds after a massive fire and partial collapse.

“After a partial collapse, the structure is considered structurally unsound,” Pittsburgh Public Safety officials said today in a Twitter post. “The building is now slated for demolition.”

Fire crews fought for hours Monday to contain the blaze reported at about 2:30 p.m. that sent flames and smoke poured from the building. At one point, the side of the building facing 11th street collapsed, showering the streets with bricks, glass and other materials. No one was injured. The cause of the fire is under investigation.

The Pittsburgh Post-Gazette reported that the first floor of the 3½-story building houses a barbershop and the South Side Welcome Center, home to the area’s Chamber of Commerce, with residential units above. The building dates back to sometime between 1860 and 1879, according to a historic survey done in 1981 by Pittsburgh History & Landmarks Foundation. At that time, the Socialist Workers Party was based in the building, the paper said.

The American Red Cross said it will provide resources and immediate assistance including food, shelter and clothing to six people left homeless.