YOUNGSTOWN, Ohio (AP) — Two people were missing and seven were injured when a natural gas explosion caused extensive damage to a building in downtown Youngtown, Ohio, authorities said.

The blast, which occurred around 2:45 p.m. Tuesday, blew off the façade of Realty Tower. Firefighters helped some people get out of the building, which houses a Chase Bank on the ground floor and has apartments in upper floors.

Youngstown Fire Chief Barry Finley said a man and a woman were missing following the blast. One is a Chase employee, he said.

The blast collapsed the first floor into the basement, Finley said, and the building’s structural integrity is in question so no firefighters were being allowed in to conduct a search.

The seven injured people were taken to Mercy Health Hospital in Youngstown. A hospital spokesperson said one person was in critical condition, but did not release further details.

A social media post by the Mahoning County Emergency Management Agency said there was a natural gas explosion and the situation is “fluid but under control.”

The blast shook the downtown area of the city of about 60,000 residents. Bricks, glass and other debris littered the sidewalk.