BALTIMORE, Maryland — Firefighters say 21 people were transported to the hospital after being injured in an explosion at the BGE building in Baltimore this morning.

First responders rescued 23 people from the building after an explosion caused a partial roof collapse. Two people were saved from scaffolding hanging in a precarious position off the building.

Firefighters said at least 9 people were in critical condition and 1 in serious condition. The cause of the explosion is under investigation.