23 people were injured, nine of them critically, on Wednesday after an explosion shook a downtown Baltimore office building and left two window washers dangling from a scaffold outside the structure, authorities said.
The Baltimore City Fire Department said it responded to an explosion and partial roof collapse at the Baltimore Gas and Electric Co building, which the company said was likely the result of an accident.
Of 21 people taken to local hospitals, nine were in critical condition and one was in serious condition, the fire department said in a statement.
Two window washers were rescued after they were trapped several stories up on the exterior of the building when their scaffold partially gave way and was left dangling, the local firefighters' union said.
Firefighters quickly extinguished a blaze on the 16th floor of the building where evidence suggests the explosion occurred, Local 734 of the International Association of Fire Fighters said in a statement.
Rescue workers treated at least 20 people at the scene, the IAFF local said.
At the time of the explosion, construction work was being done on the building’s air handling and boiler system, "which likely caused the incident," said Baltimore Gas and Electric Co, which is owned by Exelon Corp.
"The building was largely empty due to the upcoming holidays and the pandemic," the company said.