An explosion in New York City’s East Village injured 19 people and triggered two buildings to collapse on Thursday, fire officials said. Four firefighters were among the 15 people taken to area hospitals, four of whom were in critical condition. At least one person was reported missing. More than 250 firefighters were dispatched to battle a seven-alarm fire, which damaged four buildings in total. Mayor Bill de Blasio said initial evidence suggests "a gas-related explosion" was caused by plumbing and gas work done inside a restaurant in the building. Residents of five buildings in the area were evacuated and unable to return home Thursday night.