A massive brick chimney running 20 stories up the side of a New York City apartment building collapsed after an explosion Wednesday, sending tons of debris plummeting to the ground.

Mayor Eric Adams said no injuries or deaths were reported in the collapse of the chimney, which rose up from the building’s boiler room. Officials notified of an explosion in the Bronx just after 8 a.m. were trying to determine if there was a gas leak.

City officials in charge of public building said they need to investigate to see what went wrong.