WATCH: NYC Mayor Adams holds briefing on partial collapse of apartment building in the Bronx

NEW YORK (AP) — 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.

Watch the news conference in the video player above.

The falling bricks buried a sidewalk, landed on the public housing building’s playground and sent a cloud of dust billowing over the block in the Bronx, but amazingly did not injure anyone.

“We avoided a major disaster here,” said Bronx Borough President Vanessa Gibson at a news conference.

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

An aerial view of a partially collapsed building in the Bronx, in New York City, New York, Oct. 1, 2025. Image provided by New York City Fire Department/Handout via Reuters

The mound of debris was littered with air conditioners, which appeared to have been ripped out of apartment windows by the falling bricks. News helicopter footage showed a rescue dog bounding over the huge pile of bricks at the bottom of the building, sniffing for anyone who might be buried under the rubble.

A witness, Diamond Freeman, told WPIX-TV that there was a loud boom.

“And all the side of the building just fell. It was crazy. All you see is smoke,” Freeman said.

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

Department of Buildings Commissioner James Oddo said he believed work was being done on the boiler.

The city’s Emergency Management Commissioner, Zach Iscol, said building inspectors are checking the building’s foundations and the apartments in the impacted area to make sure they are sound. The mayor said the building will be repaired.

Officials said that some apartments were being evacuated as a precaution and services for residents were being made available at a nearby community center.

Around half a million New Yorkers live in aging buildings run by the city’s housing authority, known as NYCHA, which is the largest in the nation.

Many of the properties date back to the 1940s, ’50s and ’60s. In 2019, a federal monitor was appointed to address chronic problems like lead paint, mold and lack of heat. When he wrapped his five-year term in 2024, the monitor, Bart Schwartz, noted that the overarching issue for residents remained the “poor physical state of NYCHA’s buildings.”

Associated Press writers Dave Collins in Hartford, Connecticut, Michael Hill in Albany, New York, and Bruce Shipkowski in Toms River, New Jersey, contributed.