“Any building that is demolished is a dangerous scene,” Dempsey said. “Probably more dangerous than when they put them on.” Boston Police Chief Kelley McCormick said the worker was operating a “smaller” worker crane when the floor collapsed. There was debris on the equipment after it fell. Suffolk County Attorney Kevin Hayden said the worker was a young man, but did not reveal his name. He is a member of the International Union of Operating Engineers Local 4. Boston firefighters were initially called to the area at 1 Congressional Street shortly after 5:30 p.m. on a report of a partial garage collapse. John Moriarty & Associates issued a statement about the site and the incident, saying a ninth-floor concrete slab on the east side of the Haymarket garage collapsed on the eighth floor. “Our heartfelt thoughts and condolences are with the family of the worker who lost his life. “JMA remains committed to providing a safe and healthy workplace for all our employees and business partners,” they wrote. All other subcontractors working on the demolition at that time were evacuated from the building safely. Workshops have been working to demolish the empty garage for months. Traffic was severely disrupted in the area for the rest of Saturday night as engineers made sure the area was safe for MBTA riders and riders using the Orange Line. Roads around Haymarket, including the Sumner Tunnel, were closed overnight. “Orange Line runs just below this site,” McCormick said. “Therefore, just for safety reasons, we want to ensure that the site is not damaged due to the weight of all the material that is collapsing. So MBTA does this assessment with civil engineers and our engineers will do the building to make sure the building is stable. “ Boston Mayor Michelle Wu spoke with city officials Saturday night, calling the incident a “horrific tragedy.” He said the city is committed to understanding what happened. “My heart goes out to the worker’s family and loved ones here tonight,” Wu said. “This is a very complicated site and we know that the workers who take the risk of it τους their families should never have to worry about coming home at night.” People stopped and watched the scene all Saturday night, trying to figure out what had happened. The Boston EMS says a passerby was taken to hospital for evaluation but had no injuries. “Completely crazy,” said witness Danah Ringel. “I was in my apartment watching TV and listening to all the sirens.” OSHA has taken over the stage for the rest of Saturday night. The incident is still under investigation.