A building under construction partially collapsed Friday in New Haven, Connecticut, when a concrete pour went awry, injuring eight workers, including two critically, city officials said, adding there were no fatalities.

City firefighters and other authorities were called to Lafayette Street shortly after 12:30 p.m.

“Our units responded immediately within minutes and found several persons in varying degrees of injury, from broken bones to three that were partially buried under the rubble,” Fire Chief John Alston Jr. said during a news conference.

Firefighters used ladders and ropes to get to the victims through sharp, broken rebar and other debris, witnesses and officials said. Some victims were hoisted out of the deep hole in rescue baskets attached to ropes, while others were pulled out of the side of the building.

“We heard a crash and we jumped up,” said Danean Doheny, a medical assistant who was working on the fourth floor of a neighboring building and witnessed the rescues. “It was crazy. It was very emotional and scary. I'm just glad everybody for the most part is OK.”

Doheny said the concrete delivery equipment was still running for a time after the collapse, sending the construction mixture onto the injured workers in the hole.

There were 36 people at the work site at the time, and all were accounted for, officials said. All eight injured people were construction workers. Six were pulled out of the building by firefighters, while two were able to escape on their own, officials said. Officials later brought in dogs to search the building for any other people.

“They were doing a concrete pour on this building and as they were pouring concrete a portion of the second floor collapsed onto the first floor and then into the basement," Mayor Justin Elicker said.

Workers at the site told first responders the concrete was being poured faster than they could spread it, and it pooled too much in one area and caused the collapse, Alston said. First responders had additional urgency to rescue the victims because the concrete was drying, he said.

Elicker said the property is owned by nearby Yale University and is being developed into what will be a seven-story residential building by RMS Companies, based in Stamford, Connecticut, which bills itself as a builder of “upscale, modern apartments and luxurious boutique hotels” on its website.

The building is currently two stories high, with two parking levels underground. Plans call for 112 residential units, Elicker said.

“There will be a significant investigation as with any construction situation like this,” the mayor said.

A person who answered the phone at RMS said the company was not commenting at this time.

Investigators with the Occupational Safety and Health Administration were at the scene. City officials said they planned to issue a stop work order at the site until it is safe.

Lafayette Street is a short distance from Yale New Haven Hospital and the Yale School of Medicine and is home to several medical offices, about five blocks from the New Haven Green and Yale's main campus.

Alston said city emergency officials had been talking about responding to building collapses in recent days, in response to the partial collapse of an apartment building in Davenport, Iowa, on Sunday that left three people missing and feared dead.

“They did some excellent work under some harrowing conditions,” Alston said about New Haven first responders. “I'm very proud of that considering what happened in Iowa recently. We've been talking about collapses in our area so they responded admirably.”