At least six people, likely construction workers, are unaccounted for after the Francis Scott Key Bridge collapsed Tuesday morning. Search parties were battling cold, murky waters, shifting tides and, most importantly, the clock as recovery efforts drag on.

The bridge collapsed around 1:30 a.m. after being struck by the cargo ship Dali. An eight-person construction crew was on the bridge, repairing potholes, when the center spans of the Key Bridge crumbled, Maryland Transportation Secretary Paul Wiedefeld said. Two workers were pulled from the waters.

Jeffrey Pritzker, executive vice president of Brawner Builders, said in a phone interview that he doesn’t think the other six workers could have survived, although no official word has come down.

“We’re presuming that they are not alive, because they were thrown into the bay in an area that’s 50 feet deep, with 46 degree temperature, probably buried under tons of steel,” Pritzker said.

“The company is in mourning and it’s a terrible, unanticipated tragedy.”

The crew worked from around 9 p.m. until 5 a.m. from Sunday to Thursday, said Jesus Campos, who works the day shift for Brawner Builders, the company who employed them. An employee at the company office said they did not have any information when reached by phone Tuesday morning.

(Read full coverage of Key Bridge collapse)

Campos knew the workers — Alex, Julio, Jose, Miguel, Minor and Ricardo — and said they were from El Salvador, Guatemala, Honduras and Mexico. Authorities haven’t released their names.

“This catastrophe has already disproportionately impacted our city’s immigrant community, one that often toils in demanding and dangerous jobs to the benefit of all who call Baltimore home,” said Krish O’Mara Vignarajah, president and CEO of Baltimore-based Global Refuge. “Having walked alongside our city’s newcomers for decades, we know firsthand how courageous and resilient our immigrant neighbors are.”

Search efforts have been underway since before daybreak. Two people were pulled from the water early this morning, and one person was taken to a hospital. The other was uninjured, authorities said.

“We can certainly dive in these conditions, but we have to take a lot of factors into play,” Baltimore Fire Chief James Wallace said around 6:30 a.m. High tide was at 8:30 a.m.

Crews are having to navigate debris in addition to water with low visibility. Would-be survivors have been subject to water temperatures below 50 degrees, according to the National Oceanic and Atmospheric Administration.

“We’re going to rely on our experts, our dive teams that are here, to tell us when they’ve reached that non-survival point,” Wallace said earlier.

A person in water that cold without protective equipment can expect to remain conscious for about an hour, and can survive for about three hours, according to the National Weather Service. Officials in a press briefing around 10 a.m. said rescue efforts were still underway, but Gov. Wes Moore alluded to “victims” and “loss.”

At an afternoon press availability, Gov. Wes. Moore said he’s had the opportunity to spend time with families and pray with them and described their strength as “absolutely remarkable.”

A prayer vigil was held for the victims at Mt. Olive Baptist Church in Turner Station Tuesday evening. As sounds of an organ echoed through the church, community organizers, city and state officials and members of various religious congregations prayed for the families of the six construction workers. Consuls of El Salvador, Guatemala and Mexico were also at the vigil. Mayor Brandon Scott spoke of the city’s resilience and ability to come together in times of crisis. He asked people to support families of the six construction workers and to “lift them up” for the foreseeable future.

Jenny Luna said in an interview that her father-in-law was one of the workers on the bridge, and that he had been in construction for the last 10 years. The family has not received any information from authorities about the progress of recovery efforts.

Search teams are using infrared cameras and sonar, both in the air and on the water, to find possible survivors. Sonar showed several vehicles submerged in the water, but officials did not know how many. It’s also unclear if those vehicles belonged to the construction crew.

Moore said the boat lost propulsion before hitting the bridge and called Mayday, alerting officials on land about an imminent allision (a ship running into a stationary object). Authorities on land were able to divert traffic from the bridge in the moments before the cargo ship struck it, which potentially saved lives, Moore said. However, the workers were not able to be cleared, it appears.

Campos, the construction worker, said he doesn’t think there was enough time to warn the workers. It happened too fast, he said.

”You never know when a tragedy like this will happen,” he said.

Rescuers are also searching for survivors on the deck of the ship, and are aided by helicopters from city and state police. However, local fire officials said earlier this morning that damage to the ship needed to be assessed before rescuers could board.

This article may update.

Baltimore Banner reporter Clara Longo de Freitas contributed to this report.