A construction company employee who said he had labored alongside the six men missing after a Baltimore bridge collapse on Tuesday said that many of his co-workers were migrants working to support their relatives.

“We’re low-income families,” said Jesus Campos, who has worked at the construction company, Brawner Builders, for about eight months. “Our relatives are waiting for our help back in our home countries.”

The men worked for Brawner, a contractor based in Baltimore County, a senior executive at the company said on Tuesday. The executive, Jeffrey Pritzker, and the Coast Guard said that all of the missing workers were presumed dead, given how long it had been since the collapse.

“They were wonderful family people,” Mr. Pritzker said, before describing the victims’ survivors. “Spouses, children.” He added, “It’s just a very, very bad day.”

The company routinely does maintenance on bridges operated by the state. Its workers were repairing the bridge’s roadway when it was struck by the ship. Mr. Pritzker said that Brawner’s owner was distressed and had spent the early hours of Tuesday near the bridge hoping for a rescue, and had also since met with families of all of the missing workers.

Mr. Campos spent much of Tuesday afternoon at a gas station near where the police had blocked off the road to the Francis Scott Key Bridge. He wore a black sweatshirt bearing the construction company’s name and milled about, waiting for news and speaking on the phone.