Missing employees were working to support their families, a co-worker says.

A construction company employee who said he labored alongside the six men missing after a Baltimore bridge collapse on Tuesday said 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 missing men worked for Brawner, a contractor based in Baltimore County, a senior executive at the company confirmed to The Associated Press on Tuesday. He said they were all presumed dead.

“This was so completely unforeseen,” the executive, Jeffrey Pritzker, told The A.P. He said the crew was working in the middle of the bridge when it came apart.

“It’s tough,” Mr. Campos said in Spanish. He 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.

Officials said that in addition to the six workers missing, two had been rescued from the water. One did not need medical treatment, and another was taken to a hospital and released later in the day.

At least one of the missing men, Miguel Luna, was an immigrant from El Salvador, according to We are Casa, a nonprofit that provides services to the immigrant community in Baltimore. Mr. Luna, 40, is married and has three children, said Gustavo Torres, the organization’s executive director. He learned that Mr. Luna was one of the missing from Mr. Luna’s family. He said Mr. Luna had been living in Maryland for at least 19 years.

Guatemala’s foreign affairs ministry confirmed that two of the missing workers are Guatemalan nationals, from the regions of Petén and Chiquimula. The ministry, which did not release the names of its citizens, said that the country’s consul general in Maryland has spoken with the siblings of the two workers and is hoping to meet with their families.

State officials said the construction crew had been fixing potholes when the ship crashed into the bridge.

Brawner was founded in 1980, according to its website, and its employees work on schools, historic properties, bridges and other infrastructure. The company has performed other work for the state, which manages the bridge, in the past. A woman who answered the phone at the company on Tuesday said she did not have any information.

Mr. Pritzker, the company executive, did not respond to inquiries from The New York Times.

“This situation is very difficult,” Mr. Campos said. He told The Baltimore Banner that the employees who remained missing were from El Salvador, Guatemala, Honduras and Mexico.

The Mexican Consulate in Washington said in a statement that the nationalities of the missing people were still being determined. Embassies for the other two countries did not immediately respond to requests for comment.

Jacey Fortin, Miriam Jordan, Patricia Mazzei and Emiliano Rodríguez Mega contributed reporting. Kirsten Noyes contributed research.