Two construction workers were killed Friday when a trench collapsed on them and flooded, Boston Fire Department officials said.

Workers frantically tried to rescue the men when the trench walls caved where they were repairing water lines for a home on Dartmouth Street in the city's South End. A water main broke when the trench collapsed and quickly filled the trench with water.

The two men who were pinned in the trench drowned, authorities said. The trench was estimated to be about 12 feet deep. 

The workers were under contract with Atlantic Drain Service Co. and were not employed by the city, according to WCVB

The two workers were later identified as Kelvin Marrocks, 53, of Brockton, and Robert Higgins, 47, of Warren, Rhode Island, according to the NBC affiliate in Boston.