A Westmont Public Works employee is dead after being trapped in an underground water main vault for nearly an hour Thursday morning, according to Westmont fire officials.

The man, identified by city officials as Matthew Heiden, was repairing a water main break at the intersection of 60th Street and Deming Place when the water main vault burst and filled with water, trapping him inside about 11:45 a.m., fire officials said.

Emergency responders said they administered life-saving measures at the scene about 12:40 p.m. before transporting Heiden to Good Samaritan Hospital, where he died a short time later.