A tugboat captain working on the New York Thruway Hudson River bridge project collapsed in the wheelhouse Monday night, the victim of a possible cardiac arrest, local police and emergency services agencies said.

The 52’x22’x6’ 1,200-hp pushboat Pilgrim was near the Tilcon quarry at Haverstraw, N.Y., when a report came of a medical emergency on the vessel around 9:55 p.m., according to the Rockland County Sheriff’s Office.

The boat and its barge were aground on a mud shoal, and when officers from the sheriff’s marine unit boarded they found Capt. Edward T. Smith, 50, of Norwalk, Conn., unresponsive in the wheelhouse with a crew member performing cardiopulmonary resuscitation. The officers took over CPR and, with the Westchester County Police marine unit and the Stony Point Fire Department, evacuated Smith off the tug and to the west bank of the river.

Smith was transported to Nyack Hospital where he was pronounced dead. The sheriff’s office said the cause of death was unknown pending investigation by the sheriff’s office, county medical examiner, and the Coast Guard.

The Pilgrim is part of a fleet of workboats and barges operated by Tappan Zee Constructors LLC, the consortium building the new bridge alongside the 1950s-era Tappan Zee Bridge crossing the river between Rockland and Westchester. The project was the scene of tragedy March 12, when New York Marine Towing’s 84’ tugboat Specialist was sunk in an allision with an anchored construction barge, killing all three crewmen on the tug.