SHIRLEY, N.Y. (CBSNewYork) — A man has died after participating in a triathlon on Long Island Sunday morning.

According to authorities, Vincent Fleck, 69, of Mount Kisco, was rescued from the waters of Narrow Bay at Smith Point County Park in Shirley at around 7:25 a.m. after authorities noticed he was in distress.

READ MORE: With Injuries Piling Up Across New York City, Mayor De Blasio Is Considering Bicycles Being Required To Have License Plates

Fleck was taken to Brookhaven Memorial Hospital Medical Center where he was later pronounced dead, police said.

READ MORE: Bronx Man Takes It Upon Himself To Clean Up NYC Park, But City Says Not So Fast

Fleck was participating in the 500-meter swim section of the Smith Point Sprint Triathlon at the time of the incident.

MORE NEWS: New York City Subways Resume 24-Hour Service

The exact cause of Fleck’s death is still under investigation.