Authorities say a 15-year-old Hayden High School student is dead after suffering cardiac arrest at the school's football field.

Routt County Deputy Coroner Mitch Locke identified the student as Robert Donelson.

Donelson collapsed on the field at about 1 p.m. Tuesday.

Bryan Rickman, chief of the West Routt Fire Protection District, says the boy wasn't breathing and had no pulse when emergency responders arrived.

He says responders tried to resuscitate the boy but were unsuccessful. Donelson was transported to the Yampa Valley Medical Center, where he was pronounced dead.

Rickman says the boy suffered cardiac arrest, but that the underlying cause was unknown.

Hayden School District Superintendent Greg Rockhold declined to comment until he could speak with the family.