Steamboat Springs — Emergency personnel responded to the scene of a fatal single-vehicle rollover at about 4:25 p.m. Sunday.

Both on-duty ambulances and a fire engine from Steamboat Springs Fire Rescue responded to the accident at mile marker 126 of U.S. Highway 40 between Steamboat Springs and Milner.

A bystander had been performing CPR on one of three occupants of the vehicle, who was later pronounced dead at the scene.

A second occupant was outside of the vehicle with multiple injuries when emergency personnel arrived, and a third passenger was trapped inside the vehicle.

Responders used the “jaws of life” to extricate the passenger trapped inside.

The second and third occupants were transported to Yampa Valley Medical Center with serious injuries.

Steamboat Springs Fire Rescue was assisted at the scene by three Routt County Sheriff’s Department deputies and two Colorado State Patrol officers.

While Steamboat Springs Fire Rescue responded to this accident, four of the agency’s off-duty personnel were called to an unrelated potential critical patient call.

The cause of the accident was under investigation Sunday night by the Colorado State Patrol and its accident investigation team.

To reach Teresa Ristow, call 970-871-4206, email tristow@SteamboatToday.com or follow her on Twitter @TeresaRistow