Authorities say a search-and-rescue volunteer responding to a first-aid call was struck and killed at the popular San Luis Obispo County tourist spot Oceano Dunes by an ambulance responding to the same call.

Sheriff's officials say 24-year-old Christopher Meadows of San Luis Obispo died Sunday when he lost control of the all-terrain vehicle he used to assist state parks rangers. The vehicle flipped and was hit by the ambulance.

The California Highway Patrol says the two men in the ambulance, 36-year-old Michael Talmadge and 33-year-old Brandon Simmons, were not hurt.