One emergency medical technician died and three co-workers are hospitalized after being overcome by carbon monoxide while on duty in east Texas.

A spokeswoman at Good Shepherd Medical Center in Longview, which operates Champion EMS in White Oak, says the victims were discovered around 7 a.m. Friday by other workers during shift change.

Victoria Ashworth told The Associated Press that the carbon monoxide apparently was from a generator left running on an ambulance.

Ashworth says a 29-year-old female EMT, who was in training, was pronounced dead after being transported to the hospital. Ashworth says a paramedic and two emergency medical technicians, all male, are in good condition. Their names were not immediately released.

White Oak is a town of about 6,200, located 115 miles east of Dallas.