An Oregon City, Ore., man found his daughter and father dead from apparent carbon monoxide poisoning.

The Umatilla County Sheriff’s Office says Gary Maitland found his 7-year-old daughter, Destiny, and his father, 62-year-old George Edward Maitland, Sunday.

The two had been sleeping in a cargo trailer, roughly 19 miles south of Ukiah. Umatilla County Sheriff John Trumbo says they apparently died from carbon monoxide poisoning from their nearby generator that operated a heater in the trailer.

Police say the generator was placed about a foot away from the backdoor and was close enough to the trailer that fumes came inside. Police say the symptoms of the deaths were consistent with carbon monoxide poisoning.