ALGONA, Iowa (AP) — A 17-year-old girl who died after helping to clean a hog confinement building in Kossuth County was overcome by carbon monoxide poisoning, authorities said.

Victoria Marie Parra-Lerdo was found unconscious in the building in rural Swea City. She was taken to the Kossuth Regional Health Center in Algona, where she was pronounced dead, the Kossuth County Sheriff’s office said.

Autopsy results from the Iowa Medical Examiner’s Office said Parra-Lerdo’s death was accidental.

A power washer was being operated in the building’s hallway near where Parra-Lerdo was working, and inadequate ventilation caused her to be overcome by the fumes, authorities said.

Property tax records show the deed holder of the facility is Cottonwood Investment Company, and it is managed by Christensen Farms of Sleepy Eye, Minn., The Mason City Globe-Gazette reported.

Parra-Lerdo was not employed Christensen Farms. Her mother owns the company that was cleaning the facility