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Six dairy workers died of exposure to toxic gas, Weld County coroner determines

Six people, including a high school student, died in what Weld County authorities initially called a “dairy accident” at Prospect Valley Dairy in Keenesburg on Aug. 20.
Six dairy workers died of exposure to toxic gas, Weld County coroner determines
These are victims of the deadly Colorado dairy accident in Keenesburg
What is a 'confined space'? Denver7 digs into OSHA's definition and workplace safety standards
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WELD COUNTY, Colo. — The six workers who died at a Keenesburg dairy farm in August died from exposure to a toxic gas, the Weld County Coroner's Office announced Thursday.

Six people, including a high school student, died in what Weld County authorities initially called a “dairy accident” at Prospect Valley Dairy in Keenesburg on Aug. 20. The victims were identified as Oscar Espinoza Leos, 17, of Nunn; Alejandro Espinoza Cruz, 50, of Nunn; Jorge Sanchez Pena, 36, of Greeley; Carlos Espinoza Prado, 29, of Evans; Ricardo Gomez Galvan, 40, of Keenesburg; and Noé Montañez Casanas, 32, of Keenesburg.

Seventeen-year-old Oscar Espinoza Leos was a student at Highland High School in Ault and the son of Alejandro Espinoza Cruz. Oscar was helping his father out before returning to school, sources told Denver7.

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Weld County

These are victims of the deadly Colorado dairy accident in Keenesburg

Óscar Contreras

The Weld County Coroner's Office said Thursday that all six victims died as a result of hydrogen sulfide gas exposure in a confined space.

According to the Occupational Safety and Health Administration (OSHA), hydrogen sulfide is an extremely flammable and highly toxic gas that occurs naturally in manure pits. It can collect in low-lying and enclosed spaces and can lead to immediate death in high concentrations, making work in confined spaces "potentially very dangerous."

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Local

What is a 'confined space'? Here's OSHA's definition

Allie Jennerjahn

While investigators have not publicly shared details about how the victims died, Denver7 spoke with two separate sources in the dairy industry with knowledge of the deadly incident in the days after.

Sources told Denver7 that a contractor was at Prospect Valley Dairy conducting work on an underground manure pit, where workers had been several times throughout the day on Aug. 20. At the end of the day, one of the workers went back down into the pit to do some additional work and possibly "adjust a valve."

The sources told Denver7 they suspect the worker then accidentally turned on a valve or pump with his phone, which caused a release of hydrogen sulfide. The worker inside the pit then immediately collapsed due to exposure (it only takes a matter of seconds for hydrogen sulfide to cut off oxygen to the brain, the sources said), before five other workers rushed in to save him, despite an on-site supervisor yelling at them not to go in.

The incident remains under investigation by OSHA and the Weld County Sheriff's Office.

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