Six people who died at a Colorado dairy farm this summer were exposed to hydrogen sulfide gas, authorities said Thursday.
The Weld County coroner's office drew its conclusions from autopsies and toxicology tests.
The deaths of five men and a teenager on Aug. 20 sent shockwaves through the rural communities in and around Keenesburg, 35 miles (55 kilometers) northeast of Denver, where emergency responders entered a confined space to recover the bodies.
Authorities had immediately expressed concern that the deaths were linked to harmful gases.
The coroner's findings will factor into an investigation by federal workplace safety and health investigators into determining what happened at the industrial-scale dairy, owned by California-based Prospect Ranch, as well as the role of a dairy equipment contractor.
Operators of the dairy and federal workplace safety authorities have said little about what went wrong.
The hazards of confined spaces on farms and dairies are a well-known and persistent cause of death in agriculture across the U.S. — often from exposure to odorless and colorless noxious gases, or due to asphyxiation in closed spaces where oxygen has been depleted.
All those who died in Colorado were Latino men, ranging in age from 17 to 50. Four of them, including the teenage high school student, were from the same extended family.
As the news spread of the deaths, people in the community organized fundraisers including a dance, haircuts and a car wash to benefit the families of those who died. Several local churches organized a memorial gathering at the local fair grounds in Keenesburg in early September that included singing “Amazing Grace."
“People are in shock. Everybody in the ranching and dairy community knows it’s difficult, hard work and there are accidents,” said the Rev. Thomas Kuffel, a priest at Catholic churches including Holy Family in Keenesburg. “But this is very foreign to them, in that accidents are typically one or two people.”
First responders from a rural fire district in Weld County were dispatched at around 6 p.m. on Oct. 20 to Prospect Ranch and took their own safety precautions as they entered a confined space.
Alejandro Espinoza Cruz, of Nunn, was found dead along with his 17-year-old son Oscar Espinoza Leos and a second son, 29-year-old Carlos Espinoza Prado of Evans.
The Espinozas are related by marriage to another 36-year-old victim from Greeley — Jorge Sanchez Pena, according to Jolene Weimer, deputy county coroner for Weld County.
The other two men — Ricardo Gomez Galvan, 40, and Noe Montañez Casañas, 32 — lived in Keenesburg. The remains of Montañez Casañas, a veterinarian who was employed under a U.S. visa, were repatriated to the central Mexican state of Hidalgo, according to Miguel Barradas Cerón of the Mexican consulate in Denver.
Silos that store grain and feed are among the most deadly confined spaces on farms, with hazards that include gases from fodder for feeding cattle ferments and releases carbon dioxide and nitrogen oxide, according to William Field, a professor at Purdue University who compiles annual reports on injuries and fatalities.
The next most deadly group of hazards are associated with the handling and storage of animal manure, which also include dangers from harmful gases. As manure decomposes it releases toxic gases that can replace available oxygen with carbon dioxide, methane, ammonia and hydrogen sulfide, which is especially toxic.
Proven safety precautions include access to a self-contained breathing apparatus with a short supply of oxygen and emergency response planning and training, Field said.
“Having an emergency action plan — that would eliminate the cascading effects, so that if somebody is down, somebody doesn’t just jump in there” is important, he said.
The Occupational Safety and Health Administration can take six months or longer to complete an investigation into workplace fatalities and typically focuses on identifying root causes.
OSHA has launched inspections and investigations of Prospect Ranch, with ownership based in Bakersfield, California, as well as Johnston, Colorado-based Fiske Electric, whose subsidiary High Plains Robotics services dairy equipment and employed several of the workers who died. The companies have not commented publicly on what led to the deaths.
It’s unclear if the teenager was assigned specifically to hazardous work, though that wouldn’t be unusual or prohibited by law. Federal regulations allow those who are 16 and older to do hazardous jobs in agriculture, while the minimum age is 18 in other industries, under child labor provisions of the Fair Labor Standards Act.
Renée Anthony, an environmental engineer and director of the Great Plains Center for Agricultural Health at the University of Iowa, said federal regulations leave out detailed standards for confined space safety in the agriculture sector even where permits are required.
Still, Anthony said all industry sectors, including agriculture, have an obligation under federal law to keep workplaces free from recognized hazards that can cause death or serious injury.
