Federal workplace safety regulators announced proposed penalties totaling $246,609 on Tuesday against a Colorado dairy and two contractors over their failure to protect six workers who died from hydrogen sulfide gas exposure in August 2025. The deaths occurred after a manure pipe disconnected in an enclosed space at Prospect Ranch in Keenesburg, about 35 miles northeast of Denver, shocking rural communities in the region.

Confined-space deaths in agriculture remain a persistent hazard despite well-documented risks, with exposure to odorless toxic gases like hydrogen sulfide continuing as a leading cause of farm fatalities across the United States.

On August 20, 2025, six workers entered a pump room at Prospect Ranch in Keenesburg, Colorado, after a manure-system pipe disconnected. The enclosure filled with hydrogen sulfide gas—a colorless, odorless compound released when the manure pipeline ruptured. All six workers died.

The Incident and Response

The U.S. Occupational Safety and Health Administration said in its findings that a Fiske employee and a Prospect Ranch employee initially attempted to stop the gas flow but were overcome. Three more Fiske employees and one additional Prospect Ranch employee then entered the pump room in an effort to rescue their colleagues. Each entry added to the toll, and the incident resulted in the loss of all six workers.

The Victims

All six were Latino workers, ranging in age from 17 to 50. Four worked for Fiske Inc.’s equipment-service division, High Plains Robotics.

Alejandro Espinoza Cruz of Nunn worked at the ranch. His 17-year-old son Oscar Espinoza Leos and another son, 29-year-old Carlos Espinoza Prado, also died in the incident. Jorge Sanchez Pena, 36, of Greeley, was related by marriage to the Espinoza family and also perished.

Ricardo Gomez Galvan, 40, and Noe Montañez Casañas, 32, both of Keenesburg, were the other two victims. Montañez Casañas, a veterinarian employed under a U.S. visa, had his remains repatriated to Hidalgo, Mexico, according to the Mexican consulate in Denver.

The Weld County coroner’s office determined from autopsies and toxicology tests that the workers were exposed to hydrogen sulfide, though the coroner provided limited additional detail on the circumstances beyond identifying the incident as an industrial accident in a confined space.

Federal Penalties

On Tuesday, February 24, 2026, OSHA announced proposed penalties totaling $246,609 against three businesses:

  • Prospect Ranch LLC, the dairy owner, faces $132,406 for serious violations including failures in training, planning, and protecting workers from atmospheric hazards.
  • Fiske Inc., the Colorado-based contractor servicing the dairy equipment, faces $99,306 for failing to protect employees and provide hydrogen sulfide detection training.
  • HD Builders, another contractor working on the manure management system, faces $14,897 for failing to have a written hazard communication program and provide training on detecting hydrogen sulfide. Company employees were present during the incident but unharmed.

Company Responses and Next Steps

Fiske Inc. and company owner Kevin Fiske said in a statement that “our hearts are heavy as we review OSHA’s citations.” The statement added: “We have cooperated with the investigation proceedings to date. While we disagree with the findings and are reviewing our options to determine next steps, we are focused on doing what is in our power to ensure that a tragedy like this never happens again.”

A representative for HD Builders said the company had no comment. Prospect Ranch LLC did not immediately respond to requests for comment.

The companies have 15 days to comply with the proposed penalties, request an informal conference with safety regulators, or challenge the findings before an occupational safety review commission.

William Field, a professor at Purdue University who compiles annual reports on farm confined-space deaths, noted that OSHA fines in agriculture, while substantial, are often reduced upon appeal or partially waived in exchange for safety improvements. “That part of it quite frankly is peanuts compared to the civil liability potential in situations where private lawsuits are allowed,” Field said.

A Persistent Hazard

Confined spaces on farms and dairies remain a well-known cause of death in U.S. agriculture. Workers die from exposure to odorless and colorless noxious gases like hydrogen sulfide, or from asphyxiation when oxygen is depleted in sealed environments. The hazard has persisted despite documented awareness across rural communities for decades.

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