Six people died at a dairy in the central US from an apparent accident involving exposure to gas, authorities said.

The dead are all male and Hispanic, said Jolene Weiner, chief deputy coroner for Weld County in the state of Colorado.

Their identities were being withheld pending notification of the families.

“We are investigating these deaths as the possible consequence of gas exposure in a confined space,” Weiner said on Thursday.

Autopsies are planned and investigators are looking into what kind of gases may have played a role in the deaths.

The dairy, Prospect Valley Dairy, is located along a rural road near Keenesburg, about 55km north-east of Denver.

Crews entered a confined space at the dairy on Wednesday and recovered the bodies, officials said.

Weld County Sheriff’s Office spokeswoman Melissa Chesmore said her agency didn’t find anything criminal in nature.

“It looks like an accident,” she said.

She didn’t elaborate on the nature of the emergency or say where exactly the bodies were found, referring questions to occupational safety regulators.

A spokesperson for the US Department of Labor said that the Occupational Safety and Health Administration was investigating and that more information would be available after it’s complete.

Dairy Farmers of America said a “tragic accident” occurred at a member farm in Keenesburg that resulted in the deaths of six people.

“We are deeply saddened by this incident, and our thoughts and most sincere condolences go out to the friends and families of the deceased. At this early stage, we have no further details,” the cooperative of dairy farmers said in a statement.

County tax records say the property is owned by Prospect Valley Dairy LLC and list a Bakersfield, California, address for the owners. Phone messages left for a number at the California address were not immediately returned.