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 equip

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