A farmer and 16 cows have died after a being trapped in "deadly dome of air" while he was cleaning out a paddock of cow manure.
WAOW reports that Michael Biadasz, 29, who worked on his father's farm in Wisconsin, was found dead around 6:30am on Monday.
Biadasz was overcome by either methane or sulphur oxide fumes that got trapped in a "deadly dome of air" but more investigation will be needed to know exactly, the coroner said.
His father, Bob, said the tragedy was the "perfect storm" of strange weather conditions and noxious fumes.
Authorities say the young farmer was caught in a "deadly dome of air" when after "agitating" the tank before it was to be pumped.