A farmer and 16 of his cattle have died in a freak accident after a “deadly dome of air” formed in a Wisconsin farm’s manure holding tank.

According to WAOW, a 29-year-old farmer named Michael Biadasz, from Amherst, Wisconsin, died of gas poisoning on his family’s farm after being overcome by fumes of either methane or sulfur oxide. Initially, 13 of the farm’s cattle died as well; later, three more expired, bringing the total to 16 cattle deaths.

The 29-year-old’s father, Bob Biadasz, co-owner of Biadasz Farms, said that the tragedy was the result of a “perfect storm” of unusual and unexpected weather conditions. When the tank was prepped to be pumped, warm upper air temperatures trapped the gases in a dome of air which then poisoned Michael and the cattle.

Biadasz was reportedly found dead when other workers arrived to begin hauling manure away from the tank.

“The family is devastated, absolutely devastated,” Portage County Coroner Scott Rifleman told WAOW.

Rifleman told WSAW that gas poisoning deaths typically occur in closed areas, making the incident even more surprising. The coroner said that atmospheric pressure prevented the gases from dissipating.

The coroner went on to say that an investigation is underway to determine exactly what caused Biadasz’s death. According to Rifleman, Biadasz had safely emptied the same tank hundreds of times prior to the fatal incident.

The Biadasz family honored Michael by parking a line of tractors and machinery along the road that passes the farm. Among the vehicles parked are a blue tractor, several red trucks, and Michael’s black pickup truck.