Two Wisconsin men died after falling into a manure pit and being overcome by the gases.
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The incident happened at a family farm in the town of Woodmohr (about 25 miles north of Eau Claire) around 5:15 p.m. Thursday, the Chippewa County Sheriff's Office said in a press release.
On the scene, deputies learned the two men – both of Bloomer, Wisconsin – were trying to get a piece of equipment that had fallen into the pit.
While doing that, they were "overcome by the manure gas," the sheriff's office says, and became unresponsive.
First responders were able to pull both the men from the pit, but efforts to revive them were unsuccessful.
Chippewa County Chief Deputy Chad Holum described it as "tragic."
Dangers of manure pits
Manure pots are pretty much exactly what they sound like – a collection of manure that farm animals produce that gets stored together, and can sometimes be repurposed into fertilizer. (If you're interested in the step-by-step process, check out this blog post by Dairy Carrie).
But they're also dangerous.
As the Centers for Disease Control and Prevention explains, the manure in the pit "undergoes anaerobic digestive fermentation" – and that generates four potentially dangerous gases: Methane, hydrogen sulfide, carbon dioxide, and ammonia.
Those gases can build up, and the air around the pit can be depleted of oxygen.
Occupational Safety & Health Administration statistics show, in the past 15 years, six people have died while on the job in connection with manure pits: two died from asphyxiation, the others drowned.