Sucks.
Are those dairy manure pits enclosed some? Sounds like they could use someone above with extraction equipment like we had to have on station some places I've worked.
Condolences to their whole community and family.
There are many variations oh how they're built. A very common method is an underground tank where anerobic bacteria break down the manure in to usable fertilizer. They produce lots of gases and are very dangerous to enter without breathing equipment. The article said they were in there repairing a pump. They should have known how dangerous that can be.
