[Yeti]

He hardly took more than a few steps and was totally overcome by fumes and died, as did the calf.

Is it ammonia or methane or what that is so overpowering?

[Wednesday's Child]

I always believed it was mainly the methane but I just did a search and this is what I found out...A pit is filled with toxic and oxygen displacing gas. The gasses present are hydrogen sulfide, ammonia, carbon dioxide and methane. The most dangerous of all is hydrogen sulfide which will cause death in seconds. It is most dangerous when the pit is being agitated........