The decomposition of waste that occurs in manure pits can create oxygen-deficient, toxic, and/or explosive atmospheres. ... Deaths can occur from lack of oxygen or from the toxic effects of these gases [Donham 1983; CES 1980]. In addition, methane and hydrogen sulfide may present an explosion hazard.

Can manure kill you?

There is, however, a serious risk from the gases that can be generated from manures of any kind. This is something that everyone should be fully aware of. While the odd whiff in the open air will do no harm, if you inhale methane or hydrogen sulphide gases in a confined space, it will kill you.

How can you die falling into a manure pit?

Since manure pits are confined spaces that are usually poorly ventilated, concentrations of these gases can quickly rise to levels that are immediately dangerous to life and health. These gases may also displace the oxygen in the pit, which may cause workers in the pit to suffocate due to a lack of oxygen.