Distillers’ grains (DGs) are much higher in sulfur than whole corn, which can lead to higher hydrogen sulfide levels in manure. That, in turn, can make manure gases more deadly, says Jeannine Schweihofer, a member of Michigan State University’s Animal Agriculture and the Environment Team.
DGs have sulfur concentrations of 0.6% to 1% while normal corn ranges from 0.07% to 0.15%. While researchers have not found hydrogen sulfide levels above OSHA standards at pen floor level, levels in manure storage areas and pits can increase during agitation.
When manure pits are agitated, hydrogen sulfide levels can climb to 1,200 ppm in just a few minutes. Levels are usually highest in the first 30 minutes of agitation.
At concentrations of less than 1 ppm, hydrogen sulfide is just an irritant that smells like rotten eggs. But at higher concentrations, it deadens the sense of smell and is more difficult to detect. Abrupt exposure to high concentrations of 500 ppm or more has killed humans. Extended exposure to lower levels can cause serious illness.
“Never enter a pen or barn if you see problems with animals during pumping,” Schweihofer says. “Observe animals from a distance and discontinue agitation at the first sign of trouble. Most human deaths associated with manure removal occur when someone enters a barn or pit that has high levels of hydrogen sulfide.
“When feeding coproducts containing high levels of sulfur, producers are advised to remove additional sources of sulfur from mineral supplements.”
Source: Michigan State University