Understand Safety when Dealing with Hydrogen Sulfide in Manure

The risks of hydrogen sulfide in swine operations have been known for years, but beef operators also need to be aware of the dangers this gas can pose. Increasing this awareness led Dan Andersen, assistant professor and agricultural engineering specialist with Iowa State University Extension and Outreach, to create a series of four publications that provide information and resources to help farmers stay safe when working with manure.

“One breath of hydrogen sulfide at 500 parts per million is enough to render someone unconscious almost immediately,” Andersen said. “Once you realize the gas is a problem it’s usually too late. Hydrogen sulfide gas smells at 1-2 ppm, but levels above that knocks out your ability to smell, so our natural detection system goes away.”

Information about the importance of monitoring for hydrogen sulfide and the types of monitors available for purchase is available in publication AE 3603, “Hydrogen Sulfide Safety – Monitoring.” Monitors are available from ISU Extension and Outreach agricultural engineering specialists who have several models for farmers to test.

“Personal protection meters are a low cost investment, usually around $200, that will notify you if gas is present,” he said. “These instruments can be taken anywhere and are always monitoring the air.”

The second publication in the series, “Hydrogen Sulfide Safety – Manure Agitation” (AE 3604), discusses how to stay safe when agitating manure.

“Manure that is stagnant and sitting around has minimal loss of hydrogen sulfide,” said Andersen. “These levels of hydrogen sulfide are typically not hazardous. But when the manure is agitated and the crust is disrupted, hydrogen sulfide levels can elevate quickly.”
 
The final two publications in the series focus on barn ventilation for both cattle and swine facilities. “Hydrogen Sulfide Safety – Barn Ventilation at Cattle Facilities” (AE 3605) and “Hydrogen Sulfide Safety – Swine Barn Ventilation” (AE 3606) discuss how to set up a ventilation strategy when working with manure.

“The most important thing to do is to try to maximize airflow,” Andersen said. “When agitating there should be at least a 10 mile per hour breeze and fans can be set up to bring in additional air.”

Proper positioning can also help minimize risks of exposure to gas.

“Think about where you are setting up,” Andersen said. “Don’t stand downwind from the barn if at all possible.”