Manure emissions during agitation and processing


Recent deaths associated with hydrogen sulfide exposure from manure systems have highlighted the need for increased awareness to reduce health risks. While information on some aspects of hydrogen sulfide release from manure are available, there is limited information on the characteristics when agitating manure storages and in manure processing buildings that result in concentrations that are dangerous to human health. This project aimed to gather data on emissions from manure storages and processing to assess risks and develop mitigation strategies for these risks.

What Did We Do?

Our research team acquired over 20 days of field data (at multiple livestock farms) to assess the air concentrations from manure storages with and without agitation, for hydrogen sulfide, methane, ammonia, and particulate matter. The emissions were measured over the course of eight hours using numerous sets of sensors around the manure storage during agitation for each sampling event. Each sampling event had one backpack that was worn by a researcher with a set of sensors to represent the concentrations relevant to someone working in the area. Five additional sensor sets were placed around the manure storage. Some sensor sets remained in the same position throughout sampling (e.g., at the location of the agitation equipment controls) while others were moved around the storage.  Researchers also measured the concentrations of these gases inside a manure processing room to assess the concentration changes with different air exchange rates. During each event manure samples were collected as well as weather data to relate to the manure emissions data.

What Have We Learned?

This research assessed the environmental and design conditions of manure systems that may lead to increased concentrations of gases that have human health implications. The results indicate critical operating parameters on how to manage manure systems to limit risk from gases produced from manure processing and storage areas. More details on the study results will be available soon and will be presented at the conference.

Future Plans

This information is also being integrated into an existing fact sheet,, to provide an updated resource which integrates this new data. This information will be shared in a variety of settings to increase awareness and guide practices to reduce health risks to those working with livestock manure.


Rebecca A. Larson, Associate Professor & Extension Specialist, Biological Systems Engineering, University of Wisconsin-Madison

Corresponding author email address

Additional author

Anurag Mandalika, Assistant Professor, Audobon Sugar Institute, LSU AgCenter

Additional Information

Reducing Risks from Manure Storage Agitation Gases


This work is supported by Foundational Program CARE 2019-68008-29829 from the USDA National Institute of Food and Agriculture.


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