Livestock manure gases: don’t succumb


Any time manure is stored, toxic gases can build up and threaten both the wellbeing and/or life of those working around or with it.

Adopting and using a “Safety Hierarchy” greatly reduces potential for these types of events:

1. Eliminate the hazard whenever possible.

2. Ensure that all possible safeguards are in place: ventilation, guards, fencing and gas sensors.

3. Use clear warning signs and labels in areas of danger.

4. Complete training regarding the dangers of handling manure, appropriate response to an event and effective procedures to help limit negative consequences.

5. Always use required respirators, harnesses, etc.

Personal protective equipment required to safely work around stored manure includes:

1. A second person standing by outside the enclosed area;

2. Ventilation whenever possible;

3. A self-contained breathing apparatus (SBA);

4. Harness, which can be used to help rescue a person who’s overcome while in the storage facility;

5. Hydrogen sulfide gas monitor.

“Among the greatest dangers related to working with stored manure are drowning, toxic gases, and flammable gases,” said Amy Schmidt, University of Nebraska – Lincoln Associate Professor and Livestock Manure Management Engineer. “There are some very tragic stories about farmers working around manure storages in the early morning who didn’t see the edge of the storage pond and drove into it. These stories often end with the person becoming trapped or disoriented and drowning.”

To prevent this type of tragedy, Schmidt recommends installing either fencing or barriers around the edge of the storage pond/pit to help keep workers and children away from the area and ensure that no one accidentally drives into the pond.

“Think of it in terms of protective measures used around a swimming pool,” Schmidt said. “Pool owners are advised to install fencing around their pool to prevent accidental entry. Using a fence or some kind of barrier around manure storages to prevent accidental entry is also an important safety recommendation.”

As manure decomposes, hydrogen sulfide gas forms at the surface of the manure storage area. This highly toxic gas is heavier than air and its odor is similar to rotten eggs. When hydrogen sulfide concentrations are high, the gas paralyzes the olfactory nerve, so its odor cannot be detected. Victims often believe the absence of odor signals they are safe, when it actually means their life is in peril.

“Ideally, any time a person needs to enter a confined space where hydrogen sulfide may be accumulated, the recommendations would be to monitor the concentration of the gas with a sensor and wear a self-contained breathing apparatus that supplies oxygen to the person entering the space. However, most people don’t have access to these items when they work around manure,” Schmidt said. “For that reason, it’s critical to never enter a manure storage area when you’re alone. At the very least, have a person observing from outside the manure storage who can summon emergency help if you are overcome by the gas. Even better, wear a harness with a rope or line that the person outside the storage can use to pull you out if you are overcome by gases.”

Schmidt illustrates the importance of this safety measure by sharing the experience one farmer had when the pressure of time caused him to enter his farm’s manure storage area without summoning any help. His thought was that everyone was engaged in other chores and his work on the pump at the storage area would only require a few moments of his time.

“In no time at all, this farmer felt lightheaded and dizzy,” Schmidt said. “He made a conscious decision to reach for the ladder and climb out of the pit. However, the last thing he remembers is reaching for that ladder rung.”

Fortunately, a family member discovered what had happened and immediately called for help rather than attempting to rescue him.

“It’s really a miracle that he survived to tell his story,” Schmidt said.

Another tragic story involved a teenage boy who died after entering a tractor-pulled manure tanker. The young man was spreading manure and it’s suspected that he may have entered the tank once it was empty because the unit had been malfunctioning.

“Any time manure is held in a space that is not well ventilated, hydrogen sulfide gas can reach deadly concentrations,” Schmidt said. “Anyone entering such a space can quickly be overcome by the gas, with very little time to react and try to escape the area.”

Beneath the slatted floors of swine facilities, researchers are learning that methane gas, generated during manure decomposition, can be trapped in foamy bubbles on the manure surface, creating a foam that is very dangerous. This poses a threat to animals and humans because methane is highly combustible and can cause a flash fire or explosion if an ignition source is present.

“Methane is odorless,” Schmidt said. “You won’t smell it.”

Researchers have been investigating manure pit foaming for several years and believe changing microbial populations in the manure may be the cause. Whether the shift has occurred due to adjustments in swine diets, water conservation practices, increased solids content of stored manure, or even reduced use of antibiotics in animals is not certain.

“What we know for sure is that the presence of pit foam in a swine facility indicates a likely accumulation of methane gas, which can be very dangerous,” Schmidt says.

Schmidt advises that, if foam is observed beneath the slats or at pump-out ports of a swine barn, the producer should take precautions to reduce foaming as quickly as possible. Spraying water or running a sprinkler in the building can break the bubbles in the foam and slowly release the methane. If a farmer is preparing to pump and apply manure, agitating the pit prior to pumping also will break up the foam and release the methane. Agitation should begin slowly to avoid a quick release of the methane. Schmidt stresses that it’s very important to take precautions any time manure foam is being disturbed.

“The most desirable option is to pump the manure when the building is empty so that animals are not at risk,” Schmidt said. “However, this isn’t always an option. At the very least, people should remain outside the building during the pumping process. Ignition sources such as heaters, motors and other electrical components should be turned off. Ventilation of the building should be maximized by adjusting curtains and vents. While fans present a potential ignition source, they also provide ventilation, which is a highly important safety measure.”

Farming is a dangerous profession and management of manure contributes to the injury risks for farmers.

“It’s always better to take the time to understand the risks related to handling manure,” Schmidt said. “Gases are just one element of danger. We’ve all heard or experienced an incident when moving parts on equipment such as power-take-off or spreader bar caught a pant leg or shirt sleeve. The results are always tragic and often deadly.”

Schmidt prefers to hear from a farmer who wants to find out if something is a risk rather than learn about a tragic accident that could have been prevented.

Recently, she was contacted by a swine producer who, while doing some necessary welding inside his barn, noticed tiny flashes of fire beneath the slats as particles from the welder fell into the pit.

“He thought it seemed really odd and believed he should find out what was causing it,” Schmidt said. “What he didn’t realize is that methane was present in his pit and the welding sparks could have easily caused an explosion or fire. I thanked him profusely for taking time to stop and seek information rather than forging ahead with the task.”

Safety practices to help reduce issues with manure handling equipment include:

1. Ensure all employees understand how to safely operate equipment.

2. Clearly communicate to employees that they will not be penalized for taking time to work safely.

3. Use all equipment safeguards, including dead man switches, equipment guards, etc.

4. Use lockout/tagout practices during equipment maintenance.

Additional tips for staying safe during manure application season:

1. Fence manure storage areas to prevent accidental entry.

2. Recognize the potential for hydrogen sulfide risks, know how to address the situation if it occurs, and don’t assume it can’t happen to you.

3. Heed warning signs on equipment and do not disable safety features.

4. Recognize the potential for methane pockets and address methane concerns as soon as possible.

5. Train everyone, encourage safety over speed, provide PPE, and stop and think!

Find additional details about safely handling manure at this link to “Mindful Manure Management” –


The Sabetha Herald1963 Posts

The Sabetha Herald has been serving Sabetha since 1876.


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