Manure Pit Gas Hazards Safety Facts And Tips

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Manure Pit Gas Hazards Safety Facts And Tips

Principal Author / Publisher:Safetyhow Admin

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A confined-space hazard that often claims multiple lives before anyone realizes there is a danger is manure gas. Manure pits can be oxygen-deficient, toxic and explosive. There are four gases in manure pits that are of primary concern.

Hydrogen Sulfide is a highly toxic gas that is heavier than air. It can cause dizziness, unconsciousness and death. At low concentrations it may smell like rotten eggs, but at higher concentrations it deadens the sense of smell so that no odor can be detected.

Carbon Dioxide is an odorless, tasteless gas that is heavier than air. It displaces the oxygen supply in the bloodstream, which can cause unconsciousness and death.

Ammonia is a gas that is lighter than air. It has a pungent smell and can irritate the eyes and respiratory tract. Ammonia also displaces oxygen in the bloodstream.

Methane is also a gas that is lighter than air. The primary hazard of methane gas is that it can create an explosive atmosphere. This gas also displaces oxygen.
Safety tips

Never enter a manure pit alone.
Label the manure pit and manure storage areas to warn of the gas hazards.
Obtain and use monitoring equipment to determine the level of gases present in the manure storage area.
A self-contained breathing apparatus must be worn when entering a manure storage area and the person wearing it should be trained in its use. A safety harness should also be worn and personnel should be available outside the storage area to monitor the entrant's progress.

Inspection

Do fences/metal-grill covers restrict pit access?
Are there manure gas warning labels near pit?

Toxic gases, especially in confined spaces such as manure pits, silos and grain bins, can pose hazards to humans and animals (Figure 2). Four gases of major concern can be found in manure pits. They are hydrogen sulfide (H2S), ammonia (NH3), carbon dioxide (CO2) and methane (CH4).
The primary health hazards of these gases are:

Toxic or poisonous reactions that can occur in people or animals. Hydrogen sulfide is the most toxic of these gases.
Oxygen depletion, which can result in asphyxiation. Hydrogen sulfide, ammonia and carbon dioxide gases are all heavier than air. During agitation of the pit and under conditions of poor ventilation, these gases will replace the oxygen in the air.
Explosions that can occur when oxygen mixes with the gases. This is primarily a problem with methane.

Characteristics

Hydrogen sulfide:

Most dangerous gas associated with waste decomposition.
Distinct rotten egg smell; heavier than air.
After breathing this gas a short time, sense of smell becomes fatigued and you may no longer be able to detect any odor. Gives a false sense of security. At low concentrations the gas irritates the eyes and respiratory tract; at moderate levels, causes headaches, nausea and dizziness; at high concentrations, death will occur.

Ammonia:

Distinct, sharp, penetrating odor detectable at very low concentrations.
Heavier than air.
At moderate levels of concentration, can irritate eyes and respiratory tract; at high concentrations, can cause ulceration to the eyes and severe irritation to the respiratory tract.

Carbon dioxide:

Odorless, heavier than air, difficult to detect.
Primarily replaces oxygen in air and acts as an asphyxiant. At moderate concentrations, shortness of breath and dizziness can occur.
A major contributing factor to animal deaths by asphyxiation in confinement buildings, which often occurs during ventilation failure.

Methane:

Odorless and lighter than air, so it tends to accumulate near the tops of manure pits.
Considered an asphyxiant at extremely high concentrations. Main hazard is its flammable, explosive nature.

PREVENTION

Under normal conditions in a well-designed, properly constructed building with good ventilation, you should not have many problems with gas accumulation. But serious problems can occur if the proper precautions are not followed.
Provide as much ventilation as possible in the pit and building during agitation of the waste. Although pits are agitated only a few times a year, most human and livestock deaths or illnesses occur at these times.
No workers should be near the pit or in the building during agitation. If possible, remove all animals from the building.
Avoid entering a manure pit at any time, if at all possible. Even if the pit has been emptied, it still may be lacking in oxygen or have high concentrations of toxic gases.
Always keep at least one foot of space between the highest manure level and the slats. This protects the animals who lie on the slats and inhale the gases that will accumulate at the surface of the pit.

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Videos

References

http://www.mysafetysign.com/deadly-manure-gases-po ... -7874
http://www.nsc.org/news_resources/Resources/Pages/ ... mUdqU
http://nasdonline.org/document/1090/d000876/animal ... .html
https://www.youtube.com/watch?v=jSBqxfDpoyI
https://www.youtube.com/watch?v=9pk4JZAlcLw

Manure Pit Gas Hazards Safety Facts And Tips

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