Livestock and Poultry Environmental Learning Center:

Home Page
Newsletter
Topics
Webcasts
More...

All articles about:

Handling, Storage & Mortalities

Manure storage structures are an integral part of livestock feeding operations. They allow for manure containment until conditions are favorable for land application or other treatment. Manure may be stored in enclosed structures, near or directly below the animal housing facility or it may be stored in open structures such as above ground tanks or storage ponds/lagoons.

The risks differ for each type of manure handling system. Enclosed structures are commonly associated with asphyxiation hazards related to gases produced during manure decomposition. Open structures are most often associated with drowning. Most types of systems include pumps or other mechanical components that present the risk of entanglement. It is critical that producers take the time to assess the risks on their operation and evaluate ways to prevent hazardous situations and to develop emergency response plans.

Enclosed Structure Hazards

Enclosed structures, especially those located below ground, are potentially the most hazardous for people and livestock. While being stored, manure undergoes decomposition. As a result, many potentially harmful or fatal gases are produced, but most remain at low levels or are adequately diluted by the ventilation system. Situations in which these gases can become deadly include:

• Agitation of the liquid manure prior to or during pumping from the pit
• Power outage or other failure of the ventilation system

The gases of greatest concern in these situations are listed below.

Hydrogen Sulfide

Hydrogen sulfide is the greatest danger to humans in enclosed manure storage areas. It has a characteristic “rotten egg” smell and is heavier than air, so it tends to collect in the lower levels of a structure and in corners of the storage area where air circulation is least available. It quickly desensitizes the sense of smell so that a person does not detect greater levels of the gas after breathing it. It can be rapidly released when manure is agitated. At low levels (10 ppm) it can irritate the eyes. Death can occur when it reaches levels of 500 ppm or greater. More information on this gas is available in the publication Hydrogen Sulfide in Manure Handling Systems: Health and Safety Issues.

Ammonia

Ammonia has a distinctive, sharp odor and is heavier than air. It becomes irritating to humans at around 50 ppm. If it reaches levels of 1000 ppm or more, it can be deadly, although most people are so uncomfortable at this level, they usually seek relief by leaving a building before it reaches dangerous concentrations. Prolonged exposure to high ammonia levels can also impact animal performance.

Methane

Methane is a concern because it is potentially explosive at levels above 50,000 ppm. It is lighter than air and odorless. With a properly designed manure treatment system, such as an anaerobic digester, that favors methane production, this gas production can be enhanced and possibly captured for use in electrical generation.

Carbon Dioxide

Carbon dioxide is odorless, but can cause asphyxiation if it displaces enough oxygen in the air. It is heavier than air and tends to accumulate in the same areas as hydrogen sulfide.

Open structure hazards

Open manure storage ponds or above ground storage tanks also pose hazards, the most obvious of which is drowning. A storage pond may form a crust on the surface that appears solid and capable of holding a person’s weight. Unfortunately, this is not always the case. Children are also at risk of drowning in these structures and safety considerations must always include ways to prevent access to these areas, such as fencing, gates with locks and outside walls on concrete structures that preclude easy entry.

This lagoon is enclosed by a fence to control access.

Recommended Reading

• University of Illinois Certified Livestock Management and Commercial Manure Haulers program.
  • Human Illness and Disease Issues in Livestock and Poultry Production Environments
  • Human Safety Issues in Livestock and Poultry Production Environments
• Manure Storage Hazards from Pennsylvania State University is a concise description of the hazards associated with manure storage structures and steps you can take to mitigate the risks.
• Safety Considerations for Manure Handing discusses the safety considerations for dry manure collection, handling and transportation. From the University of Wisconsin.
• National Ag Safety Database (from the Center for Disease Control) manure information is a collection of publications and resources from sources across the country.
• National Institute for Occupational Safety and Health (NIOSH) agricultural statistics includes general statistics on injuries and deaths on US farms. It also includes links to fatality investigation reports.

Authors: Chip Petrea, University of Illinois and Jill Heemstra University of Nebraska
Reviewers: Saqib Mukhtar, Texas AgriLife Extension; Jennifer Zwicke, USDA NRCS; Troy Chockley, USDA NRCS