HARRISBURG, Pa. — Several farm accidents have recently been reported in Pennsylvania, New York and Ohio involving livestock deaths, people being overcome with gases, stronger than usual odors and nuisance complaints due to increased odors, all where gypsum was used as a bedding material.
The Natural Resources Conservation Service (NRCS) is strongly recommending that farmers err on the side of caution. Until research is completed, implement additional safety measures prior to agitating manure storages when adding gypsum or any type of sulfur-containing material to manure.
When manure is stored in either open or closed structures, a variety of gasses can form and reach dangerous levels. The gases are produced by the natural breakdown of the manure. Gases can include hydrogen sulfide, ammonia, methane and carbon dioxide.
Normally, these gases are released into the atmosphere by passing through the surface of the manure. It is common to see these gases slowly bubbling off of the surface of stored manure.
Hydrogen sulfide is the most dangerous of the manure gases and can be deadly. At low levels, this colorless gas smells like rotten eggs and can cause discomfort, headaches, nausea and dizziness.
At higher levels, its odor is undetectable and can suddenly cause respiratory failure. A person could suddenly collapse, go into a coma or even die. At high concentrations, hydrogen sulfide does not give the shortness of breath warning that some of the other gases would present.
Hydrogen sulfide production levels can be elevated with the addition of sulfur-bearing ingredients. Sources of the additional sulfur can be gypsum bedding materials, poor-quality water, some low-cost feed ingredients such as distiller’s grains and silage leachate.
Hand-held gas meter readings taken during the last month at four farms have indicated highly elevated hydrogen sulfide (H2S) levels during agitation near and downwind of gypsum-bedded manure storage facilities.
At the manure storage surface, dangerously high levels of hydrogen sulfide were detected without any agitation. Readings at the nongypsum manure storage were much lower, within acceptable safety targets.
Anecdotal evidence and lab data has been reviewed from other recent farm accident reports where gypsum was used as a bedding material. It appears that the sulfur in gypsum may have contributed significantly to the harmful levels of hydrogen sulfide gas being released during manure agitation.
Although used in the U.S., some European countries have recently banned gypsum use for livestock bedding due to the potential for high hydrogen sulfide gas being formed under anaerobic, moist conditions.
Currently, there are no published or technical reports on hydrogen sulfide gas exposure levels with gypsum bedding use and its consequences in dairy manure. This information would surely aid in developing a safe solution to high levels of gas exposure.
Davis Hill, senior Extension associate at Penn State University, is developing a proposal for laboratory and on-farm analyses to study these issues.
It is important for farmers, their families and their employees to know of the unintended consequences of using gypsum and other sulfur additives. Normal safety precautions are not sufficient when materials known to increase levels of hydrogen sulfide are used.
The following standard safety actions and precautions need to be considered to ensure everyone’s safety for any activities involving manure storage or lagoon agitation for all operations.
• First aid and other safety equipment should be supplied and located near manure storage facilities.
• An emergency action plan including emergency telephone numbers should be developed and posted near the safety equipment and near all telephones.
• Open storage facilities should be fenced and posted with “Keep Out” signs.
• Signs should be prominently posted and maintained that warn of the hazard. Children and those who cannot read must be given special instruction or use symbols to ensure that they are aware of the hazard.
NRCS has developed a warning sign that will be required to be displayed on all new manure storage facilities. It is highly recommended that existing storages have the signs displayed as well.
• To minimize hazards, agitation of manure is best done on windy days.
• Access to underground storages shall be grated or gated.
• Do not enter a manure pit unless absolutely necessary and only then if the pit is first ventilated, air is supplied to a mask or a self-contained breathing apparatus, a safety harness and attached rope is worn, and there are two people standing by.
• Never attempt, without assistance, to rescue humans or livestock that have fallen into a manure storage structure or reception pit.
• Properly ventilate animal housing adjacent to agitation area or when animals are housed above storage.
Until more is known, additional safety measures should need to be taken for sites where any type of sulfur product has been added to the manure. They include, but are not limited to the following:
• Inform your custom hauler and employees about the additional hazards.
• Post additional signs warning of potential deadly gases associated with agitation at all agitation locations.
• Verify that humans and animals are away from the agitation area prior to startup.
• Use a gas monitor or a self-contained breathing apparatus when operating or within agitation drift area.
• Remove all animals housed above the storage if underground facilities are agitated. Removal is the only recommended option. Opening the facility or adding ventilation may not be sufficient.
• Add these additional requirements to the existing Manure Management Safety Plan.
In summary, the agitation of manure has always been a potentially dangerous operation; however the addition of sulfur additives to the manure requires a greater level of safety measures to ensure no additional loss of life happens.
For additional information, contact your local USDA NRCS office, Penn State Extension and other farm-related experts.
Denise Coleman is state conservationist for the Natural Resources Conservation Service.