Spring is traditionally a time when manure from liquid storage structures gets agitated, pumped, hauled and applied to fields. Farmers, farm workers and custom operators all need to be aware of the safety threat posed by manure gases. At the recent conservation tillage conference, I attended a session entitled “Safety Around Manure Storage Areas” by Kent McGuire from the OSU Extension Agricultural Safety and Health Program. Manure pits and manure lagoons produce four main toxic gases during the anaerobic digestion process that occurs in storage. Agitating and pumping manure from those structures releases those gases.
The gases of most concern are hydrogen sulfide, methane, ammonia and carbon dioxide. Methane and ammonia are lighter than air and hydrogen sulfide is heavier than air. Hydrogen sulfide has been responsible for numerous tragic, manure storage related deaths. It has a characteristic “rotten egg” smell at low concentrations, but as the concentration increases, the sense of smell becomes paralyzed. Low concentrations will cause dizziness, headache, nausea and respiratory tract irritation. High concentrations cause unconsciousness, respiratory failure and death. A lethal concentration is 1,000 parts per million (ppm). At this concentration, death is quick, within minutes. Ammonia has a characteristic sharp, pungent odor. At concentrations ranging from 6 to 20 ppm, ammonia will irritate the eyes and throat. Higher concentrations can irritate the respiratory system, resulting in wheezing and shortness of breath. Methane poses a threat because it is lighter than air and is explosive at levels of 50,000 ppm and higher. The threat from carbon dioxide is that it replaces oxygen in our breathing mix. We need 19 to 20% oxygen in the air we breathe for good health. Carbon dioxide lowers the percentage of oxygen in our system and can affect our cognitive processes. Breathing a concentration of 20% to 25% carbon dioxide will result in death.
Don’t overlook the danger of moving parts on machinery and equipment as the manure structure is agitated and manure is loaded into hauling equipment. Manure pumps, agitators and PTO shafts all have the potential to snag and draw in loose clothing, long hair, jewelry, fingers or feet with tragic consequences.
For more information about safety tips when working around manure storage structures, contact the Wayne County Extension office at 330-264-8722.