Like other hazards farmers become accustomed to, manure pit gases pose a lethal threat to the farmer, other workers, and livestock. Gases of concern in manure pits include:
- Hydrogen Sulfide: a highly toxic gas that can cause dizziness, unconsciousness, and death by suffocation. At low concentrations the gas has a smell similar to that of rotten eggs, but at high concentrations the victim can succumb the gas before even smelling it. Hydrogen Sulfide is heavier than air, as such it has the potential to concentrate in low places such as manure pits.
- Methane: a gas lighter than air, though it has the potential to displace oxygen in the bloodstream, the primary threat is that of explosion in higher thresholds.
- Ammonia: a gas also lighter than air, also displaces oxygen in the bloodstream. Ammonia has a pungent smell that can irritate the respiratory tract as well as eyes.
- Carbon Dioxide: an odorless, tasteless gas that also displaces oxygen in the bloodstream. Carbon dioxide is heavier than air, so it will also tend to concentrate in the pit near the surface of the manure.
- Oxygen: the oxygen level needs to be 19.5% at minimum.
To protect themselves and other farm workers, farmers should be utilizing a four-gas meter to monitor the atmosphere in and around manure pits, and especially before entering a confined space area such as the pit area. When monitoring the atmosphere, famers should test in the direction they are traveling and including 4 feet on each side.
Dan Neenan, Director of the National Education Center for Agricultural Safety offered this advice, “As with grain bins, avoid entering manure storage areas if at all possible. If you must enter the manure storage area, assign an attendant to monitor the situation. If you are the attendant and something goes wrong, call 9-1-1; do not attempt a rescue. If in or around the manure storage area, use a four-gas monitor to monitor levels of oxygen, hydrogen sulfide, carbon dioxide, and methane to ensure they remain at safe levels. It is also important to remember that when a pit is being agitated, the danger can expand to the area surrounding the pit, as some of the dangerous gases are heavier than air and can displace oxygen, possibly causing loss of consciousness or even death.”
- Restrict access to manure pits to keep others safe
- Educate others on the farm of the dangers of manure pits
- Use a four-gas meter to monitor the atmosphere when working around manure pits
- Never enter a manure pit alone
- If you are the attendant outside the pit, do not enter the pit under any circumstance