Working with manure presents some special safety challenges beyond the basic farm dangers of working with large machinery, stress, and fatigue. One of those challenges is harmful manure gases.
Manure gas safety risks
The first step to manure gas safety is to understand the risks. In most operations, hydrogen sulfide and methane are of the biggest concern. Other gases such as ammonia, carbon dioxide, and carbon monoxide can also cause health concerns but can be more easily managed through ventilation and equipment upkeep.
Hydrogen sulfide is a colorless gas created during anaerobic (low/no oxygen) decomposition of manure which is most commonly found in liquid storage pits. It accumulates in the manure and is then released during agitation and pumping. Though it can smell like rotten eggs, you can’t solely trust your nose since your sense of smell becomes dulled to persistent odors. Levels as low as 0.1 ppm can cause eye irritation, and death can occur at just 200 ppm if there is extended exposure. Hydrogen sulfide is also dangerous because it can cause unconsciousness that can lead to drowning if near the pit, fall injury, and prolonged exposure that can cause lung damage and even death. Animals are also susceptible to these gases and may be in harm’s way, especially in below-barn pits. Keep in mind that high levels of this gas don’t just occur in deep pits or in confinement; open pits can also accumulate high hydrogen sulfide levels since it tends to hang near the ground.
Methane is also a colorless gas that is heavier than air and is created by manure decomposition. While the gas itself is not typically toxic, it can cause asphyxiation as it displaces oxygen and breathable air. The other concern with methane is that it’s highly flammable. When levels reach fove to 15 percent by volume, fires and explosions become a hazard. It is also quite mobile and can accumulate in unexpected areas, so ignition points far across the barn from the agitated manure can still pose a threat.
Safety tips
To avoid the above risks, develop safety protocols for your farm or operation when it comes to handling manure, especially activities like agitation and pumping. When working with manure, follow these tips:
Agitation and pumping:
- Remove livestock and personnel from the manure basin area where they might inhale dangerous gases.
- Turn on any fans and open any ventilation pathways available.
- Disconnect any electrical equipment that may cause a spark.
- Have the proper personal protective equipment (self-contained breathing apparatus and harness with lifeline) on hand in case you need to enter the pit or basin.
- Use personal gas monitors that have been calibrated recently.
- Have an Emergency Response Plan with updated phone numbers and contacts in case of an accident or spill.
- Put up signage or other communication measures to inform others that agitation and pumping are occurring.
- Train all employees and personnel to follow safety protocols and plans.
- If you see a person is overcome by gas, call 911 and do not follow them into the pit to attempt a rescue unless you are wearing a self-contained breathing system. The same gases that rendered the other unconscious will likely cause you to pass out too.•
