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The Danger of Slurry Gas – A Timely Reminder

10 May 2024
Type Media Article

By Serena Gibbons, Education Officer, Teagasc Galway/Clare

The Health and Safety Authority in Northern Ireland (HSENI) recently highlighted a near miss incident involving slurry gas.

The near miss incident occurred on Sunday April 21st 2024. The farmers concerned were extremely fortunate and thankfully came away from the incident with their lives. It was a timely reminder that being complacent when agitating slurry could prove fatal. The extremely wet spring has all farmers and contractors under pressure to catch up on work and with the amount of work to be completed safety can be overlooked. It’s often not until a farmer encounters a “near miss” or worse, that attention quickly reverts to safety.

When slurry is agitated, bacterial decomposition of the slurry causes toxic gases such as Hydrogen Sulphide, Ammonia, Methane and Carbon Dioxide to be released. Hydrogen Sulphide is extremely poisonous both to people and animals. It affects the nervous system and even small concentrations can cause death. Smell is no indicator of the absence of gas, as many gases are odourless. Hydrogen Sulphide has a ‘rotten egg’ smell at low levels, but cannot be smelt at higher levels. High levels are released when slurry is agitated therefore you cannot rely on smell to indicate its presence.

On that Sunday, the root causes of the incident on the farm were:

  1. The day was warm, dry and calm with little wind to disperse the slurry gas
  2. The farmers left cattle in the shed

These are the two most common causes of slurry incidents

If animals are left in the shed during slurry agitation, there is the potential to put yourself and others at very serious risk of exposure of a deadly Hydrogen Sulphide (H₂S) gas. If a housed animal or animals go down in the shed, there is high chance you will instinctively enter the shed to get the animal(s) out, this could lead to an increased risk of a family member entering the shed to save you if you are overcome with slurry gas. If you remove animals in the first place there should be no need to enter the shed. While it may seem impractical to get animals out, it is not impossible. Think of the areas that you can improve around the yard with solid structures to allow you to temporarily put cattle out into the yard, is it possible to get lighter stock out into a paddock close to the shed? Farmers must ensure their own safety and that of their family and farm workers. This incident could very easily have been another tragic multiple death on farms.

It’s important to follow a safe system of work when working with slurry, especially during mixing operations. The late spring has meant that cattle were housed longer than usual and it has also reduced the amount of slurry that has been spread on land. This year there will be a higher amount of slurry spread after the first cut of silage. Housed animals will not be as big of a factor in summer months but nevertheless there are still practical issues to think about. It is important that safety is paramount when getting slurry out on the land. Take a minute to recap on the slurry code points below to ensure that you reduce the risks associated with slurry.

Please follow the Slurry Code:

  • Never agitate slurry in still air conditions, mix on a windy day
  • keep children away from the area at all times when working with slurry
  • take all animals out of the building before starting to mix slurry
  • ensure dogs are kept away for the duration of agitation
  • Open all doors and outlets to provide a draught.
  • Never stand over slats or near tank access points when agitation is in progress.
  • Avoid vigorous agitation in confined spaces.
  • start the pump/mixer and then stay out of the building for as long as possible -at least 30 minutes or longer depending on the size of the tank
  • if you have to re-enter to move the pump, or change the direction of the pump, leave the building as soon as this is done - do not go back in for at least another 30 minutes or longer depending on the size of the tank
  • Never enter the slurry tank unless you are wearing suitable breathing apparatus and/ or a harness attached to a lifeline controlled by at least two other adults positioned outside of the area.
  • Avoid smoking or the use of naked lights as slurry gases are highly flammable.
  • Gases can build up and remain in partially emptied tanks above the slurry
  • Communicate with family that agitation is taking place.