Slurry season brings renewed risks to farmers

Date published: 25 January 2022

With the closed period for spreading slurry coming to an end at midnight on 31 January, the Health and Safety Executive for Northern Ireland (HSENI) is urging farmers to take extra care when working with slurry.

Slurry mixing - one breath can kill

The mixing of slurry comes with many risks as it produces a dangerous mixture of gases, including methane, carbon monoxide, ammonia, and the extremely poisonous gas, hydrogen sulphide.

Slurry gas is a mixture of gases, including the extremely poisonous gas, hydrogen sulphide. Even a low concentration of hydrogen sulphide can knock out your sense of smell so you won’t even know it’s there. At higher concentrations you will rapidly find it harder to breathe and become confused - and at certain concentrations, just one breath can kill.

Camilla Mackey, Principal Inspector of HSENI’s Agriculture and Food team, said:

“It is that time of year again when our farmers start to prepare to empty their slurry tanks, some of which have filled up completely over the winter months.

“Before starting any job on the farm, including slurry mixing, take time to stop, think and safely plan the work ahead. Keep children and animals far AWAY during the slurry mixing process, ventilate the area and mix on a windy day where possible. ALWAYS remove livestock from the shed before starting to mix. Stay out of the building for AT LEAST 30 minutes after the mixing starts AND every time you move the pump or change the direction of mixing.

“Sadly in 2021 HSENI recorded one fatality involving slurry gas, however, there are countless near misses every year where farmers, employees or family members are gassed. It is critical that farmers follow the slurry mixing code. Slurry gas kills, it is as simple as that. Farmers are fully aware of this but continue to take chances. If you follow the slurry mixing code there should be no issue.”

The advice to farmers is to follow the slurry mixing code:


  • keep children away from the area at all times
  • if possible, mix on a windy day
  • open all doors
  • take all animals out of the building before starting to mix slurry
  • use outside mixing points first
  • if slats are removed, cover exposed areas of the tank beside the pump/mixer to stop anything falling in
  • start the pump/mixer – then get out and stay out of the building for as long as possible - at least 30 minutes
  • any time you have to go into the building try to make sure that another adult knows what you are doing and can get help if necessary
  • 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 as long as possible – at least another 30 minutes


  • rely on filter type facemasks
  • use gas monitors as a substitute for working safely
  • have naked flames near slurry, as slurry gas mixture is flammable
  • stand close to the exhaust of a vacuum tanker when it is being filled

For more information about working safely with slurry or general farming health and safety issues please contact the HSENI helpline on: 0800 0320 121 or visit our website at:

Notes to editors: 

  1. The Farm Safety Partnership’s ongoing ‘Stop and Think SAFE’ farm safety campaign focuses on the four main causes of death and injury on our farms – slurry, animals, falls and equipment (SAFE)
  2. The Farm Safety Partnership, which comprises the HSENI, the Department of Agriculture, Environment and Rural Affairs (DAERA), the Ulster Farmers’ Union (UFU), NFU Mutual (NFUM), the Young Farmers’ Clubs of Ulster (YFCU), the Farm Safety Foundation and the Northern Ireland Agricultural Producers Association (NIAPA), is tasked with assisting Northern Ireland’s farming community to work safely and tackle the problem of work-related fatalities and injuries on farms
  3. The Health and Safety Executive for Northern Ireland (HSENI) is an Executive Non-Departmental Public Body, sponsored by the Department for the Economy (DfE), and is the lead body responsible for the promotion and enforcement of health and safety at work standards in Northern Ireland
  4. For media enquiries please contact HSENI Press Office on 028 9024 3249 or email For out of office hours please contact the Duty Press Officer on 028 9037 8110

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