With the closed season around the corner – HSENI are reminding farmers to remain vigilant when mixing slurry

Date published: 05 October 2022

The Health and Safety Executive for Northern Ireland (HSENI) is reminding farmers to follow the slurry mixing code to stay safe, as the closed period for slurry spreading is due to commence at midnight on Saturday 15 October 2022.

Mixing slurry - one breath can kill

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.

Mixing slurry can be a dangerous job as the gas is released very quickly, and in large quantities, as soon as the mixing starts. 

The first 30 minutes are the most dangerous, so it is important to remove all stock from the shed before mixing starts and for farmers to leave the building as soon as the mixing starts. It is also vitally important to stay out of the shed for at least 30 minutes after the mixing starts. 

Camilla Mackey, Principal Inspector of the Agri-Food team at HSENI, said: “Coming up to the closed period can sometimes be hectic for farmers trying to get the last of their tanks emptied. Do not take any chances when mixing slurry, it is not worth losing your life over. Stop and think about the entire job and ensure you follow the slurry mixing code.

“Always keep children and animals away at all times during the mixing process. Farmers must stay out of the shed for 30 minutes after mixing starts or after moving or re-directing the pump.”

The slurry mixing code:

  • open all doors and windows
  • if possible, 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
  • 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
  • if you have to go into the building, make sure that another adult who knows what you are doing stays outside and can get help if needed
  • 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
  • rely on monitors at the start of mixing, the volumes of gas could exceed the capacity of the monitor
  • have naked flames near slurry, some parts of the slurry gas mixture is flammable
  • stand close to the pump/exhaust of a vacuum tanker when it is being filled

For more information about working safely with slurry contact the HSENI helpline on 0800 0320 121 or visit our farm safety topic page: www.hseni.gov.uk/farmsafety

Or you can visit our hseni.gov.uk/essentials page on our website and find out more information about how to ‘Give Slurry Space’.

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 (from height) 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 Northern Ireland Agricultural Producers Association (NIAPA) and the Farm Safety Foundation (FSF) 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 Farm Safety Partnership Affiliate is made up of the following organisations – AbbeyAutoline Insurance; ABP Group; Asda; Carson McDowell; Dale Farm; Danske Bank; Girlguiding Ulster; IOSH NI; Lakeland Dairies; Lantra; Livestock and Meat Commission Northern Ireland; Northern Counties Co-Operation; Northern Health and Social Care Trust; Northern Ireland Safety Group; Polaris Safety; Power NI; Ulster Bank and Rural Health Partnership. These organisations support the Farm Safety Partnership by working to raise the profile of farm safety in Northern Ireland. 
  4. The Health and Safety Executive for Northern Ireland (HSENI) is an Executive Non-Departmental Public Body, sponsored by the Department for the Economy.
  5. HSENI is the lead body responsible for the promotion and enforcement of health and safety at work standards in Northern Ireland.
  6. For media enquires please contact:  HSENI Press Office on 028 9024 3249 or email: media@hseni.gov.uk
  7. For out of office hours please contact the Duty Press Officer on 028 9037 8110.

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