Farmers urged to take extra care when mixing slurry

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

Because of the wet year many cattle were kept indoors for extended periods of time in 2017, meaning this year many tanks are already at capacity.

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

‘One breath can kill’

Reminding farmers of the dangers, Malcolm Downey, principal inspector of HSENI’s farm safety team, said: “Before starting any job on the farm – including slurry mixing – take time to stop, think and safely plan the work ahead.

Do not take any chances when mixing slurry. As the closed period comes to an end, I urge farmers to reflect on the safe slurry mixing code – remembering that just one breath can kill.

“Cover openings and keep children and animals far away during the mixing process.

“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.”

The slurry mixing code

  • Keep children away from the area at all times when working with slurry;
  • 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 or mixer to stop anything falling in;
  • Start the pump or mixer and 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.

What is released is a mixture of gases – including the extremely poisonous gas hydrogen sulphide. Even a low concentration of hydrogen sulphide can be dangerous.

At higher concentrations you will rapidly find it harder to breathe and become confused – and at certain concentrations, just one breath can kill.

The first 30 minutes are the most dangerous; so, it is important for farmers to leave the shed as soon as mixing starts – and to stay out for at least 30 minutes.


  • Rely on filter-type face masks;
  • Use gas monitors as a substitute for working safely;
  • Have naked flames nearby, as slurry gas mixture is flammable;
  • Stand close to the exhaust of a vacuum tanker when it is being filled.

Seven fatal accidents took place on farms in Northern Ireland in 2017.

What to do if something goes wrong?

  • If you find someone has been overcome during slurry mixing, if possible, stop the pump and get the person to fresh air; but, do not put yourself at risk in the process;
  • If breathing is weak or stopped, artificial respiration may be effective;
  • Contact the emergency services and seek immediate medical attention.

For more information about working safely with slurry or general farming health and safety issues please contact the HSENI helpline on: 0800-0320121.

Alternatively, those seeking more information can visit the farm safety page on the HSENI website: