FARMERS are being warned about the dangers of mixing slurry after toxic fumes killed several dairy cattle at a farm in Lanarkshire.

This most recent accident – on an un-named farm – has served as a potent reminder to the farming industry of the hazard of slurry fumes and the necessity to take vital precautions when mixing it when cattle or people are present.

A senior environmental consultant with SAC Consulting, Malcolm Sharp, told The Scottish Farmer: “When a farmer empties or mixes their slurry, a bacterial breakdown occurs, releasing a number of slurry gases – methane, carbon dioxide, ammonia, hydrogen sulphide, with the latter being the most dangerous.

"When mixed, these gases are released in large concentrations and it only takes one breath of hydrogen sulphide to kill somebody,” he stressed, adding that slurry gas is one of the biggest causes of casualties on farms – both human and animal.

Mr Sharp warned that farmers must prioritise a safe system of work before dealing with slurry and when mixing begins, all animals, children and people must be kept away from the shed for at least half an hour after the job is finished to give the gas time to disperse.

He added: “If possible, mixing should be done on a windy day as it will rapidly dilute and disperse hydrogen sulphide. H2S is heavier than air and tends to collect down at a low level just above the slats in a shed. Someone bending down to attend to a slurry pump can also put themselves at risk,” he said.

“When you start pumping the mixture and need to return to the building, for example to reposition the slurry pump, there is a chance that gases can be released again. Farmers need to be aware that you can’t use your sense of smell to detect the gas and often, with hydrogen sulphide monitors, by the time they detect the gas, it’s often too late.

"Also, farmers and contractors need to be aware that they can never rely on a filter face mask as they give no protection whatsoever,” he added.

As a final message, he stressed that no matter how experienced operators believe themselves to be, risks will remain: “It is very difficult to predict a biological process, therefore, a farmer might have been doing this job for a long time but that doesn’t reduce the potential risks involved.”

NFU Scotland president, Andrew McCornick, added: “Slurry gas is a silent killer and can quickly put the lives of man and animals in jeopardy. Farm deaths in other parts of the UK have served as a stark reminder of the dangers attached to mixing slurry but this loss of livestock in Lanarkshire shows there can be no room for complacency,” he stressed.

“I urge all livestock keepers to remind themselves of best practice when it comes to mixing slurry and to put safety first.”

* SRUC offers a whole risk assessment service and farmers are encouraged to talk to their local advisors with any concerns they may have with safety around slurry.