Farmers have again been warned of the dangers of slurry tanks in the wake of an accident that claimed the lives of a young rugby star, his brother and their father.
Ulster Rugby player Nevin Spence, 22, brother Graham, 30, and 58-year-old father Noel were killed after being overcome by poisonous fumes and falling into an underground slurry tank at the family farm in Co Down on Saturday. Relatives said the men died trying to save each other.
The region's Health and Safety Executive, which is investigating the incident, has reiterated its advice that farmers should not enter tanks and only mix slurry in ventilated areas.
"Our advice is not to go into slurry pits," said Jim King of the HSENI, adding that only experienced contractors should enter slurry tanks. "For the average farmer - don't go in, stay out and keep as much as you possibly can."
Mr King said he was aware of reports that the incident was triggered after a dog entered the tank but said the exact sequence of events could only be confirmed after consulting eyewitnesses, including grieving family members.
Nevin and Graham's sister Emma, who also inhaled fumes, has been released from hospital following treatment. Along with her mother Essie and sister Laura, the artist was being comforted by friends and relations at the family home on the Drumlough Road.
Ulster Rugby's next scheduled game on Friday night has been postponed as a mark of respect while a minute's silence will be held at all other RaboDirect PRO12 fixtures over the weekend. Books of condolences were opened at the home of Ulster Rugby at Ravenhill in east Belfast as supporters gravitated to the ground to pay their respects.
Mr King said the incident unfolded in an underground slurry tank on the Spences' diary farm, which has around 250 cows.
"We know that unfortunately both Noel, Graham and Nevin were overcome by the fumes of slurry gas and then fell into some slurry at the bottom of the tank," he told BBC Radio Ulster. It is understood the three men had been mixing slurry from outside the tank throughout the day. They entered the tank at around 6pm.
"They were working with the slurry all day, they had been mixing and drawing slurry all day, we understand," said Mr King. "That brings a particular problem as the slurry levels go down ... the space above the slurry becomes almost covered with an invisible mist of slurry gas which is mostly hydrogen sulphide. It's particularly poisonous and it also has the effect that in high concentrations it knocks out your sense of smell and sense of taste."