Farmers warned over toxic slurry gas
Farmers have been warned to exercise caution around stored slurry after four cattle were killed by toxic gas emanating from a slurry store in a freak accident. A Scottish beef producer in the Borders region took advantage of recent favourable weather conditions to empty a slurry store underneath a cowshed, but large quantities of gypsum (Calcium Sulphate) from waste plaster board being used to dry straw in a separate building had washed into the slurry and started a reaction that led to the production of lethal gaseous Hydrogen Sulphide.
Hydrogen Sulphide is a dangerous heavier-than-air gas that accumulates in poorly ventilated spaces and has a characteristic smell of rotting eggs. It attacks the respiratory and central nervous systems, and is rapidly fatal. Nine people were killed in a Hydrogen Sulphide leak in Denver City, Texas in 1975, and it was previously used as a chemical weapon by the British Army during the First World War.
Although the incident was an unusual one, the Scottish Agricultural College (SAC) has issued a special hazard warning to farmers. “SAC warns producers who are using waste plaster board or other gypsum sources to remember this message and, as an additional safeguard, ensure that the product is stored and used in a way which completely avoids any potential contamination of slurry supplies. While this use of gypsum sources is relatively uncommon in Scotland it is believed to be more widely used in England where there is more available.” said a spokesperson.
The warning was seconded by NFU Scotland spokesman Bob Carruth, who added that the Union had received reports of a similar incident in which nine dairy cattle were also killed by toxic gas generated during slurry mixing on a Lanarkshire farm. “The dangers to farmers, their staff and their stock from mixing slurry are stark. SAC’s clear advice on removing stock from buildings, providing proper ventilation, staying clear of buildings while mixing is taking place and having staff support should be followed at all times. The loss of stock and the threat to human life are avoidable. Even though farmers may be under pressure to get slurry out, their own safety and the well-being of their staff and their animals must remain uppermost in their minds.” he said.
The BSAVA has opened submissions for the BSAVA Clinical Research Abstracts 2026.
