9TH August 2012
Gypsum in Animal Bedding Briefing
Potential risk to human health from hydrogen sulphide gas generated when
gypsum is used as animal bedding.
Issue
Since the beginning of the year, concerns have been raised in the EA, NIEA, SEPA, Health & Safety
Executive (HSE) and key industries about the practice of adding gypsum and gypsum based
products, e.g. recycled plasterboard, to livestock bedding.
Hydrogen sulphide is a toxic gas that can be generated by slurry and manure. There is evidence to
suggest that when gypsum and gypsum containing wastes are used as livestock bedding the
concentration of hydrogen sulphide gas produced significantly increases. There have been instances
reported in the media recently of cattle dying from Hydrogen sulphide poisoning. This is also being
investigated, by the HSE, in relation to two recent human fatalities caused by exposure to high levels
of hydrogen sulphide in a slurry system.
Hydrogen sulphide is highly toxic and can cause unconsciousness after taking a single breath
at high concentration. Hydrogen sulphide has a rotten egg odour at low levels but at higher
levels it cannot be detected.
Atmospheric monitoring devices may not give adequate warning of the danger so do not rely
on them - agitation of the slurry, for example to make pumping out easier, can greatly enhance the
rate at which gas is given off and suddenly release high concentrations of hydrogen sulphide.
What you need to do
Check what bedding is being used for livestock before entering buildings or areas near manure and
slurry systems. If the bedding is gypsum, mixed with gypsum or is plasterboard do not enter or keep
livestock in buildings or any confined / restricted spaces.
For further information see the Environment Agency’s position statement. There are no waste
exemptions that allow waste gypsum or plasterboard to be used as animal bedding. Plasterboard
backing paper with the gypsum removed can be used as bedding in accordance with U8 exemption.
Although there are no controls over virgin gypsum being used as animal bedding, the risks are
identical.
There is guidance from HSE on the generation of toxic slurry gases whilst stirring slurry available in
'Managing confined spaces on farms' http://www.hse.gov.uk/pubns/ais26.pdf