SAC Consulting and SEPA urge Scottish farms to heed gypsum
6 December 2012
SAC Consulting (a Division of SRUC), and the Scottish
Environment Protection Agency (SEPA), Scotland's environmental
regulator, have today (6 December 2012) called on farmers in
Scotland to continue with strict protocols on how gypsum and
slurries are mixed and handled.
Recent reports have suggested a link between the use of gypsum,
from waste plasterboard and other gypsum-containing wastes, in
animal bedding and a number of livestock deaths when mixed with
The agitation and mixing of manures and slurries in livestock
sheds is already known to release hydrogen sulphide (H2S). The
toxic gas affects the nervous system causing a range of symptoms
including discomfort, disorientation, collapse, or sudden
As gypsum contains sulphur, mixing it with slurries will
increase the total amount of hydrogen sulphide gas produced.
Hydrogen sulphide will produce an odour but at concentrations above
140 parts per million, the human sense of smell becomes unable to
detect the odour. At concentrations of 700 parts per million,
hydrogen sulphide can be lethal. Farmers are reminded that
the use of waste gypsum in slurry and dry bedding systems for
livestock is illegal.
To understand the potential levels of hydrogen sulphide
associated with the use of gypsum in animal bedding, SAC Consulting
Environment and Design conducted an air quality assessment in
September 2012. The assessment aimed to determine whether
detectable levels of hydrogen sulphide gas could be found during
the removal of farm yard manure from a site where gypsum had been
It was found that as soon as the farm yard manure was disturbed
hydrogen sulphide gas was detected at levels up to 2705 parts per
million, while carbon dioxide readings also increased.
Gavin Hill from SAC Consulting's Farm Rural Business Services
said: "No matter what advantages are seen in using gypsum as animal
bedding, it is simply not a risk worth taking. Recent
tragedies have highlighted the issues that face us and we must take
all steps to eliminate the risks."
Gary Walker, Principal Policy Officer (Waste), of the Scottish
Environment Protection Agency (SEPA), said: "The results of this
study illustrate the dangers associated with the use of waste
gypsum in animal bedding. The use of plasterboard, gypsum and
gypsum-containing wastes can lead to the production of the highly
toxic gas hydrogen sulphide (H2S).
"When used in animal bedding, it is likely waste gypsum will
produce considerable levels of hydrogen sulphide due to the damp,
non-ventilated conditions. In such circumstances, hydrogen sulphide
presents a significant risk to animal and human life, as well as
the environment, and we would advise against anyone using it for
Information from SAC Consulting and SEPA on the use of waste
gypsum and slurry can be found at: www.sruc.ac.uk/gypsum
position statement can be found here
Notes to editors
SRUC was formed by the merger of Barony, Elmwood and Oatridge
Colleges with SAC (Scottish Agricultural College).
For information and advice from SAC Consulting, please contact
Gavin Hill on 0131 535 3434 or firstname.lastname@example.org.
SEPA Regulatory position
SEPA advises against the use of waste gypsum and gypsum from
waste plasterboard in animal bedding on basis that it may present a
serious risk to life.
As there are no exemptions in the waste legislation to allow the
use of waste gypsum and waste plasterboard as animal bedding, any
such uses may be reported to the Procurator Fiscal as an offence
under section 33 of the Environmental Protection Act 1990.
SEPA will not agree to the use of plasterboard and waste gypsum
as animal bedding until there is clear scientific evidence to
demonstrate that it does not pose a risk to livestock, humans and
the environment from hydrogen sulphide generation.
SEPA is aware that research into the use of gypsum in different
bedding systems may be undertaken and we will review this SEPA
Position Statement if and when the results of research become
The SAC study underlines the reasons for SEPA's clarification of
SAC General enquiries
Jane Smernicki, Head of Communications
Tel: 0131 535 4331 or 07979 245 943