A slurry pit (also farm slurry pit, slurry tank, slurry lagoon, and slurry store) is a hole, a dam, or a circular concrete structure where farmers gather all animal waste and unusable organic matter, such as hay, and the run-off water from the washing of dairies, stables, and barns, in order to convert the slurry, over a lengthy period of time, into fertilizer that can be used to fertilize croplands.[1] [2] The decomposition of the slurry waste material produces noxious and poisonous gases that make a slurry pit potentially lethal for a person without a breathing apparatus.[3]
The slurry (blend of liquid manure) is a very rich source of nitrogen, phosphorus, and potassium.
Slurry pits present risks of drowning, as well as of suffocation. Decomposition generates gases such as ammonia, methane, carbon dioxide, and hydrogen sulphide. The latter two are heavier than air and will not disperse quickly from low places. Carbon dioxide is odorless, and hydrogen sulfide quickly becomes undetectable by odor by destroying victims' sense of smell. If inhaled, they can cause rapid unconsciousness by poisoning or displacement of oxygen leading to hypoxia. Death may follow then from poisoning or hypoxia directly, or by drowning caused by unconsciousness.[4] [5] [6] [7] [8] [9] The UK Health and Safety Executive also warns against the creation of naked flames near slurry pits, as gases such as methane are inherently flammable.[10] The Health and Safety Executive of Northern Ireland specifies activity in a slurry pit as specialist work, requiring the worker to have a separate air supply and a harness lifeline managed by two additional people outside the tank. According to the Health and Safety Authority of Ireland, between 2000 and 2010, 30% of all child fatalities on farms occurred from drowning in slurry or water.[11]