The farming and agriculture sector plays an irreplaceable role in our lives, reliably bringing an array of crops, fruits, vegetables, dairy and meat products to our tables and businesses every day. However, due to the processes involved, this industry is also confronted by regular toxic gas risks. Hydrogen sulphide (H2S) is a particular concern, with toxic levels found on an array of farms, including in slurry pits and wastewater.
Alongside H2S, methane, carbon dioxide, and nitrous oxide emissions make the farming and agricultural sector, livestock farming in particular, a large contributor to global greenhouse gas emissions. Hazardous gases can be located within and emitted from silos, manure storages, anaerobic digesters, grain bins and improperly ventilated barns to name a few. All of these, if left unmonitored and undetected, can cause harm to humans, livestock and the environment in both the long and short term.
As well as seeking to utilise less hazardous, alternative materials within farming and agricultural processes, it is down to those in the sector to implement reliable and robust monitoring and gas detection equipment to stay abreast of the gas levels in each environment. Using this information, the control of said substances and gases is much more achievable.
The colourless and odourless methane (CH4), is a combustible gas, and comes from the process of anaerobic digestion of organic material. Depending on the storage and management of manure, which undergoes anaerobic decomposition over long periods of time, the concentrations of the gases it produces vary. Poorly ventilated spaces and higher temperatures can increase the amount of methane emitted. If there is a lack of airflow, such as in covered buildings and barns, methane levels can build up, get trapped and cause explosions. However if stored safely it can be used as fuel for agricultural equipment and engines.
Hydrogen sulphide (H2S), which can be found within a range of agricultural processes related to producing and consuming biogas, is a risk because it prevents oxygen being carried to the body’s vital organs and tissues. The chemical asphyxiant, again comes from anaerobic decomposition of organic materials, like manure, and is well known for its rotten egg smell. However higher concentrations of the gas hinder the sense of smell rendering it undetectable by human senses and increasing the danger.
Ammonia (NH3), is found in animal waste and can be spread and emitted further through slurry spreading on farming and agricultural land. It is characteristically a colourless gas with a pungent smell, and technically arises through the decomposition of nitrogen compounds in animal waste. It is harmful to human health as well as livestock wellbeing, as it has the capacity to cause respiratory diseases in livestock, and eye irritation, blindness, lung damage, alongside nose and throat damage and even death in humans. Poor ventilation heightens the damage caused by this gas.
Carbon dioxide is naturally produced in the atmosphere, however levels are dangerously increased through farming and agricultural processes. CO2, which is colourless and odourless, is emitted from agricultural equipment, crop and livestock production and other farming processes. CO2 can gather in certain areas, such as waste tanks and silos, causing the oxygen in the air to be displaced and increasing the risk of suffocation for animals and humans. Sealed silos, waste and grain storage spaces are specifically dangerous as CO2 can accumulate here and lead to them being unsuitable for humans without an external air supply.
Nitrogen dioxide (NO2), one of the highly reactive nitrous oxide group, can, at its worst, cause sudden death when consumed even from short term exposure. This gas causes suffocation, and is emitted from silos following specific chemical reactions of plant material. It is recognisable by its bleach-like smell and tends to create a red-brown haze. As it gathers above certain surfaces it can run into areas with livestock through silo chutes, and therefore poses a real danger to humans and animals in the vicinity. It can also affect lung function, cause internal bleeding, and ongoing respiratory problems.
In the UK, the Control of Substances Hazardous to Health is a regulation relevant across all sectors in which those within are regularly exposed to a number of harmful chemicals. This is no more applicable than in the farming and agricultural sector, through which workers encounter detergents, disinfectants, pesticides, fertilisers including ammonium nitrate and veterinary medicines. COSHH provides guidance and compliance outlines for employers to protect employees from these hazards.
The UK’s Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions was created by DEFRA in collaboration with the farming sector. It details the steps that need to be taken to reduce ammonia emissions within the given timeframe; of 8% by 2020 and 16% by 2030. Steps to be taken include, the best way to store and apply organic manures, ways to apply manufactured fertiliser, and ways to amend livestock diet and housing.
In the EU, the European Commission has launched a range of directives and schemes to govern safety within the farming sector in its member states. These include EU regulation 1151/2012 on quality schemes for agricultural products and foodstuffs, and EU regulation 668/2014 on how EU regulation 1151/2012 on quality schemes for agricultural products and foodstuffs should be applied.