How to safely handle and store fertiliser on-farm

Ammonium nitrate (AN) fertilisers, such as OCI Nutramon, are a key requirement for many farms across the UK. They are a typically non-toxic and will not burn or explode unless exposed to excessive heat.

However, AN fertilisers are susceptible to thermal decomposition – a chemical reaction caused by heat – and as a result can begin to release toxic fumes if left exposed to sun or other forms of heat for extended periods of time.

Indoor fertiliser storage

In ideal circumstances fertiliser should be stored in a dedicated dry, covered, and well-ventilated storage unit. Due to its susceptibility to thermal decomposition, it is important to ensure that AN is kept in an area away from direct sunlight or intense heat.

  • Bags should be stored on a clean, flat surface, interlocked with each other, at no more than three bags high
  • Each stack of bags should consist of a maximum of 300 tonnes of fertiliser, with at least one metre spacing between each stack
  • Stacks of fertiliser should be far away from any type of combustible or materials or those that could cause contamination e.g. bedding, fuel, pesticides, urea, or manure

Outdoor fertiliser storage

If the option to store fertiliser indoors is not available, there are several precautions you can take to protect the health and safety of those working on the farm, and the farm itself, from any risks associated with outdoor fertiliser storage.

Firstly, it is important to ensure that fertiliser storage areas are secure and fully fenced, to prevent any unauthorised individuals from accessing the space.

Inside the fenced area, stacks should be stored on pallets on level ground. It is essential to ensure these are fully sheeted with tarpaulin to protect from the elements and excessive temperate changes, as well as preventing any environmental contamination.

It is strongly advised to avoid leaving any fertiliser in fields or open access areas overnight.

Large quantities

If storing more than 25 tonnes of AN fertiliser, comprising of 28% or higher nitrogen, farmers should inform their local fire service, in addition to the Health and Safety Executive (HSE).

If combined with open flames fertiliser can leak toxic fumes or explode. This will ensure that the emergency services are fully prepared in the unfortunate event of a farm fire.

Top tips for safe fertiliser storage

The HSE recommends the following top tips for safe and secure fertiliser storage.

  • Ensure all stacks are secure and stable
  • Clear any spillages immediately, do not use organic materials, such as shavings or woodchips, as a cleaning aid
  • Carry out regular checks or all fertiliser stores and report any missing quantities to the police
  • Keep all walls, floors, and ceilings clean and dry to prevent contamination
  • Only purchase fertiliser from Fertiliser Industry Assurance Scheme (FIAS) approved suppliers

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