On a Friday afternoon in July, a massive explosion ripped through an industrial unit at Highlands Farm in Rettendon, Essex, sending a huge fireball into the sky and shaking houses up to 15 miles away. The blast, which was heard across the county, came from fertiliser inside one of the units catching alight during a fire. More than 100 firefighters were called to the scene, and a major incident was declared as crews worked to bring the blaze under control.
Fertiliser explosions are a known but rare hazard when certain types of fertiliser — particularly those containing ammonium nitrate — are involved in a fire. In the Essex incident, the fire service confirmed that fertiliser inside one of the industrial units exploded while crews were on the scene. The explosion was powerful enough to be felt and heard across the county, with residents comparing it to a sonic boom. The blaze was first reported at 4:50pm, and by the evening the fire service said the fire was under control and there was no wider risk to the public.
“Why fertiliser explodes in fires and what it means for UK safety”
Why does fertiliser explode? Ammonium nitrate is a common ingredient in agricultural fertilisers. It is also used in explosives. When heated in a fire, ammonium nitrate can decompose rapidly, releasing oxygen and causing a chain reaction that leads to a massive explosion. This is why fires at facilities storing large quantities of fertiliser can be so dangerous. In the Essex case, the fertiliser was stored in an industrial unit on farmland. The explosion occurred while fire crews were already tackling the blaze, which had spread to multiple industrial units and a field.
The incident in Essex is a reminder of the risks associated with storing fertiliser, particularly in rural areas. Farms and industrial units across the UK hold significant quantities of such chemicals. While safety regulations exist, accidents can still happen. The emergency services advised nearby residents to keep windows and doors closed due to smoke and evacuated some locals. Roads were closed, and firefighters remained at the scene overnight.
For UK readers, the question is whether similar incidents could occur in their area. Many agricultural communities store fertiliser, and a fire at a storage site can lead to dangerous explosions. The Health and Safety Executive (HSE) regulates the storage of ammonium nitrate, but compliance is not always perfect. The Essex event, while under control, shows how quickly a fire can escalate into a major incident.
Q: What is a fertiliser explosion? A fertiliser explosion occurs when a type of fertiliser containing ammonium nitrate is exposed to high heat, such as from a fire. The chemical decomposes rapidly, releasing gases that cause a massive blast. It can happen when fertiliser is stored in large quantities in industrial or agricultural settings.
Q: How common are fertiliser explosions in the UK? They are rare but serious. The most famous UK incident was the 2001 explosion at a fertiliser plant in Buncefield, Hertfordshire (though that was a fuel depot), and there have been smaller incidents at farms. The Essex fire is a recent example of how fertiliser can explode during a building fire, but such events are not a daily occurrence.
Q: What should I do if I live near a fertiliser explosion? Follow emergency services advice: keep windows and doors closed, avoid the area, and if you are told to evacuate, do so. The main danger is the blast itself and the smoke, which can be toxic. In the Essex incident, residents were advised to stay inside and keep windows shut.
Essex Fire Service said the blaze was under control by the evening, but the investigation into how the fire started will take time. The emergency services will review their response to mitigate future risks. For now, the incident serves as a stark reminder of the hidden dangers in everyday agricultural materials.