What are the 3 most common causes of fuel spills?
Fuel spills are notorious for the damage they can cause to the environment and surrounding wildlife, as well as to your business reputation too. You probably don’t need us to go into the details – they’re already very well documented – and anyway, the scale of their effects has also been extensively covered in other industry research. For example, the Highways England Diesel Spillage Best Practice Guide shows that most incidents have surprisingly simple causes. The Transport Research Laboratory carried out a major survey in 2010 and revealed that unsecured, damaged, or missing fuel caps accounted for many of the spills recorded.
Other frequent issues were drivers filling tanks right up to the brim, the absence of protective anti-spill devices, and the failure of tanks that had become corroded or ruptured. They’re all particularly valuable insights, especially since they can help to provide useful areas to focus on in terms of preventing fuel spills in the first place.
Poor maintenance and inspection practices
Vehicles and fuel tanks are generally subjected to stress and wear over time, and without regular checks, small defects can grow into big problems. Corrosion is one of the clearest examples of this. Metal tanks especially can gradually degrade when they’re exposed to water, road salt, and temperature changes, and this process tends to compromise the integrity of the tank. Once it’s weakened, even minor impacts or vibrations could cause cracks or leaks – and a ruptured tank can often be in danger of spilling significant amounts of fuel.
Inspection routines can also play a part. Without systematic checks of caps, seals, and connecting components, that can lead to the risk of missing crucial damage. A worn seal or degraded gasket might not seem urgent at first glance, but these weaknesses easily end up causing larger leaks. It’s one of the many reasons why preventive maintenance is so important – it helps extend the life of your fuel system, and reduces the likelihood of disruption caused by an incident on the road.
Human error during handling and transfer
It’s one of those unfortunate truths that repetition can lead to complacency. A simple mistake like not securing a fuel cap properly after refuelling could result in a steady drip of fuel that escapes without anyone noticing until it has become a hazard. Further risks can also be caused by practices such as ‘brimming’ or ‘necking’ a tank by filling it right up to the cap. Once the vehicle begins moving, heat expansion or vibrations can push fuel out of the filler neck, leaving a dangerous trail behind.
Handling mistakes can also contribute in other ways. Connecting the wrong hose or leaving a valve open during a transfer are small lapses that can quickly turn into significant spills. Unfortunately, sometimes it’s the very familiarity of the task that allows oversights to creep in. One of the most important ways of dealing with this generally involves training and reinforcement of best practice – both vital to reduce the risk of fuel loss caused by mistakes.
Equipment faults and failures
Equipment faults are one of the most common culprits of spill incidents, and missing or defective fuel caps remain one of the biggest contributors to preventable leaks. A cap that’s cracked, warped, or absent completely lets fuel escape while the vehicle is in motion. Even if the cap looks tightened, a damaged thread or compromised seal can still make it useless and leave your fleet at risk of spills.
Thankfully, anti-siphon devices like our very own TankSafe Optimum provide a reliable way to address this. Its primary function is to secure your fuel, preventing theft from your tanks via ‘skimming’, where the top six or more inches of fuel are removed, often by company employees or other people in positions of trust. TankSafe Optimum has been type-approved, and as well as a specific anti-spill flap, it includes a float valve which rises to the top of the chamber as the tank is filled. This creates a seal which is held in place by the pressure of the fuel itself. This means overfilling is impossible, effectively preventing spillage.
In addition to developing TankSafe Optimum, we’ve also produced guidance for commercial vehicle drivers and operators. Reinforcing the findings of Highways England and the Transport Research Laboratory, our guidance includes simple things like carrying out vehicle checks and the value of having spill kits in your vehicles. We also cover fitting fuel caps with anti-siphon devices and self-sealing tanks; and installing guard rails to the sides and extended catwalks on the top of the fuel tank for protection.
And of course, if you’re looking for peace of mind against all the risks associated with diesel spills, you’re in exactly the right place. You can read more about how TankSafe Optimum works, or don’t hesitate to get in touch with our team here at TankSafe if you have any further questions about the best ways to protect your fuel in 2025. Give us a quick call on 01253 400 401, and we'll be happy to help however we can!