If your site stores oil, fuel, chemicals or any hazardous liquid, you almost certainly have legal duties around spill containment. Get it wrong and you risk Environment Agency enforcement, clean-up bills and prosecution. This guide explains, in plain English, what UK law requires, what the 110% bunding rule means, and how to choose containment that keeps you compliant.
Is spill containment a legal requirement in the UK?
For most businesses, yes — though the duty comes from several overlapping pieces of legislation rather than one single "spill containment law". The main ones are:
- The Control of Pollution (Oil Storage) Regulations — if you store 200 litres or more of oil (in England), you must provide secondary containment such as a bund or drip tray. Similar rules apply across the devolved nations.
- COSHH 2002 — the Control of Substances Hazardous to Health Regulations require you to control exposure to hazardous substances, which includes preventing and containing spills.
- The Environmental Protection Act 1990 and your general duty of care — you must not allow pollutants to escape to land, drains or watercourses.
- DSEAR — where flammable liquids are involved, the Dangerous Substances and Explosive Atmospheres Regulations add containment and ignition-control duties.
The practical upshot is the same across all of them: if a container leaks, splits or overflows, you must have something in place to catch the liquid before it reaches the environment. That "something" is secondary containment.
Primary vs secondary containment
Primary containment is the container itself — the drum, IBC, can or tank. Secondary containment is the bund, sump or spill pallet that sits beneath it and catches the contents if the primary container fails. Regulators expect both. A drum on its own is primary containment only; put it on a bunded spill pallet and you have the secondary layer the law expects.
The 110% bunding rule explained
The capacity benchmark almost every UK site works to is the 110% rule. Your bund or spill pallet must be able to hold whichever is greater of:
- 110% of the volume of the largest single container stored within it, or
- 25% of the total volume of everything stored on it.
Two quick worked examples:
- A pallet holding four 205-litre drums (820 litres total). 110% of the largest drum = 225 litres. 25% of the total = 205 litres. You take the greater figure, so the sump must hold at least 225 litres.
- An IBC bund for a single 1,000-litre IBC. 110% of 1,000 = 1,100 litres — so you need an IBC spill pallet with at least an 1,100-litre sump.
Where liquids are stored in a water protection zone or close to a watercourse, regulators may expect containment of up to 100% of the total stored volume, so always check the local requirement for sensitive sites. Every spill pallet and bund lists its sump capacity precisely so you can match it to the rule.
What are the requirements for a spill pallet?
A compliant spill pallet should:
- Provide a sump sized to the 110%/25% rule for the containers it carries;
- Be made of a material that resists what you're storing — polyethylene for acids, solvents and most chemicals; steel where higher fire resistance is needed near flammables;
- Have a removable grid or deck so the bund underneath can be inspected and emptied;
- Be kept free of rainwater if outdoors — a sump full of rain has no spare capacity, so use a covered vault or lidded unit outside;
- Be inspected regularly and any captured liquid removed and disposed of correctly.
For drums, two- and four-drum spill pallets are the standard; for 1,000-litre containers, choose an IBC spill pallet or bund with an integral dispensing area so you can decant from a tap safely. To bund a whole area rather than single containers, sump flooring and floor sump pallets create a low-level bunded platform. You'll find all of these in our spill containment range.
What are the three C's of spill response?
Containment is only half the job — you also need a plan for when a spill happens. The widely used framework is the three C's: Control, Contain, Clean up:
- Control — stop the source. Right the drum, close the valve, plug the leak and stop more liquid escaping.
- Contain — stop the spill spreading. Your spill pallet or bund does this passively; spill kits with socks, booms and absorbent pads contain anything that escapes the bund and protect drains.
- Clean up — recover the liquid, decontaminate the area and dispose of contaminated absorbents as hazardous waste.
Is a spill kit a legal requirement?
No single UK regulation says "you must have a spill kit" by name — but COSHH 2002, the Environmental Protection Act and your duty of care all require you to be able to respond to a foreseeable spill. In practice that means a risk assessment will almost always conclude you need spill kits available wherever liquids are handled or stored. Treat them as the active partner to your passive containment: the bund catches the spill, the kit lets you deal with it.
Storing flammables and chemicals safely
Spill containment rarely sits on its own. If you store flammable liquids or COSHH substances indoors, the containers themselves should be kept in a compliant cabinet — see our COSHH and flammable storage cabinets, which combine a leak-tight sump with fire-resistant construction. For bulk drum storage, pair a sump pallet or bunded store with the right cabinet and a spill kit nearby.
A simple compliance checklist
- Identify every oil, fuel and hazardous liquid stored on site and its volume.
- Provide secondary containment sized to the 110%/25% rule for each store.
- Match the containment material to the liquid (poly for chemicals, steel for flammables).
- Keep outdoor bunds covered so rainwater doesn't use up capacity.
- Place spill kits where liquids are handled, and train staff in the three C's.
- Inspect bunds and pallets regularly; empty captured liquid and dispose of it correctly.
Containment is one of the lowest-cost ways to stay on the right side of environmental law — a spill pallet costs far less than a single pollution clean-up. Browse the full spill containment range to size the right solution for your site.
This guide is general information, not legal advice. Always check the current requirements for your site and activities — the HSE (hse.gov.uk) and your environmental regulator publish the definitive guidance.