GPP 2 (Guidance for Pollution Prevention) for above-ground oil storage tanks is used across UK industry to reduce the risk of oil spills reaching drains, surface water and groundwater. If your site stores diesel, heating oil, lubricating oils, hydraulic oils or transformer oils in above-ground tanks, GPP 2 helps you answer the key operational questions: what good storage looks like, what secondary containment (bunding) is needed, how to manage deliveries and inspections, and what to do if a spill occurs.
Who is this for? Facilities and maintenance teams, EHS managers, site owners, landlords, data centres, industrial estates, logistics hubs, workshops, plant rooms and any operation with tanks, IBCs and day tanks feeding generators or critical systems. GPP 2 aligns well with typical data centre spill risks where fuel systems and resilience infrastructure run alongside drainage networks and sensitive equipment spaces.
Question: What is GPP 2 and why should we care?
Solution: GPP 2 is a recognised UK pollution prevention guidance note that sets out practical measures for the safe storage of oil in above-ground tanks. Its purpose is to prevent spills and leaks from becoming pollution incidents, enforcement action, fines, clean-up costs and reputational damage. In day-to-day terms, it supports your environmental compliance by helping you implement:
- Robust secondary containment (bunding) and drip control
- Good tank and pipework integrity (inspection and maintenance)
- Safe deliveries (filling controls, supervision, overfill prevention)
- Effective spill response (spill kits, drain protection, training)
For many sites, the highest risk is not the tank itself but the surrounding reality: pipework joints, fill points, valve operation, delivery mistakes, and spills travelling via yard drainage. That is why spill control and drain protection sit alongside bunding in a practical GPP 2 approach.
Question: What does compliant above-ground oil storage look like in practice?
Solution: A GPP 2-led setup focuses on preventing releases and containing any loss before it can escape the storage area. Practical measures usually include:
- Correct tank siting away from drains, watercourses, and high traffic impact zones where possible
- Secondary containment (bunding) designed to hold oil if the tank or fittings fail
- Protected fill points with clear labelling, secure caps and controlled access
- Valves, vents and gauges that are maintained, readable and protected from damage
- Spill response equipment stored nearby and sized to the likely incident
- Drain management so that oil cannot readily enter surface water drains
On mixed-use sites (including data centres, hospitals, and industrial parks), tanks often sit near plant rooms, generator compounds, and delivery routes. These areas should be treated as spill-critical zones, with bunding and quick-access spill kit provision as standard.
Question: How do we choose bunding and secondary containment for oil tanks?
Solution: Secondary containment is one of the most searched compliance topics because it is the most visible control. Your bunding solution should match the tank type, location, and operational use. Common approaches include:
- Bund walls and bunded tank compounds (masonry or proprietary systems) for fixed installations
- Bunded pallets and IBC bunds for smaller containers and intermediate storage
- Drip trays under valves, hose connections, filters and sampling points
As a practical rule, bunding should be maintained as usable containment capacity, not a permanent storage area. Keep bunds clear of rainwater where appropriate (without pumping contaminated water to drain) and repair cracks, failed sealants, or degraded linings quickly.
If you need product selection support, use dedicated containment categories such as spill containment, drip trays and bunded solutions across the SERPRO range (internal links).
Question: What are the common failure points for above-ground oil tanks?
Solution: Most incidents come from predictable points you can control with routine checks and engineered containment:
- Overfills during deliveries (wrong tank, unattended filling, failed gauges)
- Leaking valves and flexible connections at day tanks and generator feed lines
- Damaged pipework from vehicle impact or vibration
- Corrosion on older tanks or poorly protected fittings
- Bund defects such as cracks, gaps, penetrations, or blocked drains
Data centre and critical infrastructure sites have an additional operational reality: tight change windows and high uptime requirements. Build inspections into planned maintenance and keep spill response tools at point-of-risk so you can act without waiting for stores access.
Question: How should we manage deliveries to reduce spill risk?
Solution: Treat every delivery as a spill-risk activity. Reduce risk with a written delivery procedure and a simple checklist. Controls often include:
- Confirm correct tank and product before connection
- Supervise filling and maintain communication with the driver
- Use overfill prevention and verify level indication works
- Protect fill points with drip trays and absorbents under coupling points
- Keep drain protection ready where a spill could enter gullies
For practical readiness, position a dedicated oil spill kit at the delivery point and another at the tank compound exit route. See spill kits for options (internal link).
Question: What should our inspection and maintenance routine include?
Solution: GPP 2 is best implemented as a repeatable routine rather than a one-off project. A typical inspection approach includes:
- Visual checks for staining, seepage, corrosion, and unusual odours
- Bund condition checks for cracks, penetrations and debris that reduces capacity
- Pipework and joints checks around valves, filters, pumps and flexible hoses
- Gauge and alarm functionality checks (where installed)
- Housekeeping to ensure absorbents, drain covers and spill kits are complete and accessible
Document what you checked, what you found, and what you fixed. Records provide evidence of control and help trend emerging issues before they become incidents.
Question: How do we stop oil getting into drains and causing a reportable incident?
Solution: Drains are the fastest route from a small spill to a major pollution problem. Combine preventative measures (good storage, bunding) with rapid intervention tools:
- Drain covers and drain blockers for immediate isolation of gullies
- Absorbent socks and booms to ring-fence a spill and stop migration
- Oil absorbent pads and rolls for fast clean-up of hydrocarbon spills
Where sites have multiple gullies (typical in loading bays, generator yards and car parks), map drain locations and store drain protection at the nearest point. For product options see drain protection and absorbents (internal links).
Question: What spill kit should we keep near above-ground oil tanks?
Solution: Select oil-only spill kits for hydrocarbons so they repel water and perform well outdoors. Position spill kits at the highest probability points: fill points, transfer pumps, generator day tanks and bund exits. A practical spill kit setup typically contains:
- Oil absorbent pads, socks and disposal bags
- Instructions and basic PPE (site-dependent)
- Drain protection items where drains are present
Match capacity to credible spill scenarios: small leaks (valves/filters), hose disconnect spills, and delivery coupling failures. SERPRO spill control guidance for critical environments is also relevant here: Spill Control in Data Centres (internal link).
Question: What does GPP 2 mean for data centres and critical infrastructure?
Solution: Data centres commonly store diesel for standby generators and may use day tanks, bulk tanks, transfer pumps and pipework routes across compound areas. GPP 2 controls translate into practical outcomes:
- Reduced downtime risk from fuel-related incidents
- Improved site safety in high-traffic delivery areas
- Better environmental compliance and incident prevention
- Faster response with point-of-need spill kits and drain protection
Example scenario: a minor leak from a generator day tank connection can migrate across a hardstanding and enter a gully within minutes. With a drip tray under the connection, an oil-only absorbent sock staged nearby, and a drain cover ready, you can contain and clean without escalation.
Question: What should we do if a spill happens despite controls?
Solution: Use a simple, rehearsed response that prioritises safety, containment and preventing drain entry:
- Stop the source if safe (close valve, isolate pump, stop delivery)
- Protect drains immediately (covers/blockers)
- Contain using absorbent socks/booms to prevent spread
- Recover and clean using oil absorbents and suitable tools
- Dispose of waste correctly as contaminated material
- Report and review internally, then improve controls to prevent recurrence
For sites with formal environmental management, build this into your spill response plan and train staff who might be first on scene: security, engineers, facilities teams and delivery reception.
Question: Where can we find official guidance for citation and compliance context?
Solution: Use recognised sources for policy and technical context, then implement practical controls on site.
These sources support a defensible approach to oil storage, bunding, spill control and drain protection, particularly where regulators or insurers request evidence of good practice.
Next steps: turn GPP 2 into a practical site standard
Solution: If you want GPP 2 to work operationally, keep it simple and repeatable:
- Audit your tanks, fill points, pipework routes, and nearby drains
- Verify bunding and drip control are adequate and maintained
- Stage spill kits, oil absorbents and drain protection at point-of-risk
- Train first responders and rehearse the first 5 minutes of a spill
Browse related controls: spill kits, drain protection, absorbents, and drip trays.