| EPA Rule | SPCC — 40 CFR Part 112 |
| Sizing Requirement | 110% of the largest single tank |
| Applies To | Oil/chemical storage >660 gal (single) or >1,320 gal total |
| PE Certification | Required for SPCC plans above 10,000 gal |
| IBC Tote (275 gal) | Minimum 303-gallon rated containment pallet |
| Water Tanks | SPCC not required — check state/permit requirements |
What Is Secondary Containment?
Secondary containment is a backup system that captures spills or leaks from a primary storage tank before they reach the ground, stormwater drainage, or navigable waterways. The "secondary" part means it's the second line of defense — the tank itself is primary, the containment structure around or under it is secondary.
For above-ground storage of oil and petroleum products, EPA's SPCC regulations (40 CFR Part 112) require secondary containment as a federal legal requirement. For chemical storage, OSHA 29 CFR 1910.120 and state environmental regulations typically apply. Many facilities also face secondary containment requirements through their NPDES stormwater permit or facility operating license, regardless of stored fluid type.
EPA SPCC Requirements — Who Needs Secondary Containment
The Spill Prevention, Control, and Countermeasure (SPCC) rule under 40 CFR Part 112 applies to facilities that store above-ground oil in quantities that could reasonably be expected to discharge to navigable waters. The thresholds that trigger SPCC requirements:
| Storage Situation | SPCC Triggered? | Requirements |
|---|---|---|
| Single tank <660 gallons oil | ❌ No (federal) | Check state regs |
| Single tank ≥660 gallons oil | ✅ Yes | Secondary containment required |
| Multiple tanks, total <1,320 gallons | ❌ No (federal) | Check state regs |
| Multiple tanks, total ≥1,320 gallons | ✅ Yes | SPCC plan + secondary containment |
| Total >10,000 gallons | ✅ Yes | SPCC plan must be PE-certified |
| Water or non-oil fluids only | ❌ No SPCC | State/permit regs may still apply |
The 110% Sizing Rule
Secondary containment must be sized to hold at least 110% of the volume of the largest single tank within the containment area. This is the most commonly misunderstood rule in SPCC compliance — it's the largest individual tank, not the total combined volume of all tanks.
| Tank Size | 110% Minimum | Typical Containment Needed |
|---|---|---|
| 275-gal IBC tote | 303 gallons | IBC containment pallet (303–330 gal rated) |
| 330-gal IBC tote | 363 gallons | IBC containment pallet (363+ gal rated) |
| 500-gallon tank | 550 gallons | Poly containment basin or earthen berm |
| 1,000-gallon tank | 1,100 gallons | Poly containment basin or concrete berm |
| 2,500-gallon tank | 2,750 gallons | Concrete berm, earthen berm, or liner system |
| 5,000-gallon tank | 5,500 gallons | Engineered earthen berm or concrete basin |
| 10,000-gallon tank | 11,000 gallons | Engineered containment — PE certification required |
Two or more tanks sharing one containment area: size the containment for 110% of the largest individual tank, plus the volume of all other tanks below their overflow point. In practice for most small facilities, designing the containment for 110% of the largest tank is the standard approach.
Types of Secondary Containment
1. IBC Tote Containment Pallets
The standard solution for 275- and 330-gallon IBC totes. A containment pallet is a poly or steel platform with an integrated sump that the tote sits on. The sump captures leaks from the tote's bottom valve or any fitting failure. Critical to verify: not all IBC pallets meet secondary containment requirements — look for pallets with a rated sump capacity of at least 110% of the tote volume and check that they're listed as secondary containment compliant, not just spill pallets.
2. Drum Containment Pallets
For 55-gallon drum storage, containment pallets hold 2 or 4 drums and provide a rated sump capacity of 66–88 gallons — meeting the 110% rule for individual drum storage. Available in poly (corrosion-resistant, lighter) and steel (heavier loads, forklift accessible).
3. Poly Spill Containment Basins
For tanks in the 500–2,500 gallon range that are too large for pallets, poly containment basins are the practical solution. These are pre-molded polyethylene structures that sit on a level pad and surround the tank. Snyder Industries and Norwesco manufacture standalone containment basins in capacities from 500 to 5,000 gallons. Advantages: no field fabrication, inherently corrosion-resistant, fast installation. Limitation: must be sized correctly for the tank and can be difficult to move once the tank is in place.
4. Portable Spill Berms
Folding or pop-up berms made from reinforced PVC or HDPE liner material. Used for temporary containment — vehicle maintenance areas, portable generator fuel tanks, construction site chemical storage. Capacities range from a few hundred to several thousand gallons. Not a permanent SPCC solution in most jurisdictions but accepted for temporary operations and emergency response staging.
5. Concrete and Earthen Berms
For permanent large-volume installations — bulk fuel tanks, large poly storage tanks, above-ground storage tank (AST) farms — concrete curbing or compacted earthen berms with a compatible liner are the standard. These are engineered structures that must be designed to meet the 110% rule, remain impermeable, and include a controlled drainage point for rainwater removal. Facilities over 10,000 gallons require a licensed PE to certify the SPCC plan, which includes the containment design.
6. Double-Wall Tanks (Integral Secondary Containment)
A double-wall tank integrates secondary containment into the tank itself — an inner primary tank sits inside an outer containment tank. Any leak from the inner tank is captured by the outer shell. For facilities where external secondary containment is impractical (limited space, aesthetic requirements, mobile installations), double-wall tanks satisfy SPCC requirements without a separate containment structure. Available in poly and steel from multiple manufacturers. Higher upfront cost but eliminates the external containment footprint entirely.
IBC Tote Spill Containment — Specific Requirements
IBC totes used for oil, fuel, DEF, or regulated chemicals are among the most common secondary containment compliance scenarios at industrial facilities. A few specifics that apply to IBC tote containment that don't always appear in generic SPCC guidance:
- The pallet must be rated for containment, not just spill control. Many standard IBC pallets are sold as "spill pallets" and have a lower sump capacity than required for secondary containment. Confirm the pallet's rated sump volume is ≥110% of the tote volume before purchasing for compliance purposes.
- Caged IBC totes need adequate clearance. The outer steel cage extends beyond the inner HDPE bottle. Make sure the containment pallet's dimensions accommodate the full cage footprint, not just the bottle.
- Multiple totes on one pallet. Pallets designed for two IBC totes exist — the containment sump must be sized for 110% of the largest individual tote, not the combined volume of both.
- Forklift access. Many containment pallets have integrated fork channels. Verify they're compatible with your lift equipment before specifying.
Spill Containment for Large Above-Ground Tanks
For poly storage tanks in the 500–10,000 gallon range used for fuel or chemical storage, secondary containment typically takes one of three forms:
Manufacturer-supplied containment basin: Snyder Industries, Norwesco, and other poly tank manufacturers offer matching containment basins designed to fit their tank lines. These are the fastest path to a compliant installation — the basin is sized correctly for the tank and the pair is documented together. Ask your tank supplier about matching containment at time of order.
Pre-cast concrete containment: Standard for commercial fuel storage. Pre-cast concrete curbing systems surround the tank and a liner is installed at the base. The drain must include a positive shut-off valve, normally kept closed and opened only to drain accumulated rainwater after visual inspection confirms no contamination.
Earthen berm with liner: Used for large agricultural and rural fuel storage where concrete work isn't practical. The berm is graded and compacted, then lined with an HDPE geomembrane rated for the stored fluid. Must be maintained — inspect annually for liner integrity, erosion, and berm condition.
Do You Need a Formal SPCC Plan?
An SPCC plan is required if your facility stores more than 1,320 gallons of oil above-ground in aggregate. The plan must include:
- Facility description and oil storage inventory
- Containment sizing documentation (showing 110% compliance)
- Inspection and testing procedures
- Personnel training records
- Emergency response contacts and procedures
- Drainage management procedures (the controlled drain requirement)
Facilities under 10,000 gallons with fewer than 3 spill incidents in the past 3 years can self-certify their SPCC plan — no PE required. Over 10,000 gallons, a licensed Professional Engineer must certify the plan. EPA provides a Tier I and Tier II qualified facility classification that determines the level of plan detail required.
Where to Find Spill Containment Products
Related Tank Guides
Frequently Asked Questions
Secondary containment is a backup system designed to capture spills or leaks from a primary storage tank before they reach the ground, stormwater drains, or navigable waters. It's required by EPA SPCC regulations for above-ground oil storage above 1,320 gallons aggregate capacity (or any single tank of 660+ gallons). The secondary containment must be capable of holding 110% of the volume of the largest tank it serves.
EPA SPCC regulations require secondary containment to hold at least 110% of the volume of the largest single tank within the containment area. For example, a 1,000-gallon tank requires containment that holds at least 1,100 gallons. If multiple tanks share one containment area, the containment must hold 110% of the largest individual tank — not the combined volume of all tanks.
EPA SPCC regulations apply specifically to oil storage, not water. If your tank stores only potable water, process water, or non-hazardous fluids, SPCC secondary containment is generally not required at the federal level. However, state regulations vary and some operating permits impose containment requirements on water tanks used in industrial or construction settings. Always check your state and local requirements.
A standard 275-gallon IBC tote requires a containment pallet rated for at least 303 gallons (275 × 110% = 302.5 gallons). A 330-gallon tote requires a pallet rated for at least 363 gallons. Always verify the pallet's rated sump capacity — not all IBC pallets marketed as "spill pallets" meet the 110% secondary containment requirement.
An SPCC (Spill Prevention, Control, and Countermeasure) plan is a written document required by EPA for facilities storing above-ground oil in quantities above 1,320 gallons aggregate. The plan must describe the facility's spill prevention measures, secondary containment systems, inspection procedures, and emergency response protocols. Facilities storing over 10,000 gallons must have their SPCC plan certified by a licensed Professional Engineer.
A containment pallet is a small platform with an integrated sump designed to sit under a single IBC tote or a few drums — typically 66 to 363 gallons of capacity. A containment basin is a larger structure surrounding one or more above-ground storage tanks, handling hundreds to thousands of gallons. Pallets are for small containers; basins are for bulk storage.
Water and wastewater treatment professional with 18+ years of hands-on experience including metals pretreatment, refinery DAF operations, and industrial facility compliance. Has designed and documented SPCC-compliant secondary containment systems for chemical feed and storage installations across multiple industrial facilities. He founded TankAuthority to bring real operator knowledge to water storage decisions.