Secondary containment — a physical barrier designed to capture liquid released from a primary container — is one of the most commonly misunderstood compliance obligations in industrial and agricultural liquid storage. Many operators believe it applies only to petroleum tanks or hazardous waste facilities. In reality, a much broader set of operations storing liquids in IBC totes must maintain secondary containment under federal EPA rules and state environmental regulations. Getting this wrong exposes businesses to significant penalties and, more importantly, to real environmental and liability risk.
Which Regulations Apply to You?
Three main federal frameworks govern secondary containment for liquid storage, and your operation may fall under one, two, or all three:
- —EPA 40 CFR Parts 264/265: Applies to facilities that generate, store, or treat hazardous waste as defined under RCRA. Part 264 covers permitted TSD facilities; Part 265 covers interim status facilities. Section 264.175 requires secondary containment for container storage areas that hold hazardous waste.
- —EPA SPCC Rule (40 CFR Part 112): Applies to non-transportation-related facilities with aboveground oil storage capacity exceeding 1,320 gallons total (or a single container exceeding 660 gallons) that could reasonably be expected to discharge oil to navigable waters. This is where most agricultural and industrial IBC users encounter the secondary containment requirement.
- —State environmental regulations: Kansas, Missouri, Nebraska, and Oklahoma all have state-level storage tank and spill prevention rules that may be more stringent than federal minimums. Kansas Department of Health and Environment (KDHE) rules under K.A.R. 28-29 govern many liquid storage scenarios not covered by federal SPCC.
SPCC Secondary Containment Sizing Requirements
Under 40 CFR 112.7(c), secondary containment for oil storage (including petroleum products, lubricants, and many agricultural chemicals classified as oils) must have sufficient capacity to contain the largest single discharge that could occur. The regulatory standard — widely referred to as the "110% rule" — requires the containment to hold at least 110% of the capacity of the largest single container within the containment area.
For example: if you store four 330-gallon IBCs in a single containment area, the largest single container holds 330 gallons. Your secondary containment must hold at least 363 gallons (330 x 1.10 = 363 gallons). The other three IBCs' volumes do not need to be added to the containment sizing — only 110% of the largest single vessel.
However, this assumes your containment is designed so that a failure of any one container cannot cascade into others (e.g., a domino failure). If your IBC layout is such that one failure could breach all containers simultaneously, regulators may require sizing for 110% of total storage capacity. Consult your SPCC plan's Professional Engineer if uncertain.
The alternative sizing standard — 10% of the total storage capacity of all containers in the area — applies when drainage from the containment area is controlled and the facility can demonstrate the ability to respond adequately to a spill. In practice, the 110%-of-largest-container standard is more commonly applied and more straightforward to document.
Construction Material Requirements
40 CFR 112.7(c) requires that secondary containment be "constructed so that any discharge from a primary containment system will not escape the secondary containment before cleanup occurs." The material must be compatible with the stored product and capable of resisting the chemical, thermal, and physical stresses it may encounter.
- —Concrete: The most common material for permanent secondary containment berms. Must be treated or coated with a chemical-resistant sealant if storing acids, caustics, or solvents — bare concrete is porous and will absorb petroleum products over time. Reinforced concrete containment walls of 6 inches or more are typical for IBC storage areas.
- —HDPE liners: Used for earth-berm containment areas. Must be a minimum 30 mil thickness for most applications; 40–60 mil is preferred for long-term installations. Liner must be inspected annually and replaced when breached or degraded.
- —Steel: Galvanized or coated steel containment pans are appropriate for petroleum products but will corrode rapidly with chlorinated solvents or acids. Verify chemical compatibility before specifying steel containment.
- —Portable polyethylene containment pallets: Molded HDPE containment pallets sized for one or two IBCs are widely available and appropriate for lower-risk, non-hazardous-waste applications. They do not require an SPCC-compliant engineering design but are a practical solution for smaller operations and temporary storage situations.
Indoor vs Outdoor Containment Considerations
Indoor secondary containment has the advantage of eliminating rainwater accumulation — a significant operational issue with outdoor containment. Open outdoor containment areas that collect precipitation must be pumped or drained after rain events, and the collected water must be tested and properly disposed of if it could be contaminated. This creates an ongoing operational burden and potential disposal cost.
For outdoor IBC storage, covered containment areas (a roof over the berm or containment pad) are strongly preferred. They eliminate precipitation management, reduce UV degradation of the IBCs, and simplify the containment inspection regimen. The roof structure does not compromise the containment function as long as the walls and floor are properly sealed and sloped to an inspection sump.
Portable IBC Containment Pallet Options
| Type | Capacity | Approx. Cost | Best Use |
|---|---|---|---|
| Single-IBC HDPE pallet | 70–85 gal | $180–$350 | Indoor, lower-risk products |
| Double-IBC HDPE pallet | 140–175 gal | $350–$600 | Indoor, grouped IBC storage |
| Steel containment pallet | 100–120 gal | $400–$700 | Petroleum products, outdoor |
| Collapsible berm system | Variable (200–2,000 gal) | $500–$3,000 | Temporary/field deployments |
Inspection Requirements and Documentation
SPCC-regulated facilities must conduct regular inspections of secondary containment as part of their SPCC plan implementation. Under 40 CFR 112.7(e), facilities are required to inspect container storage areas at regular intervals and maintain written records of those inspections. A common inspection frequency for IBC storage areas is weekly visual inspection plus a more detailed quarterly inspection documented on a standardized form.
Key inspection checkpoints for IBC secondary containment include: integrity of containment walls and floor (cracks, spalls, liner breaches), presence of accumulated liquid in the containment area (precipitation or leakage?), condition of drainage valves or pumps (must be closed/secured except during active drainage events), IBC valve and fitting condition (drips, weeps), and vegetation encroachment on outdoor earthen berms (roots can breach liners).
Common Violations Found During EPA and State Inspections
- —Containment volume insufficient — the most common finding. Many facilities calculate based on container nominal capacity rather than actual maximum fill capacity, resulting in undersized containment.
- —Drainage valves left open — open valves allow spilled product to bypass the containment system entirely. All containment drain valves must be kept closed and locked except during controlled drainage operations.
- —Incompatible containment material — concrete not sealed against the stored chemical, or steel containment used with corrosive products.
- —No inspection records — facilities that inspect but do not document are treated the same as facilities that do not inspect. Paper or electronic records must be retained for at least three years.
- —SPCC plan not updated to reflect current storage configuration — if you added IBCs to a storage area not covered in the original SPCC plan, the plan must be amended.
When Is an SPCC Plan Required?
A facility needs an SPCC plan if it has aboveground oil storage capacity exceeding 1,320 gallons in aggregate (or any single aboveground container over 660 gallons) AND there is a reasonable possibility of discharge to navigable waters or adjoining shorelines. Eight 275-gallon IBCs of petroleum-based products (2,200 gallons total) at a facility near any drainage ditch that flows to a creek clearly meets this threshold. Tier I Qualified Facilities (total aboveground capacity of 10,000 gallons or less, with a good spill history) can self-certify their SPCC plan without a Professional Engineer's stamp.
Secondary containment is an area where investing modestly in proper infrastructure upfront is vastly cheaper than dealing with a spill event after the fact. A concrete containment pad with 110% capacity for your IBC storage area might cost $3,000–$8,000 to construct properly. Compare that to KDHE spill response costs (which can easily reach $50,000–$500,000 for a meaningful release) and federal SPCC violation penalties of up to $25,000 per day, and the ROI calculation becomes straightforward.