EPA SPCC Rule (40 CFR 112): Secondary Containment Requirements

Overview

The Spill Prevention, Control, and Countermeasure rule, codified at 40 CFR Part 112, is the EPA regulation that requires certain facilities storing oil to prevent oil from reaching navigable waters and adjoining shorelines. It is a prevention rule, not a cleanup rule: the central obligation is to plan for and physically contain a discharge before it leaves the facility. The rule traces back to the Clean Water Act and is administered by the EPA under the broader oil pollution prevention regulations.

SPCC covers a wide definition of oil: petroleum and non-petroleum oils, fuels, lubricants, hydraulic fluids, and animal and vegetable oils. The most visible requirement, and the one that drives most equipment buying, is secondary containment: a backup barrier such as a containment pallet, a dike, or a curbed area that catches oil from a leaking or ruptured container so it does not run off the site.

The full regulation text is published in Title 40, Part 112 of the Electronic Code of Federal Regulations. This page summarizes the parts of the rule that govern who must comply and how containment is sized. It is a plain-language overview, not legal advice, and your facility's plan should be prepared or reviewed against the current rule and, where required, certified by a Professional Engineer.

Who Must Comply (Applicability)

A facility is subject to SPCC when it meets all three of the following conditions under 40 CFR 112.1:

• It is non-transportation-related and stores oil. Farms, manufacturers, fuel distributors, warehouses, fleet yards, and similar fixed facilities are covered; vehicles in transit are regulated under DOT rules instead.
• It exceeds an oil storage capacity threshold. The aggregate aboveground oil storage capacity is more than 1,320 US gallons, or the completely buried storage capacity is more than 42,000 US gallons. Capacity, not the amount on hand, is what counts.
• There is a reasonable expectation of a discharge to water. Because of the facility's location, a spill could reasonably reach navigable waters of the United States or adjoining shorelines.

A facility that meets all three conditions must prepare and implement a written SPCC Plan. The plan documents the containment, inspection, and response measures the facility uses, and it must be available for EPA review. Many of the same drums that put a facility over the SPCC threshold also fall under workplace flammable liquid storage rules; see OSHA 1910.106 and NFPA 30 for the fire-code side of liquid storage.

What 40 CFR 112.7 Requires

Section 112.7 is the general requirements section, and it is the one people cite most often because it sets what every SPCC Plan has to contain no matter what the facility stores. The rule opens by requiring the plan be written, prepared in accordance with good engineering practices, and given the full approval of management at a level of authority to commit the resources needed to implement it. A plan organized in some other order is allowed, but it has to be supplemented with a section cross-referencing each Part 112 requirement against wherever that requirement lives in your document.

• 112.7(a): layout, diagram, and procedures. Describe the physical layout and include a facility diagram marking the location and contents of every fixed oil container and the storage areas where mobile or portable containers sit. The plan also covers oil type and capacity per container, routine handling and transfer procedures, drainage controls, countermeasures for discovery and cleanup, disposal of recovered material, and a contact list that includes the National Response Center.
• 112.7(b): failure prediction. Where experience shows a reasonable potential for equipment failure, predict the direction, rate of flow, and total quantity of oil that could be discharged from each type of major equipment failure.
• 112.7(c): general secondary containment. The containment requirement itself, covered in the next section.
• 112.7(d): impracticability. If containment is genuinely not practicable, say why in the plan, add periodic integrity testing of containers and integrity and leak testing of valves and piping, and provide an oil spill contingency plan under 40 CFR Part 109 plus a written commitment of manpower, equipment, and materials.
• 112.7(e): inspections, tests, and records. Inspections and tests follow written procedures, and the records, signed by the appropriate supervisor or inspector, are kept with the plan for three years.
• 112.7(f): personnel and training. Train oil-handling staff on the equipment, the discharge protocols, the applicable rules, and the plan itself. Designate one person at the facility as accountable for discharge prevention. Hold discharge prevention briefings at least once a year.
• 112.7(g): security. Describe how access to the oil handling, processing, and storage areas is controlled, including master flow and drain valves, pump starter controls, and out-of-service loading connections.
• 112.7(h): loading and unloading racks. Tank car and tank truck racks need a quick drainage system where rack drainage does not flow to a catchment basin or treatment facility designed to handle discharges, and the containment must hold at least the maximum capacity of any single compartment of a vehicle loaded or unloaded at the facility.
• 112.7(k): oil-filled operational equipment. Transformers, hydraulic systems, and similar equipment at a facility with a clean discharge history can substitute a documented inspection or monitoring program plus a contingency plan for general containment.

The Secondary Containment Requirement

Secondary containment is the heart of the rule. Primary containment is the container itself, the drum, tank, or tote. Secondary containment is the backup barrier that holds the oil if the primary container leaks, overfills, or fails. Under 40 CFR 112.7(c), facilities must provide appropriate containment or diversionary structures to prevent a discharge, and the entire containment system, including walls and floor, must be capable of containing oil and constructed so that any discharge will not escape before cleanup occurs.

Two ideas govern whether a containment system passes:

• Sufficiently impervious. The containment surface has to hold the oil long enough for it to be cleaned up. A bare gravel pad or untreated soil drains oil into the ground and does not qualify. A molded polyethylene sump pallet, a coated concrete dike, or a lined berm does. The phrase sufficiently impervious to contain oil is attached to dikes, berms, and retaining walls in 112.7(c)(1)(i) and to diked areas in 112.8(c)(2), among other provisions. It is a property the barrier has to have, not a material the rule names.
• Adequate capacity. The containment volume must be large enough to hold the oil that could be released. For bulk storage containers, the rule sets a specific capacity floor, covered in the next section. For general areas such as a transfer point or piping run, 112.7(c) says you need only address the typical failure mode and the most likely quantity of oil that would be discharged, which is a lower bar than the sized rules and a judgment your plan has to document.

Containment can be passive or active, and 112.7(c)(1) lists eight acceptable onshore systems: dikes, berms, or retaining walls; curbing or drip pans; sumps and collection systems; culverting, gutters, or other drainage systems; weirs, booms, or other barriers; spill diversion ponds; retention ponds; and sorbent materials. Sorbents being on that list is the part most facilities miss. Under the general containment provision a stocked, staged supply of spill control sorbents is one of the methods the rule itself names, though it only works as active containment when trained people are there to deploy it.

A spill containment pallet is the most common way to give individual drums and totes compliant secondary containment. The drum sits on a grated deck, and the molded sump underneath catches any leak. Browse stocked units on the spill containment collection.

Sizing Containment: the Largest-Container Rule

For bulk storage containers, 40 CFR 112.8(c)(2) sets the sizing floor: the secondary containment must hold the capacity of the largest single container in the system, plus additional freeboard for precipitation when the containment is exposed to rain. That is the regulatory minimum, 100 percent of the largest container, and it is the largest single container, not the sum of every container in the area.

The common engineering convention adds a margin on top of that floor. Designers routinely size outdoor containment to 110 percent of the largest container so the extra 10 percent absorbs rainfall and provides freeboard before the sump fills. The 110 percent figure is a widely used design practice that satisfies the rule; it is not a separate number written into 40 CFR 112. Indoor containment that never sees rain may be sized closer to the 100 percent floor, subject to the facility's engineering judgment.

The rule leaves freeboard deliberately open, and the reason is on the record. In the 2002 preamble the EPA wrote that the proper standard for sufficient freeboard is the precipitation from a 25 year, 24 hour storm event, then declined to make it a rule requirement because of the difficulty and expense of getting that storm data. The agency's own guidance for regional inspectors states the consequence plainly: a 25 year, 24 hour storm event is not enforceable as a standard for containment freeboard. The 110 percent number entered the same rulemaking record as a commenter's suggested alternative, which is why it behaves like an industry default rather than a citation. What the EPA does expect is that whatever number you use is an engineering determination you can produce on request, so keep the calculation with the plan.

This is why a sump platform is rated by sump capacity rather than by the number of drums it holds. Drums and totes are usually not bulk storage tanks, so the paragraph that governs them is 112.8(c)(11), the rule for mobile or portable oil storage containers. It carries the same arithmetic as 112.8(c)(2): position the container so it cannot discharge, and furnish a secondary means of containment sufficient to hold the capacity of the largest single compartment or container with sufficient freeboard for precipitation. Either way a 55 gallon drum calls for a sump of at least 55 gallons indoors, not 30, and outdoors the documented precipitation freeboard pushes the number higher. Smaller sumps, such as a 2 drum 30 gallon platform, do not satisfy that sized requirement for stationary drum storage. EPA treats drums, skids, and totes as portable containers under 112.8(c)(11), so size to the largest container plus freeboard unless your plan documents a formal impracticability determination under 112.7(d). For IBC totes, the 400 gallon sump IBC containment unit clears the 110 percent design target for a 330 gallon tote with freeboard to spare.

General vs Specific Containment

40 CFR 112.7 distinguishes between two kinds of containment, and a facility plan usually relies on both.

IBC Containment: Totes vs the Building Code

IBC means two different things in a spill containment search and the answers are not the same. On the storage side an IBC is an intermediate bulk container, the 275 or 330 gallon caged tote. On the code side IBC is the International Building Code. Buyers land here from both, so here is each one.

Where the two regimes really part company is the sizing basis.

The fire code also puts a hard floor under containment pallets, which SPCC does not. Where a pallet is used as the alternative to spill control and secondary containment for outdoor storage, IFC 5004.2.3 asks for a liquid-tight sump with access for visual inspection, a sump designed to hold not less than 66 gallons, exposed surfaces compatible with the material stored, and protection against rainwater collecting in the sump. That 66 gallon number is a useful screen when you are comparing pallets, because it rules out the small two-drum platforms before you get to the SPCC math. How to work through both sets of numbers for a specific yard is covered in the secondary containment selection guide, and the fire-code side of liquid storage is covered under NFPA 30.

Plan Types and Self-Certification Tiers

The kind of SPCC Plan a facility needs depends on its size and spill history. The rule creates a lighter path for smaller operations through the qualified facility provisions in 40 CFR 112.6.

• Tier II qualified facility: aggregate aboveground oil storage of 10,000 US gallons or less and a clean discharge history. The owner can self-certify the plan in the facility's own format. The discharge test is specific: no single discharge to navigable waters over 1,000 US gallons, and no two such discharges each over 42 US gallons within any twelve month period, in the three years before self-certification. Discharges caused by natural disasters, acts of war, or terrorism do not count against you, and neither do spills that stayed on the pad.
• Tier I qualified facility: a Tier II facility that also has no individual aboveground container larger than 5,000 gallons. Tier I is a subset of Tier II rather than a separate track, so a facility under both limits qualifies for the lighter path. Tier I owners can self-certify on the EPA Appendix G template, which becomes the plan once completed and signed.
• PE-certified plan: facilities above 10,000 gallons aggregate, or that fail the spill-history test, need a full SPCC Plan reviewed and certified by a licensed Professional Engineer.

Across all tiers, 112.5 requires a review and evaluation of the plan at least once every five years, and an amendment whenever the facility makes a change that materially affects its discharge potential. Commissioning or decommissioning containers, moving them, reworking piping, construction that alters a containment structure, and a change of product or service are the examples the rule gives. An amendment has to be prepared within six months of the change and implemented no later than six months after that. The containment hardware itself, pallets and sumps, is the same regardless of tier; the tier determines who signs the paperwork.

Inspection and Recordkeeping

SPCC is not a one-time filing. The plan obligates the facility to inspect, test, and document on a recurring basis, and inspectors expect to see the records.

• Container inspections: aboveground containers are inspected regularly for leaks, corrosion, and signs of deterioration, on a schedule and with criteria set in the plan.
• Integrity testing: under 112.8(c)(6) each aboveground container is tested or inspected for integrity on a regular schedule and whenever you make material repairs. The rule leaves the frequency, the method, and the tester's qualifications to industry standards, sized to the container; the examples it lists run from visual inspection through hydrostatic, radiographic, ultrasonic, and acoustic emissions testing. Supports and foundations get inspected too.
• Containment inspections: sump pallets, dikes, and curbed areas are checked so accumulated rainwater or product is removed and the containment volume stays available. A sump full of rain has no capacity left for a spill.
• Records retention: 112.7(e) requires inspection and test records, signed by the appropriate supervisor or inspector, to be kept with the SPCC Plan for three years. Records kept under usual and customary business practices satisfy this, so a maintenance system you already run will do.
• Personnel training: oil-handling staff are trained on the plan, spill procedures, and the equipment, with a designated person accountable for discharge prevention. Discharge prevention briefings happen at least once a year and are supposed to cover any discharges, failures, or malfunctioning components since the last one.

Keeping a sump pallet drained and free of debris is the single most common containment maintenance task, and an overdue drain is a routine inspection finding. The response equipment that backs up the containment, sorbents and ready-to-grab kits, is covered in the hazmat spill kit selection guide.

Frequently Asked Questions

Related Resources

• Secondary Containment Selection Guide (how to choose a pallet or sump)
• Spill Containment Pallets and Platforms (collection)
• Hazmat Spill Kit Selection Guide (spill response)
• OSHA 1910.106: Flammable Liquid Storage
• NFPA 30: Flammable and Combustible Liquids Code
• Eagle Manufacturing (the containment brand we stock)
• Safety & Compliance Standards (index)