The Complete SPCC Compliance Guide for 2026

The Spill Prevention, Control, and Countermeasure rule has been in force since 1974 and amended repeatedly since. It is also, in our experience reviewing member facilities, the environmental regulation most often assumed not to apply. This guide walks the determination, the tiers, the plan contents and the containment maths in the order you actually need them.

Who the rule covers#

40 CFR 112.1 sets three tests. All three must be met for the rule to apply.

Capacity. Aggregate aboveground oil storage capacity greater than 1,320 US gallons, counting only containers with a capacity of 55 gallons or more. Or completely buried storage capacity greater than 42,000 gallons, excluding tanks already subject to the underground storage tank rules at 40 CFR 280 or 281.

Oil. “Oil” is defined broadly and is not limited to petroleum. Animal fats, vegetable oils, synthetic lubricants, transformer mineral oil and used oil all count.

Navigable waters. A discharge must be reasonably expected to reach navigable waters of the United States or adjoining shorelines. This is the test operators most often talk themselves out of, and it is broader than intuition suggests: a roadside ditch that drains to a creek has been held to establish the connection.

Note the word capacity, not contents. A 5,000-gallon tank holding 200 gallons of diesel counts as 5,000 gallons.

Counting capacity correctly#

• Count shell capacity, not working or fill volume
• Count every container of 55 gallons or more, including drums, totes and mobile tanks stored on site
• Count oil-filled operational equipment such as transformers and hydraulic reservoirs
• Exclude permanently closed containers as defined in the rule
• Exclude containers under 55 gallons from the threshold count

Which tier you fall into#

The 2008 and 2009 amendments created qualified-facility tiers that let smaller operators self-certify instead of paying for P.E. certification.

Tier I qualified facility. Aggregate aboveground capacity of 10,000 gallons or less, no single container larger than 5,000 gallons, and a clean discharge history: no single discharge over 1,000 gallons and no two discharges each over 42 gallons within any twelve-month period in the three years before certification. A Tier I facility may use the self-certified template at Appendix G to Part 112.

Tier II qualified facility. The same 10,000-gallon and discharge-history tests, but with no limit on individual container size. A Tier II facility prepares a full plan and the owner or operator self-certifies it.

Everything else. A full plan prepared in accordance with good engineering practice and certified by a licensed Professional Engineer.

One limit applies to both qualified tiers: the environmental-equivalence and impracticability provisions are not available. If you need to deviate from a standard requirement, a P.E. must be involved regardless of size.

What the plan must contain#

There is no mandated format for a full plan, but if a plan does not follow the sequence of the rule it must be cross-referenced to it. In practice every plan we review contains the following.

1. Facility description and diagram. Every container of 55 gallons or more, its contents and capacity, transfer points, drainage paths and the route a discharge would take off site.
2. Secondary containment. A sized, written calculation for every bulk storage container, plus the general containment provisions for transfer areas and mobile refuelers.
3. Inspection and testing. Written schedules and forms for containers, containment areas, and transfer equipment, with integrity testing on a recognised industry standard. Records kept three years.
4. Personnel training. Annual discharge prevention briefings, and a named person accountable for discharge prevention who reports to facility management.
5. Security. Valve and pump controls, lighting and access control proportionate to the site.
6. Discharge response. Notification procedures with current numbers, staged equipment, disposal arrangements and a written sequence for the first hour.
7. Management approval and certification. Signature of management with authority to commit resources, plus the P.E. seal or self-certification statement.

Sizing secondary containment#

Section 112.8(c)(2) requires containment for bulk storage to hold the capacity of the largest single container plus sufficient freeboard for precipitation. The rule names no percentage. The 110% convention exists because it satisfies that wording in most climates, and several state programs adopt it outright.

The calculation, in order:

1. Identify the largest single container in the containment area. Required volume is its full shell capacity.
2. Add freeboard for the 25-year, 24-hour precipitation event at your location, unless the area is drained under an engineered, written procedure.
3. Compute gross containment volume: footprint area multiplied by wall height.
4. Subtract displacement from every other tank, foundation, pump skid and structure inside the dike below the containment liquid level.
5. Compare. If net available is less than required plus rainfall, the area is undersized.

Displacement is the step most often skipped, and on a congested pad it routinely costs 10 to 15 percent of nominal capacity. Our containment sizing tool runs this calculation interactively.

Worked example#

A containment area 40 feet by 30 feet with 24-inch walls holds 40 × 30 × 2 = 2,400 cubic feet, or about 17,953 gallons. The largest tank is 10,000 gallons, so 11,000 gallons is required. Three additional 4,000-gallon tanks and their foundations displace roughly 1,900 gallons below the containment level. A 4-inch design storm across the footprint adds about 2,992 gallons. Net available becomes 16,053 gallons against a requirement of 13,992. The area is adequately sized, with about 2,000 gallons of margin.

Change the largest tank to 15,000 gallons and the same area fails by roughly 800 gallons. This is why the plan is amended when a tank is swapped.

Keeping the plan current#

Two clocks run. The plan is reviewed and evaluated at least once every five years, with the review documented whether or not it results in changes. Separately, the plan is amended within six months of any change in facility design, construction, operation or maintenance that materially affects discharge potential – a new tank, a relocated transfer point, a changed product, a modified containment area.

A technical amendment is certified by a P.E. unless the facility is a qualified facility that self-certifies. Administrative changes such as a phone number do not require recertification, but they do require a dated record.

The five findings we see most#

1. Containment drain valves left open. An open gravity outfall means there is no containment. Valves stay locked closed and are opened only under a written, logged procedure after the water is inspected.
2. No displacement deduction. The capacity calculation shows gross volume, not net.
3. Inspection records that stop. Forms exist, were used for four months, and then stopped. Three years of records is the requirement.
4. Training undocumented. The briefing happened. Nobody signed anything.
5. Stale contact lists. The notification procedure names a person who left in 2022.

Notification thresholds#

A discharge to navigable waters that causes a sheen, a sludge or an emulsion is reported immediately to the National Response Center at 1-800-424-8802. Separately, EPA requires a written report within 60 days where a facility discharges more than 1,000 gallons in a single event, or more than 42 gallons in each of two events within any twelve-month period. State reporting thresholds are frequently lower – check yours and write both into the plan.

Where to start#

If you are not sure whether the rule applies, run the four-question applicability check, then work the plan development checklist. If you already have a plan, the fastest useful audit is to open it, find the containment capacity calculation, and see whether displacement appears anywhere in it.

OCA members can submit a plan and tank schedule for technical review by the committee. We are not a substitute for your engineer. We are the people who have stood in the containment areas where these plans failed.