What Is Secondary Containment—and Why It Matters
Secondary containment refers to a backup system designed to catch and control hazardous spills—especially oil or chemicals—if the primary container fails. It’s an essential safeguard to protect soil, groundwater, and navigable waters from contamination. Common implementations include:
- Spill berms (portable or drive-over)
- Diked areas around tanks or loading zones
- Containment sumps, sealed rooms, or pits
These systems enhance environmental protection and help ensure regulatory compliance in industries such as oil & gas, utilities, agriculture, and chemical storage.
EPA Standards: What the SPCC Rule Requires in 2025
1. Capacity & Freeboard
Under the U.S. EPA’s SPCC (Spill Prevention, Control, and Countermeasure) rule, secondary containment for bulk storage must:
- Be able to hold 100% of the largest single container’s volume, plus additional freeboard for precipitation.
While some interpretations add a 10% safety margin, the regulatory baseline is clear: largest container priority plus precipitation allowance.
2. Material & Structural Requirements
Containment systems must be:
- Impervious—free from cracks or gaps
- Chemically compatible with stored substances
- Engineered for drainage, with sloping or removal systems for liquid buildup
3. Transfer Areas & Operations
Areas used for oil transfer—such as loading/unloading zones—even around exempted underground tanks, must have secondary containment or diversion infrastructure based on good engineering practices.
4. Inspections & Maintenance
EPA mandates regular inspections to identify structural issues, degradation, or chemical incompatibilities, with proper maintenance to guarantee containment integrity over time.
What’s New in 2025: Emerging SPCC Trends
A. Enhanced Inspection & Monitoring
As of mid-2025, the EPA has signaled intentions to tighten secondary containment standards and require more rigorous tank inspection protocols—including the promotion of remote monitoring technologies within SPCC frameworks.
B. PFAS & Hazardous Waste Considerations
In 2025, EPA expanded focus on PFAS chemicals (per- and polyfluoroalkyl substances), adding new reporting and inventory thresholds. While not directly in the SPCC rule, facilities managing containment systems for these chemicals must prepare for stricter oversight.
Best Practices for Secondary Containment
- Design for Compliance & Beyond
Aim to exceed the minimum EPA requirement to protect against extreme weather events. - Choose the Right Materials
Geomembranes, polyethylene liners, or coated concrete ensure chemical resistance and long service life. - Account for State Rules
States like California, Texas, and New York may enforce stricter standards. Always confirm state-level compliance. - Regular Training
Staff should know how to inspect, test, and respond to containment system failures. - Leverage Technology
Remote monitoring sensors and automated drainage systems can improve both compliance and safety.
Frequently Asked Questions About Secondary Containment
1. What does secondary containment mean?
Secondary containment is a back-up safety system designed to catch hazardous liquids (like oil, fuel, or chemicals) if the primary container fails.
2. What are the EPA’s secondary containment requirements in 2025?
The EPA requires that systems hold 100% of the largest container volume plus rainfall allowance. They must also be impervious, compatible, and inspected regularly under the SPCC rule.
3. What industries need secondary containment?
Industries include oil & gas, chemical storage, utilities, agriculture (fertilizer/manure), and construction/mining.
4. What types of secondary containment are most common?
- Berms & dikes
- Double-walled tanks
- Geomembrane liners
- Sumps or trenches
- Portable containment units
5. How often should containment be inspected?
Most facilities inspect monthly and after significant rainfall, with annual engineering reviews recommended.
6. What happens if you don’t comply?
Consequences include EPA fines, cleanup liability, and reputational damage—especially in highly regulated sectors.
7. Has anything changed for 2025?
Yes: enhanced inspections, remote monitoring expectations, and PFAS-related reporting are now emphasized.
8. Do state laws differ from EPA rules?
Yes. Some states have stricter capacity, materials, or inspection standards, so local compliance is critical.
9. How do you calculate berm capacity?
Capacity = Largest tank volume + rainfall/freeboard allowance.
E.g., a 10,000-gallon tank requires >10,000 gallons plus rain margin.
10. Who can help design and install systems?
Environmental engineers and geosynthetic containment specialists provide SPCC-compliant designs.
Secondary containment is more than a regulatory requirement—it’s a safeguard for environmental protection, financial stability, and corporate reputation. With 2025 regulatory updates highlighting stricter inspections and monitoring technologies, now is the time for facilities in oil, gas, agriculture, and chemical industries to ensure their containment systems are compliant, durable, and future-ready.