Above ground storage tanks (ASTs) storing petroleum products, chemicals, and other liquids require systematic inspection to maintain structural integrity and prevent environmental releases. The EPA’s Spill Prevention, Control, and Countermeasure (SPCC) rule under 40 CFR 112 requires facilities above threshold oil storage quantities to implement integrity testing programs referencing industry standards. The two primary standards are API 653 for large field-erected tanks and STI SP001 for shop-fabricated tanks. Approximately 30 states also have their own AST regulations that may exceed federal requirements. Tank failures can result in catastrophic spills with significant environmental damage, cleanup costs, and regulatory penalties. This guide covers all inspection requirements with a free downloadable checklist.
Free Above Ground Storage Tank Inspection Checklist
Download our Word document checklist covering shell condition, foundation, secondary containment, piping, and appurtenances per API 653 and STI SP001.
Download Checklist (.docx)Regulatory Framework
EPA SPCC Rule — 40 CFR 112
- Applicability: Facilities storing more than 1,320 gallons of oil in above ground containers (aggregate) or more than 42,000 gallons underground, where a reasonable expectation of discharge to navigable waters exists.
- Integrity testing: Containers must be tested or inspected for integrity on a regular basis and whenever material repairs are made. The SPCC plan must reference an applicable industry standard.
- Secondary containment: Must be sized to hold the capacity of the largest container plus sufficient freeboard for precipitation. Constructed of impervious materials.
- Record retention: EPA recommends retaining inspection records for each container’s lifespan. Records must be available for a minimum of 3 years.
Industry Standards
- STI SP001: Steel Tank Institute standard for shop-fabricated ASTs. Risk-based approach with 3 categories. Monthly periodic inspections by owner. Formal external inspection by certified inspector every 5–20 years based on risk category and tank size. Formal internal inspection or leak test every 10–20 years for tanks over 5,000 gallons. Tanks under 5,000 gallons in Category 1 may not require certified formal inspections.
- API 653: American Petroleum Institute standard for large field-erected tanks. Routine in-service inspections by owner. Formal external inspection by API 653 certified inspector every 5 years. Internal inspection within 10–30 years of initial service, subsequent intervals based on corrosion rate calculations (typically 20 years). Covers shell, bottom, roof, foundation, and appurtenances.
- State regulations: Approximately 30 states have additional AST regulations. Requirements may include registration, financial assurance, specific inspection frequencies, and certified inspector qualifications. Always verify state and local requirements.
SPCC plan requirement: Your SPCC plan must specify which industry standard applies to each tank and document your inspection frequency and procedures. The plan must also identify the qualifications of inspection personnel. Failure to have an adequate SPCC plan or to conduct required inspections can result in enforcement action by EPA with penalties up to $25,000 per day per violation.
Part 1: Tank Shell, Roof & Structure
| Inspection Item | What to Check |
|---|---|
| Shell condition | Exterior shell free of visible corrosion, pitting, dents, bulges, or cracks. Paint or coating system intact with no blistering, peeling, or bare metal exposure. No streaks or staining indicating product leakage from shell or welds. Shell plumb and not distorted. Ultrasonic thickness testing results (if API 653) within acceptable range. |
| Roof condition | Fixed roof free of corrosion, holes, sagging, or ponding water. Roof drain system functioning (no standing water). Roof-to-shell junction intact. Floating roof (if applicable): seals in good condition, no product on roof surface, drain system functional, guide poles and rollers operating freely, no sinking or tilting. |
| Welds and seams | Visible weld seams free of cracks, corrosion, or leakage. Shell-to-bottom weld junction inspected for corrosion and product weepage. Nozzle welds intact. Repair welds (if any) documented and inspected per API 653 or STI SP001 requirements. No evidence of fatigue cracking at stress concentration points. |
| Tank bottom (external) | No evidence of product leakage at shell-to-bottom junction. Settlement monitoring points (if installed) checked and recorded. Ground surface around tank base free of product staining. Leak detection system (if installed) functioning and alarming properly. Bottom edge visible and accessible for inspection. |
| Venting | Pressure/vacuum vents functioning properly and not obstructed. Flame arrestors clean and unblocked. Emergency vents (if installed) operational and not corroded or painted shut. Normal venting capacity adequate for filling and emptying rates. Vent screens intact to prevent bird and insect nesting. |
Part 2: Foundation, Containment & Piping
| Inspection Item | What to Check |
|---|---|
| Foundation | Concrete ring wall or pad free of cracks, spalling, or settlement. No erosion of soil beneath or around foundation. Grading slopes away from tank base. No vegetation growing against tank or foundation. Foundation bolts (if applicable) intact and not corroded. No differential settlement causing tank to tilt. |
| Secondary containment | Dike, berm, or retaining wall structurally sound with no cracks, erosion, or deterioration. Containment capacity sufficient to hold the largest tank volume plus freeboard for precipitation. Liner (if installed) intact with no tears or punctures. No product staining inside containment area. Containment area free of debris, vegetation, and stored materials. |
| Containment drainage | Drain valves closed and locked when not in active use. Valve accessible and operable. No unauthorized discharge from containment area. Accumulated rainwater inspected before controlled discharge (no oil sheen). Drain piping intact and not leaking. Sump pump (if installed) operational and discharge directed properly. |
| Piping and connections | All piping, valves, flanges, and fittings free of leaks, corrosion, and mechanical damage. Valve positions correct (open/closed per operating procedures). Pipe supports and hangers in good condition. Flexible connections (if used) not worn, cracked, or kinked. Pipe identification and flow direction markings legible. |
| Gauging and overfill prevention | Level gauge functioning accurately and readable. High-level alarm tested and operational. Overfill prevention device (if installed) functioning per API 2350 or facility requirements. Manual gauging access point in safe condition. Tank capacity and working volume clearly identified. |
Part 3: Safety, Labeling & Documentation
| Inspection Item | What to Check |
|---|---|
| Labeling and identification | Tank identification number clearly visible. Contents identification (product name) displayed. NFPA 704 diamond or equivalent hazard markings posted. Capacity marked on tank. API or STI nameplate legible (if applicable). DOT placarding in place for regulated materials. |
| Fire protection | Fire extinguishers appropriate for product type, inspected, and accessible. Fire suppression system (if installed) in service and inspected per NFPA 25. Foam equipment (if installed) operational and foam supply not expired. Clearance from buildings and property lines per NFPA 30 and local fire code. “No Smoking” signs posted. |
| Spill response | Spill kit available and stocked near tank area. Spill response procedures posted or accessible. Emergency shutdown procedures documented and personnel trained. SPCC plan current and accessible. Emergency contact information posted. |
| Security | Tank area secured to prevent unauthorized access. Fencing, gates, or barriers in good condition. Locks functional on access points and valve handles. Tamper-evident seals intact (if used). Lighting adequate for nighttime security and inspections. |
| Inspection records | Periodic (monthly) inspection records current and on file. Most recent formal external inspection report available. Most recent internal inspection or leak test report available (if applicable). Corrosion rate calculations and remaining life estimates documented (API 653 tanks). Repair and alteration records maintained. SPCC plan review date current (within 5 years). |
Inspection standard selection guide: Shop-fabricated tanks (typically under 50,000 gallons): STI SP001. Large field-erected tanks (built to API 650/API 12C): API 653. Intermediate bulk containers and 55-gallon drums: STI SP001 or visual inspection per SPCC plan. Double-walled tanks: interstitial monitoring per manufacturer requirements plus exterior visual inspection per applicable standard. Non-metallic tanks (fiberglass, polyethylene): manufacturer inspection procedures; not covered by STI SP001 or API 653. Your SPCC plan must specify the standard for each container and document your inspection program.
Download the Free Checklist
Get our above ground storage tank inspection checklist in Word format. Covers shell, foundation, containment, piping, and documentation per API 653 and STI SP001.
Download Checklist (.docx)Go digital with Ecesis. Replace paper tank inspection logs with Ecesis inspection software. Track corrosion monitoring data and inspection intervals. Document tank conditions with timestamped photos. Automate certified inspection scheduling. Integrate with your SPCC plan and environmental compliance program. Request a free demo.
Ecesis EHS Software
Inspections
Monthly tank inspections with condition tracking, photo documentation, and corrective action management.
Environmental Data
Track tank inventory, corrosion rates, thickness readings, and remaining life calculations.
Compliance Calendar
Schedule monthly inspections, certified external inspections, internal inspections, and SPCC plan reviews.
Task Management
Assign corrective actions for coating repairs, valve replacements, and containment maintenance.
Document Management
Maintain SPCC plans, inspection reports, repair records, and API/STI certifications.
Training
Track operator training, inspector certifications, and spill response qualifications.
