Underground Storage Tank (UST)
Last reviewed · By Chad Griffith
Underground Storage Tanks (USTs) are tanks (or tank-and-piping systems) with at least 10% of the volume below ground surface, used to store regulated substances — typically petroleum products. EPA's UST program at 40 CFR Part 280 covers tank construction, release detection, spill and overfill prevention, operator training (Class A/B/C), 30-day walkthrough inspections, financial responsibility, and corrective action for releases. The 2015 final rule (effective October 13, 2018 for most provisions) expanded operator training requirements and added regular walkthrough inspections. UST violations can result in civil penalties up to $25,000 per tank per day per violation.
Frequently Asked Questions
What tanks are covered by UST regulations?
Per 40 CFR 280.10: underground tanks with at least 10% of volume below ground, storing petroleum or hazardous substances regulated under CERCLA. Excluded: farm/residential heating oil tanks under 1,100 gallons, tanks holding heating oil for on-site consumption, septic tanks, pipelines regulated under DOT, surface impoundments, and storm water drains.
What are Class A, B, and C operators?
Class A: primary responsibility for daily operation (typically corporate compliance officer or facility manager). Class B: day-to-day on-site responsibility (typically station manager). Class C: first response to emergencies and alarms (typically clerks and station attendants present during operating hours). Initial training required within 30 days of designation.
What is a 30-day walkthrough inspection?
Per 40 CFR 280.36, owners must conduct walkthrough inspections at least every 30 days covering spill prevention equipment and release detection equipment, plus every 365 days for containment sumps and hand-held release detection equipment. Records retained at least 1 year. Walkthrough non-compliance is among the most-cited UST violations.
What happens after a UST release?
Per 40 CFR 280 Subpart F, owners must report to the implementing agency within 24 hours, take immediate action to mitigate fire/safety hazards, take initial response within 7 days, and submit a site characterization report typically within 45 days. Cleanup follows state-administered corrective action. Costs commonly run $50,000-$500,000+ for typical service station releases.
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