Underground Storage Tank System Closure

An underground storage tank (UST) system closure is an action that results in a tank no longer being regulated by the Office of Land Quality (OLQ). There are three types of closures.

• Removal: All USTs, piping, and dispensers are physically removed.
• In-place: A portion or all of the USTs, piping, and dispensers are closed without removal, often due to being inaccessible. This type of closure requires prior approval from OLQ.
• Change-in-service: A UST system is converted from storing regulated substances to unregulated substances. This change requires prior approval from OLQ.

The owner/operator of a UST system must complete and submit State Form 56553- Thirty (30) Day Request for Underground Storage Tank Closure (available on the IDEM Forms page) to request closure 30 days prior to beginning the activity. If the permanent closure or change-in-service is a part of the response to corrective action, then the notification requirements of Corrective Action (329 IAC 9-5) apply. OLQ will respond in writing with the closure notification approval letter, and the closure notification approval letter will expire 12 months after the date of the letter. The owner or operator must:

• Keep the authorization on site during the closure process and make it available upon demand.
• Notify OLQ, the Indiana State Fire Marshal, and the local fire department at least 14 days in advance of the intended closure date. For change-in-service closures, only notify OLQ.
• contact IDEM within 24 hours of discovery of a suspected or confirmed release.

OLQ requires an environmental site assessment of soil and ground water for all UST system closures. The assessment must be consistent with the Remediation Closure Guide (Waste-0046-R2, available on the IDEM Effective Nonrule Policies page) and the Remediation Program Guide.

Within 30 days after closure, the owner/operator must submit State Form 56554- Underground Storage Tank Closure Report Form and the UST Closure Report Document together arranged in the order listed in Section X of State Form 56554 (available on the IDEM Agency Forms page). The site assessment must be included in the report.

Soil Sampling

Always collect soil samples from the area most likely to be contaminated. Bottom samples are always required. Collect samples from native soil, except when sampling excavated material. Composite samples are not acceptable. Sampling should be consistent with the guidance found in Soil Sampling Techniques for VOCs [PDF]. The sampling standards for different closure types are as follows:

• Removal
  • Bottom samples
    • USTs ≤10,000 gallons – Two within two feet below both ends of the each UST.
    • USTs >10,000 gallons – One additional within two feet below the middle of the UST.
  • Sidewall samples
    • UST pit perimeter <80 feet – Four sidewall samples taken at a point half the distance from the surface to the bottom of the UST excavation.
    • UST pit perimeter ≥80 feet – One sidewall sample for every 20 linear feet from halfway between the surface to the bottom of the UST excavation.
  • Piping samples
    • Pipe run <20 feet – One sample halfway between UST and dispenser or fill port.
    • Pipe run ≥20 feet – One sample for every 20 linear feet of pipe run.
    • One sample under every piping elbow or connector.
  • Dispenser samples – One sample under each dispenser.
  • Excavated material – Sampling of excavated material must occur for every 50 cubic yards of material that is treated, disposed, or returned to the excavation area as backfill.
• In-place or change-in-service
  • Borings – If the exact location of the UST and piping is not known, install the borings as close as practicable.
    • One continuously sampled boring within three feet of the UST and every 20 linear feet around the UST, with a minimum of four borings and extended at least two feet below the bottom of the UST.
    • Borings ≤15 feet – A minimum of two samples taken from:
      • A point where contamination is detected and at the bottom of the boring, or
      • At the midpoint and bottom of the boring.
    • Borings >15 feet – Three samples at ≥1 foot below ground surface, where release is suspected and/or detected.
  • Piping samples – Borings within three feet of and two feet below pipe run, elbow or connector.
    • Pipe run <20 feet – One sample halfway between UST and dispenser or fill port.
    • Pipe run ≥20 feet – One sample for every 20 linear feet or fraction thereafter, along the piping run.
    • One sample under every piping elbow or connector.
  • Dispenser samples – One boring within three feet of and two feet below each dispenser.

Ground Water Sampling

• Removal
  • Excavation – At least one ground water sample from each excavation where ground water is encountered.
  • Borings – A boring must be installed within any area where a release is suspected or substantiated by visual observations, odors, or field screening. A water sample must be collected within the first saturated zone or at a total depth of 30 feet below grade at the area of suspected or confirmed release. If ground water is not encountered within a depth of 30 feet below grade, a soil sample must be collected at the base of the boring.
• In-place or change-in-service
  • Borings – Four borings must be installed in each of the principal directions within 10 feet of the area most likely to have contaminated ground water. The aforementioned ground water sampling boring procedures for removal must also be followed when sampling for in-place or change-in-service closures.

Sample Analyses

Table 3.1 in the Remediation Program Guide lists potential petroleum contaminants for various product or waste types and media. For source types not listed in the table, contact OLQ.

Certification Requirements

Under Indiana Code 13-23-3, the Indiana State Fire Marshal must certify all persons who install, upgrade, and decommission USTs. Owners/operators of UST systems must use certified persons to oversee any tank system installations, testing, upgrading, closures, removals, and changes-in-service. In addition, State Form 45223 - Notification for Underground Storage Tanks requires a signature and certification number from a certified worker or contractor.