Thinking of Removing an Underground Fuel Tank?

Written by: Brian Pottebaum, Director of Training Services

After fulfilling the intended use, every underground storage tank (UST) is taken out of service and permanently closed by filling in place or being removed. Industry experts suggest that USTs on average will last around 25 to 30 years. Tanks can be permanently closed because of facility upgrades, tank failure, incompatibility with future product, or simply because the system is no longer going to store petroleum.

Regardless of the reason, the tank owner or operator is required by state and federal regulations to follow a specific process for removal. Underground storage tanks are not allowed to sit abandoned indefinitely, so proper environmental assessments and closure procedures must be followed.

Here is a quick rundown of the steps when permanently closing a regulated UST system

1.  Notify State and Local Governments

No later than 30 days prior to any tank removal activity, the tank owner is required to give the state regulatory agency (IA DNR) formal notification of permanent tank or piping closure. Yes, even if you are only closing/removing some or all the piping, you are required to follow the same permanent closure process.

2. Certified Contractor Involvement

All tank and piping closures must be conducted by a certified remover. The IA DNR maintains a list of these certified companies. In addition to the qualified remover, the project requires closure soil and groundwater samples to be collected by a certified groundwater professional (CGP). The sample results determine if contamination levels are elevated enough to require additional cleanup measures at this facility.

3. Remove All Product From the Tank System

Before the tanks or piping are removed from the ground, all product must be removed from the tank system. This includes the sludge and debris that has collected on the bottom of the tank. All tanks should be emptied to 1 inch or less from the bottom. Tank and piping cleaning are very important to prevent any product being released to the environment during the removal process.

4. Inert the Tank System

Before the system is removed from the ground, it must be made safe temporarily by inerting the tanks. This is a process that removes flammable vapors from the tank system and allows the contractors to work in and around the tanks safely. The tank system must be monitored for hazardous conditions during the entire removal process, so petroleum vapors do not regenerate and create an unsafe work environment for everyone in the area.

5. Excavation

After the tank system has been inerted and is “safe” to work around, the tank remover company excavates the soil over and around the tanks to prepare the system for removal. The area around the excavation zone needs to be properly secured and no traffic or pedestrians are allowed in the work zone for the entirety of the removal. While the tanks are being removed from the ground, the CGP makes visual observations of the excavation condition to determine if there are any obvious signs of petroleum contamination. Remember, any evidence of a petroleum release to the environment must be reported to the IA DNR UST Section by the owner within 24 hours of discovery, or 6 hours if it is a hazardous condition. The DNR does have a prescribed process and forms that must be used to report the petroleum release.

6. Clean and Remove Tank(s)

Once the inerted tank or tanks have been removed from the ground, they are thoroughly cleaned internally and properly decommissioned. Once the tanks have been cleaned and rinsed, they are ready to be transported away from the site. Monitoring the tanks for hazardous vapors must continue to control the atmosphere in and around the tanks. Also, make sure to obtain a signed certificate from the tank cleaning company certifying the cleanliness of the tanks. This will be included in the closure report that is submitted to the regulatory agency.

7. Prepare Tank(s) for Disposal

The certified remover is responsible for proper disposal of all waste materials generated during the tank removal process. This includes, but is not limited to, excavated material, non-salvageable storage system components, the tank itself, any fuel or sludge in the tank, and the water used to clean the tank. Waste material must be transported and disposed of using transporters and disposal facilities which possess all required federal, state and local licenses or permits. Submit manifests certifying the proper transport, receipt, and disposal of waste materials with the closure report.

Most tanks removed from the ground are not safe for re-use, so they are scrapped or destroyed and disposed of in a landfill. Before transporting the tanks from the site, they must be properly labeled with hazard warnings, previous contents, and the date of removal. The decommissioned tanks are quickly hauled away from the site on trailer, as they still pose an extreme safety hazard while they are stored at the facility.

8. Manage Contaminated Soils

The CGP will conduct continuous field analysis of the excavated soils to determine if heavy levels of contamination exist at the facility. All contaminated soils removed from the tank excavation must be disposed of properly. Contaminated soil cannot be pushed back into the excavation. This requires access to enough clean backfill material that can be used to fill the excavation soon after the tanks are removed. The certified remover will manage the contaminated soils and arrange for it to be transported away for proper disposal or treatment.

9. Follow Sampling Protocol

Before the excavation can be backfilled, the CGP must collect the appropriate number of soil and groundwater samples to be analyzed for contamination. The sampling protocol is outlined in the  DNR Closure Guidance  as well as in the Iowa Administrative Code. Samples are drawn in and around the excavation area to best represent the existing conditions at that specific location. These samples are then sent to a certified lab to be further analyzed for petroleum contamination.

10.UST Closure Report

At the conclusion of the tank removal process, the CGP will construct a permanent closure report with sampling data, along with any additional steps that may result from the remaining contamination if you had a leaking tank system. The closure report must be submitted to the DNR within 45 days of the tank system closure.

Petroleum tank system removal can be a very dangerous and complicated process. It is wise to rely on professionals to handle this work.

2894 106th St. Ste. 220 Urbandale, Iowa 50323