Underground Storage Tank Removal in Missouri: DNR Closure, Testing and PSTIF Coverage

What is an underground storage tank, and which ones does Missouri regulate?

Missouri DNR defines an underground storage tank (UST) as a tank plus any connected underground piping with at least 10 percent of its combined volume underground. Whether the state regulates it depends on what the tank held and its purpose. Call DNR to confirm before you plan work.

DNR says a UST “may be regulated under Missouri’s Underground and Petroleum Storage Tank Law, depending on what is or was stored” in it. The DNR Underground Storage Tanks Section answers questions at 573-751-6822.

Above ground tanks follow different rules. DNR does not regulate how they operate, but it does oversee cleanup of petroleum releases from leaking ones. See the glossary entry for underground storage tank (UST).

Missouri takes leaks seriously. DNR reports over 4,900 releases from USTs in the past 10 years. Releases can start fires and contaminate groundwater, which is why the closure steps exist.

This page covers the owner’s decisions and the money. The step-by-step DNR process lives in our guide to tank removal and closure in Missouri, so we do not repeat it here.

When does a tank have to be closed?

Missouri sets two clocks once a tank goes out of use. A site assessment is due within 12 months. Permanent closure is due within five years. A tank is out of use when no more than one inch of product, or 0.3 percent by weight of capacity, remains.

The five-year clock starts when the tank goes out of use, not when you complete the assessment. Out-of-use tanks keep being assessed registration fees until they are removed or permanently closed. Waiting costs money.

For the exact forms (MO 780-2121, MO 780-2120 and checklist PUB2218), use the DNR closure page.

Should I remove the tank or close it in place?

Both count as permanent closure under DNR’s rules, and both need notice to DNR beforehand. Removal pulls the tank and piping out of the ground. Closure in place seals the tank where it sits. Your site, your plans for the land and DNR approval decide which fits.

Removal takes the tank out so the soil under it can be sampled. In-place closure leaves the tank sealed underground. DNR lists a Statement of Closure Deed Notice for in-place closures. Ask DNR which one it will accept for your site.

Ask your contractor or consultant to explain both options for your site in writing. Tell them if you plan to sell or build on the land.

Tank work often sits inside a bigger project. If a building comes down first, the same survey and notice steps may apply. See the AES demolition service and the guide to demolition from survey to debris.

What testing happens when a tank comes out?

DNR requires soil and groundwater sampling where a release would most likely have occurred. Soil borings go on each side of the tanks, piping and pump islands or dispensers, deep enough to collect groundwater samples if groundwater is found. Results feed the closure report.

Sample data from an earlier site assessment can serve in the closure report only under strict conditions. The tank must not have held regulated substances since the sampling, there must be no new signs of a release, DNR must approve a written request, and extra soil samples must be taken beneath the tanks during removal.

In plain terms, expect fresh samples when the tank comes out. The lab results show whether the soil is clean or needs more work.

If the results show contamination, the next step is cleanup. See soil remediation and the glossary entry for soil remediation. DNR oversees site characterization and cleanup at regulated leaking tank sites.

What if we find a leak?

Tell DNR immediately. DNR says all spill and leak reports go to its Environmental Services Program Emergency Spill Line at 573-634-2436. Do not wait for the closure report. Make the call as soon as the crew sees staining, odor or liquid in the excavation.

A confirmed release changes the timeline. DNR reviews site investigation reports, corrective action plans and quarterly monitoring reports at regulated leaking tank sites. Cleanup can include soil removal and monitoring. Ask your contractor how contaminated soil is handled and where it goes. See the glossary entry for hazardous waste.

AES offers soil remediation and environmental remediation alongside tank removal. One contractor for both can save hand-offs. Ask which parts AES does itself and which a consultant does.

Does PSTIF pay for tank cleanup?

It may. The Missouri Petroleum Storage Tank Insurance Fund (PSTIF) provides coverage for cleanup and third-party damages for participating tanks. A $10,000 deductible applies to each incident, with limits of $1 million per incident and $2 million annual aggregate.

PSTIF says about 3,500 properties with tanks in use participate at any given time. Coverage meets the state’s financial responsibility requirement. Check your participation status before work begins.

Only PSTIF can tell you whether a claim qualifies. Call the claims line at 800-765-2765 or read the PSTIF page. Do not assume your tank is covered, and do not start cleanup before you know.

How much does underground storage tank removal cost?

AES does not publish a price for tank removal. Cost depends on tank size, how many tanks, access, what the tank held, whether the soil is clean, and how much sampling DNR requires. Call AES for a quote on your site.

A fair number needs the tank size, what it held and a site visit. Without those details, any figure is a guess.

To compare bids, ask each contractor the same questions:

1. Does the price include cleaning, removal, hauling and disposal?
2. Who files the DNR notices and writes the closure report?
3. Is sampling included, and who pays the lab?
4. What happens, and what does it cost, if the soil is contaminated?
5. Does the bid mention PSTIF paperwork?

What does AES do on a tank job?

AES says its tank services include industrial tank cleaning, decontamination, and tank demolition and disposal. It states the work is compliant with all federal and state regulations. It offers tank removal for residential buildings and commercial sites, and lists oil, fuel, gas, asbestos and septic tanks.

AES says a tank is cleaned before removal to clear hazardous materials and residues, then dismantled and disposed of with safe transportation. Read more on these pages:

• Tank removal, the main AES service page
• Oil tank removal
• Fuel tank disposal
• Gas tank disposal
• Septic tank removal

Tank work can involve asbestos insulation on older industrial tanks. See asbestos tank removal.

Next step

Start with the AES tank removal service, then call (314) 865-2662 or use the quote form on the contact page. Send the tank size, what it held, its location and any DNR paperwork you already have.