Skip to main content

Petroleum contamination and leaking underground storage tanks

Gasoline, oil and other petroleum products are used daily in Wisconsin businesses and homes. Many petroleum discharges come from storage tanks, known by the acronyms UST (underground storage tank), AST (aboveground storage tank) and LUST (leaking underground storage tank).

The Department of Agriculture, Trade and Consumer Protection (DATCP) maintains Wisconsin's tank registration database and is responsible for tank regulations for both underground and aboveground tank systems, while the DNR is responsible for cleanups that result from contamination. Tank registration and operator licensing questions should be directed to DATCP Bureau of Weights and Measures.

When petroleum products are discharged into the soil or groundwater, the DNR will work with the responsible party and environmental professionals to clean up the contamination to standards.


solar panels
A leachate/gas extraction well at the Refuse Hideaway Superfund site in Dane County.

The DNR regulates cleanup of contamination from petroleum storage tanks and administers the Petroleum Environmental Cleanup Fund Award (PECFA) and Abandoned Tank System Removal Program.

The DNR is responsible for the following activities:

  1. Establishing investigation and remedial action requirements for contamination in the s. NR 700, Wis. Adm. Code, series of environmental rules.
  2. Oversight of cleanups at petroleum tank discharges. (BRRTS on the web)
  3. Administration of the fund for reimbursement of petroleum environmental cleanup costs (PECFA).
  4. Maintenance of the list of registered PECFA consultants.
  5. Administration of the Tank System Removal Program, in coordination with the Department of Justice (DOJ) and Department of Agriculture, Trade and Consumer Protection (DATCP).

Other resources

Wisconsin tank regulations

Mandatory reporting

Petroleum discharges

Tank system owners and operators, and property owners at properties with tank systems, must immediately report discharges to the environment as required by state law. This may be done using the online Notification for Hazardous Substance Discharge Form - Non-Emergency Only (Form 4400-225). (Directions for submitting the form are available on the RR Program Submittal Portal web page.) A contractor or environmental consultant may report on behalf of the owner or operator.

Keep in mind the following when reporting the source and cause of the discharge:

  • Spills occurring during delivery of product to a tank should be reported as a delivery problem.
  • Discharges from piping or submersible turbine pumps can be caused by damage or corrosion but cannot be caused by spill or overfill.
  • Delivery equipment is not part of the tank system. If the filling port attached to the tank system is damaged, this should be reported as a spill or overfill, whichever is more accurate.

Additional information on sources and causes of petroleum discharges can be found in the federal reports tab.

Tank closure site assessments (TSSAs)



The Petroleum Environmental Cleanup Fund Award (PECFA) is the DNR's reimbursement program for cleaning up contamination from storage tank systems. More information can be found on the PECFA webpage.

Tank System Removal Program

The DNR has the ability to directly hire contractors certified by DATCP for tank closures in limited situations where the property owner does not have the financial resources to close the petroleum storage tank(s) as required by law.

Federal reports

Federal Energy Act reports

The federal Energy Act of 2005 amended state public record requirements for discharges from petroleum underground storage tank systems (UST). Federal law now requires states to collect information about the sources and causes of environmental discharges from UST's and include that information in their public records.


This data is collected throughout the year and posted annually. The period of collection is Oct. 1 to Sept. 30 (federal fiscal year). Reports are posted by the end of the calendar year.

Report contents

The data provided by the notification of a release is broken down in two categories; source and cause. The "source" is where the release started. The "cause" of a release is an indication of why the component or transfer failed.


The first four sources listed here are physical components of a tank system.

  • Tank - The tank that stores the product and is part of the UST system.
  • Piping - The piping and connectors running from the tank or submersible turbine pump to the dispenser or other enduse equipment. It does not include vent, vapor recovery or fill lines.
  • Dispenser - Includes the dispenser and equipment used to connect the dispenser to the piping. For example, a release from a suction pump or components located above the shear valve would be considered a release from the dispenser.
  • Submersible turbine pump (STP) area - Includes the submersible turbine pump head (typically located in the tank sump), the line leak detector and the piping that connects the STP to the tank.
  • Delivery problem - Identifies releases that occurred during product delivery to the tank. Typically causes associated with this source are spills and overfills.
  • Other - Used when the release does not fit into one of the above categories. For example, releases from vent lines, vapor recovery lines and fill lines.


  • Spill - A discharge from the system while product is being delivered to or removed from the tank system.
  • Overfill - A specific type of spill caused by attempting to place a greater volume in the tank system than its designed capacity.
  • Physical or mechanical damage - Failure of a tank system or component due to an external element.
  • Corrosion - Failure of a tank system or component due to chemical breakdown, i.e. rust.
  • Installation problem - Used when the cause is a direct result of improper installation.
  • Other - Used when the cause is known, but does not fit one of the categories above.
  • Unknown

Additional information