What is a Decommissioned/Abandoned Oil Tank?

An abandonment/decommissioning of an oil tank involves rendering a tank inoperable, clean, structurally stable and eliminates or documents the possibility of contamination risk to the surrounding environment.   For examples, please visit our gallery and check out our pictures of abandoned/decommissioned tanks.

What is Involved in a Proper Decommissioning/Abandonment of an Oil Tank?

It is important that all of the proper steps are taken when decommissioning an oil tank to ensure that it is done safely, effectively and to the standards of the local municipality.

  • Obtain confirmation that you are allowed to decommission the oil tank the appropriate local municipality governing body.
  • Have a geo technical or structural engineer authorize and oversee the project if necessary.
  • Excavate the tank
  • Flush, pump and clean the inner walls of the oil tank
  • Take samples surrounding the oil tank to ensure that the oil tank has not leaked into the nearby soil.
  • Fill the tank with a product that will maintain the structural integrity of the tank and not pose a risk to the structure.

 

What is a Partial Abandonment?

A partial abandonment takes places when a portion of the oil tank is located under a structure and cannot be safely removed without risking the integrity structure.  When partially abandoning an oil tank the accessible portion of the tank is removed and the remainder of the tank is filled with a product that will maintain the structural integrity of the tank and not pose a risk to the structure.  Before the tank is removed soil samples must be taken to ensure that the soils surrounding the tank are not contaminated beyond the legal limit set by the Ministry of Environment.  The abandonment process should be overseen and/or approved by a registered geotechnical or structural engineer, to ensure that the proper steps have been taken, prevent damage, and to obtain a seal of approval for the work completed.

 

My Oil Tank was Decommissioned/Abandoned Years Ago; Can I Just Leave it in the Ground?

In most cities, it is still mandatory to remove a decommissioned/abandoned oil tank if it does not pose a risk to the structure of any buildings.   When cities began to allow oil tanks to be decommissioned, there were no strict guidelines, sampling procedures, or inspections, subsequently making it difficult to certify that the process was done properly and does not pose any environmental issues.  Since previously the process of decommissioning was not monitored or inspected, most times homeowners would decommission there tanks themselves or have a contractor who was not familiar with the industry to perform this task.  These practices lead to the improper abandonment of tanks; therefore, leaving the risk of contamination on the property.

The most common mistakes that were made when they were attempting to decommission the oil tanks were as follows:

  • They did not pump and clean the inner walls of the tank properly.
  • They did not fill the tank properly with backfill.
  • They did not fill the tank completely.
  • They did not take any samples.
  • They did not provide a report that documents, outlines and confirms the correct procedures of the abandonment process.