If you have switched from home heating oil to natural gas or electricity as a means of heating your home, and your heating oil tank is no longer in use, and known as abandoned. Abandoned underground storage tanks that are out of service for 12 months must be properly decommissioned. If removal isn’t possible you can decommission your home heating oil tank by closing it in place. Closing in place involves pumping out the oil, triple rinsing the tank, then filling the tank with an inert solid material.
Have all unused heating oil removed from your tank
Tanks by Dallas and The Washington State Department of Ecology recommend that you have all unused heating oil removed from your tank.