In the event your heating oil tank is no longer used, the tank must be taken out of service and properly closed. Proper closure for both an aboveground storage tank (AST) and underground storage tank (UST) is defined as emptying the tank and related piping of heating oil. After the oil is drained, the tank must be properly cleaned to remove all vapors and residual oil. Once the AST has been emptied and cleaned and there is no evidence that the tank leaked, the tank is considered closed and can be removed. Additional information can be found in EGLE's Home Heating Oil Tanks brochure and on LARA's Home Heating Oil Tanks FAQ webpage.