The gas boiler went in years ago. The old oil tank is still against the basement wall. That's common enough that homeowners sometimes forget about it until a renovation or sale brings it back into view.
Look for the paperwork from the heating change. Did the installer disconnect the tank, drain it or arrange removal? Those aren't the same thing.
The old tank may still contain oil
A disconnected oil line does not mean that all oil or residue was removed. Ask the professional handling the work how any remaining fuel, vents and outside fill pipe will be managed. Do not attempt to drain or cut an old tank.
Questions after a gas conversion
Find the old installation or conversion paperwork if possible. Ask if it identifies the tank and its status. If a home is being sold, ask the buyer, attorney and lender what documentation they expect.
Questions after a heat-pump conversion
If the property used a utility or incentive program, retain the program documents and confirm whether it imposed any requirements about the old heating system. Program terms change and should be checked directly; eligibility for an equipment rebate does not automatically pay for tank removal.
NYC removal and out-of-service requirements
Queens follows New York City tank rules. What needs to be filed depends on the tank and the work—not the neighborhood name.
The FDNY's published code guide describes requirements for fuel-oil tanks taken out of service. Have a qualified professional determine which provisions apply to your property.
Official references
Check these agencies' current guidance for your property and type of work: