A new gas boiler doesn't mean the oil tank left with the old equipment. It may still be sitting in the basement, or a buried tank may still be under the yard.
First find out where the old tank was. Then look for proof of what happened to it. A final oil-delivery bill shows when deliveries stopped, not whether the tank was removed.
What happened to the old fuel supply?
Look for the old fill and vent pipes, exposed supply lines and any fuel-company or heating-contractor records. Ask the contractor to identify which pipes serve the old system and whether the tank contains remaining oil.
Removing a tank from a narrow basement
Basement steps and doorways can complicate removal. A qualified company should propose safe handling and explain whether dismantling would be necessary. Never cut or haul a former fuel tank yourself.
Underground tanks need a different plan
If the former tank was buried, an old gas-conversion document does not prove that it was excavated. Obtain closure or permit records where available and have a professional inspect the actual site.
Next step for a homeowner
Queens follows New York City tank rules. What needs to be filed depends on the tank and the work—not the neighborhood name.
Before accepting an estimate, ask who's responsible for the leftover oil, pipes, disposal and any permits. Have the company put those details in writing.
Official references
Check these agencies' current guidance for your property and type of work: