Your local county Fire Chief or Fire Marshal defines how to address heating oil tanks that are no longer in service. Most fire districts comply with the 2021 International Fire Code (IFC) Section 5704.2.13 which requires underground heating oil tanks that are out of service for at least one year must be:
- Removed from the ground, or
- Permanently closed in place.
Closing Tanks in Place
Per the International Fire Code, if an underground heating oil tank is closed in place, then all of the following procedures must be met:
- Flammable and combustible liquids must be removed from the tank and connected piping, excluding vent lines.
- Clean tank of all liquid and built-up sludge.
- The suction, inlet, gauge, vapor return and vapor lines must be detached.
- The tank must be filled fully with an approved inert solid material.
- All remaining underground piping must be capped or plugged.
- A record of the tank size, location and date of desertion or closure must be retained by the property owner for up to five years.
- All outside above-grade fill piping must be permanently removed.
- Within 30 days after tank closure actions are complete, the underground storage tank decommissioner is required to fill out a Permanent Closure Notice and submit it to the Department of Ecology.
If you have further questions regarding decommissioning please contact your local county Fire Chief or Fire Marshal regarding the requirements in your area.