An old oil tank has to be decommissioned properly when you switch from oil to a heat pump, replace a tired tank or clear a commercial site. Even a tank that looks empty holds oil, sludge and flammable vapour. Cutting into it without cleaning and gas freeing it first can cause an explosion.
This guide explains how decommissioning works, who should do it and how the waste is dealt with.
Who should decommission an oil tank?
Use an OFTEC registered technician or a specialist tank decommissioning company. They’ll assess the fire and pollution risks, handle the waste legally and give you the paperwork to prove it was done properly. Removing a tank yourself is dangerous and can easily lead to a spill.
The decommissioning process step by step
- Inspection. The technician checks how much oil is left, looks for leaks and identifies the sludge and water that collect at the bottom of the tank.
- Removing usable oil. Clean oil above the sludge layer can be pumped out and, in some cases, transferred to a new tank.
- Removing sludge and contaminated oil. The layer at the bottom is pumped into containers as hazardous waste.
- Cleaning and gas freeing. The tank is cleaned, ventilated and tested to confirm it’s free of flammable vapour. You should receive a gas free certificate.
- Disconnection and removal. Pipework is disconnected and capped, and the tank is cut up or lifted out whole.
- Paperwork. You receive a consignment note for the hazardous waste and a waste transfer note for the tank itself.
What happens to the waste?
Residual oil and sludge are hazardous waste. They must be collected by a carrier licensed for hazardous waste, with a hazardous waste consignment note. Keep your copy for three years. Our oil and fuel disposal service covers waste heating oil, diesel and tank sludge.
Steel tanks can be recycled as scrap metal once they’ve been cleaned and certified gas free.
Plastic tanks can usually be cut up and recycled once cleaned.
Never put an uncleaned tank, or any part of one, in a skip.
What if the old tank has leaked?
Look for staining, dead vegetation, an oily smell or a sheen on nearby water. If oil has escaped, contain it with a spill kit and report it on the environmental incident hotline, 0800 80 70 60, if it has reached a drain, watercourse or the ground. Let your insurer know too, as some home insurance policies cover oil leaks.
Soil soaked in heating oil is usually hazardous waste and may need testing before it’s removed. See our contaminated soil disposal service.
Underground tanks
Buried tanks are harder to remove. Where removal isn’t practical, a specialist may clean the tank and fill it with an inert material such as foam concrete so it can be left safely in place. Keep the records, as buyers and their surveyors will ask about it.
Replacing the tank
If you’re fitting a new tank, installation must meet Building Regulations, which an OFTEC registered installer can self-certify. Businesses in England and Wales storing 201 litres or more of oil must also meet the oil storage rules, including secondary containment that holds 110% of the tank’s capacity.
Need an old tank or oily waste cleared?
Select A Skip arranges collection of waste oil, tank sludge and contaminated soil across the UK, with the right paperwork. See our hazardous waste services, get a quote or call 01743 341 000.
Sources: BoilerJuice, Oil tank removal and disposal; GOV.UK, Storing oil at a home or business; NetRegs, GPP 22 Dealing with spills.