Heating Oil Underground and Above Ground Storage Tank
are a Big Expensive Problem
Issues regarding oil tanks, whether underground oil storage tanks (USTs) or above ground indoor or outdoor tanks, include: oil tank leaks, oil tank leak testing methods, oil storage tank removal, environmental damage, oil spill cleanup, oil tank abandonment procedures, and oil storage tank regulations. Leaks and environmental contamination issues are important for homeowners and homebuyers.
Before natural gas became available in 1957, most homes were heated by furnace oil. The many tanks were stored underground and held up to one-thousand gallons of oil. When homes converted to natural gas, the tanks were often left buried. In many cases, they were not thoroughly emptied.
Burying oil tanks in the ground has never been a good idea. When a very old tank develops a leak, we never know about it and it just leaks oil into the ground for years, creating quite an environmental problem. That is why it is no longer legal to bury residential oil tanks. So they either go on the outside of the house, or in the basement. But the outside location is unsightly and the tank is subject to mechanical abuse as well as early rusting.
Oil tanks just sitting in the corner of the basement can also leak and that oil goes into the concrete and into the soil below as well. In fact because of the high costs of removing concrete and digging out polluted soil, insurance companies now put various special restrictions on oil tanks, some simply won’t insure tanks over a certain age, forcing you to change the tank even if it appears to be in perfect shape.
In fact in most areas today you have to have your tank inspected by the furnace service person, an inspection report filled out and a dated green OK tag put on your fill pipe outside. Without that tag, the oil delivery person will not deliver oil.
So just what should you look for when inspecting an oil tank yourself?
Check the bottom of the tank for condensation. You will probably have some condensation the day they deliver the oil, because now the tank will be cold, but you don’t want constant condensation that could rust the tank from the outside in. Touch up scratched paint, precisely to prevent rusting. If you do have constant dampness on the bottom of the tank, and do not have condensation problems in the rest of the basement, that is a sign that the bottom of the tank is filling up with sludge. That sludge will make the bottom of the tank colder than the rest and draw basement moisture to the tank. The tank needs flushing out or, usually by the time you have a lot of sludge in a tank, it probably needs replacing.
Next, follow the copper pipe all the way from the tank to the furnace. Check all joints for leaks and inspect the pipe to be sure that nothing has bumped into it to cause a fitting to leak, or crimp the pipe itself. Make sure there is mechanical protection anyplace this pipe is exposed, particularly where it can potentially be stepped on.
The strangest, but most common problem with oil tanks is when they ‘rust’ through from the inside out. Run your hand all over the bottom of the tank, looking for little dime sized blisters in the paint. If you find one or more, they are a result of sludge accumulating in a little clump inside the tank. That clump of foreign matter causes an electrolytic reaction that can eat through the tank from the inside out, despite all that oil. You wouldn’t dream that a tank filled with oil could possibly ‘rust’ from the inside out, but that is what kills most tanks. When you do find those blisters, it is time to change the tank because it has already eaten most of the way through the tank wall.
It is possible today to find a plastic tray to place under the tank, even one with a built in alarm. This will catch any spills, prevent a problem of oil soaked concrete, and even alert you to the problem. Ask whoever is supplying a new tank for you to include a catch basin.
Who Are The Removal Specialists?
Buried tank removal is handled by environmental services companies. Usually the specialist arranges testing, excavation, and disposal. Or tanks can be abandoned in place using the procedures explained in this paper. These companies employ certified hazardous materials technicians capable of removing oil tanks from residential and commercial properties in a safe, cost effective manner. They detect whether a tank exists and provide the best options for remediation or removal. They can also implement abandonment procedures as described below.
What if a buried oil storage tank is installed on your property?
Think seriously of removing and replacing this source of heating oil. Even installing a new tank in the basement is an improvement.
Buried oil tanks raise increasing environmental, safety, legal and economic concerns for homeowners and homebuyers because oil leaks underground or even within buildings can lead to both environmental damage and very costly cleanup operations. The environmental issue is obvious: heating oil leaks cause soil and water contamination. The economic issues include the cost and risks of testing, tank removal, and site cleanup. Safety is also involved as an old tank can collapse. Major costs may be involved.
Environmental regulations regarding oil storage tanks for U.S. states and Canadian provinces cover identification, testing, and removal or abandonment of buried tanks.
These vary widely from state to state in the U.S. Home heating oil tanks are excluded from U.S. Federal Regulations about oil storage tank reporting and monitoring, but in some states and provinces, are addressed by state or local DEP/DNR/DEC (Department of Environmental Conservation) or similarly named agencies and regulations.
In any case, should a home heating oil tank cause a release of oil into the environment, at that point the owner of the tank is not exempt from the other provisions of the Federal Regulations – the source of leak/spill would have to be stopped, a site characterization would have to be completed, appropriate corrective action (cleanup) would have to initiated, and the incident would have to be reported.
Such components are not inspected during a home or building inspection unless specific prior test arrangements have been made. Tank inspection (other than casual visual inspection), tank tests, as well as removal or abandonment require that you use an appropriate expert. Tank Removal Funding Assistance is sometimes available. Ask your government.
Oil Tank Testing Procedures
Specialty companies and some oil companies have equipment to test buried tanks for leaks. Both simple pressure testing and very sophisticated electronic testing are commonly used, mostly on commercial equipment rather than residential tanks. Testing for water in the tank is simple and can be done by any service person. Tank testing methods vary in their risk to the tank, cost, invasiveness, length of time to complete, and more.
Life Expectancy of Buried or Underground Tanks
The common life expectancy of buried oil tanks is 10-15 years. Buried gas tanks are probably about the same. Buried tanks should be tested for amount of water present in the tank bottom, and water should be pumped out. Water corrodes the tank and leads to leaks. Leaks are also due to damage at time of installation, improper installation, corrosive soils, or piping defects. If the tank is to remain in use, ask your fuel supplier about using an additive or other methods to help remove water.
Oil Tank Leak/ Failure Causes
Underground fuel storage tanks usually fail from rust perforation due to several effects of water inside the tank including, in the case of heating oil, a combination of water with sulphur in the fuel, bacterial action, and other factors. External rust, unless very heavy, isn’t highly correlated with internal rust. Leaks can occur due to tank damage or at piping connections. A new tank is relatively expensive.
Oil Tank Abandonment Methods
Without actually excavating and removing them (provided there is not evidence of leakage), a proper abandonment procedure involves pumping out remaining fuel, confirming that there has been no leakage, cleaning the tank, and filling the tank with an approved filler. These measures, if required, involve significant expense.
Environmental Issues Regulations for Oil Tanks
Some DEP/DEC/DNR (Department of Environmental Conservation in the U.S., or similarly named agencies in other countries) have programs for registering buried tanks at any site storing more than a certain number of gallons of heating oil. Requirements for gas (auto fuel), or other fuels may be different. Eventually this environmental concern may spread to smaller residential tanks. Tanks located where they may leak into a local waterway or into the water supply are a especially dangerous.
Because significant site cleanup costs can be involved if an oil tank leaks, unless there is reliable documentation that the tank has been tested recently, it would be prudent for a home buyer to have testing performed before purchasing the property.
This paper is intended for informational purposes only. Nothing contained herein constitutes legal, financial or other professional advice. Transmission of these materials is not intended to create, and receipt does not constitute, any relationship of any kind between the provider and the recipient. Some of these points may not apply in your area. Different term and conditions may vary from state to state and province to province. All articles, text and photographic material presented here is for the use and pleasure of the recipient only. Download PDF