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Statistics
indicate as many as 25% of all Underground storage tanks (USTs)
may now be leaking. These underground tanks may hold oil or gas
but can most frequently be found at homes heated with oil. Over
time, there is a tendency for these older tanks to corrode and leak
their contents into the ground and possibly into the ground water.
Because of the great expense involved in cleaning up the contamination
caused by leaking tanks, it behooves those that have older underground
tanks, to have them or the soil tested.
Because most underground oil tanks are steel,
this steel can rust over time allowing the oil or gas to leak into
the ground. Although it is hard to pinpoint exactly what age this
may occur, the state of Maryland has stated that any tank over the
age of fifteen may be at risk of leaking. It is recommended that
any tank over twenty to twenty five should be checked to insure
it's integrity.
If a tank begins leaking its contents into
the soil the owner of the tank (house where tank is located) whether
a new owner or long time resident may be responsible for the cleanup.
It is important to remember that the only time that cleanup is required
is when the oil or gas actually contaminates the ground water or
public waterways. Obviously, those with high water tables or in
close proximity to a public waterway, ie. stream, creek, river or
bay have a higher risk of being responsible for cleanup. If a new
homeowner buys a house with an oil or gas tank that has contaminated
a body of water, that new owner is responsible. There are many horror
stories of "new" home owners finding out that they are
responsible for thousands of dollars worth of contaminated soil
removal from a newly discovered leaking tank. Unfortunately, the
first person who usually finds out about it after the homeowner
is the Realtor. As such, both the Real Estate agent and the buyer
should contractual stipulate to underground tank testing to alleviate
their liability. It should be noted that in most situations homeowners
insurance does not cover the expense involved.
There are two common forms of testing available
to test underground oil tanks for leakage: Soil sampling and Pressure
test of tank. Soil sampling requires the pulling of soil samples
from under the tank and then sending them to a laboratory where
there are then analyzed for the presence of oil. Normally no more
than four samples will need to be pulled unless special circumstances
dictate differently. Because the samples must be sent to a lab,
time should be budgeted for the lab to analyze and then report results.
There are a variety of different methods for pressure testing of
a tank. Normally, a vacuum test of the tank is conducted to find
any leaks. Unfortunately this type of test may require that the
tank have no more than 1/2" of water in bottom, no bends in
the oil fill (it must be straight) and the tank must be level or
the fill needs to be on the lower end of tank. Some companies are
now using sensitive equipment to measure liquid loss in the tank.
Either of the above tests may take many hours on-site to conduct.
If a tank is found to be leaking oil or
gas, the tank must either be abandoned or removed. The process of
abandoning an underground tank is called Closure. Through this process,
the tank must be pumped dry of its contents and then filled with
sand or a cement slurry mix. The state of Maryland has asked those
that are abandoning a tank to report it to the state so they have
a record of the location of the tank. Each jurisdiction has different
requirements and organizations responsible for USTs. In some areas,
the only time a tank may be abandoned is if the removal "would
endanger a building structure if removed." It is important
that the local agency responsible for USTs be contacted to obtain
local regulations. This may be the local fire department, health
department, or other county agency.
The desired method for leaking USTs is removal
of the tank. Following is the recommended steps when removing an
underground oil tank as dictated by the Maryland Department of the
Environment (MDE).
- Notify the Oil Supplier to discontinue
oil service to the home.
- Obtain an approved contractor to conduct
the work. MDE maintains a list of those approved.
- Local jurisdictions may have specific
permits to conduct removal, contact governing agency.
- Have all oil pumped from the tank and
lines. Some companies provide a credit for reusable oil removed.
- Excavate the top of the tank and expose
the piping.
- All piping should be disconnected and
drained including the tank fill line.
- Oil sludge and residue on exterior of
tank should be removed and disposed of properly.
- If tank is clean, it can be disposed
of in an approved manner. The contractor or MDE can assist in
locating a proper disposal site.
- If soil or groundwater contamination
is found during excavation, it must be reported to MDE immediately
upon discovery. Phone number: 410/631-3442 or after hours 410/974-3551.
- Any residential tank greater than 1,100
gallons in capacity are required to be registered with MDE. Forms
may be obtained by calling 410 / 631-3442.
Any home that has an older UST should have
it periodically inspected to prevent unforeseen expense to the homeowner.
Any house that is being bought and may have an older UST on site
should be checked for its condition whether it is requested by the
homebuyer or the Realtor. For further information on this subject,
contact your local governing agency regulating USTs, the Department
of the Environment or the Environmental Protection Agency (EPA).
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