Underground storage tanks, or USTs as they are commonly
called, have for many years been used at facilities to store bulk quantities of
liquids for on-site use or for retail storage. Materials stored in USTs commonly
include heating oil and gasoline. USTs are extremely common, and continue to a
preferred means of bulk liquid storage at properties where aboveground storage
vessels are neither practical or desirable. However, the presence of a UST at a
property represents a potential environmental concern, since the accidental
release of oils or other substances to the subsurface can result in significant
cleanup costs.
In the past decade, many large oil companies have
replaced their USTs at their retail gas stations with newer tanks of double
walled and/or fiberglass construction. However, most smaller tanks currently
still in use for oil storage in residences or commercial/industrial properties
are of single-walled, steel construction, and many are greater than 20 years in
age. Tanks of this type commonly undergo some degree of deterioration in the
subsurface over time, due to the effects of moisture and corrosion. Small leaks
can develop, which may initially be undetectable on inventory records. In such a
case, significant impacts to the subsurface can occur before any inventory loss
or other evidence of problems are detected. Releases can also occur through
spills during filling or other operational errors. The net result of a
reportable release of any kind is often an investigation and cleanup of soils
and/or groundwater. These efforts can be time-consuming and expensive, and are
usually subject to oversight by regulatory agencies.
The potential for the UST-related scenarios can create
significant liabilities at a site. However, there are certain tools which are
used to assess the potential for release to the subsurface from a UST. These
include:
- Tank tightness tests
- Narrow-diameter (GEOPROBE) boring investigations in
the tank area
- Removal of out-of-use USTs
A Federal EPA deadline, carried down to each of the
state environmental regulatory agencies, has come due, requiring certain
upgrading features such as leak detection, corrosion protection and secondary
containment to be installed in all USTs which fall under a certain definition of
use as defined by the state agency. For instance, in Pennsylvania, all regulated
tanks are subject to ruling and therefore require the upgrades to be in place.
This ruling states that all regulated tanks not properly upgraded by December
1998 will not be permitted for future use, and the operation of tanks not
meeting the new criteria will result in significant fines. For this reason, tank
owners should refer to their state UST regulations to see if their tanks fall
within the qualifying criteria; if so, upgrading should be installed as soon as
possible. If tanks are out of use, they should be removed from service to avoid
regulatory penalties, as well as the real estate liabilities associated with
them.
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