Practical Environmental Solutions, P.C.Practical Environmental Solutions, P.C.
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Tank Closure

There are two acceptable methods to properly close a tank: 1) tank removal and 2) closure-in-place.   However, for most tanks, unless it is under or partially under a building foundation, the State will not allow a closure-in-place as an acceptable closure method. 

Additionally, tank removal is the only way to conclusively and thoroughly assess whether or not the tank has leaked. 

All tanks should be pumped and washed before removal and proper disposal.
Buyer Beware! Proper tank removal with assessment is the only situation that you should accept before purchasing a property.  This protects you from assuming environmental liability for a leaking tank and associated contamination.  We recommend that you require the seller to conduct a proper tank removal with adequate assessment before you purchase the property.  Please see our Property Values, Tanks, and Contamination Page.

Valid Tank Closures: Do's

  1. Proper Tank Removal (with assessment)
  2. Proper Closure-in-Place (with State approval)

Invalid Tank Closures: Do Not's

  1. Filling a Tank with Sand or Concrete
  2. Removing a Tank without a Proper Assessment
  3. Collecting a Soil Sample without Proper Tank Closure


1)  Proper Tank Removal (with adequate assessment):

Buyer Beware! Proper tank removal with assessment is the only situation that you should accept before purchasing a property.  This protects you from assuming environmental liability for a leaking tank and associated contamination.  We recommend that you require the seller to conduct a proper tank removal with assessment before you purchase the property.  Please see our Property Values, Tanks, and Contamination Page.

Unless your tank is under or partially under a building foundation, removal is the only valid closure option that is accepted by the State. 

Additionally, tank removal is the only conclusive method to determine if contamination is present.  Tank removal allows PES to examine the tank for holes.  Because residential oil tanks are commonly 7.5 feet long, knowing the location of corrosion holes enables us to concentrate our assessment efforts where contamination is most likely to be present. 

It is much better to conclusively determine if a leak is present, conduct the appropriate cleanup, and have the Trust Fund assist paying for it than to have this liability come back on you 10 years from now when the Trust Fund coverage may be less than it is currently. 

Usually obvious holes are discovered in tanks after removal.  This includes tanks that have been "abandoned" tanks (out-of-use) but it also includes tanks that were being used at the time they were removed.  Most in-use-tanks are leaking.  See our In-Use Tanks Page. 

In sandy soil (much of New Hanover County), the horizontal extent of soil contamination may be a very small area immediately underneath the tank.  However, as the leaking fuel moves vertically through the soil, it spreads out horizontally away from the "footprint" of the tank.  Checking the soil 2 to 3 feet below the tank bottom is often the best way to assess for potential contamination.  This requires the tank to be removed.    

A tank/contamination issue is not resolved for the seller (previous property owner) until it is either documented that no contamination exists or until contamination is identified and appropriately cleaned up.  Buyers are not protected from assuming liability until a proper tank closure is conducted and the seller takes responsibility for the contamination.    

PES's Tank Removal Procedure:
Because of the potential cost implications, PES will first help you determine your Trust Fund eligibility and acquire the necessary Trust Fund eligibility documents before conducting any "tank removal" activities. 

"Tank Removal" Includes:
Trust Fund eligibility research and document acquisition, logistical site planning, underground utility location, scheduling and coordinating all tank removal tasks (tank pumping, soil trucks, etc.), pumping and washing the tank, excavating of the tank, transport and proper disposal of the tank, collection of a soil sample to confirm the status of soil contamination, back filling the excavation, general site cleanup, and a professionally sealed report that documents the tank and contents disposal and explains the soil analysis results. 

(There will be no re-landscaping except for the items listed on your site specific estimate/contract.  The excavation will be filled with "fill sand" slightly above the original land surface in an attempt to compensate for possible, gradual settling.) 

Timing:
PES needs a minimum of about one week of preparatory time and about 4 hours on site to properly remove the oil tank. 

If contamination is discovered, it must be reported to the State of North Carolina within 24 hours of discovery.  (This is very important to preserve your Trust Fund coverage.)  If contamination is discovered, PES will return to the site after the tank removal day to excavate contaminated soil as required by State regulations and Underground Storage Tank Section Guidelines.  Excavation may take a complete day and will remove as much contaminated soil as is practical or up to the State's maximum allowed excavation tonnage (56.8 tons).  (See Contamination Cleanup Page

Soil sampling is conducted according to specific State Guidelines and reported as required (where applicable).  Where tanks have leaked, soil sampling must be conducted by a licensed professional.  PES holds Geology License Number C-348 issued by the North Carolina Board for Licensing of Geologists and has a licensed geologist on staff.  See our About PES Page.

Tanks Previously Removed without contamination assessment:
In this situation, tank removal was done although it was not required.  Contamination assessment and cleanup is required but was not done.

Buyer Beware! Tank removal without assessment is a very bad situation for a property buyer to purchase.  We recommend that you require the seller to correct this situation before you purchase the property.  Please see our Property Values, Tanks and Contamination page.

There are actions that can correct this potentially complicated situation. 

Please see our What if I removed my tank or filled it in place but did not check for contamination? Page

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A proper in-place tank closure includes cutting it open for pumping and washing and the collection of soil samples according to state guidelines.


2)  Proper Closure-in-Place (with State approval):

A tank closure in place is only allowed by the State if a portion of the tank is under a foundation structure and can not be removed without threatening to damage the building foundation. 

PES's Closure-in-Place Procedure:
When appropriate and approved by the State, PES will close an underground oil tank in place by the following procedure. 

Some portion of the tank is cut open so that all liquid and sludge can be pumped from the tank and the interior of the tank can be washed.  All wash water is also pumped from the tank before filling.  Pumping is conducted using a high vacuum pump truck to ensure that all liquids are removed from the tank and are properly disposed of.  The contents disposal is documented with disposal manifests. 

The tank is then filled with concrete.  This ensures that no settling will occur as the tank continues to corrode; the foundation will be supported and will not be undermined. 

Soil sampling is conducted according to specific State Guidelines and reported as required (where applicable).  Where tanks have leaked, soil sampling must be conducted by a licensed professional.  PES holds Geology License Number C-348 issued by the North Carolina Board for Licensing of Geologists and has a licensed geologist on staff.  See our About PES Page.  

Tanks Previously Closed-in-Place without contamination assessment:
Tanks that were closed-in-place without State permission and/or without soil samples to document a "clean closure" are not considered "closed" tanks. 

Buyer Beware! Tank closure without assessment is a very bad situation for a property buyer to purchase.  We recommend that you require the seller to conduct a proper tank removal with assessment before you purchase the property.  Please see our Property Values, Tanks, and Contamination Page. 

Unless State approved, this action really didn't accomplish anything.  It did not bring the property/tank closer to compliance with State and Federal laws and it did not end the responsibility or liability for the current property owner (seller) or protect the future buyer from assuming the tank and cleanup responsibility. 

Most tanks closed-in-place by persons other than environmental professionals are not conducted according to any accepted protocol.  An in-ground tank can not be pumped empty without uncovering and cutting a sizeable hole in the top of the tank.  This is very rarely done.  This means that most if not all previously filled tanks were filled with 2 to 5 gallons of fuel still in them (possibly more).  Eventually, this "residual" fuel will leak out of improperly filled-in-place tanks.  It may seem hard to believe, but even a leak of 2 gallons from an underground tank can make a significant contamination problem requiring cleanup and costing approximately $10,000.  Please see our Property Values, Tanks, and Contamination page and our Common Questions page.

There are actions that can correct this potentially complicated situation. 

Please see our What if I removed my tank or filled it in place but did not check for contamination Page

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3)  Filling a Tank with Sand (or Concrete) without Assessment

This is not a valid or acceptable tank closure method.

Buyer Beware! Tank closure without assessment is a very bad situation for a property buyer to purchase.  We recommend that you require the seller to conduct a proper tank removal with assessment before you purchase the property.  Please see our Property Values, Tanks, and Contamination Page.

Tanks that are closed-in-place without State permission and/or without soil samples to document a "clean closure" are not considered "closed" tanks. 

Filling a tank with sand (or concrete) is a waste of time and money.  It doesn't accomplish anything because it does not address the contamination which is likely to be present.  Remember the required contamination cleanup is the larger, more costly concern than is "tank closure."

Filling with sand (or concrete) without assessment also will not bring the property/tank closer to compliance with State and Federal laws and it does not end the liability for the current property owner (seller) or protect the buyer from assuming the tank and cleanup responsibility. 

Filling the tank is not required by State and Federal law, but cleaning up petroleum contamination that has leaked out of the tank is required.  How does filling a tank with sand or concrete make the situation better than leaving it empty?  It doesn't! 

Additionally, if the tank is located under the building foundation, "filling it with sand" will not provide adequate foundation support as the tank continues to corrode. 

Remember the State is not concerned with what is in the tank: sand, concrete, water, fuel, or air (empty).  The important issue is: what has leaked out of the tank over the years and what is the level of contamination in the soil and groundwater.

The life expectancy of a bare steel tank is 15 to 20 years.  Most oil tanks have been corroding in the ground for 50 to 60 years and that's why PES finds an 88% leak rate.  There is really no good way for a tank operator to know if there tank is or was leaking. 

Additionally, putting sand in the tank will increase the price of a proper tank closure conducted later.  Filling a tank with concrete that could have been removed could significantly increase the cost of a proper tank closure conducted later. 

Filling the tank (with sand, concrete or water) is not illegal but it doesn't really accomplish anything

For Tanks Previously Closed-in-Place without contamination assessment; please see our What if I removed or filled it in place but did not check for contamination? page.

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4)  Removing a tank without a thorough assessment

This is not a valid or acceptable tank closure method and is perhaps the worst scenario of all. 

Buyer Beware! Tank removal without assessment is a very bad situation for a property buyer to purchase.  We recommend that you require the seller to correct this situation before you buy the property.  Please see our Property Values, Tanks, and Contamination Page. 

Unfortunately, many oil tank removals, particularly those conducted many years ago, were done by well meaning back hoe operators instead of environmental professionals.  The back hoe operator may have done a great job driving the equipment and removing the tank but adequate contamination assessment was left undone.  Simply looking in an excavation after a tank has been removed or smelling the air surrounding the excavation is not adequate to determine if contamination is present. 

PES is licensed to conduct proper tank removals in compliance with State and Federal regulations and guidelines.  Please see our About PES Page. 

A tank/contamination issue is not resolved for the seller (previous property owner) until it is either appropriately documented that no contamination exists or until contamination is identified and the properly cleaned up.  Buyers are not protected from assuming liability until a proper tank closure is conducted and the seller takes responsibility for the contamination.

Furthermore, the Trust fund may only reimburse contaminated soil cleanup if the excavation is conducted within 90 days after tank removal.  After 90 days, there is still a requirement for contamination assessment but without the benefit of contamination soil excavation.  In other words, you may loose your opportunity to have the Trust Fund pay to clean up your property unless you conduct the soil cleanup (excavation) with the tank removal. This may significantly lower the value of the property.  See our Property Values, Tanks, and Contamination Page. 

In this situation, tank removal was done but is not required.  Contamination assessment and cleanup is required but was not done.  Please see our What if I removed my tank or filled it in place but did not check for contamination? Page

There are actions that can correct this potentially complicated situation. 

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5)  Collecting a Soil Sample without proper tank closure: 

This is not a valid or acceptable tank closure method.

Buyer Beware! This practice does not yield accurate results and therefore is not adequate to determine if the tank has leaked or not.  Additionally, the tank can leak after the sample is collected and you, the buyer, may be responsible for a leaking tank requiring cleanup.  We recommend that you require the seller to conduct a proper tank removal with assessment before you purchase the property.  Please see our Property Values, Tanks, and Contamination Page.

Collecting a sample doesn't "close" the tank.  The tank is still present and could leak at a later date.  Additionally, tank and contamination responsibility is not resolved for the sellers (previous property owners) or for the property buyers. 

We do not recommend taking soil samples by boring beside an underground oil tank.  However, we do provide this service when requested.

This practice does not yield accurate results and usually simply increases the cost to resolve the oil tank and associated contamination.  Soil boring analysis conducted prior to tank removal suggests that approximately 30% of all tanks have not leaked.  However, over half of these expected "clean closures" are found to be contaminated once the tank has been removed and a thorough assessment can be conducted directly underneath tank. 

Why conduct a costly procedure that is not accurate or effective in ending your legal responsibility? 

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