Everyone wants to know what happens when your tank leaks. Allow GreenTRAX, Inc. to help you with this concern, as it is a very valid concern. As always when we are discussing oil tanks, we must differentiate between underground vs. aboveground heating oil storage tanks.
Underground Storage Tank Leaks
Lets start with an underground (buried) storage tank which is abbreviated as (UST).
How do you know with 100% certainty that your RESIDENTIAL UST has leaked? YOU DON’T!
The rule of thumb is that buried tanks last on average 20 years. If your UST is older than 20 years, it is really a waste of money to test the tank or test the soil because the tank really needs to be removed & replaced as it is past its useful lifespan. So any money you spend on the OLD tank is really throwing good money after bad because you could put this money towards the tank removal & replacement. If you pay to perform a tank test or a soil test, either can be done, but they both have pros & cons with them. Plus if either test fails, the tank has to be pumped out right away AND the tank still has to be removed. So you just wasted that money you spent on the test and now you still have to pay the full cost for the tank removal. We have seen over the years that a tank test on a really old buried tank has shown FALSE positives & FALSE negatives. Plus the test is only good for that day, so it could leak tomorrow, and the tank test wont tell you if the supply or return line is leaking (which can happen in rare occasions).
Test Your Soil For Contamination
A soil test is a more accurate picture of what is going on with the tank because this will check the soil next to the tank, BUT NOT below the tank. So there have been false positives and false negatives with this as well. So we never recommend someone spend money to perform testing when the tank is over 20 years old. Most buried tanks in Maryland ARE well over 20 years old as post year 2000 not many people still had new tanks buried. Most (but not all) new tank installations are ABOVEGROUND.
Underground Tank Removal
So then what happens when the UST has leaked? Normal cases are never as bad as horror stories you may have heard or see online. For the most part after the UST removal is performed the process for dealing with a leak is fairly routine & simple. What needs to happen, is that the soil is checked with a meter onsite and if contamination is found then remediation is performed. So what that involves is to dig down and remove contaminated soil to a depth where clean soil is found. Depending on the levels of contaminated soil, the amount of dirt removed could be small such as 6 to 10 tons of soil. Or it could be an average amount of around 20 tons. (for perspective 1 ton roughly equates to what will fit in the back of a pickup truck)
If the tank is a larger size such as a 1000 gallon or larger then the hole that needs to be excavated is larger OR if the tank has leaked very bad and the soil type is permeable then it is possible that the amount of dirt needed to be removed will be more than 20 tons.
Aboveground Storage Tank Leaks
Aboveground Storage Tank Leaks – The AST leak can sometimes actually be WORSE than a UST. This is because if the AST is located in the basement and the leak is not caught right away or if the house is vacant the leak can grow and contaminate not only concrete floor below the tank but then the soil below that. Not to mention the smell of oil in the house and if tank is located near the sump pump then you will have oil in the sump pump basin. In this scenario if the tank has leaked on the floor in the basement, if the leak is small and caught right away it is possible the floor can be cleaned and once the basement is aired out to get rid of the smell of oil then that is all that is required. If the leak is extensive then a portion of the concrete floor will need to be jackhammered up and removed by hand. Then the dirt below that area may need dug out with shovels and carried out of the house in 5 gallon buckets. Once clean soil is found then the hole can be backfilled with stone or gravel and the concrete patched.
Outdoor Aboveground Oil Tank Leaks
If the AST is located outside and starts to leak, most of the time we see that unless someone catches the leak by accident, the leak will continue for awhile until a large black stain is seen, oil is smelled or dead vegetation is discovered around the tank. (just a note about AST leaks) – these tanks never “burst” and you lose all the oil at once, it usually always first starts as a weep. Meaning a wet spot or stain on the bottom of the tank. Then that will progress to one or more drips.
So the problem here is that with AST’s there is nothing to slow the drip down. With UST’s the soil is packed tightly around the tank so that helps slow the drips/seepage. With AST’s it will keep dripping, and let’s be honest who is going out and looking at their heating oil tank daily??? So usually by the time someone notices the drips, the damage is already done and there is at least a little bit of contaminated soil.
The Clean Up
When an aboveground outdoor heating oil tank leaks, the way we deal with that is first, obviously pump out and remove the tank. The similarity to a UST, the dirt is checked with a meter to assess the levels of contamination. Then the soil is excavated (usually with a machine) until the extent of contamination is found and removed. What’s different also about AST leaks is that if the ground is sloped the oil leak will spread farther over the yard. And when the oil seeps into the ground it does not always go straight down. The oil will spread out laterally, thus creating a larger area that needs to be excavated and removed.
The most important thing is that after any contaminated soil removal, at least one soil sample from the bottom of the excavation needs to be obtained. Then that gets sent to a lab for analysis. Hopefully that will show the soil is clean at the bottom of the hole and then the MDE will close the case.
Disposing of Contaminated Soil
After any UST or AST leak and the soil is removed/remediated it gets placed on plastic at the property, then covered up with plastic. That pile of soil will have a soil sample taken from it & that sample will need to be sent to a lab for testing. Then those results are sent to the MDE approved disposal facility, and once approved for disposal. Then the soil that is piled on the property can be picked up at a later date by the contractor and hauled away to that disposal facility.
Typically after the soil is removed from the excavation it is then backfilled the same day so the owner does not have a big hole on the property for an extended period. Then the property can be restored with seed & straw or whatever the particular situation is at that property. If the soil sample taken from the bottom of the hole is NOT clean then the MDE will make the determination if additional work is needed onsite. Occasionally this could be additional soil removal down deeper with a larger machine, but that is not common on every job. More often it depends on the exact levels detected in the lab tests. MDE may determine to close the case anyway or they may ask for additional soil sampling around the property.
In any case GreenTRAX has dealt with it before. We have the knowledge and experience to handle your particular situation with efficiency and professionalism. Call GreenTrax and we will take care of it all for you. 410-439-1085