Buried oil tanks rust (rust never sleeps) so oil tanks can leak.
Do not be naïve that the tank that you are removing is rust free and has zero chance of leaking. Anyone you hire to remove a tank should discuss the possibility of the tank leaking and what the steps would be to address a tank leak. In short, it should not be surprised that a buried metal object decades old may have leaked, so you should be aware of your options.
In Pennsylvania what drives the need to remediate a heating oil tank discharge is if petroleum levels in the tank excavation are above the PADEP Statewide Health Standards relative to number two heating oil in soil. The standards are as follows:
• Benzene:– (PADEP Standard is 0.5 ppm)
• Ethylbenzene: (PADEP Standard is 70 ppm)
• Isopropylbenzene (Cumene) : (PADEP Standard is 600 ppm)
• MTBE: (PADEP Standard is 2 ppm)
• Naphthalene: (PADEP Standard is 25 ppm)
• Toluene: (PADEP Standard is 100 ppm)
• 1,2,4- Trimethylbenzene: (PADEP Standard is 8.4 ppm)
• 1,3,5- Trimethylbenzene: (PADEP Standard is 74 ppm)
*Exceedance of any of the eight compounds indicates petroleum levels are above PADEP residential soil standards. Please note that the most representative soil sample is one obtained below the tank which is only possible when the tank is being removed, or if the tank is being closed in place coupons or holes can be cut into the tank to obtain samples..
On the day of tank removal no one can tell you with 100% certainty that if they see holes in the tank that you need remediation. You see without lab testing you don't know 100%. If you are pushed to remediate right after a tank is removed, DON'T. There are no savings and you risk spending money you may not have to spend. We see firs recommending you jump into remediation if your tan leaks because they already have equipment on site, this approach is sure to lower your bank account balance with no guarantee of solving any problem.
So to understand oil in soil from a tank leak, you can compare it to cholesterol levels. There are low levels of cholesterol (healthy levels, that require you to take medicine or change your diet or life style) and there are high levels of cholesterol (you need to change your diet, possibly take medicine), in short high levels require corrective (remedial) action.
You have to base any driver (need) to remediate a tank leak on laboratory analysis, which is obtained from sampling the soil after tank removal and which takes about a week to be analyzed by an independent laboratory. So you sit in limbo for about a week to know where you stand. Very similar to a Dr. visit with lab work.
Fact, many tanks, do not leak, many do, but not evert tank that leaks needs remediation.
Curren has over 2 decades of environmental experience, thousands upon thousands of sites worked on. If you want professional advice from the professionals, call Curren.