This past July the EPA released a field study on the state of USTs storing diesel fuel. Of the 42 operational USTs that they observed, 35 showed moderate to severe corrosion of metal components inside the tanks. The EPA stated that they cannot be sure that this corrosion is a widespread epidemic. Although the scope of the research was not large enough to prove this to be a pervasive problem, the EPA believes it is prudent for “tank owners to further investigate the issue.”
- Upper Vapor Spaces
- Flapper Valves
- Ball Floats
- ATG Probe Shafts
- Turbine Pump Shafts
The risk of corrosion is a loss of functionality in the release prevention equipment inside the tanks. Equipment deterioration increases the chance of diesel fuel leaking into the environment. Tank owners are under obligation to pay for the costs of any leakage that may incur.
- Check filters of USTs for sludge or particles resembling coffee grounds.
- Check inside UST access points for corrosion occurring prior to filter symptoms
- Remove any water found in the bottom of tanks storing diesel fuel
- Contact UST servicing companies for further evaluation
So far, the cause of this corrosion has not been determined. The EPA has been working with industry to gain insight on the problem so that the issue can be rectified. A possible cause is microbiological activity happening at the microscopic level in USTs, but no final conclusion has been determined. The EPA is supporting another phase of research on the issue that is being developed by the Coordinating Research Council.