Corrosion Lab Tests Suggest Need for Underground Gas Tank Retrofits
In recent years, field inspectors in nine states have reported many rapidly corroding components of underground gas storage tanks. These incidents are generally associated with use of gasoline-ethanol blends and the presence of bacteria, Acetobacter aceti, which convert ethanol to acetic acid, a component of vinegar. Following up on the inspectors’ findings, a National Institute of Standards and Technology (NIST) laboratory study has demonstrated severe corrosion—rapidly eating through one millimeter of wall thickness per year—on steel alloy samples exposed to ethanol and acetic acid vapors. The study focused on sump pump components, especially the pump casings, which are typically made of steel or cast iron.
Based on their findings, NIST researchers suggest gas stations may need to replace submersible pump casings, typically made of steel or cast iron, sooner than expected. Such retrofits could cost an estimated $1500...