Underground Storage Tanks: A Review of an Unseen Aging Infrastructure

Underground storage tanks (USTs) are a critical infrastructure for the storage of petroleum and other hazardous substances. As with much of the nationwide infrastructure, USTs are aging beyond their intended lifetime. In 1985, the average age of a UST removed for replacement or closeout was 17 y old; USTs removed today are on average 33 y old. Corrosion in UST systems can lead to tank failure resulting in leaks that can contaminate soil and groundwater and also result in vapor intrusion in nearby buildings. Presently, there are approximately 65,000 leaking USTs in the United States With increased flooding, both inland and coastal, there is greater potential for accelerated corrosion, where there are approximately 33,000 USTs within Federal Emergency Management Agency’s 100 y floodplain. With changes in the fuel supply through the introduction of alternative fuels, unintended consequences to fuel storage and delivery infrastructure have been observed. Biofouling and corrosion can be exacerbated by adding relatively small volumes of alternative fuels. The current standards for monitoring the potential leakage events of USTs are wholly inadequate in terms of predictive capabilities. In this present work, the past, current, and future of UST infrastructure are detailed. The materials used in the construction of the USTs including plastics and steels are reviewed as well as their compatibilities with the current and future fuels. A geospatial database application developed by the Environmental Protection Agency is highlighted for insights into correlations between UST data (e.g., age, type, location, and fuel) and natural disasters (e.g., flooding, fires) to identify potentially vulnerable systems.