In July of 2016 the EPA Office of Underground Storage Tanks (OUST) released findings of the corrosion investigation- Investigation of Corrosion-Influencing Factors in Underground Storage Tanks with Diesel Service (EPA 510-R-16-001, July 2016).

We have summarized the findings below:

Research focused on better understanding a type of rapid and severe corrosion of metal components in underground storage tanks (USTs) storing diesel fuel. UST owners first began reporting this corrosion to UST industry servicing companies in 2007. To address the potential for corrosion problems, the U.S. Environmental Protection Agency’s (EPA) Office of Underground Storage Tanks began working on this research in 2014.

“The major finding from our research is that moderate or severe corrosion on metal components in UST systems storing diesel fuel in the United States could be a very common occurrence. Observations suggest that corrosion may be commonly severe on metal surfaces in the upper vapor space of UST systems, an area that before 2007 was not known to be prone to corrosion.”

“The corrosion phenomenon appears to only be happening in underground storage tank systems, not in steel terminal tanks, refineries or pipelines. EPA cannot project the actual percentage of USTs storing diesel that are affected by corrosion nationwide.

“The EPA report concludes that, “It does appear that microbial-induced contamination (MIC) is likely occurring in USTs storing diesel. Taking action to limit the environmental conditions necessary for microbial growth is recommended by multiple industry groups and anecdotally appears to be successful in minimizing the chances of severe corrosion in USTs.”

The EPA also developed a notice about corrosion risks in underground storage tanks (USTs) storing diesel fuel. Contributors to the research into this phenomenon include regulators, oil producers, equipment manufacturers, the automotive industry, tank owners and others.

Drew Fuel Services has conducted its own research on numerous tanks and found that the best defense against corrosion and microbial contamination is establishing a good preventative maintenance program. This includes monthly sampling, adding biocide to prevent microbial contamination, removing water and analysis.

EPA Report Links

Investigation of Corrosion-Influencing Factors in Underground Storage Tanks with Diesel Service  (EPA 510-R-16-001, July 2016)Notice of Corrosion Risks in Underground Storage Tanks Storing Diesel Fuel  (EPA July 2016)
Questions and Answers About Corrosion in Underground Tanks Storing Diesel Fuel  (EPA July 2016)
Coordinating Research Council (CRC)
Report 672,  Preventive Maintenance Guide for Diesel Storage and Dispensing Systems
Report 667, Diesel Fuel Storage and Handling Guide
Clean Diesel Fuel Alliance: Guidance For Underground Storage Tank Management at ULSD Dispensing Facilities
Steel Tank Institute,  Recommended Practice for Storage Tank Maintenance R111 Revision March 2016