Ryan Haerer, EPA Office of Underground Storage Tanks

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1 Corrosion in Underground Storage Tanks Storing Ultra-Low Sulfur Diesel (ULSD): An Update on 2014 Research Efforts Attempting to Determine the Causes of Severe and Rapid Corrosion Ryan Haerer, EPA Office of Underground Storage Tanks

2 Overview 1. Corrosion in USTs Storing ULSD: Reports, Observations, and Impacts 2. Research efforts: 2012 and ongoing 2014 research 3. Path Forward to address the corrosion

Corrosion in USTs Storing ULSD - History Since 2007, nationwide reports of severe corrosion on metal components, often with rapid onset Internal

with the corrosion report timeframe (compared with LSD) Lower sulfur in highway grade ULSD beginning 2006 from 500 ppm to 15 ppm Increased

3 Corrosion in USTs Storing ULSD - History Since 2007, nationwide reports of severe corrosion on metal components, often with rapid onset Internal corrosion, different than what we are seeing in the sumps of tanks storing ethanol blended fuels 3 changes to fuel supply that roughly correlate with the corrosion report timeframe (compared with LSD) Lower sulfur in highway grade ULSD beginning 2006 from 500 ppm to 15 ppm Increased blending of ethanol into gasoline Increased use of biodiesel blended fuels, including in ULSD Photos Courtesy of Lorri Grainawi, Steel Tank Institute

Flapper valves Shear valves Coffee Grounds from filter Premature replacement of STP shafts or ATG probes due to heavy corrosion Extent of impacts

4 Corrosion in USTs Storing ULSD - Impacts Slow flow, clogged fuel filters with coffee grounds corrosion Increased need for filter changes and maintenance hours Reports that equipment in USTs storing ULSD failing functionality testing at higher than average rates Line leak detectors Flapper valves Shear valves Coffee Grounds from filter Premature replacement of STP shafts or ATG probes due to heavy corrosion Extent of impacts within vehicle not yet known liability or reputation concerns for retailers Photos Courtesy of Lorri Grainawi, Steel Tank Institute Corrosion on STP shaft

5 Search for Solutions 2012 Study (Former) Clean Diesel Fuel Alliance, through Battelle, attempted to collect and analyze fuel, water, vapor and corrosion samples of tanks nationwide to attempt to figure out what was going on Looked at 6 fiberglass tanks - Attempted to examine 5 corroded sites and a clean control site but found that all sites had corrosion Results suggested possibility that ethanol contaminating the ULSD was a possible cause, but results were not conclusive, and suggested possible alternative pathways Certain acids present suggested the possibility that glycerol could have been present and acted as a food source for bacteria in a similar manner as the ethanol Biodiesel allowed to be blended into ULSD up to 5% without labeling according to ASTM D975 specification for diesel fuel

glycolic acid) Images courtesy of John Wilson, EPA

6 Search for Solutions 2012 Study (continued) Ethanol into acetic and butryic acid (and possibly into glycolic acid) Images courtesy of John Wilson, EPA ORD Glycerol into gylceric, lactic, and proprionic acid

Search for Solutions 2012 Study (continued) Analytical parameters of study allowed identification of ethanol as a possible cause; but were not able to eliminate glycerol

7 Search for Solutions 2012 Study (continued) Analytical parameters of study allowed identification of ethanol as a possible cause; but were not able to eliminate glycerol (or a combination of these) as a possible cause; Proprionic acid, the only of the three acids expected to result from bacterial oxidation of gylcerol, found in all samples

8 Theories on Severe, Rapid, Selective Corrosion in USTs storing ULSD Microbial Corrosion Ethanol from cross contamination (during shipping or USTs with manifolded vents) Glycerol from allowable concentrations in ULSD Has this potential for corrosion causing bacteria always existed in diesel, but kept in check by higher sulfur LSD before 2006? Fuel Quality Variations ULSD blended out of specification, or biodiesel blended into the ULSD blended out of specification? Fuel stability in storage lower throughput sites may be more prone to corrosion onset Contaminants (in fuel and entering UST from external environment) Seasonal and locality variation of biodiesel distribution in ULSD Other unknowns, or any combination of these factors

9 Buildup to 2014 Study Extensive outreach to stakeholders and experts Petroleum Industry Biofuel/Biodiesel industry Scientists at EPA, NREL, ORNL, private labs Coordinating Research Council ASTSWMO UST owners/operators private, and public, national and local Multiple study designs locations, sampling targets and methods, corrosion designations, allowable technology decisions Wanted to expand the study to include numerous sites government, retail, fleet, fiberglass, steel, high and low throughput

10 2014 Study Overview Goal: Determine what conditions are common to USTs that experience severe corrosion and what conditions are common to those that don t Goal: Create study that can allow meshing with prior and future research efforts Similar methodology to 2012 study Corrosion classifications based on STP shaft condition match the criteria developed by CRC for their future research Notable Changes from 2012 Report Focus on additional corrosion pathways find out role of gycerol (common in ULSD) in addition to ethanol (possibly in ULSD) Evaluate steel and fiberglass tanks Evaluate a larger sample of USTs Collect and preserve samples for possible future DNA analysis but not perform them at this time

samples for chemical analysis Gather extensive background information on each tank history, maintenance, corrosion reports, equipment failures, fuel

11 2014 Study Design Details 42 USTs at 42 sites nationwide: 21 steel, 21 fiberglass Look inside each tank with Tanknology cam to evaluate level of corrosion on metal components, focusing on STP shaft classify as expected, moderate, or severe corrosion Collect vapor, fuel, and water bottom samples for chemical analysis Gather extensive background information on each tank history, maintenance, corrosion reports, equipment failures, fuel distributor, etc. Merge field results and background data to attempt to identify across the six categories any trends or conditions common to each corrosion result

12 Map

14 Looking Inside the Tank

15 Preliminary Observations and Lessons Learned (unofficial from verbal accounts, official data not yet collected or reviewed by contractor please do not cite) Water bottoms for sampling not available at many sites But majority of tanks showing corrosion Anticipated that most sites would be minimal or severe but many so far are moderate Because we were not able to pre-arrange sites based on corrosion categories, results will likely not be balanced or as definitive as we would like to help identify differences in causes Background data is subjective, limited and difficult to get detailed history from each site, and difficult to verify may make deriving results challenging Learning more about useful background questions ex. on site fuel cleaning

16 Plan for study completion Chemical analysis of fuel and water bottoms in September and October, attempting to have initial peer-reviewed report available by spring of 2015 Outreach and get feedback on report from owners, contractors, scientists, industry, implementing agencies Nationwide owner survey to gather more data on extent of the corrosion issue and maintenance practices that may correlate with observations of corrosion or equipment functionality failure Could help spread the word on why corrosion needs to be addressed while providing large qualitative dataset to help identify causes What are the next steps to find solutions or minimize impacts to owners?

17 Possible areas for further research Fill in the holes of this and 2012 study What additional items should we have tested for? Questions we should have asked? Improved methodologies? Expand existing study population - site selection not representative of entire population Analysis of DNA samples to corroborate any microbial induced corrosion results Address any new or more targeted questions that may arise from the results of this study Additional contaminant sources additives, liners, external environment? Look up the supply chain for correlations due to patterns in biofuel blending and/or possible sources or causes in distribution networks? Prospective studies of newly installed tanks watching them over time Others

18 Wrap Up Corrosion in USTs storing ULSD is happening around the country Can cause difficulties in servicing, Possible increased expenses for premature replacement, and Possible failure of important safety equipment to function as designed Research is ongoing to determine cause or causes Input and additional data from those in the field will help to generate a better picture of the situation and best practices that help to avoid the worst impacts of the corrosion EPA, States, Scientific Community and Industry all share the same interest in keeping the fuel safely in the tank and out of the ground

19 Please reach out to EPA to share Input, Ideas, Information or with any Questions Ryan Haerer EPA Office of Underground Storage Tanks Michael Pomes EPA, Region 7 Pomes.michael@epa.gov

Corrosion in Underground Storage Tanks (USTs) Storing Ultra-Low Sulfur Diesel (ULSD):

Corrosion in Underground Storage Tanks (USTs) Storing Ultra-Low Sulfur Diesel (ULSD): EPA Research on Risks, Prevalence, Causes, and Next Steps Presented at the National Tanks Conference September 16,