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Topic: Risk-Based Closure Criteria for Colorado’s Petroleum Storage Tank (PST) Program

Speaker:  Tom Fox, PG, Environmental Protection Specialist III, Colorado Division of Oil & Public Safety

Time: Tuesday, September 10, 11:30am-1pm

Location: Davis Graham & Stubbs, LLP

CEMS has received one (1) CLE for this presentation          

CEMS September 2019 luncheon – Presentation notes

The Colorado Division of Oil and Public Safety (OPS) has established risk-based closure criteria for petroleum releases based on the risk that contaminants of concern pose to receptors at points of exposure (POEs) by evaluating exposure pathways using multiple lines of evidence.  When the PST program was created in 1988 following the promulgation of federal UST regulations, a Tier I closure was the only option and required remediation of dissolved phase contamination to meet drinking water maximum contaminant levels.  After the risk-based corrective action (RBCA) strategy was developed by the American Society of Testing Materials, OPS adopted the Tier II closure in 1999, which allowed credit for onsite natural attenuation to the downgradient property boundary using conservative contaminant fate and transport modeling (i.e., site-specific target levels).  Tier III and Tier IV closure criteria were established in 2014 to allow for offsite contamination to remain in place if the risk evaluation indicates a low risk to receptors and the release source area has been remediated to the maximum extent practicable with consideration of factors such as risk reduction, application of feasible remedial technologies, access, and cost.  Tier III criteria apply to release sites where a public roadway property boundary is the only impacted POE and multiple lines of evidence such as empirical data, a receptor survey, and contaminant fate and transport modeling support a Tier III closure.  Tier IV criteria apply to release sites where a private property boundary is the only impacted POE and there is no longer an active tank system on the release property.  As with Tier III, other lines of evidence must support a Tier IV closure.  Since 2014, OPS has closed 140 release sites using Tier III and Tier IV criteria.  All Tier III and Tier IV closures are mapped into the Colorado 811 system and posted on OPS’ online GIS map tool with a link to a closure summary fact sheet.

Tom Fox, PG, is an Environmental Protection Specialist and the technical lead for the Remediation Section of the OPS Petroleum Program.  He earned a BS in Geology from Millersville University (PA), an MS in Geology from Michigan State University, and has over 30 years of experience in environmental site assessments and remediation. Tom’s expertise includes the use of activated carbon as a remedial technology, and the assessment, risk characterization, and remediation of light non-aqueous phase liquid (LNAPL).  He has been actively involved with the Interstate Technology and Regulatory Council (ITRC) for several years working on the LNAPL Team and recently with the High Resolution Site Characterization Team. Presentations and publications include two full-day ITRC training courses in China for staff of Tsinghua University, the Beijing Research Academy, and the Henan Research Academy (June 2019); National Tanks Conference presentation on Colorado’s RBCA program for petroleum releases (Sep 2018); co-author of the ITRC LNAPL Technical and Regulatory Guidance update (Mar 2018); co-author of “Current State of In-Situ Subsurface Remediation by Activated Carbon-Based Amendments” (Nov 2017); activated carbon presentation at US EPA Region 3 meeting in Pittsburgh, PA (Sep 2016); participant in Battelle Labs and US EPA panel discussion of carbon-based amendments (May 2016); presentation on carbon-based amendments at the ASTSWMO mid-year meeting (Apr 2016); presenter at ASTWMO annual meeting in Phoenix, AZ sharing OPS’ experience and progress evaluating carbon-based amendments (Sep 2015).

LOCATION: PLEASE note that the location for the September CEMS luncheon will be Davis Graham & Stubbs LLP, 1550 17th Street, Suite 500 (5th Floor), Denver, CO 80202. When entering the building, please proceed to the fifth floor to register with the CEMS representative.      

MEETING FORMAT: Members may either bring their own lunch and attend the meeting for no charge, or they may request that CEMS order a box lunch for them. The cost of the box lunch for members is $16.00; for non-members, $19.00.

RESERVATIONS: PLEASE give your name, company name and phone number via email to admin@coems.org. PLEASE INDICATE IF YOU ARE RESERVING A BOX LUNCH OR BRINGING YOUR OWN. Reservations must be received BEFORE Friday, September 6, 2019 at 5:00PM. No reservations will be taken after this date! Payment of $16.00 for members, $19.00 for non-members will be accepted at the door with prior reservation. Please cancel your reservation by Friday, September 6, 2019 if you are unable to attend. It is the policy of the Society to bill for meals reserved but unclaimed.  You may also pay with credit card via PAYPAL below:


Box Lunch

NOTICE: CEMS would like to thank Davis Graham & Stubbs LLP for the use of meeting space and would like to emphasize that the use of Davis Graham & Stubbs LLP space does not constitute endorsement of CEMS, sponsors of CEMS functions, or the content of CEMS workshops or meetings.