You have probably seen previous articles by EnviroForensics talking about the importance of a well-defined investigation and remediation due to the potential long term stewardship responsibilities and costs that could be incurred following cleanup activities. Those potentials are now becoming reality, since just this month the Wisconsin Department of Natural Resources (WDNR) released two guidance documents on this topic. The first is an internal DNR guidance document, RR-5474, Vapor Intrusion Continuing Obligations Applied in DNR Closure Approvals. RR-5474 addresses DNR processes specific to closure approval letters. The second is a companion document, RR-042, DNR Case Closure Continuing Obligations: Vapor Intrusion, which speaks to responsible parties and environmental consultants, and provides information for completing the necessary Case Closure-GIS Registry Form 4400-202. These new documents describe the application and implementation of these vapor intrusion continuing obligations and are applicable at sites closed with residual contamination left in place in order to prevent exposure from the vapor intrusion pathway.
You may have been directed by the WDNR to conduct investigation and remediation for the release of tetrachloroethene (perc) or other chemicals. Much attention in the past few years has been given to vapor intrusion and mitigation if a release of perc has been found. Vapor mitigation (exposure control) often has been in the form of a sub-slab depressurization system, or SSDS for the short term. These systems, while effective at temporarily stopping vapor intrusion or preventing it from happening, are often forgotten pieces of the investigation and remediation puzzle once closure is attained. In a very formal way the WDNR has now said vapor intrusion mitigation systems can no longer be forgotten relics of the investigation past. They must be maintained and monitored into the future.
Both WDNR documents contain contaminant level considerations that WDNR staff, contaminated site owners, or consultants may use to make decisions for applying vapor intrusion continuing obligations.
How do these new guidance documents affect you? Well, if you are approaching the point of closure, you and your consultant should reference RR-042 and the included table, “Considerations for Applying Vapor Intrusion Continuing Obligations”, to determine which continuing obligations will be required by the WDNR. They may even dictate continuing obligations prior to approving the remedial action.
By the time closure is anticipated following remediation, all vapor intrusion pathways and ongoing mitigation should be fully understood and all involved parties fully engaged (i.e. off-site property owners with SSDS installed. However, by thoroughly evaluating and remediating to a greater extent, the need for continuing obligations for the vapor intrusion pathway may be eliminated.
Once you have completed your investigation and remediation to the extent possible and you have submitted your Form 4400-202 for case closure, the DNR will review the proposed closure and the need for continuing obligations as guided by RR-5474. Should the DNR find a deficiency in the proposed closure continuing obligation plan, they may deny closure or make closure contingent on additional continuing obligations. These may include operation and maintenance of vapor mitigation systems, additional monitoring, or property use restrictions until such time it can be demonstrated that the potential exposure is no longer present.
The continued operation of vapor mitigation systems or additional testing can be costly over time. As written, the WDNR documents indicate costs associated with continuing obligations will be incurred by the individual property owner, which may represent long term liabilities for the responsible party. Currently the DERF does not provide a mechanism to fund activities beyond closure. In fact the guidance indicates formal changes to continuing obligations, land use changes, and removal from the GIS registry may in some cases cost several thousand dollars per off-site property. As such, alternative funding sources may be necessary to manage these costs.
In the end, the best approach is to eliminate as many long term obligations through detailed assessment and adequate remedial actions. When making short and long term decisions for your site, consider all scenarios prior to accepting a long term continuing obligation for your closure. Keep in mind that DERF funds are limited and the DNR’s ability is limited in approving remedial efforts that are aggressive enough to minimize costly continuing obligations. If you think that you may incur such post-closure costs, please don’t wait until a remedy has been approved by DERF to start seeking alternative funding.
About the Author:
Mr. Hoverman is the Wisconsin Regional Manager and a registered professional geologist with more than 14 years of professional environmental services with a focus on contaminated site management. Mr. Hoverman currently serves as senior project manager for several projects in Indiana and Wisconsin. His diversified professional experience includes research, scoping and budgeting, project management, data analysis and interpretation for both hazardous and non-hazardous substances, including compounds such as chlorinated solvents, petroleum related constituents, as well as metals. Mr. Hoverman has managed numerous investigation and remediation projects regulated by state programs, and his responsibilities involved every aspect of projects from proposal preparation through project closure, regulatory negotiations and stakeholder communications. Beyond technical evaluation and interpretation duties include obtaining contract approval, job initiation, budgetary analysis, budget tracking, and subcontractor contracting and management. Mr. Hoverman has also served as technical support for numerous vapor intrusion including soil gas, sub-slab, indoor air sampling and mitigation. As the Regional Manager for EnviroForensics, Mr. Hoverman maintains momentum and resources for Wisconsin projects.