The Wisconsin Department of Natural Resources (DNR) has had vapor intrusion guidance in place since December 2010.
PUB RR-800, entitled “Addressing Vapor Intrusion at Remediation & Redevelopment Sites in Wisconsin,” provided an early roadmap for the assessment and mitigation of vapor intrusion risks created by the presence of volatile organic compounds like trichloroethylene (TCE), tetrachloroethylene (PCE) and benzene.
In June 2015, the U.S. Environmental Protection Agency issued its own technical guidance on vapor intrusion (VI) for use at sites being addressed under Comprehensive Environmental Response, Compensation, and Liability Act (Superfund or CERCLA) and Resource Conservation and Recovery Act (RCRA).1 The EPA’s technical guidance was more specific and focused on implementing response actions when an investigation demonstrated risk to human health.
Piggybacking on the EPA’s guidance, in August 2017, the DNR proposed revisions to PUB RR-800.
The Proposed Changes
Overall, the proposed guidance continues to describe the conditions where assessment is necessary, sets forth criteria for evaluating health risks, identifies appropriate response actions, explains long-term stewardship and continuing obligations, and outlines how to obtain closure.
Of the many proposed changes to the guidance, a number simply involve clarifying references and deliverables that are expected as part of the VI assessment process. While this will not have a substantial impact on practitioners, the added clarity and accuracy is beneficial.
Access to Off-site Properties
There are several substantive changes as well. The proposed changes address one of the biggest challenges faced during the VI assessment: access to off-site properties. When contaminant vapors have potentially migrated to an adjacent property, it requires assessing the threat to any structures on the neighboring property.
Ted Warpinski, Marquette 1987, is a shareholder with Friebert, Finerty & St. John, S.C., Milwaukee, where he practices primarily in the area of environmental law and litigation.
M. Andrew Skwierawski,, U.W. 2007, is a shareholder with Friebert, Finerty & St. John, S.C., Milwaukee, where he practices environmental law and litigation, and holds significant experience in electronic discovery and information technology.
It is all too common that these neighboring owners are reluctant to grant access. And it does not seem to matter if they are residential or commercial, some owners will insist upon specific terms and conditions before they will grant access or they will outright refuse. The proposed guidance clarifies that if a responsible party is unable to gain access to a potentially impacted property, the responsible party will need to document at least two attempts before DNR will step in and make its own attempt.
This is a significant improvement, as it standardizes what before had been a more site-specific approach that could often seem to have no end.
Selecting and Implementing Mitigation Efforts
The proposed guidance also sets forth a new framework for the selection and implementation of mitigation efforts undertaken to address a VI problem. Once an assessment has been completed and it is determined that mitigation is needed, the next step is the design and commissioning of that mitigation system. The proposed guidance places a strong emphasis on documenting that the selected mitigation approach will be effective.
The new guidance also puts a particular emphasis on the commissioning of mitigation systems to establish their effectiveness. This additional rigor may well add cost and time to the remediation effort.
This emphasis on system design and commissioning is a recognition that the long-term stewardship of any mitigation system falls on the affected property owner and not the responsible party.
The problem, especially with chlorinated solvent sites, is that the contaminants can be very persistent, requiring that the mitigation system be operated for decades. Impacted property owners may be rightly concerned with the cost or time of maintaining a system. To address this, the proposed guidance will lead to multiple sampling events to show a systems effectiveness and to determine the baseline conditions and then using that information to establish a long-term operations and maintenance plan.
However, the proposed guidance does not address how the existence of these long-term obligations may affect a property owner’s ability to transfer the property. Both the 2010 version of the guidance and the proposed edition leave the transfer of these obligations to the responsible party and the property owner.
Continuing Obligations a Major Concern
Finally, as many practitioners are aware, the existence of these types of continuing obligations is a major concern and an area where disputes can often arise in the closure process. The proposed changes make it clear that the DNR will not withhold closure of a site because a mitigation system will remain in operation after closure.
But, given the contentious nature of these interactions and the fact that these systems may need to run for decades, when feasible it is always preferred to reduce the contaminant source to avoid or minimize how long a system may be needed.