Vapor intrusion is the process where contamination in soil and groundwater volatilizes and enters indoor air in buildings. Understanding and evaluating the risks to occupants of buildings with vapor intrusion issues has received dramatic new focus nationally in recent years.
In Ohio, scrutiny of vapor intrusion issues is at an all time high. This post details some of the recent significant initiatives and actions taken by Ohio EPA to address vapor intrusion.
Ohio EPA Revokes 2010 Vapor Intrusion Guidance
On May 27, 2016, Ohio EPA announced that it was revoking prior guidance in place since 2010 on analyzing the risks associated with vapor intrusion. Ohio EPA revoked two entire chapters of its 2010 vapor intrusion guidance document. It also indicated that environmental consultants should utilize U.S. EPA’s guidance document titled, “Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (June 2015)” and U.S. EPA’s Vapor Intrusion Screening Level (VISL) calculator.
The VISL calculator is a new tool utilized by U.S. EPA to quickly determine whether a site presents a potentially unacceptable health risks due to vapor intrusion. Using the VISL, soil gas, soil and groundwater sample results are plugged into the calculator to determine if risk presented by the detected contaminant levels exceed screening levels. If screening levels are exceeded, the Agency can require either more investigation or cleanup.
The VISL replaces prior modeling techniques that have been utilized for years to evaluate contaminated properties. Ohio EPA’s 2010 Vapor Intrusion Guidance document relied heavily on the Johnson & Ettinger (J&E) model to analyze risk. J&E was used to evaluate vapor intrusion at hundreds of site in Ohio.
Some consultants tell me that the VISL is approximately 50 times more conservative than the J&E model. As a result, site contamination issues previously thought to present no issues under J&E are now viewed as significant problems under VISL.
Ohio EPA’s revocation of portions of its 2010 vapor intrusion guidance includes the chapters regarding the J&E model. Ohio EPA’s announcement included a statement that all sites currently being evaluated will no longer consider J&E data valid and will require use of the VISL.
Ohio EPA Reviews TCE Site Inventory
Ohio EPA has also decided to heavily scrutinize any site with trichloroethylene (TCE) contamination (typically associated with a solvent used to clean metal parts). A new study determined that the risk presented by exposure to TCE contamination to woman of child bearing years and pregnant women are greater than previously thought. Those risks are also thought to be acute risks (i.e. short term) versus the long term risk based upon 30 years of exposure used to develop many cleanup standards.
Beginning in the later part of 2015 and continuing through today, Ohio EPA has been internally evaluating any site where it has data showing TCE contamination. Those sites are being analyzed using the new TCE cleanup standards and the VISL calculator. Due to the fact both the cleanup standard and VISL are more conservative, sites are much more likely to be deemed to present potential health issues.
Ohio EPA has sent letters to owners of sites with TCE contamination requesting additional investigation or cleanup. In some cases, Ohio EPA has demanded additional testing and if the property owner refused, Ohio EPA performed its own sampling.
In February 2012, at an Ohio EPA brownfield training course, environmental consultants were told of Ohio EPA’s position regarding vapor intrusion and TCE. Here are some of the key points discussed:
- Ohio EPA will not "sit on data" if it believes an issue exists it will move quickly to seek or take additional action;
- In terms of sampling techniques to evaluate vapor intrusion, Ohio EPA wants to see sub-slab paired with indoor air samples to analyze the risk;
- In analyzing vapor intrusion, Ohio EPA will want multiple sample locations and multiple sampling events (to address seasonal variation in contaminant levels);
- If off-property vapor intrusion needs to be analyzed, the Agency’s expectation is the owner/developer will do it. In not, the Agency will collect the data it needs;
- Agency is not going to have long technical debates whether a health issue may exist. If the Agency thinks there may be an issue it wants to act quickly;
- On Voluntary Action Program (VAP) cleanups, if a consultant is aware of data that indicates a potential health issue, the Agency expects the consultant to come forward with the information even if the property owner or developer doesn’t want the information released to the Agency;
- Due to TCE’s short term risks to sensitive populations, the Agency expects quick action and evaluation of data at sites where TCE is at issue.
At the Spring 2016 Ohio Brownfield Conference many of these points were reiterated by Agency representatives. In particular, participants were told the Agency will act quickly and aggressively when it believes contamination has the potential to present a public health issue.
Ramifications to Property Owners and Developers
The changes relative to analysis of vapor intrusion in general as well as the specific initiative on sites with TCE, has major ramifications for property owners and developers. Here are some the issues or considerations for owners/developers:
- Consultants are under increasing pressure to disclose any data to Ohio EPA that suggests a public health issue may exist;
- Expectation is that properties with potential vapor intrusion issues on or off site will be evaluated very quickly;
- The standards and models use to analyze vapor intrusion risk have become significantly more conservative. Sites are much more likely to be deemed to present potential issues than even a year ago;
- All ASTM compliant Phase I reports are supposed to evaluate the potential for vapor intrusion. In light of the increased focus on vapor intrusion, it is critically important to conduct high quality due diligence prior to acquisition that includes a robust evaluation of the potential for vapor intrusion;
- Liability risks have increased dramatically in recent years for owners and/or developers of property that may have vapor intrusion issues; and
- Due to increased stringency of modeling and cleanup standards, what will the Agency do regarding sites that were previously deemed sufficiently cleaned up under outdated guidance and cleanup standards?