Introduction

Redevelopment of contaminated land and land adjacent to contaminated sites can be a relatively straightforward process when you work with a good environmental consultant that understands the special risks and concerns a developer faces. However, there is one issue that can get any consultant tied up in knots because of the increasing attention given to it by regulators: vapor intrusion.

What’s the Concern?

Vapor intrusion occurs when certain types of contaminants in the soil or groundwater evaporate (volatilize) and migrate through spaces in the soil into occupied spaces within a building on the property. The type of contaminants that tend to evaporate are called volatile organic compounds (VOCs) and include substances such as benzene, toluene, xylene, acetone, and perchloroethylene (dry cleaning solvent). The scientific studies that regulators rely on suggest that the presence of such VOCs in indoor air can adversely affect the health of building occupants. Because of potential health risks, regulators, especially the EPA, are increasingly focusing their attention on vapor intrusion issues. Therefore, purchasers and redevelopers can be exposed to liability (both regulatory and for personal injuries) if they acquire property with vapor intrusion issues that are not abated. A good consultant should identify such potential risks during the pre-acquisition due diligence process and, depending on site location, the consultant might use one or a combination of the following screening methodologies.

ASTM Assessment

The American Society for Testing and Materials (ASTM) has developed a recommended vapor intrusion standard (E 2600: “Assessment of Vapor Intrusion into Structures on Property Involved in Real Estate Transactions”) which is beginning to be followed by many consultants. ASTM E2600 prescribes a tiered approach to the vapor intrusion risk assessment. The first tier (Tier 1) of the analysis relies solely on documentary evidence. If information shows that there is a contaminated plume or potential plume within 100 feet of a proposed or existing building or property boundary (or within 30 feet for dissolved petroleum hydrocarbons), then a potential vapor intrusion concern (pVIC) is presumed to exist. (The consultant can modify these distances based on site specific conditions such as groundwater flow, depth to groundwater, vapor conduits, etc.). When a pVIC is identified, the consultant moves on to Tier 2 of the analysis, which can include sampling. If sampling is performed as part of Tier 2, the consultant compares the results to determine if any of the contaminants (within the 100 or 30 foot radius) exceed risk-based concentrations (RBCs) established by federal or state policy or site-specific RBCs established by the consultant. If there are any RBC exceedances, then further testing is undertaken during the Tier 3 analysis to confirm the presence of a VIC. If the presence of a VIC is confirmed in Tier 3, the consultant can propose a mitigation strategy using the Standard’s Tier 4 process.

EPA Assessment (Proposed)

On March 17, 2011 the EPA issued draft guidance for evaluating vapor intrusion entitled “Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils” (which can be accessed here). EPA’s goal is to finalize the guidance by November 30, 2012. The guidance will be used at RCRA Corrective Action, CERCLA and Brownfield sites but it will not supersede state guidance. Like the ASTM assessment, the EPA guidance is to be used to determine if there is a potential for an unacceptable risk. While this risk assessment approach is not appropriate at sites where employees are working with hazardous substances similar to those that are contaminating the site, the guidance is intended for use in other situations.

Like the ASTM standard, EPA’s VI guidance relies on a tiered analysis and the first step (Tier 1) is very similar to the first tier of the ASTM standard. In this step, the consultant determines if existing data indicates that VOCs are near (within 100 feet) of occupied buildings. If they are, then the consultant proceeds to the next step (Tier 2) which can include comparison of available indoor air concentrations to generic criteria established by the EPA or the collection of soil gas samples and comparison of that data to the generic criteria. Site specific factors such as depth of the contamination and soil type are also considered. Based on the results of Tier 2, the consultant will then move to Tier 3 to further refine the assessment by collecting site specific data such as collecting indoor air and/or sub-slab air samples. The consultant can also use modeling techniques to factor in variables such as soil type, depth to groundwater, and various building characteristics that can impact indoor air such as type of ventilation, air exchange rates, etc.

Michigan DEQ Assessment

Michigan, under Part 201 of its Natural Resources and Environmental Protection Act (NREPA), has promulgated specific numerical screening criteria for many hazardous substances. The generic criteria that are used to assess vapor intrusion to indoor air for residential and non-residential properties are the groundwater volatilization to indoor air inhalation criteria (GVIIC) and soil volatilization to indoor air inhalation criteria (SVIIC). (These generic criteria would be the RBCs relied on if the consultant uses ASTM E 2600). If soil and groundwater testing identifies an exceedance of the GVIIC or SVIIC criteria on property where buildings are or will be located, then there is a potential risk to indoor air quality. If site-specific factors such as lack of cement or block foundation, shallow groundwater plume, or preferential pathways, the rules preclude reliance on the generic criteria and the consultant must perform a site specific analysis to determine if a vapor intrusion (indoor inhalation) risk is present that must be abated.

To clarify the process set forth in its rules, the Michigan Department of Environmental Quality has prepared draft vapor intrusion guidance (“Guidance Document for the Vapor Intrusion Pathway“) that sets forth the steps that can be taken to evaluate the potential for a vapor intrusion risk. In its current form, the guidance is structured in a 4-step process like ASTM E 2600, however, it uses a 100 foot receptor radius for the preliminary screening area. Step 2 involves the collection of soil-gas data and Step 3 involves the refinement of that data through sampling of indoor air and sub-slab soil gas as well as an evaluation of conditions such as the presence of cracks, utility lines and operational uses of hazardous substances. If a vapor intrusion risk is confirmed, a remediation strategy is developed in Step 4.

As you can see, when consultants encounter a site that may have a vapor intrusion risk there are several ways of approaching the assessment that are similar but at the same time have subtle differences. Although each of the approaches allows consultants to consider site specific factors and the consultant’s professional judgment, a consultant’s ultimate conclusion could be different depending upon the assessment methodology used.

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Michigan’s Section 404 Wetland Program is one of only two wetland permitting programs approved by the EPA under Section 404 of the Clean Water Act. Michigan originally sought to implement its own program to speed up the permitting process and have greater local control given Michigan’s unique water resources. If EPA revokes its approval, the permitting process would revert to the U.S. Corps of Engineers and, based on our experience in other states, the processing time for permit applications would likely increase dramatically.

Those who are interested in submitting comments have until December 18, 2013. Comments can be submitted by going to the Regulations.gov website.

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Michigan residents are paying close attention to gas and pipeline transport issues in the region because of our water resources.

What is the main issue in Michigan? Two words – groundwater withdrawal. Many Michigan rivers and streams are fed by groundwater. With fracking pads using up to 20 million gallons of water, the concern is fracking near waterbodies will result in reducing water levels to a point that fishing and boating will be adversely impacted. Recently, because of local opposition to oil and gas leases along the “Holy Waters” section of the AuSable River, the DNR designated those leases as non-production leases. In addition, the sensitivity of this issue for Michigan residents has prompted the MDEQ to re-evaluate its fracking rules.

Michigan residents are also concerned about oil transport through the Great Lakes region. Companies like Enbridge are building or expanding pipelines in Michigan to handle the increased production of oil elsewhere. There are also plans to build an oil shipping port in Superior Wisconsin so that up to 35,000 barrels (about 1.4 million gallons) of oil from Alberta’s tar sands can be shipped to refineries around the Great Lakes.

As many recall, in 2010 one of Enbridge’s oil pipelines near Marshall, Michigan ruptured spilling over one million gallons (about 24,000 barrels) of diluted bitumen (“dilbit”) oil into the Kalamazoo River – a spill that Enbridge is still cleaning up. While Michigan residents understand the need for oil, they are not interested in a repeat of the Enbridge spill – especially one that would involve one of the Great Lakes.

Although water is abundant around the Great Lakes, it is used by many for recreational purposes in addition to industrial/commercial uses. As a result, there is significant interest and demands for it to be managed so that it can be enjoyed by the greatest number of people.

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Central to the amendments is support for self-implementation by liable parties of a GSI assessment. This flexibility in methodology, assessment and remedial design is coupled with some duties to give notice to the MDEQ. This amendment allows parties greater flexibility in demonstrating that response activities undertaken have appropriately addressed the risk of venting to groundwater. Parties can demonstrate compliance with Part 201 through ecological demonstration and modeling.

The amendment sets forth factors a party can rely upon to demonstrate that the GSI pathway is not relevant or the effect is de minimis. The amendments also allow parties to demonstrate that the venting of groundwater has no effect on a surfacewater body. The party can submit a request for a technical intractability waiver from the Michigan Department of Environmental Quality (“MDEQ”) if it can demonstrate that compliance with GSI criteria is not achievable. Parties that have concluded that venting groundwater has no or de minimis effect must give notice of its conclusion to the MDEQ. The MDEQ must disprove this conclusion within 90 days or it is deemed approved.

Parties have the flexibility to demonstrate that natural attenuation of hazardous substances present in groundwater is an acceptable form of remediation. Parties can now model the risk posed by groundwater contamination plume that has entered a sewer and define the remediation obligation even if the sewer discharges to a surfacewater body.

These amendments apply retroactively and allow parties to revise judgments, orders, consent judgments and other agreements that address the issue of GSI remediation.

In conjunction with this amendment, Administrative Rule 299.5716 entitled “Cleanup Criteria for Groundwater Based on Protection of Surfacewater Resources from Hazardous Substances in Venting Groundwater” was rescinded. This administrative rule had set forth the previous methodology for demonstrating compliance with GSI criteria.

The amendment to GSI provisions is the first step in many more amendments that are being considered over the next six months. Many of these other amendments under consideration will reflect a move away from an emphasis on only using complex prescriptive administrative rules to allow for self-implementation opportunities. These anticipated amendments will also provide clarifications in methods and flexibility in demonstrating environmental compliance in light of actual site conditions and anticipated use, along with consideration of all applicable risks scenarios.

We will continue to track these changes and provide updates on the status of revisions to Part 201.

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