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January 2017

Solid, Liquid or Gas: What’s the Matter with Vapor Intrusion?

Imagine yourself as the owner of a small company that is looking for additional office space needed to expand your business. Lo and behold, you find the perfect commercial building, on a busy street, in the town you want to be in, and at the right price. You scoop up the building, noting only in passing that the adjacent business is a large gas station. Your company moves in, and business is good, but over time you notice your employees at your new location complain about nonspecific headaches and nausea at an unusual rate. Your managers, who must take daily stock of your products that are conveniently stored in the basement level, now report that the basement smells like gasoline. Unknown to you at time of purchase, your neighbor’s underground storage tank has been slowly leaking for years. Volatile organic compounds like benzene and toluene are now rising through the soil and through cracks in your foundation and are creating a hazardous situation for your employees. You have become the victim of vapor intrusion, and the new regulations proposed by the Michigan Department of Environmental Quality (MDEQ) on April 14, 2016 have been created to prevent situations like yours.

Vapor intrusion occurs when there is a migration of a chemical, in its gaseous state, from any subsurface source into an overlying building. Vapor intrusion into buildings and other enclosed spaces was not identified as a potential problem until the 1980s and is now recognized as an issue with many hazardous substances, such as hydrocarbons, chlorinated solvents, and pesticides. When these substances are found in soil and groundwater, they may also pose threats to indoor air quality via the vapor intrusion pathway. MDEQ is attempting to address this issue with a complete overhaul of the rules and regulations governing vapor intrusion, which is done by proposing changes to the Cleanup Criteria Requirements for Response Activity (Rule 299) of Part 201, Environmental Remediation, of the Natural Resources and Environmental Act 451 (NREPA) for the first time since 2002.

The proposed changes to Rule 299 would eliminate the current vapor intrusion criteria. Instead, the new regulations take a tiered approach to addressing vapor intrusion. If soil, soil gas or groundwater samples do not exceed the Tier-1 criteria, then no further action is required. If the samples exceed the Tier-1 screening criteria, further assessment under Tier 2, and if necessary, Tier 3 is required to determine whether additional response activities are necessary to address the Volatilization to Indoor Air Pathway (VIAP). Public hearings were conducted on these revisions in September and October of 2016 and these changes remained open for comment through October 18, 2016. MDEQ may issue the finalized changes to Rule 299 at any time, but had not done so as of January 20, 2017. Any environmental due diligence or ongoing remediation of a property should be evaluated based on the new, stricter requirements for the vapor intrusion pathway. Any entity involved in property transactions, pursuing cleanup and remediation efforts, or simply conducting due care obligations on a commercial building, is encouraged to review these proposed rules and, where necessary, seek advice from experienced environmental consultants and attorneys.

Foley, Baron, Metzger & Juip’s Environmental Law Practice Group possesses the expertise, experience and technical knowledge required to handle the most complex environmental issues and are routinely selected to defend complex environmental claims throughout the country. For more information on the above pending remediation rules or other environmental issues contact Richard Baron at, Ben Fruchey at or Nicholas Andrew at