Few people have heard of vapor intrusion, so what, exactly, is it? In simple terms, vapor intrusion is a process by which subsurface contamination moves into the indoor air space of an enclosed area above it. It happens when volatile, vapor-forming chemicals move from a subsurface source—say contaminated soils or groundwater—through cracks in foundations or other pathways into the indoor air of a building located above that soil. In many instances, these vapor intrusions may not be noticeable. In others, they are: volatile chemicals readily evaporate at room temperature into the air, where you can sometimes smell it. In a worst case scenario, these vapors can accumulate and pose a risk to property or even human health.
Because of the potential risks posed by vapor intrusions, the New York State Department of Health (“NYSDOH”) issued its Final Guidance for Evaluating Soil Vapor Intrusion in the State of New York (“Soil Vapor Guidance”), dated October 2006, which it has been updating since its issuance. The Soil Vapor Guidance is not a binding regulation, but instead offers a recommended methodology for evaluating soil vapor intrusion at a site. It explains methods of sampling and investigative techniques and recommends actions depending on findings.
This past May, NYSDOH issued its latest revision to the Soil Vapor Guidance. It assigned eight common volatile chemicals to three newly revised and renamed Soil Vapor/Indoor Air Decision Matrices. The matrices offer recommendations on remediating vapor intrusions for these volatile chemicals, including Trichloroethene (“TCE”), a chemical commonly used as an industrial solvent and one that often appears at contaminated sites:
Based on the level of contaminant present, the matrices recommend several courses of action, from no action, to monitoring to mitigation.
Should vapor intrusion concern you? The short answer is it depends, but you should at least be aware of the issue.
Keep in mind that the presence of vapor intrusions does not automatically equate to health risk. Whether a person faces potentially harmful effects from vapor intrusions depends on several things, including his sensitivity to the chemical, how long and often he has been inhaling it, and the how toxic the chemical is.
That said, if you are looking to purchase a property with a legacy of industrial use, including the use of volatile chemicals like TCE, then you probably want to understand what any risks for vapor intrusion are before making any purchase. Understanding the risk of soil vapor intrusions should be part of your pre-purchase due diligence—especially if there is a risk that at some point you might get tagged with those cleanup costs.
Similarly, if you own a building where volatile chemicals were used, employees can smell chemicals, and there are cracks or conduits in a concrete floor, you may want to investigate to see if vapor intrusion is a concern. The Soil Vapor Guidance and new matrices give guidance on how to proceed.
Every case turns on its own set of facts, but if you think that vapor intrusion might be concern, a good environmental consultant is the place to start. Sometimes you may want legal advice, too. If you feel you need environmental counsel, feel free to contact Tim Lambrecht, Esq. or Kevin Murphy, Esq. at the Wladis Law Firm.