"News flash: Illinois Pollution Control Board finally adopts vapor intrusion rules"
Up until recently, Illinois’ Tiered Approach to Corrective Action Objectives (“TACO”) standards have focused on three exposure scenarios for residential or industrial/commercial property uses: incidental ingestion of contaminated soil, outdoor inhalation of chemical vapors and contaminated soil particulate matter, and the ingestion of contaminated groundwater. For the third exposure scenario, the TACO rules provide both a groundwater quality standard and a soil component of groundwater standard, which is a soil standard based on the ability of contaminants to leach from soil and contaminate the underlying groundwater.
For several years, the Illinois Pollution Control Board has been evaluating a number of proposals to incorporate a new exposure route: the indoor inhalation exposure route. On May 16, 2013, the Illinois Pollution Control Board amended the TACO rules to adopt the new indoor inhalation exposure route effective July 15, 2013.
Under this exposure scenario, commonly referred to as vapor intrusion, chemical vapors originating within contaminated soil and groundwater beneath building foundations and surrounding basement walls permeate structures and enter air spaces inside. Vapor intrusion is an issue that has received considerable attention recently, and is now commonly evaluated by the Environmental Protection Agency at Superfund sites in which organic solvents are chemicals of concern. Vapor intrusion has also been the subject of “imminent and substantial endangerment” lawsuits, including one notable recent decision related to contamination caused by a drycleaner operation in Illinois. See Forest Park National Bank & Trust v. Ditchfield, Case No. 10 C 3166, in the United States District Court of the Northern District of Illinois (July 24, 2012).
This TACO rule amendment will significantly impact the investigation and remediation of contamination sites being addressed under the Illinois Environmental Protection Agency’s cleanup programs, including sites in the state’s voluntary Site Remediation Program and the Leaking Underground Storage Tank program. Evaluating vapor intrusion also will be an even more important part of due diligence prior to property transactions, now with the benefit of adopted standards rather than the guidance offered by the various different proposals discussed over the last several years. The TACO rules continue to be amended from time to time, and as always, it is necessary to ensure that all environmental investigation, remediation, and due diligence work considers the latest requirements.
This was also published in the Illinois State Bar Association Environmental Law Newsletter (June 2013, Vol. 43, No. 4)