By Andrew H. Perellis, Kay R. Bonza, and Craig B. Simonsen


Seyfarth Synopsis: With the EPA adding the consideration of vapor intrusion in its Superfund site investigations, hundreds of sites that previously would not rank high enough to qualify for listing on the National Priorities List of contaminated sites would now likely qualify.

The U.S. Environmental Protection Agency (EPA) has just released a pre-publication version of its final rule to add a subsurface intrusion (SsI) component to the Superfund Hazard Ranking System (HRS).  EPA defines subsurface intrusion as the migration of hazardous substances, pollutants, and contaminants from the unsaturated zone or the surficial (shallow) ground water into overlying structures. The most common form of subsurface intrusion is vapor intrusion.  Vapor intrusion occurs when vapor-forming chemicals from sources including dry cleaning solvents and industrial de-greasers in ground water or soil migrate into buildings and other enclosed spaces, posing a threat to indoor air quality.

We had blogged previously when the Agency proposed this new rule. See EPA Plans to Ease Path to Superfund Listing: Vapor Intrusion Component to be Added to the Hazardous Ranking System. Before this rulemaking, the EPA addressed SsI at sites only when those sites were listed on the National Priorities List (NPL) for another contamination issue.  By adding the consideration of vapor intrusion to the HRS, hundreds of sites that previously would not rank high enough to qualify for listing on the NPL could now qualify based soley on the threat of vapor intrusion. NPL listing is a prerequisite to EPA spending sums over $2 million to investigate and conduct remedial actions under Superfund.  NPL-listed sites are generally more expensive to remediate and more difficult to sell than are other environmentally distressed properties.

In his blog on the topic Mathy Stanislaus, Assistant Administrator for the Office of Land and Emergency Management, indicates that the new rule will allow the “EPA site assessment program to address two additional types of sites: those that either have only subsurface intrusion issues, and those with subsurface intrusion issues that are coincident with a groundwater or soil contamination problem.”

In its support materials for the proposal, EPA noted that the Government Accountability Office (GAO) had concluded that “if vapor intrusion sites are not assessed and, if needed, listed on the NPL, there is the potential that contaminated sites with unacceptable human exposure will not be acted upon.”  The HRS is Appendix A to the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and is used by EPA to identify hazardous waste sites eligible to be added to the NPL.

The Agency has also provided an FAQ and an Interim SsI Superfund Chemical Data Matrix Table.

According to EPA’s news release on the rule, “this regulatory change does not affect the status of sites currently on or proposed to be added to the NPL. This modification only augments criteria for applying the HRS to sites being evaluated in the future.”

For more information on this or any related topic please contact the authors, your Seyfarth attorney, or any member of the Seyfarth Environmental Compliance, Enforcement & Permitting Team.

By Andrew H. Perellis and Craig B. Simonsen

EPA SignThe U.S. Environmental Protection Agency (EPA) has just announced a proposed rule to add a subsurface intrusion (SsI) component to the Superfund Hazard Ranking System (HRS).  Addition of a Subsurface Intrusion Component to the Hazard Ranking System, RIN 2050-AG67 (February 3, 2016).

By adding the consideration of vapor intrusion, hundreds of sites that previously would not rank high enough to qualify for listing on the National Priorities List (NPL) would now likely qualify. NPL listing is a prerequisite to EPA spending sums over $2 million to conduct remedial actions. NPL-listed sites are generally more expensive to remediate and more difficult to sell than are other environmentally distressed properties.

In its support materials, the EPA noted that the Government Accountability Office (GAO) had concluded that “if vapor intrusion sites are not assessed and, if needed, listed on the NPL, there is the potential that contaminated sites with unacceptable human exposure will not be acted upon.” The HRS is Appendix A to the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and is used by EPA to identify hazardous waste sites eligible to be added to the NPL.

SsI can be defined as the migration of hazardous substances, pollutants, or contaminants from contaminated groundwater or soil into an overlying building. SsI may result in exposure to harmful levels of hazardous substances, that may be amplified by extended time spent in buildings where SsI occurs. The EPA claims that this may raise the lifetime risk of cancer or chronic disease. In an effort to ensure that SsI contamination is consistently evaluated, the EPA has proposed to add an HRS component that will allow EPA to evaluate threats posed by SsI.

The Agency has provided an HRS Subsurface Intrusion webpage to afford the regulated community and interested parties with more detailed information on the rulemaking.

The EPA Administrator, Gina McCarthy, signed the Notice of Proposed Rulemaking on February 3, 2016.  The public comment period for the proposed rule will be sixty days from the date of publication in the Federal Register.

By Jeryl L. Olson and Craig B. Simonsen

Power Lines and Pulp Mill PollutionIn a busy day for vapor intrusion, last week the U. S. Environmental Protection Agency made several announcements about vapor intrusion.

First, it announced it had submitted a draft rule to the White House OMB seeking to add vapor intrusion to the pathways evaluated under the Hazard Ranking Scoring (HRS) System for National Priority List (NPL) Superfund sites.   Additionally, EPA published two new sets of technical guidance on assessing vapor intrusion. One guidance document has been prepared for assessing vapor intrusion from leaking petroleum underground storage tank sites, and the other guidance document is aimed at assessing vapor intrusion for sites with non-petroleum contamination.

Draft Rule on Assessing Vapor Intrusion as Part of Site Hazard Ranking

With respect to EPA’s draft rule adding assessment of vapor intrusion to the Hazard Ranking Scoring process, this is the Agency’s second effort at adding the vapor intrusion pathway to the other types of pathways which are already considered in evaluating and then listing a site on the National Priorities List. The same version of the rule was previously submitted to, but then withdrawn from, OMB consideration.

EPA believes now that it is necessary to evaluate vapor intrusion in scoring of sites for the NPL in order to ensure that health risks associated with vapor intrusion are addressed and cleaned up as part of Superfund remediations. Opponents to the process, however, believe that adding assessment of the vapor intrusion pathway to the NPL HRS scoring system will lead to more sites being listed on the NPL, despite the belief that EPA’s Superfund program is already taxed. If the draft rule receives OMB approval, the rule will be published as a Notice of Proposed Rulemaking in the Fall of 2015.

New Vapor Intrusion Guidance

With respect to new vapor intrusion guidance, EPA published guidance both on performing vapor intrusion assessments where the source is petroleum vapor from leaking underground storage tanks (“Technical Guide for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites,” EPA 510-R-15-001, June, 2015) (hereinafter “PVI Guidance”) and for vapor intrusion risks associated with all other types of sites and non-petroleum chemicals (“OSWER Technical Guidance for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air,” OSWER Publication 9200.2-154, June, 2015) (hereinafter “OSWER VI Guidance”).

According to EPA, the existing 2002 (“OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils,” EPA530-D-02-004) guidance on vapor intrusion assessment is replaced by the two new PVI, and OSWER VI Guidance documents. In promoting the two new sets of guidance, EPA indicates that the mitigation measures advocated in the new guidance are “more cost-effective” than mitigation measures considered in the previous draft guidance, and EPA is also advising its new approach to testing for vapor intrusion is more “flexible,” including sampling indoor air or sampling the external sub-slab area.

While comprehensive, and containing certain “user-friendly” features, the new draft guidance for vapor intrusion is not without controversy. EPA has acknowledged that its 2002 draft guidance indicated that OSHA, and not EPA, would take the lead in looking at occupational exposure to vapor intrusion. In the new guidance, EPA seems to back off its previous acquiescence to OSHA’s primary jurisdiction where there is occupational exposure, and merely mentions that there are Memoranda of Understanding (MOUs) between OSHA and EPA dated November 23, 1990, and February 1991, which govern the Agencies’ relative responsibilities (but of course those MOUs pre-date vapor intrusion as a current focus of concern). Tellingly, in Section 7.4.3 of the OSWER VI Guidance, EPA specifically states its reasons for its recommendation that EPA standards, as opposed to OSHA PELs or TLVs, should be used for evaluating VI human health risks for workers in non-residential buildings. EPA bases its conclusions on what it characterizes as OSHA’s own recognition that its PELs are “outdated and inadequate for ensuring protection of worker health.”


The LUST PVI Guidance is less substantial, both in terms of technical information and volume, than the OSWER VI Guidance, and is on its face aimed at EPA regulatory personnel investigating and assessing petroleum vapor intrusion (PVI). Nevertheless, the guidance indicates it is intended for all “UST regulators and practitioners.” The PVI Guidance looks at petroleum hydrocarbons (PHCs) in diesel, gasoline, and jet fuel related volatile organic chemicals (VOCs) such as BTEX, methane generated from anaerobic biodegradertory of petroleum products, and is focused on providing screening criteria based on the distance between PVI sources and potential receptors.

It is interesting to note the PVI Guidance states it is applicable to “…new and existing releases of PHCs and non-PHC fuel additives from leaking USTs and to previously closed sites where the implementing agency has reason to suspect that there may be a potential for PVI.” [Emphasis added]. Despite that statement, the PVI Guidance does acknowledge that it “…does not impose legally binding requirements on implementing agencies or the regulated community”; and, thus, the guidance should not be read as triggering a need for VI assessments at closed LUST sites.

Other features of the PVI Guidance are two “user-friendly” features: a Table, and separate Flowchart, each summarizing EPA’s recommended actions for addressing PVI at LUST sites, and an entire section discussing computer modeling of PVI.


Of the two VI policies published June 11, the OSWER document on non-petroleum VI is the more robust of the documents published, with 245 pages of technical guidance. One of the stated purposes of the OSWER Guidance is to “…promote national consistency in assessing the vapor intrusion pathway …” while providing a “…flexible screening based approach to assessment…”. As with the PVI Guidance, the OSWER VI Guidance is ostensibly aimed at any CERCLA , RCRA or Brownfield sites being evaluated by EPA, or for authorized state RCRA corrective action programs or state-led CERCLA sites, however, it is expected that particularly in states with fledgling VI policies, the OSWER Guidance will become the standard for VI assessments and mitigating measures.

Features of the OSWER VI Guidance include a comprehensive guide to preliminary and detailed VI sampling and assessment technologies in myriad settings (VI in inclusion zones, settings with multiple buildings evaluating concurrent indoor and ambient air sources, etc.). The guidance also discusses strategies for risk assessment under numerous exposure scenarios. Finally, there is a lot of attention focused on mitigation systems in buildings, and subsurface remediation.

By Andrew H. Perellis, Philip L. Comella, and Craig B. Simonsen

Speaking of the U.S. EPA’s draft guidance addressing vapor intrusion at contaminated sites, Mathy Stanislaus, the Agency’s Assistant Administrator for Solid Waste and Emergency Response, recently told BNA Bloomberg that “my plan is to get this out this year.”

The Agency published its original notice in November 2002, of its “Draft Guidance For Evaluating The Vapor Intrusion to Indoor Air Pathway From Groundwater And Soils (Subsurface Vapor Intrusion Guidance)”. The Agency has been operating with this draft guidance since that time. Comments on this initial notice were due in February 2003.  A subsequent request for comments was then published in March 2011, which public comments were due in May 2011. The rulemaking docket was then again re-opened on April 16, 2013, for public comments on two draft documents. One was the original broad vapor intrusion guidance for all compounds, and two was a second narrower guidance on petroleum hydrocarbon vapor intrusion from underground storage tanks.  Public comments were then due by June 24, 2013.

The Agency indicates that it has “extensively engaged stakeholders and considered extensive and substantive public comments received in 2011 and 2012.” Indeed, the rulemaking docket indicates that over 170 comments were filed. In a bit of confusion, BNA Bloomberg indicates that “Stanislaus said the agency received about 1,000 comments in 2013 on the draft guidance, which it is currently evaluating.” Whether the docket contains 170 or 1000 public comments, the Agency “is working to complete its work expeditiously and issue final subsurface vapor intrusion guidances so that it can be applied in forthcoming decisions.”

By Andrew H. Perellis and Jeryl L. Olson

Properties in Illinois that are currently contemplating or pending sale, and properties with existing No Further Remediation (NFR) letters, may encounter difficulties and issues arising under the recent indoor inhalation rules adopted in Illinois. In the Matter of: Tiered Approach to Corrective Action Objectives (TACO) (Indoor Inhalation): Amendments to 35 Ill. Adm. Code 742.

TACO Amendments

The three hundred and twelve pages of TACO amendments were adopted by the Illinois Pollution Control Board on May 16, 2013. Opinion and Order of the Board.  We have prepared a more detailed analysis of the rules that is available in a corresponding Management Alert. The Seyfarth Environmental Safety and Toxic Torts Group has been working with environmental consulting groups to evaluate the practical impact these new regulations will have.

Our take away is this: property transfers may be slowed because consideration of vapor intrusion is likely to trigger the need for Phase II testing on properties that otherwise would not need intrusive testing.  In addition, parties need to be aware that an existing NFR letter never addressed vapor intrusion so prudent buyers will want to ensure that vapor intrusion is considered despite the NFR letter. 

Readers with questions on these complicated rules and their implementation are encouraged to reach out to us.

By Andrew H. Perellis and Craig B. Simonsen

The environmental community continues to focus on the vapor intrusion pathway — guidance has been issued by ASTM, ITRC and more than 25 States. Most recently, the U.S. Environmental Protection Agency’s (EPA or Agency) Office of Underground Storage Tanks (OUST) just published an information paper entitled, “Petroleum Hydrocarbons And Chlorinated Hydrocarbons Differ In Their Potential For Vapor Intrusion.” The purpose of this paper is to amplify the discussion of why petroleum hydrocarbons (PHCs) warrant a different analysis and approach than do chlorinated hydrocarbons (CHCs) when investigating the issue of vapor intrusion. The conclusion is that petroleum hydrocarbons in many cases do not produce a vapor intrusion risk.

In the vadose zone, PHCs behave differently than do CHCs because PHCs biodegrade easily in the presence of the oxygen in the soil, and because PHC free product is lighter than water. In contrast, CHCs typically are more resistant to biodegradation and its free product is denser.

Given these distinct characteristics, it is likely that regulators in the near future will be able to develop exclusion criteria for petroleum contaminated sites whereby, with sufficient depth of soil between the source and receptor, the vapor intrusion concern can be eliminated without further testing. See, Hartman, B., The Vapor-Intrusion Pathway: Petroleum Hydrocarbon Issues, Lustline, No. 66. The ability to screen out candidate sites without need for intrusive testing would be of substantial benefit in streamlining regulatory decision-making.

EPA’s information paper is one in a series of steps being taken by EPA’s OUST group with the goal of producing final PHC guidance in 2012, as a compliment to the vapor intrusion guidance update expected by Office of Solid Waste and Emergency Response before December 2012. See

By Philip L. Comella and Craig B. Simonsen

The U.S. Environmental Protection Agency (EPA or Agency) just released its Toxicological Review of Trichloroethylene (EPA/635/R-09/011F, September 28, 2011) (Toxicological Review). This publication represents the first time that EPA has classified trichloroethylene (TCE) (CASRN 79-01-6) as a human carcinogen regardless of the route of exposure. TCE had previously been classified as a “possible human carcinogen.”

According to the Agency, the purpose of the Toxicological Review is to provide scientific support and rationale for the hazard and dose-response assessments given in its Integrated Risk Information System (IRIS) pertaining to chronic exposure to TCE. TCE is a volatile chemical widely used by industry as a chlorinated solvent; and unfortunately, it is also widely found at contaminated sites, including hundreds of Superfund facilities across the country.

The Toxicological Review concludes that based on the available human epidemiologic data and experimental and mechanistic studies, “TCE poses a potential human health hazard for noncancer toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing fetus. The evidence is more limited for TCE toxicity to the respiratory tract and female reproductive system.”

The chief impact of this new hazard classification will likely be on the developing vapor intrusion standards and on groundwater remediation projects.