^£0SX
0\
•J % U.S. ENVIRONMENTAL PROTECTION AGENCY
\ / OFFICE OF INSPECTOR GENERAL
\Z
Catalyst for Improving the Environment
Evaluation Report
Lack of Final Guidance on
Vapor Intrusion Impedes Efforts
to Address Indoor Air Risks
Report No. 10-P-0042
December 14, 2009
-------
Report Contributors: Carolyn Copper
Tina Lovingood
Dave Goodman
Jee Kim
Barry Parker
Angela Bennett
Heather Drayton
Abbreviations
EPA
U.S. Environmental Protection Agency
IRIS
Integrated Risk Information System
ITRC
Interstate Technology Regulatory Council
OIG
Office of Inspector General
ORD
Office of Research and Development
OSWER
Office of Solid Waste and Emergency Response
PCE
Perchl oroethy 1 ene
RCRA
Resource Conservation and Recovery Act
TCE
T ri chl oroethy 1 ene
UST
Underground Storage Tanks
-------
vi£D sr^
U.S. Environmental Protection Agency 10-P-0042
December 14, 2009
0* U ¦ O • L. I I V11 Ul IIIICI I Lul a I UlCvl
Office of Inspector General
» w/ *
At a Glance
%-r CS
proI^
Why We Did This Review
We conducted this review to
determine what actions the U.S.
Environmental Protection Agency
(EPA) has taken, both general
and site-specific, to identify and
mitigate human health risks from
chemical vapor intrusion that can
be associated with contaminated
sites. When EPA had not taken
site-specific actions, we
examined the reasons why.
Background
Vapor intrusion is the migration
of volatile chemicals from the
subsurface into overlying
buildings. EPA has
acknowledged that current and
former contaminated sites could
have extensive vapor intrusion
issues and pose a significant risk
to the public. In 2002, based on
its current understanding of
subsurface vapor intrusion, EPA
issued draft guidance. The
guidance included technical and
policy recommendations for
determining whether vapor
intrusion posed a risk at sites.
The 2002 guidance remains in
draft form and has not been
finalized since it was issued.
For further information,
contact our Office of
Congressional, Public Affairs and
Management at (202) 566-2391.
To view the full report,
click on the following link:
www.epa.aov/oia/reports/2010/
20091214-10-P-0042.pdf
Catalyst for Improving the Environment
Lack of Final Guidance on Vapor Intrusion
Impedes Efforts to Address Indoor Air Risks
What We Found
EPA's efforts to protect human health at sites where vapor intrusion risks may
occur have been impeded by the lack of final Agency guidance on vapor intrusion
risks. EPA's 2002 draft vapor intrusion guidance has limited purpose and scope,
and the science and technology associated with evaluating and addressing risk from
vapor intrusion is evolving. EPA's draft also contains outdated toxicity values for
assessing risk to humans from chemical vapors in indoor air.
EPA's draft guidance does not address mitigating vapor intrusion risks or
monitoring the effectiveness of mitigation efforts. The draft guidance also does not
clearly recommend that multiple lines of evidence be used in evaluating and
making decisions about risks from vapor intrusion. The draft guidance is not
recommended for assessing vapor intrusion risks associated with petroleum
releases at Underground Storage Tank sites. EPA's outdated toxicity values allow
for the use of widely different, nonfederal toxicity values and have caused delays in
work to address possible risks.
EPA has not finalized its guidance, according to EPA managers and staff, because
the 2007 Interstate Technology Regulatory Council guidance addressed many
issues that EPA would have addressed in a final guidance, and because finalizing
EPA's guidance would take a long time in light of the emerging scientific issues in
the field. Also, previous administrative review requirements for Agency guidance
were perceived as barriers to issuing timely guidance in a rapidly changing
environment. These requirements were revoked by the current Administration, but
significant guidance remains subject to some administrative review.
Seven years later, EPA is developing a roadmap of technical documents that will
update its draft guidance. However, technical documents may not be effective for
conveying and representing Agency policy. EPA has also made some progress in
updating toxicity values for some contaminants most frequently associated with
vapor intrusion.
What We Recommend
We recommend that EPA issue final guidance to establish current Agency policy
on the evaluation and mitigation of vapor intrusion risks. The Agency should also
finalize toxicity values for trichloroethylene and perchloroethylene - common
contaminants associated with vapor intrusion. The Agency agreed with our
recommendations and provided milestones.
-------
^£Dsr^
? \ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
| | WASHINGTON, D.C. 20460
\ ' G/
PROl^
OFFICE OF
INSPECTOR GENERAL
December 14, 2009
MEMORANDUM
SUBJECT:
FROM:
Lack of Final Guidance on Vapor Intrusion Impedes Efforts
to Address Indoor Air Risks
Report No. 10-P-0042
&
Wade T. Najjum ' -
Assistant Inspector General
Office of Program Evaluation
yu
TO:
Mathy Stanislaus
Assistant Administrator
Office of Solid Waste and Emergency Response
Lek Kadeli
Acting Assistant Administrator
Office of Research and Development
This is our report on the subject evaluation conducted by the Office of Inspector General (OIG)
of the U.S. Environmental Protection Agency (EPA). This report contains findings that describe
the problems the OIG has identified and corrective actions the OIG recommends. This report
represents the opinion of the OIG and does not necessarily represent the final EPA position.
Final determinations on matters in this report will be made by EPA managers in accordance with
established resolution procedures.
The estimated cost of this report - calculated by multiplying the project's staff days by the
applicable daily full cost billing rates in effect at the time - is $454,233.
Action Required
Based on the Agency's planned actions and milestones provided, the OIG will close the
recommendations in the OIG tracking system. No further action is required, except that, within
90 days of this report date, the OIG requires that the Assistant Administrator, Office of Solid
Waste and Emergency Response, provide interim corrective actions and milestones for its
planned actions related to Recommendation 2 because the planned completion date for
-------
Recommendation 2 is nearly 3 years from this final report date. We have no objections to the
further release of this report to the public. This report will be available at www.epa.gov/oig.
If you or your staff have any questions regarding this report, please contact Carolyn Copper at
(202) 566-0829 or copper.carolvn@epa.gov, or Tina Lovingood at (202) 566-2906 or
lovingood.tina@epa.gov.
-------
Lack of Final Guidance on Vapor Intrusion
Impedes Efforts to Address Indoor Air Risks
10-P-0042
Table of C
Purpose 1
Background 1
Noteworthy Achievements 2
Scope and Methodology 3
Results of Review: EPA Lacks Final Guidance on Vapor Intrusion 4
Purpose and Scope of EPA's Draft Vapor Intrusion Guidance Is Limited 4
Lack of Current EPA Toxicity Values Allows for Use of Disparate
Nonfederal Toxicity Values and Delays Work to Address Possible Risks 6
Scientific and Administrative Issues Are Perceived as Barriers to Issuing
Final Vapor Intrusion Guidance 8
Conclusions 8
Recommendations 9
Agency Comments and OIG Evaluation 9
Status of Recommendations and Potential Monetary Benefits 10
Appendices
A EPA and Other Regulatory Guidance on Vapor Intrusion 11
B OSWER Response to OIG Draft Report 12
C ORD Response to OIG Draft Report 14
D Distribution 17
-------
10-P-0042
Purpose
The purpose of our review was to determine what actions the U.S. Environmental Protection
Agency (EPA) has taken to identify and mitigate human health risks from chemical vapor
intrusion that can be associated with contaminated sites. We addressed the following questions:
1. What steps has EPA taken to identify the potential risks of vapor intrusion from
contaminated sites?
2. What actions has EPA taken to ensure that vapor intrusion is being site-
specifically identified and addressed within in its various programs, including
Resource Conservation and Recovery Act (RCRA), Superfund, Brownfields, and
Underground Storage Tanks (UST)? Where EPA has not taken actions to site-
specifically identify and address vapor intrusion, why not?
This assignment is included in the Office of Inspector General (OIG) Fiscal Year 2009 annual
plan.
Background
Vapor intrusion is the migration of volatile chemicals from the subsurface into overlying
buildings. Volatile chemicals in buried wastes and/or contaminated groundwater can emit
vapors that may migrate through subsurface soils and into indoor air spaces of overlying
buildings in ways similar to those of radon gas seeping into homes, as shown in Figure 1.
According to EPA, in extreme cases, the vapors may accumulate in dwellings or occupied
buildings to levels that may pose near-term safety hazards (e.g., explosion), acute health effects,
or aesthetic problems (e.g., odors).
Figure 1: Vapor Intrusion Migration Graphic
Jnc.loE.jr Air
Vadp3? ZQ!i9
Soil (lits
{
{
Soil
Contamination
(rcaadual or
niohiicNA.PL)
tlfiWIUCFH ,J" !
j ,r »••••••••••• •
iiilillBi:
/; YX'hcfnicsJ VapcrMigraiioit
ititttffinirisltioii-
Note: NAPL is non-aqueous phase liquid.
Source: OSWER 2002 Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air
Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance).
1
-------
10-P-0042
According to an EPA scientist, the four chlorinated chemicals that pose the highest risks from
vapor intrusion are the ones that are most frequently found at contaminated sites. These
chemicals are perchloroethylene (PCE), trichloroethylene (TCE), dichloroethylene, and vinyl
chloride.
EPA's Integrated Risk Information System (IRIS) is an electronic database containing
information on human health effects that may result from exposure to various chemicals in the
environment. IRIS contains toxicity values for cancer and/or noncancer effects from oral and/or
inhalation exposures for more than 540 chemicals, including dichloroethylene and vinyl chloride.
In November 2002, EPA issued draft guidance titled OSWER Draft Guidance for Evaluating the
Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor
Intrusion Guidance). This guidance provides a tool for evaluating vapor intrusion at RCRA
sites, some Superfund sites,1 and Brownfields sites. Since issuing the draft guidance, EPA has
neither updated nor finalized it. Separately, States, other federal agencies, and stakeholder
groups have issued vapor intrusion guidance or technical documents. According to the Interstate
Technology Regulatory Council (ITRC), as of 2008, 26 States have issued their own vapor
intrusion guidance.2
Noteworthy Achievements
EPA has issued a number of guidance and technical documents to help regions and States
address vapor intrusion. In 1999, EPA's Office of Solid Waste developed human health
environmental indicators for the RCRA program that required regulators to consider vapor
intrusion and issued draft vapor intrusion guidance for use in environmental indicators in 2001.
EPA's Office of Solid Waste and Emergency Response (OSWER) issued draft vapor intrusion
guidance in 2002. To help address the Agency's concern that the science and technology
associated with evaluating and addressing risk from vapor intrusion is complex and evolving, it
issued a fact sheet and other documents. Specifically, in 2004, OSWER developed a
Brownfields fact sheet, "Design Solutions for Vapor Intrusion and Indoor Air Quality." OSWER
also partly funded the 2007 ITRC vapor intrusion guidance, and in 2008, OSWER issued a
Brownfields Vapor Intrusion Primer. In 2008, EPA also developed the Superfund
Environmental Indicator Guidance Human Health Revision, which includes consideration of
vapor intrusion into indoor air. EPA is in the process of creating a roadmap of technical
documents that update the draft guidance and the ITRC guidance. EPA's Office of Research and
Development (ORD) has issued a number of research papers on sampling and modeling for
1 According to the 2002 draft guidance, the guidance applies to the Comprehensive Environmental Response,
Compensation, and Liability Act (National Priorities List and Superfund Alternative Sites). The guidance does not
mention non-National Priorities List sites such as removal-action-only sites.
2 Subsequent to our field work, we learned that on September 18, 2009, the U.S. Department of Housing and Urban
Development updated its 2002 Multi-Family Accelerated Processing Guide, Environmental Review (Chapter 9).
The update requires a vapor intrusion screen to determine whether there is a potential for vapors to occur in the
subsurface below existing and/or proposed on-site structures from those hazardous substances, petroleum, and
petroleum products that consist of volatile organic compounds and semivolatile organic compounds and inorganic
volatile compounds.
2
-------
10-P-0042
specific contaminants in soil and groundwater. EPA has engaged in vapor intrusion educational
activities such as training events and symposiums.
The Agency has begun the process of drafting policy on vapor intrusion in nonresidential
settings. It has also progressed in developing IRIS toxicity values for PCE and TCE. EPA has
also evaluated the presence of vapor intrusion in some Superfund Five-Year Reviews (or
"protectiveness reviews"). It is planning to issue its Five-Year Review guidance to specifically
address evaluation of vapor intrusion.
EPA Region 3 has made the review of indoor air pollutants, including vapor intrusion, a regional
priority. As part of the Region's work in this area, it began evaluating Superfund National
Priority List sites and RCRA sites for vapor intrusion. Where appropriate, it is mitigating the
risk and also educating the public about the risks from vapor intrusion.
Scope and Methodology
We conducted our review in accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the evaluation to obtain sufficient, appropriate
evidence to provide a reasonable basis for our findings and conclusions based on our evaluation
objectives. We believe that the evidence obtained provides a reasonable basis for our findings
and conclusions based on our evaluation objectives. We performed our review from December
2008 through September 2009.
To gain an understanding of vapor intrusion, we attended two vapor intrusion conferences in
Philadelphia and San Diego and reviewed various online training materials. In addition, we
researched prior reports by EPA, Government Accountability Office, and ITRC. We identified
and interviewed EPA vapor intrusion contacts or managers.
To identify potential internal control weaknesses, we reviewed EPA's Risk/Vulnerability
Assessments and Fiscal Year 2008 Agency Assurance Letters. We also reviewed EPA's Key
Management Challenges for Fiscal Year 2008, and related Federal Managers Financial Integrity
Act documents.
We conducted our work in OSWER, ORD, and EPA Regions 1-10.
To address our first question, we reviewed documents and information and interviewed EPA
staff. To address our second question, we analyzed EPA, ITRC, selected State guidance
documents, and EPA technical/policy documents. (See Appendix A for a sample of these
documents.) We reviewed existing controls that would trigger review of vapor intrusion at
contaminated sites, such as environmental indicators, ready-for-reuse indicators, and
protectiveness reviews. We also reviewed the hazard ranking system for specific mention of
evaluating vapor intrusion, but found none.
We visited Region 3 and met with representatives and managers from various programs that
address vapor intrusion. We discussed the Region 3 draft framework, vapor intrusion priorities,
and how the programs are managing vapor intrusion.
3
-------
10-P-0042
To assess how the remaining regions address vapor intrusion, we sent an online survey to EPA's
Vapor Intrusion Forum on February 26, 2009, and analyzed the results. We also reviewed
supplementary data that were provided as part of the survey.
Results of Review: EPA Lacks Final Guidance on Vapor Intrusion
EPA does not have final guidance to establish current Agency policy on the evaluation and
mitigation of vapor intrusion risks. EPA has taken some steps to identify potential vapor
intrusion risks, developed plans to address risks, and taken actions to mitigate site-specific risks.
However, due to perceived administrative and scientific barriers, EPA has not finalized its draft
2002 vapor intrusion guidance. The draft guidance is limited in scope and purpose. It also lacks
current toxicity values, or values that estimate the risk of exposure and where action may need to
be taken. The lack of final EPA guidance has impeded Agency efforts to protect human health
and the environment at sites where vapor intrusion risks may occur.
In the absence of final and current guidance (including up-to-date toxicity values), EPA, States,
and other parties may continue to use widely different toxicity values for determining human
health risks from vapor intrusion. Some enforcement staff believe draft vapor intrusion toxicity
values and requirements may limit the Agency's ability to enforce compliance with those
standards and may encourage compliance with toxicity values that may not be universally
viewed as safe. Incomplete evaluations or actions to address vapor intrusion risks may also
continue, and vapor intrusion risk assessments at petroleum-contaminated sites may not be
conducted. According to some EPA enforcement staff, the uncertainties created by draft EPA
vapor intrusion guidance could also limit some EPA efforts to enforce responsible party clean-up
actions.
Purpose and Scope of EPA's Draft Vapor Intrusion Guidance Is Limited
EPA's draft guidance focuses on the important issue of assessing whether unacceptable risks to
human health may occur from chemical vapor exposures. However, the guidance does not
address actions to mitigate chemical vapor risks. More recently, some States' and ITRC
guidance, as well as EPA's Brownfields Primer and the U.S. Air Force, U.S. Navy, and U.S.
Army Tri-Services Guidance, include vapor intrusion risk mitigation procedures or information.
EPA's draft guidance also does not strongly recommend the use of multiple lines of evidence in
evaluating and making decisions about vapor intrusion. Use of multiple lines of evidence is
considered the current state of the science. EPA does not recommend its draft guidance be used
to assess vapor intrusion risks associated with petroleum releases at UST sites. According to
EPA, applying the draft guidance to petroleum compounds may overestimate the impact of vapor
intrusion. EPA's draft guidance refers the public to UST guidance from 1995,3 but the 1995
guidance does not discuss vapor intrusion. More recent guidances address a broader scope of
relevant vapor issues.
3 U.S. Environmental Protection Agency, Use of Risk-Based Decision Making in UST Corrective Action Programs,
1995.
4
-------
10-P-0042
The recent EPA technical paper addresses some aspects of mitigation, but it is not
guidance. In October 2008, EPA issued a technical document titled Indoor Air Vapor Intrusion
Mitigation Approaches. It focuses on "interim remedial measures" to address vapor intrusion.
Some of the strengths of this document are that it provides an overview of vapor intrusion
mitigation methods, estimated mitigation costs, discussion of long-term monitoring to assess
mitigation performance, and development of operations and maintenance plans. However, the
document provides few details on when to terminate vapor intrusion mitigation systems. It also
does not include operations and maintenance plan requirements, and it does not convey Agency
policy or guidance. The document refers readers to New York and New Jersey vapor intrusion
guidance for further information on operations and maintenance and termination of the systems.
The draft guidance does not clearly address the multiple lines of evidence approach. EPA's
2002 guidance begins to discuss, but does not clearly and strongly recommend, that multiple
lines of evidence4 are needed in evaluating and making decisions about vapor intrusion. In two
places, the draft guidance refers to using more than one line of evidence, and where it does, the
guidance discusses using evidence in a sequential order to screen out sites. The 2002 draft
guidance also does not explain the many variables that can affect the evaluation of vapor
intrusion as a pathway of concern.
According to the 2008 Tri-Services Guidance for assessing vapor intrusion, using multiple lines
of evidence in evaluating vapor intrusion has become the "state of the science." If only one line
of evidence is used, it could lead to incorrect conclusions about vapor intrusion risks. ITRC
states that it is important to use multiple lines of evidence to reach decisions based on
professional judgment. In a January 2009 memo for an interim TCE toxicity value, EPA
strongly suggested the importance of using multiple lines of evidence and explained the many
variables affecting the evaluation of vapor intrusion as a pathway of concern. However, due to
other issues regarding the content of the memo, EPA withdrew the memo in April 2009.
The draft guidance does not address vapor intrusion at petroleum sites. EPA does not
recommend use of the 2002 draft vapor intrusion guidance for assessing vapor intrusion risks
from petroleum releases at UST sites. EPA states in its guidance that this is due to "certain
conservative assumptions" (i.e., no biodegradation), and the draft guidance is unlikely to provide
an appropriate mechanism for screening the vapor pathway at UST sites that involve petroleum
releases. However, other EPA documents state that semivolatile chemicals, such as gasoline and
petroleum, can pose a vapor intrusion problem. In addition, the draft vapor intrusion guidance
does include toxicity values for petroleum chemicals that may be a component at non-UST sites.
Nonetheless, EPA does not recommend the use of the draft guidance at UST sites.
The 2002 draft vapor intrusion guidance refers readers to the Agency's 1995 guidance, Use of
Risk-Based Decision Making in UST Corrective Action Programs. However, this guidance does
not address vapor intrusion, and the UST program does not have specific vapor intrusion
guidance. According to a UST program manager, this is because mitigating vapor intrusion at
petroleum sites is an evolving area that lacks consensus.
4 Some examples of multiple lines of evidence ITRC suggests using include soil gas data, groundwater spatial data,
indoor and outdoor air data, background sources, and building construction and current conditions.
5
-------
10-P-0042
EPA's UST program delegates vapor intrusion assessments to States. However, States do not
report information to EPA about whether vapor intrusion has been evaluated, is a risk, or needs
to be mitigated at UST sites. Therefore, EPA lacks the information. In January 2009, the
Association of State and Territorial Solid Waste Management Officials requested assistance from
the EPA Office of Underground Storage Tanks to develop vapor intrusion guidance for
petroleum.
ITRC's vapor intrusion guidance acknowledges risk from petroleum vapors. It provides an
example of a site where petroleum vapors have caused human health concerns. For example,
" ... at a petroleum hydrocarbon site in Colorado, vapor intrusion caused the evacuation of two
schools. Indoor air samples were collected in another school located outside of the influence of
the contaminated plume. Following mitigation activities, the students were allowed to return to
the formerly impacted school when contaminant concentrations in indoor air were in the range of
concentrations detected in the unaffected school."
Although EPA does not recommend its broad 2002 vapor intrusion guidance for UST sites,
EPA's 2008 Brownfields Primer does address petroleum.
Other guidances address a broader scope of relevant vapor intrusion issues. The purpose of
EPA's 2002 draft guidance is to help the user conduct a screening evaluation to determine
whether subsurface chemicals are entering indoor air and, if so, whether they pose an
unacceptable risk to human health. More recent guidance documents5 are broader and go beyond
evaluation of the risk posed by vapor intrusion. Some of these documents provide information
regarding when or whether preemptive mitigation may be appropriate. Some discuss the
selection, design, installation, and/or sustainability over the long term of a vapor intrusion
mitigation system. Some documents also discuss long-term monitoring, when institutional
controls and deed restrictions are appropriate, and/or when to terminate the mitigation systems.
EPA also issued guidance in April 2009 on transferring fund-lead vapor intrusion systems to
States.6 However, this guidance does not detail an operations and maintenance plan or the types
of operation and maintenance activities that may be required. The April 2009 directive is also
not included in a comprehensive vapor intrusion guidance.
Lack of Current EPA Toxicity Values Allows for Use of Disparate Nonfederal
Toxicity Values and Delays Work to Address Possible Risks
EPA survey respondents said that EPA's guidance was outdated because it did not include
current toxicity values for some chemicals of concern in vapor intrusion assessments. As a
result, EPA, States, and other parties use alternative toxicity values that vary widely in their
definition of levels that are considered safe. Lack of some toxicity values has also delayed work
at Superfund sites with potential risks from vapor intrusion.
5EPA's Brownfields Primer (2008), ITRC guidance (2007), Tri-Services Handbook (2008), and guidance from the
States of California (2005 and draft 2008), New Jersey (2005), and New York (2006). See Appendix A for
complete bibliographical information on these documents.
6 U.S. Environmental Protection Agency, Operational and Functional Determination and the Transfer of Fund-lead
Vapor Intrusion Mitigation Systems to the State, April 9, 2009.
6
-------
10-P-0042
Our survey results show that one reason explaining outdated toxicity values is that the values
were based on oral exposure. These toxicity values assume a default inhalation rate and body
weight.7 However, according to the Agency's January 2009 risk assessment guidance,8 "risk
assessors are discouraged" from basing toxicity values on oral data, especially when default
assumptions about inhalation rate and body weight are used.
The toxicity value for TCE is one of the key values that is outdated. In early 2009, EPA issued
interim toxicity values to address risks due to TCE exposure. Specifically, EPA recommended
the use of California's inhalation risk value for evaluating the cancer effects of TCE in site-
specific risk assessments. For noncancer effects of TCE, EPA recommended two values that
could be considered in evaluating systemic toxicity at sites. One value was developed by the
New York State Department of Health, and the other was developed by California's EPA.
However, in April 2009, EPA withdrew the interim toxicity values. It believed that the two
different values for assessing noncancer risks may have led to inconsistency in the development
of preliminary remediation goals for TCE and site-specific risk assessments. In November 2009,
EPA released its draft toxicological review for TCE for public review and comment.
In the absence of current and final EPA toxicity values, regulators and others may use "other
values" such as nonfederal or State toxicity values.9 These toxicity values can sometimes vary
widely. One example is PCE in groundwater. The standard in micrograms per liter for New
Jersey is 1; for Michigan, 25,000; and for Pennsylvania, 42,000. For PCE in indoor air, the
toxicity value in micrograms per cubic meter for California is 0.41; for New Jersey, 3; for
Pennsylvania, 36; and for Michigan, 42.10 Differing State toxicity values, and EPA's lack of
some toxicity values and final guidance, have raised concerns for a regional enforcement
manager and staff. They believe that national consistency in screening standards is necessary.
However, they also stated that they have not experienced any problems yet based on existing
differing toxicity values. Enforcement staff have concerns about obtaining private party
commitments to clean up sites to levels that are specified in a draft EPA guidance.
EPA reports that document the protectiveness of Superfund site remedies (Five-Year Reviews)
show that the regions were waiting for final guidance or toxicity values before an evaluation or a
complete evaluation of vapor intrusion would be done. For example,
7 U.S. Environmental Protection Agency, OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air
Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance), November 2002, Tables 2 and 3,
third column, where the draft guidance indicates the toxicity values were extrapolated from oral sources.
8 U.S. Environmental Protection Agency, Risk Assessment Guidance for Superfund Volume I: Human Health
Evaluation Manual (Part F, "Supplemental Guidance for Inhalation Risk Assessment"), EPA-540-R-070-002,
OSWER 9285.7-82, Januaiy 2009.
9 In the absence of IRIS or ORD-developed toxicity values, EPA's guidance directs the evaluator to use "other
toxicity values." U.S. Environmental Protection Agency, Human Health Toxicity Values in Superfund Risk
Assessments, OSWER Directive 9285.7-53, December 5, 2003. The Directive contains a hierarchy for human health
toxicity values. The first tier is EPA's IRIS, the second is EPA's Provisional Peer Reviewed Toxicity Values
developed by ORD, and the third is other toxicity values. Priority is recommended for sources of information that
are the most current, the basis of which is transparent and publicly available, and which have been peer reviewed.
10 Eklund, B. et al., "An Overview of State Approaches to Vapor Intrusion," EM, February 2007.
7
-------
10-P-0042
• The 2005 protectiveness review for a Region 3 site stated, "Due to the proximity of
residential homes to the contaminated ground water plume, the potential for vapor
intrusion into basements will need to be addressed in the future, once . . . EPA
policy/guidance regarding investigation of vapor intrusion is established."
• The 2006 protectiveness review for a Region 9 site stated, "Once the guidance for
evaluating the vapor intrusion to indoor air pathway is finalized or EPA and [the state
regulatory agency] can agree to the process for evaluating the pathway, an indoor air risk
evaluation should be conducted at the Site."
• The 2007 protectiveness review for a Region 7 site stated, "Revise the vapor intrusion
risk evaluation after the new TCE toxicity factor is approved by EPA."
The protectiveness statements for the three sites were either qualified or limited. The Region 3
and Region 7 protectiveness reviews stated that the remedies for those sites were protective but
had qualifications regarding vapor intrusion. The Region 9 protectiveness review could not
make a protectiveness statement and recommends, among other actions, a vapor intrusion risk
assessment.
EPA delays in conducting vapor intrusion risk assessments result in limited assurance that site
clean-up actions have addressed these potential risks to humans and the environment.
Scientific and Administrative Issues Are Perceived as Barriers to Issuing
Final Vapor Intrusion Guidance
According to Headquarters managers and staff, EPA has not finalized its guidance because the
2007 ITRC guidance, partly funded and supported by EPA, addressed many issues EPA would
have included in a final guidance. They also believe finalizing EPA's guidance would take a
long time in light of the emerging scientific issues in the field. In addition, if EPA issued vapor
intrusion guidance, it would have been considered "significant guidance" under Executive Order
13422. The administrative review process triggered by Executive Order 13422 could be more
detailed and lengthy.11 However, in January 2009, Executive Order 13422 was revoked.12
Conclusions
EPA's efforts to address vapor intrusion and demonstrate policy positions and environmental
leadership could be strengthened by updating, finalizing, and broadening the scope of one of its
primary management controls - its guidance. Final guidance and toxicity values can promote
effective and transparent enforcement of clean-up standards and requirements. They can also
11 Executive Order 13422 created the term "significant guidance." When a guidance document is determined to be
significant, an administrative review process is triggered. This process includes review by the Office of
Management and Budget's Office of Information and Regulatory Affairs.
12 All significant policy and guidance documents remain subject to review by the Office of Management and
Budget, Office of Information and Regulatory Affairs under Executive Order 12866. See Office of Management
and Budget, Memorandum for the Heads and Acting Heads of Executive Departments and Agencies, Guidance for
Regulatory Review, M-09-13, March 4, 2009.
8
-------
10-P-0042
promote recovery of the government's clean-up costs, where applicable. Technical papers may
not be effective for conveying and representing Agency policy.
Recommendations
We recommend that the Assistant Administrator for Solid Waste and Emergency Response:
1. Identify and publicly report the portions of OSWER's November 2002 draft vapor
intrusion guidance that remain valid and the portions that should be updated.
2. Issue final vapor intrusion guidance(s) that incorporates information on:
a. Updated toxicity values.
b. A recommendation(s) to use multiple lines of evidence in evaluating and
making decisions about risks from vapor intrusion.
c. How risks from petroleum hydrocarbon vapors should be addressed.
d. How the guidance applies to Superfund Five-Year Reviews.
e. When or whether preemptive mitigation is appropriate.
f. Operations and maintenance, the termination of the systems, and when
institutional controls and deed restrictions are appropriate.
3. Train EPA and State staff and managers and other parties on the newly updated,
revised, and finalized guidance document(s).
We recommend that the Assistant Administrator for Research and Development:
4. Finalize toxicity values for TCE and PCE in the IRIS database.
Agency Comments and OIG Evaluation
The OIG made changes to the report based on the Agency's comments where appropriate.
Appendices B and C provide the Agency comments.
OSWER agreed with Recommendations 1 through 3, but was unclear about the milestones for
Recommendations 1 and 2. Based on our follow-up, OSWER provided the milestones of August
2010 for Recommendation 1 and November 2012 for Recommendation 2. The milestone for
Recommendation 3 will be May 2013. The recommendations will remain open with agreed-to
actions pending.
ORD agreed with Recommendation 4, but was unclear about the milestones for each of the
toxicity values. Based on our follow-up, ORD provided the milestones of December 2010 for
the TCE toxicity value and July 2010 for PCE. The recommendation will remain open with
agreed-to actions pending.
9
-------
10-P-0042
Status of Recommendations and
Potential Monetary Benefits
RECOMMENDATIONS
POTENTIAL MONETARY
BENEFITS (In $000s)
Rec.
No.
Page
No.
Subject
Status1
Planned
Completion
Action Official Date
Claimed
Amount
Agreed To
Amount
Identify and publicly report the portions of
OSWER's November 2002 draft vapor intrusion
guidance that remain valid and the portions that
should be updated.
Issue final vapor intrusion guidance(s) that
incorporates information on:
a. Updated toxicity values.
b. A recommendation(s) to use multiple lines of
evidence in evaluating and making decisions
about risks from vapor intrusion.
c. How risks from petroleum hydrocarbon
vapors should be addressed.
d. How the guidance applies to Superfund Five-
Year Reviews.
e. When or whether preemptive mitigation is
appropriate.
f. Operations and maintenance, the termination
of the systems, and when institutional
controls and deed restrictions are
appropriate.
Train EPA and State staff and managers and other
parties on the newly updated, revised, and finalized
guidance document(s).
Finalize toxicity values forTCE and PCE in the
IRIS database.
Assistant Administrator, August
Office of Solid Waste and 2010
Emergency Response
Assistant Administrator, November
Office of Solid Waste and 2012
Emergency Response
Assistant Administrator,
Office of Solid Waste and
Emergency Response
Assistant Administrator,
Office of Research and
Development
May 2013
December
2010 (TCE)
and July
2010 (PCE)
1 O = recommendation is open with agreed-to corrective actions pending
C = recommendation is closed with all agreed-to actions completed
U = recommendation is undecided with resolution efforts in progress
10
-------
10-P-0042
Appendix A
EPA and Other Regulatory Guidance on
Vapor Intrusion
U.S. Environmental Protection Agency. OSWER Draft Guidance for Evaluating the Vapor
Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion
Guidance). EPA 530-D-02-004, November 2002.
U.S. Environmental Protection Agency. Office of Solid Waste and Emergency Response.
Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment. EPA 542-
R-08-001, March 2008.
U.S. Environmental Protection Agency. Office of Solid Waste and Emergency Response.
Design Solutions for Vapor Intrusion and Indoor Air Quality. EPA 500-F-04-004, March 2004.
U.S. Environmental Protection Agency. Office of Solid Waste and Emergency Response.
SuperfundEnvironmental Indicator Guidance Human Health Revisions, March 2008.
http://www.epa.gov/superfund/accomp/ei/pdfs/fmal ei guidance march 2008.pdf.
California Environmental Protection Agency. Department of Toxic Substances Control. Interim
Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air,
December 15, 2004 (revised February 7, 2005).
California Environmental Protection Agency. Department of Toxic Substances Control. Vapor
Intrusion Mitigation Advisory. Draft, December 10, 2008.
Interstate Technology Regulatory Council. Vapor Intrusion Pathway: A Practical Guideline.
Technical and Regulatory Guidance, January 2007.
New Jersey Department of Environmental Protection. Vapor Intrusion Guidance, October 2005.
Also see 2009 updates at:
http://www.ni.gOv/dep/srp/guidance/vaporintrusion/whatsnew.htm#20090821.
New York State Department of Health. Center for Environmental Health. Bureau for
Environmental Exposure Investigation. Guidance for Evaluating Soil Vapor Intrusion in the
State of New York, October 2006.
U.S. Air Force, U.S. Navy, U.S. Army. Tri-Services Handbook for the Assessment of the Vapor
Intrusion Pathway. Rev 4.0. Draft Final, February 15, 2008.
11
-------
10-P-0042
Appendix B
OSWER Response to 01G Draft Report
10/29/09
MEMORANDUM
SUBJECT: Response to Draft Evaluation Report: Lack of Final Guidance on Vapor Intrusion
Impedes Efforts to Address Indoor Air Risks (Project No. 2009-0733).
FROM: Mathy Stanislaus /s/
Assistant Administrator
TO: Wade Najjum
Assistant Inspector General
Office of Program Evaluation
Thank you for the draft evaluation report of September 29, 2009, Lack of Final Guidance
on Vapor Intrusion Impedes Efforts to Address Indoor Air Risks (Project No. 2009-0733). In
general, we concur with your recommendations, and we are providing schedules for completing
the various activities. We will seek input from the public on our efforts, and the schedules
reflect this important step.
We appreciate the important role of EPA guidance in addressing risks from vapor
intrusion and understand that final guidance will be beneficial. We also recognize the important
role of our State and Tribal co-regulators who have the authority to establish and enforce
standards in their jurisdiction. Likewise, we believe it is important to acknowledge that the EPA
regions and OSWER program offices have continually taken steps to address risk from vapor
intrusion using draft guidance.
The science and technology associated with evaluating and addressing risk from vapor
intrusion is complex and evolving. A considerable amount of new information has become
available since the draft 2002 OSWER Guidance for Evaluating the Vapor Intrusion to Indoor
Air Pathway from Groundwater and Soil (Subsurface Vapor Intrusion Guidance) EPA 530-D-02-
004 was prepared. We concur with the recommendation (#1) to identify the portions of
OSWER's November 2002 draft vapor intrusion guidance that remain valid and the portions that
may need to be updated. OSWER will release the results of this review by the summer of 2010.
We also concur with the recommendation (#2) to issue final vapor intrusion guidance(s)
that incorporates information on:
• sustainable vapor intrusion mitigation, operations and maintenance, the termination of the
systems, and when institutional controls and deed restrictions are appropriate,
12
-------
10-P-0042
• when, or if, preemptive mitigation is appropriate,
• a recommendation(s) to use multiple lines of evidence in evaluating and making decisions
about risks from vapor intrusion,
• how risks from petroleum hydrocarbon vapors should be addressed,
• updated toxicity values, including TCE and PCE, and
• how the guidance applies to Superfund Five-Year reviews.
In addition to these recommendations, OSWER plans to address other relevant topics
(e.g., monitoring effectiveness of mitigation systems). Multiple guidance documents may be
needed to update parts of the 2002 draft guidance and to address the issues raised in
recommendation #2. We will seek public input early in the development of each document,
interagency review, and external peer review. If multiple documents are developed they will be
released as soon as possible with the final document being completed by the fall of 2012.
We concur with the recommendation (#3) to train EPA and State staff and managers, and
other parties, on the newly updated, revised, and finalized guidance document(s). We also intend
to provide outreach information that is appropriate for individuals that are not environmental
professionals, for example members of the public. We will develop training materials within six
months from the release of the guidance document(s).
We have attached a marked-up version of the draft report with suggestions to improve
technical accuracy. One comment that we would like to highlight is interchangeable use of the
terms toxicity values and exposure levels. We would also like to note that "standards" are
typically considered to be values that have been promulgated and enforceable values. In closing,
we would like thank you again for the draft evaluation report.
Attachment
13
-------
10-P-0042
Appendix C
ORD Response to OIG Draft Report
10/29/09
MEMORANDUM
SUBJECT: ORD Response to Draft OIG Report, Lack of Final Guidance on
Vapor Intrusion Impedes Efforts to Address Indoor Air Risks,
Project No. 2009-0733
FROM: Lek G. Kadeli /s/ Kevin Teichman for
Acting Assistant Administrator (8101R)
TO: Wade Najjum
Assistant Inspector General
Office of Program Evaluation (2460T)
Thank you for the opportunity to comment on the Draft OIG Report, Lack of Final Guidance
on Vapor Intrusion Impedes Efforts to Address Indoor Air Risks, dated September 29, 2009. We
have reviewed the draft report and generally concur with the findings as well as the one
recommendation addressed to our office. Our comments are as follows:
ORD understands the importance of being able to provide updated vapor intrusion guidance
to the public and is moving ahead to complete the Agency's toxicological reviews for the two
compounds identified in subject draft report under Recommendation 4 and enter them into the
IRIS database. Both are high priorities for ORD and are in varying stages of completion.
Predicting schedules for the completion and final posting of the assessments for these
chemicals is difficult due to the variations in duration that may be experienced at different steps
in the development, review and finalization process. Below, we present a synopsis of where the
chemicals are in the review cycle, offer an anticipated completion date for the next milestone in
the process, and projected completion dates.
Trichloroethylene (TCE)
The Interagency Science Consultation on the Draft Toxicological Review of
Trichloroethylene (TCE) was held on Tuesday, September 22, 2009. Comments from the
review are being considered, and it is expected that the draft document will be released for
External Peer Review and public comment in early November 2009. Projected completion
date for TCE is winter 2010.
Tetrachloroethylene (PERC)
The draft Toxicological Review of Tetrachloroethylene /Perchloroethylene(PERC) is
currently undergoing External Peer Review by the National Academy of Sciences (NAS),
and a prepublication draft of their final report is expected in late December 2009.
Publication of the final NAS peer review report is expected by the end of March 2010.
Projected completion date for PERC is summer 2010.
14
-------
10-P-0042
For both chemicals, it is very difficult to predict how long subsequent revisions and editing
of the Toxicological Reviews may take until we understand the nature and extent of the
comments and recommendations made by the reviewers. Finalization dates provided here
represent our current best projection for completing these assessments. Updated schedules for
both of these chemicals and many others are always available on the IRISTrack website at:
https://cfint.rtpnc.epa.gOv/ncea/i ristrac/index.cfrn?fuseaction=listChemicals.showList
Finally, we would like to clarify the purpose of these assessments and the information they
provide. A toxicity assessment for IRIS provides an "inhalation unit risk" or an "oral cancer
slope factor" for cancer that allows the risk to be calculated for various exposure scenarios. For
non-cancer effects, the quantitative aspect is usually represented by a value (a concentration in
air or an oral dose) such that if exposure is continuously below that value it is likely there will be
no appreciable risk of deleterious effects. These toxicity values are not estimates of the current
risk in any particular population because they do not include analysis of current exposure
patterns. These are also not regulatory standards, although they may be used by EPA and others
to decide upon regulatory standards appropriate to various situations. The term "exposure level"
is used in the draft OIG report in several places where the term "toxicity value" should be used:
• In the "At A Glance" summary in the last two paragraphs
• Page 2, last sentence of the first paragraph
• Page 2, second to last paragraph, second sentence
• Page 8, "Conclusions" section, second sentence
• Page 9, Recommendation #4, "exposure levels" should be either "toxicological reviews"
or "toxicity values"
ORD Corrective Action plan for Recommendation 4
Recommendation
Action Official
Corrective Action
Anticipated Completion Date
4. Finalize exposure levels
for TCE and PCE in the
IRIS database.
Assistant Administrator,
Office of Research and
Development
ORD will finalize the
toxicological reviews for
TCE and PCE by
completing the following
steps for each chemical
1. Draft Development
2. Agency Review
3.Interagency Review
4. External Peer Review
5. Final Assessment
TCE-winter 2010
PCE-summer 2010
For both chemicals, it is very
difficult to predict how long
subsequent revisions and
editing of the Toxicological
Reviews may take until we
understand the nature and
extent of the comments and
recommendations made by
the reviewers. Finalization
dates provided here represent
our current best projection for
completing these assessments.
Should you or your staff have questions or require further information, please have them
contact David Bussard at (703) 347-8647.
15
-------
10-P-0042
cc: Kevin Teichman
Donna Vizian
Amy Bataglia
Deborah Heckman
Jorge Rangel
Peter Preuss
Kathleen Deener
Ardra Morgan-Kelly
David Bussard
Gina Perovich
16
-------
10-P-0042
Appendix D
Distribution
Office of the Administrator
Assistant Administrator, Office of Solid Waste and Emergency Response
Acting Assistant Administrator, Office of Research and Development
Regional Administrators, Regions 1-10
Agency Follow-up Official (the CFO)
Agency Follow-up Coordinator
Principal Deputy Assistant Administrator, Office of Solid Waste and Emergency Response
Deputy Assistant Administrator for Science, Office of Research and Development
Acting Deputy Assistant Administrator for Management, Office of Research and Development
General Counsel
Associate Administrator for Congressional and Intergovernmental Relations
Associate Administrator for Public Affairs
Director, Office of Superfund Remediation and Technology Innovation,
Office of Solid Waste and Emergency Response
Deputy Director, Office of Superfund Remediation and Technology Innovation,
Office of Solid Waste and Emergency Response
Director, Office of Resource Conservation and Recovery, Office of Solid Waste and
Emergency Response
Deputy Director, Office of Resource Conservation and Recovery, Office of Solid Waste and
Emergency Response
Director, Office of Brownfields and Land Revitalization, Office of Solid Waste and
Emergency Response
Deputy Director, Office of Brownfields and Land Revitalization, Office of Solid Waste and
Emergency Response
Director, Office of Underground Storage Tanks, Office of Solid Waste and Emergency Response
Director, National Center for Environmental Assessment, Office of Research and Development
Deputy Director, National Center for Environmental Assessment, Office of Research and
Development
Audit Follow-up Coordinator, Office of Solid Waste and Emergency Response
Audit Follow-up Coordinator, Office of Research and Development
Audit Follow-up Coordinators, Regions 1-10
Acting Inspector General
17
------- |