[Federal Register Volume 76, Number 20 (Monday, January 31, 2011)]
[Notices]
[Pages 5370-5373]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-1934]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
[EPA-HQ-SFUND-2010-1086; FRL-9260-1]
Potential Addition of Vapor Intrusion Component to the Hazard
Ranking System
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of Opportunity for Public Input.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (``EPA'') is soliciting
stakeholder input on whether to include a vapor intrusion component to
the Hazard Ranking System (``HRS''). The HRS is the principal mechanism
EPA uses to place sites on the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) National Priorities List
(NPL). This potential addition would allow the HRS to directly consider
the human exposure to contaminants that enter building structures
through the subsurface environment and thus, enabling sites with vapor
intrusion contamination to be evaluated for placement on the NPL. EPA
is accepting public feedback on specific topics related to the
potential HRS revision (see SUPPLEMENTARY INFORMATION section of this
Notice), and will consider information gathered during this comment
period, as well as input from three public listening sessions before
making a decision on whether to issue a proposed rulemaking to add a
vapor intrusion component to the HRS. The Agency is requesting comments
only regarding this potential addition to the HRS. The Agency is not
considering changes to the remainder of the HRS.
DATES: Comments on the topics identified in the SUPPLEMENTARY
INFORMATION section of this notice must be submitted (postmarked) on or
before April 16, 2011.
ADDRESSES: Submit comments on the topics identified in the
SUPPLEMENTARY INFORMATION section of this notice, identified by Docket
ID No. EPA-HQ-SFUND-2010-1086, by one of the following methods:
http://www.regulations.gov: Follow the on-line
instructions for submitting comments.
E-mail: [email protected].
Fax: (202) 566-9744.
Mail: U.S. Environmental Protection Agency; EPA Docket
Center, Superfund Docket, Mail Code 28221T; 1200 Pennsylvania Avenue,
NW., Washington, DC 20460.
Hand Delivery: EPA Docket Center--Public Reading Room; EPA
West Building, Room 3334; 1301 Constitution Avenue, NW., Washington, DC
20004. Such deliveries are only accepted during the Docket's normal
hours of operation, and special arrangements should be made for
deliveries of boxed information.
Listening Session: Oral and written comments on the topics
in the SUPPLEMENTARY INFORMATION section of this Notice will be
accepted at each of the three listening sessions. Follow the
instructions provided on the listening session Web site at http://www.epa.gov/superfund/sites/npl/hrsaddition.htm for preparing written
comments to be submitted at one of the listening sessions.
Instructions: Direct comments on the topics identified in the
SUPPLEMENTARY INFORMATION section of this notice to Docket ID No. EPA-
HQ-SFUND-2010-1086. EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at http://www.regulations.gov, including any personal
information provided, unless the comment includes information claimed
to be Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. Do not submit information
that you consider to be CBI or otherwise protected through http://www.regulations.gov or [email protected]. Note that the http://www.regulations.gov Web site is an ``anonymous access'' system, which
means EPA will not know your identity or contact information unless you
provide it in the body of your comment.
If you send an e-mail comment directly to EPA without going through
http://www.regulations.gov, your e-mail address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the Internet. If you submit an
electronic comment, EPA recommends that you include your name and other
contact information in the body of your comment and along with any disk
or CD-ROM submitted. If EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, EPA may not be
able to consider your comment.
Electronic files should avoid the use of special characters, any
form of encryption, and be free of any defects or viruses. For
additional information about EPA's public docket, visit the EPA Docket
Center homepage at http://www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is
[[Page 5371]]
not publicly available, e.g., CBI or other information whose disclosure
is restricted by statute. Certain other material, such as copyrighted
material, will be publicly available only in hard copy. Publicly
available docket materials are available either electronically in
http://www.regulations.gov or in hard copy at the EPA Docket Center--
Public Reading Room, EPA/DC, EPA West, Room 3334; 1301 Constitution
Ave., NW., Washington, DC. The Public Reading Room is open from 8:30
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is (202) 566-1744, and the
telephone number for the Superfund docket is (202) 566-0276.
FOR FURTHER INFORMATION CONTACT: Terry Jeng, phone: (703) 603-8852, e-
mail: [email protected], Site Assessment and Remedy Decisions Branch,
Assessment and Remediation Division, Office of Superfund Remediation
and Technology Innovation (Mail Code 5204P), U.S. Environmental
Protection Agency, 1200 Pennsylvania Avenue, NW., Washington, DC 20460.
SUPPLEMENTARY INFORMATION: EPA is considering adding a vapor intrusion
component as a new mechanism to the HRS that would enable vapor
intrusion contamination to be included in an HRS evaluation. Presented
below is background information on the HRS, its statutory basis, and
further detail regarding this potential addition and related topics on
which EPA is requesting public comment.
The Agency will conduct public outreach activities, including
facilitating public listening sessions, providing public information
documents, and establishing a Web site with more information regarding
this potential addition to the HRS. The Agency will consider the
information gathered from this Notice, listening sessions, and other
sources before making a decision on whether to issue a proposed
rulemaking to add subsurface contaminant intrusion to the HRS. The
Agency is therefore requesting comments only regarding this potential
addition to the HRS, and is not considering changes to the remainder of
the HRS.
EPA is currently scheduled to hold three listening sessions
following publication of this Notice to allow interested parties to
present feedback on the potential HRS addition. EPA welcomes the input
that will be provided to the Agency by listening session participants.
This input will be considered by the Agency as it determines the need
for and nature of the addition to the HRS.
For those stakeholders who cannot attend one of the listening
sessions, comments on the topics described below in the Potential
Addition of Vapor Intrusion Component to the HRS subsection of this
Notice should be submitted in accordance with the instructions in the
DATES and ADDRESSES sections of this Notice. Written comments will also
be accepted at the listening sessions. Follow the instructions provided
on the listening session Web site at http://www.epa.gov/superfund/sites/npl/hrsaddition.htm for preparing written comments to be
submitted at one of the listening sessions; see also the ADDRESSES
section of this Notice.
In a separate effort, EPA is also preparing a final guidance
document on vapor intrusion that will replace the 2002 Office of Solid
Waste and Emergency Response (OSWER) Draft Guidance for Evaluating the
Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils
(Subsurface Vapor Intrusion Guidance). The guidance document is not
directly related to the potential addition of a vapor intrusion
component to the HRS and more information about this effort will be
provided in a future Federal Register Notice. More information can be
found on EPA's vapor intrusion Web site at http://www.epa.gov/oswer/vaporintrusion/.
Background
Vapor Intrusion
When hazardous substances, pollutants or contaminants are spilled
on the ground or otherwise migrate to the subsurface, they can move in
the subsurface environment and eventually enter buildings as a gas or
vapor, or even as a liquid in some cases. Dry cleaning solvents and
industrial de-greasers are products that contain hazardous substances
that when released to the environment, can migrate into the soil and
subsurface environment, enter buildings by seeping through cracks in
basements, foundations, sewer lines and other openings and ultimately
result in human exposures. Vapor intrusion is of particular concern
because concentrations of vapors can rise to a point where the health
of residents or workers in those buildings could be at risk. Intrusion
of contaminants in a non-vapor state may also be a pathway of concern
because of the potential for human exposure to the liquids, the
resulting precipitates, or associated vapors.
Statutory Basis
In 1980, Congress enacted the Comprehensive Environmental Response,
Compensation, and Liability Act, 42 U.S.C. 9601, et seq. (``CERCLA or
``the Act'') in response to the dangers posed by uncontrolled releases
of hazardous substances, pollutants, or contaminants. Section
105(a)(8)(A) of CERCLA required that the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP) include criteria for
determining priorities among releases or threatened releases for the
purpose of taking remedial or removal action. Criteria were to be based
upon relative risk or danger, taking into account the population at
risk, the hazardous potential of the substances at a facility, the
potential for contamination of drinking water supplies, direct human
contact, destruction of sensitive ecosystems, and other appropriate
factors. Section 105(a)(8)(B) of CERCLA requires that the statutory
criteria described in section 105(a)(8)(A) be used to prepare a list of
national priorities among the known releases, or threatened releases
throughout the United States, and that at least 400 sites be designated
for priority. The list, which is Appendix B of the NCP, is the National
Priorities List (NPL).
To implement CERCLA, EPA promulgated the revised NCP, 40 CFR Part
300, on July 16, 1982 (47 FR 31180) pursuant to section 105 of CERCLA
and Executive Order 12316 (48 FR 42237 August 20, 1981). The NCP,
further revised by EPA on September 16, 1985 (50 FR 37624) and November
20, 1985 (50 FR 47912), sets forth the guidelines and procedures needed
to respond to releases and threatened releases of hazardous substances,
pollutants, or contaminants under CERCLA. The Agency developed the
Hazard Ranking System (``HRS'') to implement Section 105(a)(8)(A). The
HRS was codified as Appendix A of the NCP. The HRS is the primary
mechanism EPA uses to evaluate a site for placement on the NPL.
CERCLA was amended by the Superfund Amendments and Reauthorization
Act (SARA) in 1986. This amendment required the HRS to be revised to
more accurately assess the relative degree of risk to human health and
the environment posed by sites and facilities subject to review.
Revisions to the HRS were proposed in 1988 (53 FR 51962) and
promulgated in 1990 (55 FR 51532). The revisions changed the way EPA
evaluates potential threats to human health and the environment from
hazardous waste sites, as well as
[[Page 5372]]
made the HRS more accurate in assessing relative risk. The revisions
included the addition of the human food chain and recreation threats to
the surface water pathway and the addition of a new exposure pathway
(i.e., soil exposure pathway). CERCLA called for the establishment of
both the NPL and the HRS.
National Priorities List
CERCLA established in Appendix B of the NCP, the NPL, which is also
commonly known as the Superfund List. The NPL is a list of contaminated
sites identified to have known releases or threatened releases of
hazardous substances, pollutants, or contaminants throughout the United
States and its territories. The NPL is intended primarily to guide EPA
in determining which sites warrant further investigation. A site can be
placed on the NPL via three methods (see 40 CFR 300.425(c) of the NCP
for further information):
Achieving a score of 28.50 or greater under the HRS;
Designating by a State or Territory as its top priority
for listing on the NPL (regardless of its HRS score); or
Using the Agency for Toxic Substances and Disease Registry
(ATSDR) listing mechanism (see 40 CFR.300.66(b)(4) of the NCP for
further information).
Rationale for Adding Vapor Intrusion to the Hazard Ranking System
In a May 2010 report (EPA's Estimated Costs to Remediate Existing
Sites Exceed Current Funding Levels, and More Sites are Expected to Be
Added to the National Priorities List, GAO Report to Congressional
Requesters, GAO-10-380, May 2010), the Government Accountability Office
(GAO) 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. GAO
recommended that the EPA Administrator determine the extent to which
EPA will consider vapor intrusion in listing NPL sites and how this
will affect the number of NPL sites listed in the future.
Many sites on the NPL that have subsurface contaminant intrusion
problems were placed on the NPL by evaluation of pathways other than a
contaminant intrusion pathway. There are other contaminated sites,
however, that did not qualify for placement on the NPL under the
current HRS. However, these sites may qualify for placement on the NPL
if the threat from vapor intrusion was included in the HRS. A new HRS
mechanism would enable EPA to identify situations in which individuals
are exposed or potentially exposed to vapor or other contaminant
intrusion in dwellings, work places, or other structures or enclosures.
Hazard Ranking System
The HRS is a screening tool used by EPA to assess the relative
threat that sites with actual or potential contaminant releases pose to
human health or the environment. The HRS is the primary mechanism EPA
uses to place a site on the NPL. (As noted earlier, there are two other
mechanisms that can be used to place sites on the NPL.) The sites on
the NPL are then further investigated to determine the extent of the
threat and whether cleanup of the site under EPA's Superfund Remedial
program is warranted. The HRS is a numerically based screening system
that uses information from initial, limited investigations that can be
collected relatively quickly and inexpensively, thus allowing most
Superfund resources to be directed to remedial actions at sites on the
NPL. The HRS does not provide a risk assessment of a specific site, but
serves as a screening level indicator of the highest priority hazardous
releases or potential releases.
The HRS score is currently based on an evaluation of up to four
separate pathways: ground water migration, soil exposure, surface water
migration, and air migration. Pathways are routes by which exposure to
contaminant releases by human or sensitive environments can occur.
1. The ground water migration pathway evaluates the likelihood that
hazardous substances will travel through the ground below and
contaminate aquifers and drinking water wells that draw on those
aquifers. The groundwater pathway does not consider the potential risk
of exposure to vapor intrusion from contaminated aquifers.
2. The surface water migration pathway evaluates the likelihood
that hazardous substances can enter surface water and affect people or
the environment. Threats to humans from this pathway include drinking
water, the human food chain (i.e., contaminants build up in the aquatic
organisms that humans in turn consume), and sensitive environments.
3. The soil exposure pathway evaluates the potential threats to
humans and terrestrial environments posed by direct, physical contact
with hazardous substances or contaminated soil. This pathway includes
threats to those living on property with hazardous substances or soils
contaminated with hazardous substances, and those living nearby with
access to the property.
4. Finally, the air migration pathway evaluates the likelihood of
release of hazardous substances into the atmosphere and how many people
and sensitive environments could be exposed to hazardous substances
carried in the air, including gases and particulates. The air migration
pathway does not consider indoor air contamination.
The scoring system for each pathway is based on a number of
individual factors associated with risk-related conditions at the site.
These factors are grouped into three categories:
1. Likelihood of exposure (i.e., likelihood that a site has
released or has the potential to release hazardous substances into the
environment).
2. Waste characteristics (i.e., inherent toxicity, mobility of the
substances and the quantity of the hazardous substances that has been
released).
3. Targets (i.e., people or sensitive environments actually or
potentially exposed to the release).
The HRS site score, which ranges from 0 to 100, is obtained by
combining the pathway scores. A site may be scored for one or more of
the pathways depending on the nature of the release. Any site scoring
28.50 or greater is eligible for placement on the NPL. As noted
previously, the HRS score does not represent a specified level of risk,
but is a cutoff point that serves as a screening-level indicator of the
highest priority hazardous releases or potential releases based on the
criteria identified in SARA.
Potential Addition of Vapor Intrusion Component to the HRS
Consistent with CERCLA Section 105 and SARA, the Agency regards it
appropriate to consider amending or adding to the HRS when such
amendments would identify sites of the highest priority for evaluation.
EPA is considering the potential enhancement of the HRS by including a
vapor intrusion component that address issues related to the intrusion
of hazardous substances, pollutants, and contaminants into structures
(e.g., homes, offices, schools, manufacturing facilities). To
comprehensively explore, and if determined appropriate, identify
approaches for adding the threat posed by contaminant vapor intrusion
into occupied structures to the HRS, EPA is beginning the process of
soliciting stakeholder input. To determine whether to move forward with
this addition, and if so, to determine a range of potential approaches,
EPA is
[[Page 5373]]
soliciting input on the topics described below.
1. The level and extent of vapor intrusion contamination that would
warrant evaluation for placement on the NPL, as well as the
identification of screening level information sufficient to perform
this evaluation.
2. Methods for incorporating vapor intrusion into the HRS while, to
the extent possible, maintaining the structure of the other pathways in
the current HRS and retaining that same structure throughout the new
mechanism for vapor intrusion (i.e., likelihood of release, waste
characteristics, and targets). These methods could include the addition
of vapor intrusion as a migration pathway (e.g., groundwater), or part
of an exposure pathway (e.g., threat within a direct exposure pathway
along with soil).
3. Consideration of the importance of evaluating the potential
threat to populations not demonstrated to be exposed to contaminant
intrusion.
4. The identification of sampling procedures available and
practical to detect the presence of contamination due to vapor
intrusion.
5. The availability of screening sampling strategies that can
adequately compensate for the variability in vapor intrusion rates
under different climatic and seasonal conditions.
6. Identification of analytical methods that are sufficiently
precise and accurate to demonstrate a significant increase in
contaminant levels from vapor intrusion.
7. The importance of the threat posed by exposure to contaminant
vapor intrusion via inhalation, dermal contact with the vapors or
condensate on surfaces, and ingestion.
8. The identification of what environmental factors (e.g., porosity
of soil, presence of a contaminated aquifer, climate) and structural
and lifestyle factors (e.g., houses with basements) should
appropriately be considered in determining whether a site warrants
sampling for contaminant vapor intrusion.
9. In addition to residences, schools and other occupied
structures, the identification of structures in which contaminant vapor
intrusion could result in a significant threat to human health (e.g.,
community recreation centers, cultural centers, museums, athletic
facilities).
10. The possible need to consider not only contaminant vapor
intrusion, but also intrusion of contaminants in solid (i.e.,
particulates) and liquid forms.
In addition to these topics, EPA also solicits input on community
outreach methods that would be most effective in gathering and
disseminating information regarding this potential addition to the HRS.
To further support this effort, EPA requests public input on the
identification of possible vapor intrusion sites. This information will
be used for informational purposes only.
EPA will consider all public input when evaluating whether changes
to the HRS are appropriate, and whether to issue a proposed amendment
to the HRS.
Listening Sessions
The first listening session will be held in Arlington, VA on
February 24, 2011. Specific details of the listening sessions,
including dates and locations for the other two sessions, and
instructions for those wishing to present oral comments will be posted
at: http://www.epa.gov/superfund/sites/npl/hrsaddition.htm. At this
site, users will also be able to sign up for a mailing list that will
be used to distribute logistical information on these listening
sessions. Registration is not required to attend a listening session
with the following exceptions.
Due to space limitations, parties interested in presenting oral
comments at the Arlington, VA listening session only, must register for
that session. Registration must be completed at least 3 calendar days
prior to the session. Details for registration will be posted on the
Web at http://www.epa.gov/superfund/sites/npl/hrsaddition.htm. If no
speakers have registered by 2 calendar days prior to this listening
session, it will be cancelled and EPA will notify those registered of
the cancellation. The Agency will also post on its Web site that the
listening session has been cancelled.
In addition to attending in person, participation in the Arlington,
VA listening session will be available via a teleconference. Those
wishing to attend via teleconference must register as described above.
EPA will provide the teleconference information to registrants via e-
mail notification in advance of the session.
The Arlington, VA listening session will be held at EPA's Potomac
Yard office located at: 2777 Crystal Drive, Arlington, VA 22202. The
listening session will begin at 9 a.m. and end at 5 p.m. The Arlington,
VA listening session may be webcast. Please refer to the Superfund
``Addition of Vapor Intrusion to HRS'' Web Site, http://www.epa.gov/superfund/sites/npl/hrsaddition.htm for information on how to access
the webcast. Please note that the webcast is a supplementary public
process provided only for convenience. If difficulties arise resulting
in webcasting outages, the meeting will continue as planned.
In general, each oral comment at listening sessions should be
limited to no more than 15 minutes in length. If, however, there are
more individuals who wish to present comments than the allotted time
for the listening session allows, an announcement will be made at the
beginning of the listening session that the time limit has been
adjusted to allow for the presentation of more comments.
Dated: January 25, 2011.
Mathy Stanislaus,
Assistant Administrator, Office of Solid Waste and Emergency Response.
[FR Doc. 2011-1934 Filed 1-28-11; 8:45 am]
BILLING CODE 6560-50-P