[Federal Register Volume 63, Number 77 (Wednesday, April 22, 1998)]
[Notices]
[Pages 19914-19916]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10720]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6000-9]


Draft Residual Risk Report to Congress

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of document availability and request for comment.

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SUMMARY: This Report to Congress (RTC) was prepared in response to 
section 112(f)(1) of the Clean Air Act (CAA) and provides the 
information requested in section 112(f)(1) and also presents EPA's 
proposed strategy for assessing any risk remaining (residual risk) due 
to the continued emissions of hazardous air pollutants (HAP) from any 
industry source category subject to the maximum achievable control 
technology (MACT) standards required by section 112(d) of the CAA. The 
CAA identified several topics to be addressed: (a) Methods of 
calculating the risk to public health remaining, or likely to remain, 
from sources subject to regulation under section 112(d); (b) the public 
health significance of such estimated remaining risk and the 
technologically and commercially available methods and costs of 
reducing such risk; (c) the actual health effects with respect to 
persons living in the vicinity of sources, any available 
epidemiological or other health studies, risks presented by background 
concentrations of hazardous air pollutants, any uncertainties in risk 
assessment methodology or other health assessment technique, and any 
negative health or environmental consequences to the community of 
efforts to reduce such risks; and (d) recommendations as to legislation 
regarding such remaining risk. Congress directed that this RTC be 
prepared ``after consultation with the Surgeon General and after 
opportunity for public comment.'' This notice of document availability 
is in fulfillment of the requirement to have a time for the public to 
comment on this RTC.

EFFECTIVE DATE: This notice announces a 60-day public comment period 
beginning April 22, 1998.

ADDRESSES: Copies of the draft RTC will be available from the Air and 
Radiation Docket and Information Center (MC-6102), Docket No. A-97-39, 
U.S. Environmental Protection Agency, 401 M Street SW, Room M-1500, 
Washington, DC 20460, telephone (202) 260-7548, between the hours of 
8:00 am and 4:00 pm, Monday through Friday, excluding legal holidays. A 
reasonable fee may be charged for copying. Written comments should be 
submitted to this address. Comments and data may also be submitted 
electronically by following the instructions under SUPPLEMENTARY 
INFORMATION of this notice. No Confidential Business Information (CBI) 
should be submitted electronically.

FOR FURTHER INFORMATION CONTACT: Dennis A. Pagano or Kelly Rimer, 
Office of Air Quality Planning and Standards,

[[Page 19915]]

Air Quality Strategies and Standards Division, Risk and Exposure 
Assessment Group, MD-15, Research Triangle Park, NC 27711, telephone 
(919) 541-0502 or 541-2962.

SUPPLEMENTARY INFORMATION: This RTC is also available electronically by 
accessing the following address: http://www.epa.gov/ttn/oarpg. Comments 
may be made electronically by sending them to EPA at: A-and-R-
D[email protected]. Electronic comments must be submitted as an 
ASCII file avoiding the use of special characters and any form of 
encryption. Comments and data will also be accepted on disks in 
WordPerfect 6.1 file or ASCII file format. All comments and data in 
electronic form must be identified by the Docket No. A-97-39. 
Electronic comments on this draft RTC may be filed online at many 
Federal Depository Libraries.

Background

    This RTC responds to the statutory directives in section 112(f) of 
the CAA and also provides EPA's strategy for assessing residual risk 
remaining from the HAP being emitted from source categories subject to 
MACT standards. Chapter 2 provides a brief legislative and regulatory 
background on the CAA air toxics program in order to provide context 
for what follows. Chapter 2 also provides a short history of the 
development of risk-based programs and of risk assessment as the 
primary tool used by EPA to analyze the potential impacts of air toxics 
emissions on the exposed population and environment. As discussed in 
Section 2.3 of the RTC, the development of EPA's risk-based program for 
air toxics has incorporated input from the National Research Council, 
the Commission on Risk Assessment and Risk Management, State and local 
air toxics programs, and a variety of risk assessment policies and 
guidelines developed (and in some cases under development) by EPA. The 
RTC then addresses, in Chapters 3 and 4, the required statutory 
elements, as shown in the text box on page 1 of the RTC. Chapter 3 
provides information on the methods for conducting human and ecological 
risk assessments for emissions of air toxics, describes the data 
required, and the methods for evaluating mixtures. Chapter 4 addresses 
the remaining statutory elements listed in CAA section 112(f)(1) (B), 
(C), and (D) in the order listed in the CAA. In Chapter 5, the RTC 
describes EPA's strategy to conduct residual risk analyses, as well as 
discuss other provisions in section 112(f) (2) through (6) of the CAA.
    The intent of this RTC is to address the legislative requirements 
of section 112(f)(1) and to provide the reader with a basic 
understanding of how EPA will conduct its risk analyses and make 
decisions concerning these risk assessments. The methodology 
descriptions provided are not presented as strict guidance but are 
discussed with enough detail to inform the reader of EPA's intentions 
and directions in implementing the ``residual risk'' analyses. The EPA 
prefers to be flexible in this process so that as changes are made in 
the way risk assessments are done, they may be incorporated as needed.
    It is important to note that this RTC does not contain the results 
of any residual risk analyses or information on EPA's potential actions 
after conducting such analyses. The EPA is currently collecting 
existing data on source categories for which MACT standards have been 
promulgated and will begin analyzing these data using the proposed 
strategy.
    Congress also requested EPA to report on additional elements 
related to residual risk. This RTC describes EPA's proposals for 
considering these elements as they apply to residual risk assessments.
     Public Health Significance: This RTC presents EPA's plan 
to use the benzene NESHAP framework (54 FR 38044, September 14, 1989) 
which provides a 2-step decision process, as a gauge of significance 
for the purposes of making regulatory decisions under the residual risk 
program. This RTC also describes when the benzene framework will be 
applied. In this context, the RTC states clearly that the benzene 
framework does not address noncancer effects nor does it address 
carcinogens for which a ``margin of exposure'' type of analysis is the 
more appropriate method to use in determining the level of concern. For 
these latter two types of effects, the RTC states that EPA is in the 
process of developing these decision frameworks, and that they will not 
be developed in time to be included in this RTC.
    The EPA is also mandated to address ecological effects. Currently 
there are no policies in place for considering them in air management 
decisions. The EPA is developing guidance for making these risk 
management decisions, but they will not be developed in time to be 
incorporated into this RTC.
     Technologically and Commercially Available Methods and 
Costs: The EPA presents a range of control options if it is determined 
that additional control is needed to reduce residual risks. This RTC 
provides an overview of these options with an emphasis on pollution 
prevention approaches.
     Actual Health Effects Information: The information 
available on actual health effects resulting from exposure to air 
toxics is very limited. This RTC presents a summary discussion of 
epidemiological data, laboratory data, and other exposure study data. 
It also briefly describes how EPA intends to use these data and any 
actual source category-specific health effects data that may become 
available when residual risk assessments are conducted.
     Background Concentrations: This RTC discusses general 
information on background levels of HAP, including EPA's cumulative 
risk policy which is under development, and presents a definition of 
background concentrations for air toxics and residual risk purposes. It 
describes approaches used by other EPA programs and includes examples 
of rules and guidance that consider the issue of background. It also 
presents a discussion of the difficulties in addressing background 
concentrations in residual risk analyses and identifies data needs to 
assess background. The discussion concludes by describing the EPA's 
options to analyze and consider background concentrations in residual 
risk analyses.
     Negative Health or Environmental Consequences to 
Communities: The EPA interprets this requirement to mean that any risk 
management options for reducing residual risks must consider other 
possible health consequences to the community resulting from those 
decisions. The EPA is aware that pollution control technologies 
targeted at a single pollutant (e.g., a specific HAP) and single medium 
(e.g., air), especially conventional end-of-the-pipe treatment 
technologies, can inadvertently transfer pollutants and risks to 
different media, different locations, and different receptors, and can 
unintentionally create new and different risks in the process of 
controlling the targeted risk. Thus, EPA intends, as it conducts its 
residual risk analyses and any subsequent standard-setting actions, to 
identify potential negative health and environmental consequences when 
possible and consider the risk-risk tradeoffs associated with any 
standards established under the residual risk program.
     Legislative Recommendations: Congress required EPA to make 
``legislative recommendations regarding any identified residual risk.'' 
The EPA has interpreted this congressional requirement to mean that if 
an unacceptable residual risk were identified, and no current authority

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within the CAA were determined to be adequate to reduce that risk, then 
EPA would propose an approach that would assure that risk reductions 
would occur. The EPA believes that the regulatory approach embodied in 
the CAA is adequate for maintaining the goal of protecting the public 
and environment's health, and, therefore, is not proposing any 
legislative changes.
    The EPA is requesting comment on this draft RTC with a special 
emphasis on the sections discussed above, i.e., the public health 
significance, technologically and commercially available methods and 
costs, the actual health effects, the background concentration, and the 
negative health or environmental consequences sections.

Peer Review

    The EPA is fully committed to environmental protection that is 
founded on sound and credible science. Objective, independent peer 
review of the scientific and technical bases of the Agency's actions is 
critical to accomplishing the Agency's mission. The Agency's commitment 
to credible, effective peer review is stated in the Peer Review Policy 
of June 7, 1994. Full implementation of that policy remains an Agency 
priority.
    Most of the major references that form the foundation of this RTC 
have undergone (or are currently undergoing) external peer review. In 
addition, EPA intends to have this RTC peer reviewed during the public 
comment period because it outlines specific applications for the 
methods and policies contained in these references. For example, the 
EPA believes that it is necessary to obtain an independent evaluation 
of questions, such as whether the RTC identifies the most relevant and 
useful methods of assessing risks from stationary sources and whether 
it properly characterizes the types of data on which these methods 
rely. The results of this peer review will be incorporated into the 
final RTC.

    Dated: April 14, 1998.
Richard D. Wilson,
Acting Assistant Administrator for Air and Radiation.
[FR Doc. 98-10720 Filed 4-21-98; 8:45 am]
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