[Federal Register Volume 63, Number 177 (Monday, September 14, 1998)]
[Notices]
[Pages 49240-49258]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24335]


      

[[Page 49239]]

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Part III





Environmental Protection Agency





_______________________________________________________________________



Draft Integrated Urban Air Toxics Strategy To Comply With Section 
112(d), 112(c)(3) and Section 202(l) of the Clean Air Act; Notice

  Federal Register / Vol. 63, No. 177 / Monday, September 14, 1998 / 
Notices  

[[Page 49240]]



ENVIRONMENTAL PROTECTION AGENCY

[FRL-6157-2; Docket No. A-97-44]


Draft Integrated Urban Air Toxics Strategy To Comply With Section 
112(k), 112(c)(3) and section 202(l) of the Clean Air Act

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: This notice provides a draft strategy for public comment to 
address health impacts from air toxics in urban areas. The strategy 
includes a draft list of 33 hazardous air pollutants (HAP) judged to 
pose the greatest potential threat to public health in the largest 
number of urban areas, based on available information. Thirty of these 
HAP are from area sources. It also provides a draft list of area source 
categories to be listed for regulation under section 112(d) of the 
Clean Air Act (Act). The draft strategy also provides a schedule for 
specific actions to address risk from air toxics in urban locations. 
This draft strategy is being developed as required in section 112(k) 
and 112(c)(3) and section 202(l) of the Act, as amended in 1990, and a 
consent decree entered in Sierra Club v. Browner, Civ. No. 95-1747 
(D.D.C. 1995) (consolidated with Sierra Club v. Browner, Civ. No. 96-
436 (D.D.C. 1996)). Even though the draft strategy identifies source 
categories for which additional standards under section 112(d) may be 
developed, the strategy by itself does not automatically result in 
regulation or control of emissions from sources within these source 
categories. The EPA will perform further analyses of HAP emissions, 
control methods for the listed source categories, and health impacts as 
appropriate, for stationary and mobile sources. These analyses will 
determine the ultimate regulatory requirements, if any, which may be 
developed under the strategy.

DATES: A draft and final strategy, including HAP and source category 
lists, are required under the consent decree to be completed and made 
available by August 31, 1998 and June 18, 1999, respectively. Written 
comments on this draft must be received by November 30, 1998. We will 
hold four stake-holder meetings on this draft. The first will be at 
Radisson Plaza Hotel at Mark Center, 5000 Seminary Road, in Alexandria, 
VA on September 23, 1998. The second at the Durham Marriott at the 
Civic Center, 201 Foster Street, Durham, NC on September 29, 1998, the 
third, in Chicago, Illinois at Hyatt Regency Chicago, 151 East Wacker 
Drive, Chicago, IL 60601 on November 5 and 6, 1998, and the final at 
Cathedral Hill Hotel, 1101 Van Ness Avenue, in San Francisco, 
California 94109, on November 19, 1998. Persons wishing to present oral 
comments pertaining to this notice should contact EPA at the address 
listed below.

ADDRESSES: A docket containing information relating to the development 
of this notice (Docket No. A-97-44) is available for public inspection 
and copying between 8:00 a.m. and 5:30 p.m., Monday through Friday 
except for Federal holidays, in the Air and Radiation Docket and 
Information Center (MC-6102), Room M-1500, U.S. Environmental 
Protection Agency, 401 M Street, SW, Washington, DC 20460; telephone 
(202) 260-7548. A reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT: Laura McKelvey, Office of Air Quality 
Planning and Standards (MD-15), U.S. Environmental Protection Agency, 
Research Triangle Park, North Carolina, 27711, telephone number (919) 
541-5497, electronic mail address: McKelvey.L[email protected].

SUPPLEMENTARY INFORMATION:
    Docket. The docket is an organized and complete file of all the 
information submitted to or otherwise considered by the Agency in the 
development of the Draft Urban Air Toxic Strategy. The principal 
purpose of this docket is to allow interested parties to identify and 
locate documents that serve as a record of the process engaged in by 
the Agency to publish today's notice. The docket is available for 
public inspection at the EPA's Air and Radiation Docket and Information 
Center, which is listed in the addresses section of this notice.
    In compliance with President Clinton's June 1, 1998 Executive 
Memorandum on Plain Language in government writing, this package is 
written using plain language. Thus, the use of ``we'' in this package 
refers to EPA. The use of ``you'' refers to the reader and may include 
industry, State and local agencies, environmental groups and other 
interested individuals.
    The information in this notice is organized as follows:

I. Introduction
II. List of Pollutants, Effects and Sources
III. Plan for Area Sources (section 112(k))
IV. Near-term Actions to Implement the Strategy
V. Longer-term Plans and Activities to Implement the Strategy for 
all Sources of Air Toxics
VI. How EPA will Communicate with the Public on Progress in Meeting 
the Strategy's Goals
VII. Regulatory Requirements

I. Introduction

    We have made considerable progress since the passage of the Clean 
Air Act Amendments of 1990 in improving air quality for all Americans 
by reducing air toxics 1 emissions through regulatory, 
voluntary and other programs. To date, we have focused mainly on 
substantially reducing emissions of toxic air pollutants entering the 
environment, primarily by setting standards for major industrial 
sources and mobile sources. These reductions are only part of the 
solution to protecting public health and the environment from toxic air 
pollutants. In addition to lowering overall emissions of these toxic 
pollutants, we need to develop focused strategies to combat problems of 
particular concern. As we continue to develop the national air toxics 
program, and planned research yields improved data on health risks, we 
envision making increased use of risk information in setting priorities 
and measuring progress.
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    \1\ Our use of the terms ``air toxics'' or ``toxic air 
pollutants'' in this notice refers specifically to those pollutants 
which are listed under CAA section 112(b) as ``hazardous air 
pollutants'' or HAP.
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    As discussed in more detail in section II.B. current information 
shows that some of the greatest health risks affecting the most people 
are in urban areas. This Federal Register notice presents our draft 
strategy to address the problem of urban air toxics, considering major 
industrial sources, smaller ``area'' sources and mobile sources. The 
Act requires us to develop a strategy for reducing urban air toxics by 
focusing on area sources. However, these sources are not the only 
contributors to toxic air pollutants in urban areas and are not the 
only sources of concern to the public. Therefore, in addition to 
satisfying our statutory obligation to address the threats presented by 
emissions from area sources, we intend to devise a broad strategy for 
reducing risks posed by air toxics from all sources. Different types of 
sources emit the same pollutants; and especially in urban areas, there 
are many sources emitting multiple pollutants. As part of our overall 
plan to target risk reductions, our draft strategy addresses the 
problems of cumulative exposures from air toxics through an integrated 
approach that considers all sources.
    In developing the urban strategy, we make use of the best available 
scientific information providing insight into health risks from 
hazardous air pollutants. Based on this information, we have suggested 
priorities for the urban air toxics program. Our aim is to achieve the 
greatest reductions in risk

[[Page 49241]]

for the largest number of Americans, in an expeditious manner. In 
addition, we intend to address cases in which specific groups of 
individuals, such as low-income communities and children, may be 
exposed to disproportionately higher risks. Available information in 
many cases is not sufficient to quantify health risks from air toxics; 
there are significant gaps and uncertainties. However, section 112 
generally provides a framework requiring the Nation to (1) move ahead 
to reduce emissions through standards under section 112(d) or section 
129, initially reducing health threats from urban air toxics, while (2) 
conducting further research to address uncertainties and improve 
information on risks under section 112(f), 112(k) and 112(m) in order 
to then act to address the remaining identified risk.
    In this introduction, we present a brief overview of the air toxics 
problem, actions that we have taken to reduce emissions, and our 
overall strategy for dealing with urban air toxics. We view this draft 
strategy as a starting point. We welcome public comment and will meet 
with various stakeholders, including direct dialogues with community 
groups such as environmental justice communities, to develop this 
approach further before the final strategy is issued in June 1999.

A. What is the air toxics situation?

    There are currently 188 HAP regulated under the Clean Air Act that 
have been associated with a wide variety of adverse health effects, 
including cancer, neurological effects, reproductive effects and 
developmental effects.2 We estimate that approximately 4.4 
million tons (or 8.8 billion pounds) of HAP were released in the United 
States in 1990, declining to 3.7 million tons in 1993 (Second Report to 
Congress on the Status of the Pollution Program under the Clean Air 
Act, October 1997). In total, we have issued 25 maximum achievable 
control technology (MACT) and two section 129 standards, achieving 
estimated emission reductions of approximately 1 million tons once 
these standards are fully implemented.
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    \2\ Section 112(b) of the Act lists 189 hazardous air pollutants 
(HAP). One of the HAP, caprolactam, was subsequently delisted.
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    We categorize anthropogenic sources of air toxics into three broad 
types: (1) major stationary sources, which are sources that emit more 
that 10 tons per year of any one HAP or 25 tons per year of a 
combination of HAP, such as chemical plants, oil refineries, aerospace 
manufacturers and steel mills; (2) area sources, which are smaller 
sources of air toxics which emit less than 10 tons per year of any one 
HAP or less than 25 tons per year of a combination of HAP, such as 
drycleaners, solvent cleaning industries and secondary lead smelters; 
and (3) mobile sources, which include cars, trucks and off-road 
engines. According to 1993 data, on a national basis, 24 percent or 
about 890 thousand tons of air toxics were emitted by major sources, 34 
percent or about 1.26 million tons, were emitted by area sources, and 
42 percent, or about 1.55 million tons, came from mobile sources (see 
emissions inventory report in docket).
    In urban areas, toxic air pollutants pose special threats because 
of the concentration of people and sources of emissions. While threats 
posed by some pollutants may be fairly common across the country, 
studies in a number of urban areas indicate that threats posed by 
others vary significantly from one urban area to the next. We are 
concerned that because minority and low income communities are often 
located close to urban industrial and commercial areas where ambient 
concentrations of HAP may be greater, their risks of exposure to HAP at 
levels above acceptable health bench marks may be disproportionately 
higher than for other segments of the population. Through this study, 
we intend to collect and evaluate additional information needed to 
determine the extent to which there may be disproportionate risks for 
these communities in urban areas.
    In order to fully understand the air toxics problem, we must 
understand the level of the pollution to which people are exposed. In 
order to do this, we would like to know the concentrations of all HAP 
as measured by ambient air monitors. However, the monitoring data are 
scarce and limited. Consequently, we estimate pollution concentrations 
through the use of models, relying on emissions measurements or 
estimates.

B. What are we doing to address air toxics?

    In amending the Act in 1990, Congress required us to establish 
national emission standards for stationary sources of air toxics and to 
study a number of air toxics problems to determine whether additional 
reductions are needed. These emission standards are known as maximum 
achievable control technology, or MACT standards, and generally 
available control technology, or GACT standards. We have promulgated 
standards for the first 47 of 174 source categories, which will reduce 
air toxics emissions by approximately 980,000 tons per year. Within the 
next 10 years, as we complete more MACT standards, the air toxics 
program is estimated to reduce emissions of toxic air pollutants by 
well over 1.5 million tons per year (Second Report to Congress on the 
Status of the Hazardous Air Pollutant Program Under the Clean Air Act, 
October 1997).
    We have also established mobile source evaporative and exhaust 
emission standards, as well as fuel standards, which are greatly 
reducing the amount of air toxics coming from motor vehicles. Between 
1995 and 2000, highway vehicle emissions of benzene, 1,3-butadiene, and 
directly emitted formaldehyde will be reduced by about 40,000 tons per 
year. Toxic emissions from non-road sources will also be reduced in 
this period. Calculations and analyses which will improve our ability 
to project the impact of planned mobile source standards are currently 
in progress.
    Congress instructed us to develop a strategy for air toxics in 
urban areas, emphasizing actions to address the large number of 
smaller, area stationary sources. Section 112(k)(1) states:

    The Congress finds that emissions of hazardous air pollutants 
from area sources may individually, or in the aggregate, present 
significant risks to the public health in urban areas. Considering 
the large number of persons exposed and the risks of carcinogenic 
and other adverse health effects from hazardous air pollutants, 
ambient concentrations characteristic of large urban areas should be 
reduced to levels substantially below those currently experienced * 
* *.

    In particular, section 112(c)(3) and 112(k) instruct us to:
     Develop a research program on air toxics, including 
research on the health effects of the urban HAP, monitoring and 
modeling improvements to better identify and address risk in urban 
areas;
     Identify at least 30 HAP from area sources in urban areas 
that present ``the greatest threat to public health;''
     Identify the area source categories or subcategories 
emitting the 30 HAP and assure that 90 percent or more of the aggregate 
emissions are subject to standards under subsection (d);
     Provide a schedule for activities to substantially reduce 
risks to public health (including a 75 percent reduction in cancer risk 
attributable to 1990 exposures to HAP emitted by all stationary 
sources) using all EPA and State/local authorities;
     Implement the strategy and achieve compliance with all 
requirements within 9 years of enactment;
     Encourage and support State/local programs in reducing 
risks within individual urban areas; and

[[Page 49242]]

     Provide a Report to Congress at intervals not later than 8 
and 12 years after enactment, on actions taken to reduce the risks to 
the public health.
    In addition, section 202(l) of the Act requires that we:
     Study the need for and feasibility of controlling 
emissions of toxic air pollutants associated with mobile sources; and
     Promulgate regulations containing reasonable requirements 
to control HAP from motor vehicles or motor vehicle fuels.
    In September of 1995, the Sierra Club filed suit against EPA 
alleging that we failed to promulgate regulations to control HAP from 
motor vehicles and motor vehicle fuels within the deadlines required 
under section 202(l)(2). Subsequently, in March 1996, the Sierra Club 
filed another suit alleging that we failed to issue the source category 
list under section 112(c) and the strategy under section 112(k) by 
their respective deadlines. These were initially separate suits but we 
agreed to address both of these requirements as part of a consolidated 
consent decree (Defendant's Motion to Consolidate, Sierra Club v. 
Browner, (D.D.C. 1996)(N0.99-1747)).
    To address the problem of exposure to air toxics in urban areas and 
to fulfill our obligations under the consent decree, we intend to 
implement an integrated urban air toxics strategy that addresses the 
urban air toxics risks from both stationary and mobile sources. This 
strategy is expected to produce a set of actions that will be more 
responsive to the cumulative risks presented by multiple sources of 
toxics and combined exposures to multiple toxics. We believe that by 
considering urban air toxics emissions from all sources, we will better 
respond to the relative risks posed by any one pollutant and/or source 
category. Thus, integration of the activities under both sections of 
the Act will more realistically address the total exposure and will 
better allow us and the States to develop activities to address risks 
posed by toxic pollutants where the emissions and risks are most 
significant and controls are most cost effective.
    As discussed previously, we have a number of Act requirements to 
address. For instance, section 112(k)(3)(B)(ii) and 112(c)(3) require 
us to list and regulate area source categories accounting for 90 
percent of the aggregate emissions of the 30 HAP identified under 
section 112(k)(3)(B)(i). Promulgating these standards is an important 
initial step in the strategy to reduce emissions. However, a separate 
but equally important requirement of section 112(k)(3)(C) requires us 
to substantially reduce the public health risk posed by exposure to 
HAP, including a 75 percent reduction in cancer incidence. It is 
important to recognize that even though they are linked, because 
emissions reductions achieved through standards required under section 
112(k)(3)(B)(ii) will help in achieving the risk goals under 
112(k)(3)(C), they are two separate requirements. There are also some 
important differences between the requirements. For example, section 
112(k)(3)(B)(ii) is limited to emission standards for area source 
categories emitting the 30 section 112(k) HAP, whereas, section 
112(k)(3)(C) refers more broadly to reducing risk from all HAP emitted 
by all stationary sources. In addition, standards addressing section 
112(k)(3)(B)(ii) must be set under the authority of section 112(d), 
whereas the risk reductions to address section 112(k)(3)(C) can be 
achieved more flexibly using any of Administrator's authorities under 
the Act or other statutes, or those of the States.

C. What is our strategy for addressing urban air toxics?

    Today's notice presents our draft strategy for addressing urban air 
toxics on a national level and for working with State and local 
governments to reduce air toxics risks in our communities. The primary 
goal of this strategy is to substantially reduce public health risks 
from air toxics. The basic framework of our strategy is to:
    1. Define the air toxics threat for urban areas from a cumulative 
perspective, considering major, area and mobile sources.
    Our implementation of the toxics provisions of the 1990 Amendments 
to date has focused on setting technology-based emissions standards for 
individual source categories and, separately, developing fuel and 
vehicle standards for mobile sources. While we have achieved 
significant toxics emissions reductions, including reductions in urban 
areas, we believe that a focused urban strategy is needed to address 
the ``urban soup'' of multiple toxic pollutants emitted by multiple 
sources. In this strategy, we have looked at the contribution from all 
sources of air toxics to develop a draft list of the relatively worst 
HAP in urban areas. This list of HAP is provided and discussed in 
Section II. We plan to use our range of authorities under the Act to 
address these problems in the most effective way possible.
    2. Improve our understanding of the risks from air toxics in urban 
areas.
    This draft strategy presents our first steps to characterize 
``urban soup'' or the cumulative problem of air toxics in urban areas 
and describe how risk can be reduced. As described in more detail in 
Section II of this notice, we have analyzed the most significant HAP in 
urban areas based on the best available data, including emissions and 
toxicity information. To understand the risks from air toxics more 
fully, however, we must address significant data gaps. For example, we 
have limited information on human health effects associated with many 
of the HAP, the extent to which people are exposed to air toxics in 
urban areas, and the effect of exposure to multiple pollutants. We will 
be providing a brief discussion of our research needs in Section V.
    3. Reduce risks from urban air toxics through near- and longer-term 
actions.
    In addition to the research and other efforts planned to improve 
our understanding of air toxics risks, we are suggesting specific 
actions that will help achieve emissions reductions in the near-term 
and longer-term. For example, as part of our statutory requirements, we 
will be proposing air toxics standards for motor vehicles and motor 
vehicle fuels, and will begin to develop area source standards by the 
end of 1999. From 2002 to 2006, we will issue emissions standards for 
these area sources that contribute significantly to emissions of urban 
air toxics. In the longer-term, we could also use our residual risk 
authority to address major sources that are already subject to 
regulation, but which continue to pose substantial risks to urban 
areas. More information on these and other actions is found in Section 
IV.
    4. Work with State and local governments on developing urban 
strategies for their communities.
    This draft strategy provides a national picture of air toxics in 
urban areas, suggests a number of actions that we could take to reduce 
toxics emissions, and discusses ways to involve State and local 
governments to address toxics risks on the local level. We anticipate 
that State and local measures, as well as Federal measures, will be 
needed to reduce urban air toxics risks. Urban areas can differ greatly 
in terms of air toxics, sources and meteorology. In addition, State and 
local programs to address air toxics vary widely; and we recognize that 
many States have successfully operated many programs to reduce air 
toxic emissions at the State or local levels. Consequently, we intend 
to seek collaborative relationships with State and local agencies, 
minority and economically disadvantaged communities, and affected 
industries to

[[Page 49243]]

assure our actions are responsive to health concerns while promoting 
environmental justice, encouraging urban redevelopment, and minimizing 
regulatory burdens. We will further encourage and provide enhanced 
technical assistance to these States' efforts and will be seeking ways 
to expand opportunities for flexible and effective State and local 
actions to address risks in more geographically-specific ways.
    In this notice, we are suggesting a broad framework for addressing 
urban air toxics with some specific actions to reduce emissions and to 
improve our understanding of risks posed by air toxics. We will work 
over the next several months with various stakeholder groups, including 
States, local governments, industry representatives, small businesses, 
local health officials and environmental groups to refine this 
strategy. In addition, through our Regional Offices, we hope to reach 
out to community groups that have not traditionally participated in 
these efforts but who may be disproportionately affected by air toxics.

D. What are the components of this Federal Register Notice?

    This draft strategy for urban air toxics presents our analysis of 
the HAP posing the greatest threats to public health in urban areas, 
near- and longer-term actions to address air toxics risks, and a 
discussion on developing State and local programs. More specifically:
     Section II discusses the health threats posed by air 
toxics, describes our emissions inventory and our methodology for 
identifying the HAP estimated to pose the greatest threats to public 
health in urban areas (based on current information on 1990 
conditions), and identifies 33 HAP from all emissions sectors.
     Section III focuses on how we are planning to address air 
toxics from area sources, as required by section 112(c) and (k), 
including a draft list of 34 categories or subcategories of area 
sources that account for 90 percent of the emissions of the worst HAP 
in urban areas, and that will be subject to additional standards.
     Section IV discusses our near-term actions to address 
urban air toxics. These include evaluating the need and feasibility for 
fuels and vehicle standards, developing area source standards, 
reviewing and expanding monitoring networks, developing modeling tools 
for national and local scale risk assessments, and beginning to work 
with State and local governments to set up air toxic programs. It also 
provides information on what EPA and State programs are currently doing 
to reduce risks.
     Section V describes our longer-term activities to address 
air toxics risks in urban areas, including residual risk standards, 
additional stationary source standards, and possible State program 
actions. It also discusses our research strategy to characterize risks 
and to measure progress toward the risks reduction goals of the 
strategy.

II. List of Pollutants, their Effects and Sources

A. General Overview

    This section provides further discussion of what air toxics are and 
what concerns they present, and describes how we evaluated and selected 
a draft list of HAP to guide our actions under the strategy. It 
includes descriptions of our emissions inventory and our methodology 
for identifying the HAP estimated to pose the greatest threats to 
public health in urban areas.
    In brief, we evaluated the health effects information available for 
the 188 HAP, estimated emissions from all known sources using a variety 
of techniques, assessed available air quality monitoring data, reviewed 
existing studies, and produced a list of pollutants based on the 
relative hazards they pose in urban areas when considering toxicity, 
emissions and related characteristics. From this effort, we were able 
to establish a list of HAP which we believe to pose the greatest 
threats to public health in urban areas, considering emissions from 
major stationary, area and mobile sources.

B. What are Air Toxics and what threats do they present to public 
health?

    Toxic air pollutants include a wide variety of organic and 
inorganic substances released from industrial operations (both large 
and small), fossil fuel combustion, gasoline and diesel-powered 
vehicles, and many other sources. The Act as amended in 1990 identifies 
188 toxic chemicals as HAP. Major categories of toxic air pollutants 
include volatile organic compounds, known as VOC, metals and inorganic 
chemicals, and semi-volatile organic chemicals. Volatile chemicals are 
usually released into the air as vapor, while semi-volatile organics 
and metals may be released in the form of particles.
    The HAP have the potential to cause various types of harm under 
certain circumstances of exposure (e.g., depending on the amount of 
chemical, the length of time exposed, the stage in life of person 
exposed). We have classified many as ``known,'' ``probable,'' or 
``possible'' human carcinogens and have included this information in 
EPA's Integrated Risk Information System.3 The HAP can also 
be described with regard to the part of the human body to which they 
pose threats of harm. For example, neurotoxic pollutants cause harm to 
the nervous system. The severity of harm, however, can range from 
headaches and nausea to respiratory arrest and death. The level of 
severity differs both with the amount and length of exposure and the 
chemical itself (i.e., how it interacts with individual components of 
the nervous system). Some chemicals pose particular hazards to people 
of a certain age or stage in life. For example, some HAP are 
developmentally toxic. That is, exposure to certain amounts of these 
chemicals during the development of a fetus or young child can prevent 
normal development into a healthy adult. Other HAP are reproductive 
toxicants, meaning that they may have the potential to affect the 
ability of adults to conceive or give birth.
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    \3\ The Integrated Risk Information System (IRIS), prepared and 
maintained by the U.S. Environmental Protection Agency (U.S. EPA), 
is an electronic data base containing information on human health 
effects that may result from exposure to various chemicals in the 
environment. IRIS was initially developed for EPA staff in response 
to a growing demand for consistent information on chemical 
substances for use in risk assessments, decision-making and 
regulatory activities. The information in IRIS is intended for those 
without extensive training in toxicology, but with some knowledge of 
health sciences. Further information about IRIS, including the 
information it contains, can be found on the IRIS web site at http:/
/www.epa.gov/iris.
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    In a recent effort to characterize the magnitude, extent and 
significance of airborne HAP in the U.S. (as part of EPA's Cumulative 
Exposure Project or CEP), computer modeling was used to estimate 
outdoor concentrations nationwide using a 1990 national emissions 
inventory compiled for 148 pollutants from major area and mobile 
sources (Woodruff et al., 1998). The estimated outdoor concentrations 
for 119 HAP were compared to health-based benchmarks. The benchmarks 
for potential cancer effects were set at HAP concentrations which, if 
experienced throughout a lifetime, are predicted to be associated with 
an upper bound excess cancer risk of 1-in-1 million. The benchmarks for 
potential health effects other than cancer were set at exposure 
concentrations for each HAP which, if experienced over a lifetime, are 
considered to have no significant risk of adverse noncancer effects. 
The study looked at more than 60,000 census tracts in the continental 
U.S. Census tracts vary in size but typically contain a population of 
approximately 4,000.

[[Page 49244]]

    It is very important to understand that this modeling estimates 
annual average outdoor concentrations for 1990 and does not incorporate 
other aspects of exposure modeling, such as differences in 
concentrations in various micro environments, indoor air and 
individuals' commuting patterns. Thus, the study did not attempt to 
estimate the number of people who might be exposed to these estimated 
concentrations of HAP, nor the frequency or duration of such exposures. 
For this reason, results should be viewed as an indicator of potential 
hazard and not as a characterization of actual risk. This effort 
suggests that HAP exposures are prevalent nationwide; and for some HAP 
in some locations, the concentrations are significant. Concentrations 
of eight 4 HAP appear to be greater than their lifetime 
excess cancer risk-based benchmarks (10-6 lifetime 
individual excess cancer risk) in all of the census tracts, primarily 
because of background concentrations (i.e., airborne levels occurring 
as a result of long-range transport, resuspension of historic emissions 
and natural sources), not just from localized current anthropogenic 
emissions. Current anthropogenic emissions, however, appear to 
contribute to concentrations of at least two HAP (benzene and 
formaldehyde) above the associated benchmark in up to 90 percent of the 
census tracts. Further, there are 28 HAP for which estimated 
concentrations were greater than the associated benchmark in a larger 
number proportion of urban areas than rural areas. In a much smaller 
number of locations, concentrations of certain HAP were estimated to be 
more than a factor of 100 greater than the corresponding cancer and 
noncancer based benchmark.
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    \4\ These HAP include: benzene, carbon tetrachloride, 
chloroform, ethylene dibromide, ethylene dichloride, formaldehyde, 
methyl chloride, and bis(2-ethylhexyl)phthalate.
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    We conclude from this analysis that for certain HAP, concentrations 
of potential concern are common in all census tracts. Additionally, 
there is a subset of the HAP at levels of potential concern in more 
urban than in rural areas. This project has highlighted many of the HAP 
on which we will be focusing our attention in the urban air toxics 
strategy.

C. How did EPA Identify the Priority HAP?

    In this section, we present our analysis of what HAP we consider to 
pose the greatest threat to public health in urban areas as of 1990. 
Although we have limited information on risks, we used the best 
available data on air toxics: (1) the National Toxics Inventory, which 
provides emissions data on the 188 HAP, combined with information on 
toxicity to determine the relative hazard among HAP; (2) monitoring 
data available from the Aerometric Information Retrieval System and our 
toxics data archive, (3) toxicological information from EPA and other 
government sources, (4) an analysis of previous studies on air toxics 
in urban area; and (5) the Cumulative Exposure Project analysis of 
modeled emissions from 148 HAP by census tracts of the contiguous U.S. 
We begin with a discussion of the emissions inventory and then explain 
our methodology for picking the HAP in more detail.
1. Emissions Inventory
    a. How was the emissions inventory developed?
    In order to provide information on all 188 HAP, we are developing 
and refining the national toxics inventory. Moreover, in order to 
implement the specific requirements of section 112(k), we believed that 
it was important to have the best information possible in determining 
which of the 188 HAP should be included on the urban HAP list. 
Therefore, we conducted an initial ranking analysis based on the 
information we had at the time and identified a candidate list of 40 
HAP. We provided the candidate list to the public for comment through 
the Internet in September of 1997. We developed a national inventory of 
sources and emissions for these 40 potential urban area pollutants 
considering the information provided by the public for the base year 
1990. The base year 1990 was used because it was the year that the Act 
was amended and, thus, the year in which EPA received congressional 
direction to take actions to address the hazards posed by HAP. 
Therefore, we believe that 1990 represents a reasonable starting point 
for our analyses and regulatory efforts. The base year inventory report 
can be obtained from our Internet World Wide Web site (www.epa.gov/ttn/
uatw/112k/riurban.html). The report notes that current emissions may 
differ from emissions calculated for the 1990 base year. We used these 
1990 emissions estimates for the urban area pollutants identified in 
the next subsection to evaluate what source categories should be 
subject to regulation.
    The 1990 base year inventory document includes estimates for all 
sources of the section 112(k) pollutants for which we could establish 
estimation techniques. We believe this base year inventory report will 
be a useful reference to those who wish to understand the relative 
relationship of stationary source emissions (and in particular those 
that have been evaluated for section 112(k) purposes) to emissions from 
other types of sources. Therefore, this inventory includes estimates 
for sources that we believe would not be subject to section 112 
regulations (e.g., mobile sources, fires, and residential fuel 
combustion). In addition, where we do not have data to support an 
emissions estimate but do have information to suggest a source category 
is a potential emitter of a section 112(k) pollutant, we note this in 
the inventory document.
    Although section 112(k) focuses on area sources, the inventory 
provides information concerning both ``major'' and ``area'' sources as 
defined in section 112(a) of the Act for each source category, as well 
as mobile source categories. This information is important to our 
ability to fully characterize risk potential, even though regulatory 
decisions under section 112(k) focus on area sources.
    To address the requirements of section 112(k), we developed a 
national inventory of sources and emissions of the urban area 
pollutants based on data collected from the MACT standards program, 
Urban Air Toxics Program, the Toxics Release Inventory (TRI), the Great 
Waters Study, the Clean Air Act-mandated Reports to Congress on mercury 
and electric utility steam generating units, locating and estimating 
(L&E) documents used as guides to identify and estimate emissions, and 
review of other published technical literature. Emission factors were 
obtained from our Compilation of Air Pollutant Emission Factors, Volume 
I: Stationary, Point and Area Sources (AP-42) document, our Factor 
Information Retrieval System emission factor database, L&E documents, 
MACT programs, Federal Aviation Engine Emission Database, and industry 
studies. Activity data were obtained from published government reports 
(e.g., vehicle miles traveled data from the Department of 
Transportation's annual highway statistics, landing and take-off cycles 
from the Federal Aviation Administration air traffic statistics, energy 
consumption data from Department of Energy publications), industry 
trade publications, industrial economic reports, industry trade groups, 
and the MACT development programs. With the exception of TRI data, the 
inventory primarily represents the product of a ``top-down'' 
calculation methodology. This means emissions

[[Page 49245]]

were estimated by using some measure of source category activity (on 
the national level) and associated emission factors or speciation 
profiles for the category and its processes. With a few exceptions 
(e.g., use of TRI, emissions data from municipal waste combustors, and 
secondary lead refining operations), section 112(k) national emissions 
are not the sum of individual facility estimates (i.e., a ``bottom-up'' 
process). The initial phase of the section 112(k) emissions inventory 
effort constituted a screening analysis since we were attempting to 
preliminarily quantify atmospheric releases of all sources of the 
section 112(k) pollutants. A top-down approach is generally considered 
an appropriate and cost-effective use of resources for screening 
efforts such as those needed to assess section 112(k) pollutants. The 
level of effort required to estimate emissions using a bottom-up 
approach for all source categories that emit these pollutants would be 
extremely costly. Should it be dictated as a result of this analysis 
and listing, such detailed facility-specific emissions information may 
be collected during the technical analysis phase of MACT program 
development for the source categories listed for future section 112(k) 
rulemaking consideration.
    b. What is the base year for the inventory?
    As noted above, we chose the base year 1990 for the emissions 
inventory because we believe that the year the Act was amended 
represents the most reasonable starting point for our analyses and 
regulatory efforts. Since section 112(k) requires a comparative 
accounting of the sources of these specific pollutants, we also 
believed it important that, to the greatest extent possible, all 
emissions be estimated from the same base year. In several cases, other 
and perhaps better, emissions estimates were available that represent 
more current emissions levels. In these instances, the more current 
estimate was noted, but the 1990 emissions estimate was used for the 
section 112(k) accounting of the sources of urban HAP. For example, 
lead emissions from gasoline distribution from the refinery to the 
storage tanks at service stations (commonly referred to as Stage I) for 
on-road mobile sources were estimated to be 0.086 tons in 1990. By 
1996, there were no lead emissions from this source due to the mandated 
phaseout of leaded gasoline by December 31, 1995. However, the lead 
phaseout does not include fuels used for aviation, non-road egines, 
marine vessels and automotive racing purposes. Data were insufficient 
to estimate the emissions from fuel usage from non-road engines, marine 
vessels and automotive racing. For this reason, we are requesting 
additional information to help quantify emissions of lead compounds 
from these sources.
    c. How were pollutants that are regulated as sets of individual 
species handled in the inventory?
    a. Polycyclic Organic Matter (POM). Various conventions were 
adopted for developing the inventory of the pollutant groups where no 
standardized methods currently exist. This is most notably the case for 
POM, which is defined in section 112(b) of the Act as organic compounds 
with more than one benzene ring and a boiling point greater than or 
equal to 100 deg.C, which would include a complex mixture of thousands 
of polynuclear aromatic hydrocarbons (PAH).
    Because compiling the inventory of all POM compounds individually 
is currently impossible, surrogate approaches have been used. For 
instance, some of the available POM data are expressed in terms of the 
solvent-extractable fraction of particulate matter, referred to as 
extractable organic matter or EOM. Other POM data are defined as being 
included in either the group of seven or group of 16 individual PAH 
species, referred to as 7-PAH and 16-PAH, respectively. The species 
that make up 7-PAH have been identified by EPA as probable human 
carcinogens, and the 16-PAH are those species that are measured by EPA 
Method 610. The 16-PAH include the 7-PAH group.
    For the purposes of section 112(k), we decided to use 7-PAH as the 
POM surrogate because of its more well-established relationship to 
health effects of concern. That is, 7-PAH includes 7 specific 
carcinogenic compounds, whereas the health significance of the 16-PAH 
surrogate is less certain.
    b. Dioxins and Furans. In developing the emissions inventory to 
support this action, we initially attempted to inventory the specific 
dioxin and furan species, but soon found a significant shortage of 
available emissions data for these pollutants for all pertinent source 
categories. During the data collection phase of the process, we found 
that more emissions estimates and emissions factors were available for 
dioxins and furans on the basis of 2,3,7,8-TCDD toxic equivalent 
quantities (TEQ, 1989 international-NATO). The MACT program, section 
112(c)(6) source category list, and the Office of Research and 
Development's Dioxin Reassessment Study predominantly report emissions 
estimates on a 2,3,7,8-TCDD TEQ basis. Therefore, to maximize the 
number of source categories for which national estimates could be 
determined on a common basis and best carry out the objectives of 
section 112(k), EPA chose to use the TEQ method for developing the 
inventory for dioxin and furan species. It should be understood that 
TEQs aggregate all of the dioxin and furan species into one value 
weighted by toxicity, so that the dioxin and furan emissions estimates 
compiled in this inventory include individual species. More information 
on the use of the TEQ method can be obtained from the section 112(k) 
inventory report (www.epa.gov/ttn/uatw/112k/riurban.html).
    d. Why and how were national emissions disaggregated to major and 
area source categories?
    For the purposes of section 112(k), determining the percentage of a 
source category's emissions that come from major sources generally 
establishes the percentage subject to a given section 112(d)(2) 
standard unless area sources for the category are also listed and 
regulated. The allocation of emissions between major and area sources 
(major/area splits) used for various source categories in the section 
112(k) analysis are a rough approximation based on our current 
understanding of the industries concerned. Where specific data 
pertaining to major/area splits are available, the splits are typically 
derived from definitions of facilities, not necessarily the allocation 
of emissions.
    Generally, we collect information on the major/area split during 
the development of each source category specific regulation by 
surveying individual facilities with detailed questions. This section 
112(k) study is considered a screening analysis, and we considered 
collecting more detailed data for this study to be cost prohibitive, as 
well as redundant, since such information will be gathered on a source 
specific basis during any subsequent regulatory development. For 
information about the specific major/area splits used in the section 
112(k) inventory, see Appendix C of the inventory report. We solicit 
public comment on the appropriateness of the major/area splits used in 
the section 112(k) emissions inventory, as well as the inventory 
estimates of emissions. This information will also be on the web.
    e. How were national emissions spatially disaggregated?
    Section 112(k) of the Act addresses HAP that ``present the greatest 
threat to public health in the largest number of urban areas.'' The Act 
does not provide a definition of ``urban,'' however. To spatially 
allocate emissions on an urban

[[Page 49246]]

and rural basis, we used Bureau of the Census statistical data (U.S. 
Bureau of the Census, 1990). The Bureau of the Census lists the 
counties included in each Metropolitan Statistical area (MSA) in the 
United States. An MSA can include more than one county. We first summed 
the county population in each MSA. We designated the counties as urban 
or rural based on the sum of their populations. Emissions were assigned 
to counties by various methods. In some cases, such as with TRI 
estimates and data obtained from MACT studies, emissions could be 
assigned to individual facilities and then summed at the county level.
    In cases where facility-specific data were not available or could 
not be provided in an appropriate format within the time constraints of 
this project, emissions were assigned to individual counties using 
surrogate approaches. Two examples of these surrogate approaches 
include proportioning national non-road vehicle emissions to counties 
based on population proportioning emissions from some industrial 
sectors to counties based on 1990 SIC code employment estimates. For a 
complete list of spatial allocation approaches used in this study, see 
appendix C of the section 112(k) Inventory Report on the previously 
mentioned web site.
    f. How reliable is the inventory?
    The emissions inventory developed to support section 112(k) 
activities contains data of highly varying specificity and reliability. 
In some cases, we or the industry prepared the emissions estimates in 
response to other regulatory initiatives. These data are, in several 
cases, based on individual facility data or representative, category-
wide data developed from extensive testing. Other more source-specific 
estimate data are based on industry-submitted estimates to TRI, which 
have been based on testing or process-specific knowledge. Other 
estimates were based on a top-down approach utilizing limited emission 
factors. Generally, activity data even for these categories were of 
reasonably good quality. The emission factor data, however, varied 
considerably in terms of number, quality, and representativeness. As 
discussed previously, the draft inventory in this notice reflects the 
input received.
    The section 112(k) 1990 emissions inventory represents the best 
data available to the Agency for that period. However, as more source 
categories are evaluated during development of rules and more data on 
industry activity, emissions factors and source tests become available, 
emission estimates should continue to improve. In addition, although 
there is currently no requirement for States to collect and/or report 
HAP emissions estimates (as there are for criteria pollutant data), 
many States are developing data bases for HAP emissions. As these 
programs evolve, emissions estimates will improve further.
    g. Has this inventory been reviewed by the public?
    A draft of the section 112(k) emissions inventory was made 
available on EPA's Internet World Wide Web site (www.epa.gov/ttn/uatw/
112k/riurban.html) for review by the public in September 1997. In 
addition, we identified a list of trade organizations, industry, and 
environmental advocacy groups and contacted them individually by letter 
to announce the availability of the inventory and to request their 
reviews. The EPA requested that any comments on the September 1997 
draft section 112(k) inventory be submitted by October 15, 1997. The 
comments submitted were summarized in the EPA document entitled 
``Public Comments Received about Technical Aspects of the 1990 Emission 
Inventory of Forty Pollutants in the Section 112(k) External Review 
Draft Report,'' which can be obtained from the EPA's Internet Web site 
mentioned earlier.
2. List of the Priority HAP
    a. What are the priority HAP?
    Table 1 presents a draft list of HAP that we believe pose the 
greatest threat to public health in urban areas. Although information 
is limited regarding actual risks posed by specific HAP emissions, the 
availability of various other types of information is sufficient to 
achieve our objective of identifying those HAP posing the greatest 
potential public health concern in urban areas. Even though section 
112(k)(3)(B)(i) requires that we list HAP emitted from area sources, we 
believe that the public is exposed to complex mixtures of pollutants, 
and these pollutants are emitted by all sources. The risk from exposure 
to HAP has public health implications regardless of what the source of 
the emissions are. We judged these HAP to pose significant health 
threats and believe it is important to include them in the strategy to 
support activities to achieve the risk reductions required under 
section 112(k)(3)(C). Therefore, in the interests of best protecting 
public health, we have identified HAP considering the cumulative 
exposure potential of mobile, area, and major stationary source 
emissions combined. Included on the draft list of urban HAP are those 
30 HAP, the identification of which is required under section 
112(k)(3), that present the greatest threat to public health and result 
from area source emissions. Emissions of only these 30 HAP were 
considered in the area source category listing required under section 
112(c)(3) and 112(k). As discussed before, those HAP that are emitted 
by major or mobile sources, without a significant contribution from 
area sources, will be addressed using our other existing authorities 
under the Act, such as section 112(c)(1), 112(d) and 112(f) (these HAP 
are noted on the table with an asterisk). For example, if there is a 
major source category that emits one of these HAP and is not currently 
addressed by MACT or section 129, we may determine additional 
regulation under section 112(b) is necessary. Alternatively, if the HAP 
presents more of a local concern, it may be appropriate for the State 
or local agency to address it under its authorities. In light of the 
requirement of section 112(k)(3) and EPA's desire to integrate other 
statutory requirements regarding air toxics, we are requesting comment 
on whether it is appropriate for us to include the HAP that do not have 
significant contributions from area sources on the list.

Table 1.--Draft list of HAP for the Integrated Urban Air Toxics Strategy
------------------------------------------------------------------------
                                                                        
------------------------------------------------------------------------
acetaldehyde...........................  ethylene dichloride (1,2-      
                                          dichloroethane).              
acrolein...............................  ethylene oxide.                
acrylonitrile..........................  formaldehyde.                  
arsenic compounds......................  hydrazine.                     
benzene................................  lead compounds.                
bis(2-ethylhexyl) phthalate............  manganese compounds.           
1,3-butadiene..........................  mercury compounds.             
cadmium compounds......................  methyl chloride*.              
carbon tetrachloride...................  methylene diphenyl diisocynate 
                                          (MDI).                        

[[Page 49247]]

                                                                        
chloroform.............................  methylene chloride             
                                          (dichloromethane).            
chromium compounds.....................  nickel compounds.              
coke oven emissions*...................  polycyclic organic matter (POM)
                                          (7-PAH).                      
1,4-dichlorobenzene....................  propylene dichloride (1,2-     
                                          dichloropropane).             
1,3-dichloropropene....................  quinoline*.                    
2,3,7,8-tetrachlorodibenzo-p-dioxin (&   tetrachloroethylene            
 congeners & TCDF congeners).             (perchloroethylene).          
ethylene dibromide (dibromoethane).....  trichloroethylene              
                                         vinyl chloride.                
------------------------------------------------------------------------

    The method by which we identified HAP for the urban HAP list is 
summarized here and more fully described in the technical support 
document in the docket. In order to use the available information in 
the most robust manner, we ranked HAP for consideration for the urban 
HAP list in the following three ways. First, we ranked HAP by combining 
indicators of toxicity and exposure into ranking indices. The 
surrogates for toxicity were the risk-based concentration (RBC) for 
inhalation or risk-based dose (RBD) for ingestion. For effects other 
than cancer, the RBC or RBD represented an exposure estimated to be 
without adverse effects in human populations, including sensitive 
individuals. For carcinogenic HAP, we used RBC or RBD values 
representing both exposures associated with a 1-in-1 million and a 1-
in-10 thousand upper-bound predicted lifetime cancer risks. Surrogates 
for exposure included measured ambient concentrations and emission 
rates from area, major and mobile sources. As more completely described 
in the technical support document, seven separate indices were 
calculated, then combined into a single ranking.
    Second, we reviewed a number of existing exposure or hazard 
assessments concerning HAP that have been conducted previously by EPA, 
State agencies and others. Fourteen studies were deemed appropriate for 
comparative ranking of HAP in urban areas because they were 
sufficiently broad in the pollutants evaluated, they included area 
sources of HAP, and they focused on the risks presented in urban areas. 
The resultant HAP rankings from each study were normalized to the same 
scale, then aggregated to make a total score for each HAP. Carcinogens 
and noncarcinogens were ranked separately. Because section 112(k) 
places special emphasis on area sources of HAP, analyses were done for 
major, area, and mobile sources combined, and for area sources alone.
    Third, we used information provided by the CEP which compares 
modeled ambient concentrations of HAP in urban areas with health-based 
benchmarks. The CEP used estimates of 1990 HAP emissions rates to model 
long-term average concentrations at the census tract level for 148 HAP 
[Woodruff et al., 1998]. A long-term Gaussian dispersion modeling 
approach was used, with emission estimates drawn from TRI and other EPA 
databases addressing major, area, and mobile sources. Contributions 
from historic emissions of persistent pollutants and from 
nonanthropogenic sources were addressed with background values drawn 
from measurements in remote locations. The CEP compared its estimated 
ambient concentrations to benchmarks corresponding to a one in a 
million upper bound estimate of excess lifetime cancer risks, or no 
significant risks of adverse noncancer effects. The HAP were 
prioritized according to the number of urban census tracts in which the 
modeled concentration was above the health based benchmark.
    In our selection of urban HAP for the integrated strategy, we 
compared and then combined the results of these three separate ranking 
analyses. Thirty-one of the 33 urban HAP on the draft list in Table 1 
were identified as significant by more than one of these separate 
analyses. Two more HAP, mercury and POM were added to the draft list of 
HAP. We were concerned that studies considered in the ranking 
methodology that we used did not fully consider these two HAP. For 
example, multipathway exposure to persistent pollutants was only 
considered in one of the ranking methodologies. Therefore, although 
mercury was identified by only one of the three analyses, it was added 
to the proposed list because it was identified due to food chain 
exposures. Moreover, the Mercury Study Report to Congress (December 
1997) provides substantial information demonstrating the health and 
ecological threats posed by mercury in the environment. Thus, in our 
judgement, had multipathway exposure been more fully considered in the 
CEP and other studies, mercury would have ranked significantly in them.
    The health effect of greatest concern is the neurotoxicity to the 
developing fetus associated with methylmercury exposure. Fish 
consumption is a principle pathway for human exposure to methylmercury. 
Since other forms of mercury are capable of methylation once introduced 
into the environment, we do not limit the scope of our regulatory 
analyses to methylmercury, but consider emissions of other mercury 
species as well. Environmental loadings of mercury which lead to 
concentrations in fish result from natural sources, historical 
contamination through different media, and from current inputs, 
including air emissions. Given the current scientific understanding, it 
is not possible to quantify how much of methylmercury in fish consumed 
by the U.S. population is contributed by U.S. air emissions relative to 
other sources of mercury.5
---------------------------------------------------------------------------

    \5\ Critical elements in estimating methylmercury exposure and 
risk form fish consumption include the species of fish consumed, the 
concentrations of methylmercury in the fish, the quantity of fish 
consumed, and how frequently fish is consumed. The typical U.S. 
consumer eating fish from restaurants and grocery stores is not in 
danger of consuming harmful levels of methylmercury from fish and is 
not advised to limit fish consumption. The levels of methylmercury 
found in the most frequently consumed commercial fish are low, 
especially compared to levels that might be found in some non-
commercial fish from fresh water bodies that have been affected by 
mercury pollution. While most U.S. consumers need not be concerned 
about their exposure to methylmercury, some exposures may be of 
concern. Those who regularly and frequently consume large amounts of 
fish-- either marine species that typically have much higher levels 
of methylmercury than the rest of seafood, or freshwater fish that 
have been affected by mercury pollution--are more highly exposed. 
Because the developing fetus may be the most sensitive to the 
effects from methylmercury, women of child-bearing age are regarded 
as the population of greatest interest. An analysis of dietary 
surveys presented in the 1997 EPA Mercury Study led the EPA to 
conclude that between 1 and 3 percent of women of child-bearing age 
(i.e., between ages of 15 and 44) eat sufficient amounts of fish to 
be at risk from methylmercury exposure, depending on the 
methylmercury concentration in the fish. These consumers should be 
aware of the Food and Drug Administration and State fish advisories 
that suggest limiting the consumption of contaminated fish. 
Advisories in the United States have been issued by 40 States and 
some Tribes, warning against consumption of certain species of fish 
contaminated with methylmercury.
---------------------------------------------------------------------------

    Given the concentrations of people in urban areas, the numerous 
area sources of mercury emissions in those areas, and the resulting 
greater potential for people to be exposed to mercury through multiple 
pathways, we believe that

[[Page 49248]]

inclusion of mercury in the list of HAP under section 112(k)(3)(B)(i) 
is appropriate. However, we are seeking comment on the inclusion of 
mercury on this list and whether it is appropriate to identify a HAP 
under this subsection based on pathways in addition to inhalation.
    Polycyclic organic matter was only evaluated under one of the three 
analyses and only partially under another and was added to the proposed 
section 112(k) list based upon its identification in one analysis and a 
recognition from the scientific literature of its potential hazard. For 
POM, we are identifying the 7-PAH surrogate, which is focused on seven 
specific carcinogenic species.
    One family of pollutants emitted primarily by mobile sources, 
diesel exhaust emissions, is not listed in Table 1 but is appropriately 
noted here as one which is presently undergoing testing or assessment 
by EPA for its role in the urban air toxics problem. Although diesel 
exhaust was not specifically investigated in the studies that we used 
to select the pollutants which do appear in Table 1, we will be 
considering it along with those specific pollutants listed in Table 1 
as we develop and implement the integrated urban strategy.
    Diesel engines in highway and nonroad mobile sources are numerous 
and widespread. There have been recent studies linking diesel emissions 
to lung cancer and other health impacts. Diesel engines are a source of 
POM which appears on Table 1. However, there may be other constituents 
in diesel exhaust that adversely affect health. We have prepared a 
draft assessment document on the health risks of diesel emissions and 
have obtained comment on it from the Clean Air Science Advisory 
Committee of the Science Advisory Board. When this document is 
completed, it will inform the further development of the integrated 
strategy for urban air toxics. There are area sources which employ 
stationary diesel engines, but we are not proposing such stationary 
engines for regulation under section 112(k) even though they emit POM 
because we do not believe these engines are a substantial urban source 
of POM or any of the other pollutants listed in Table 1. Stationary 
diesel engines used by area sources located in urban environments are 
primarily used only for emergency service and operate infrequently.
    b. How did EPA identify the 30 HAP for section 112(k) purposes?
    As discussed earlier, section 112(k)(3)(B) of the Act requires EPA 
to identify not less than 30 HAP that are estimated to pose the 
greatest threat to public health in the largest number of urban areas 
as the result of emissions from area sources. Although the Act requires 
that these HAP pose threats ``as the result of emissions from area 
sources,'' it does not state that such threats be exclusively the 
result of emissions from area sources. Therefore, for the purpose of 
meeting the requirements of section 112(k) and 112(c)(3), we identified 
those HAP that pose the greatest threat to public health in the 
analysis discussed above because they ranked highest relative to the 
other HAP and because they demonstrated significant contribution from 
area sources. By identifying the draft list of 30 HAP as those that 
have a significant contribution from area sources, we are ensuring that 
the threats posed by those HAP are ``the result of emissions from area 
sources.'' Without that contribution from area sources, the threat from 
those HAP would not be as great. We judged an urban HAP to meet this 
area source demonstration if it was identified in the CEP urban 
analysis as having estimated concentrations greater than the health 
based benchmark in a significant number of urban census tracts as a 
result of area source emissions only, or according to EPA's National 
Toxics Inventory, augmented by the section 112(k) inventory, its area 
source emissions accounted for at least 5 percent of the total 
emissions for that HAP. It is important to remember that these 30 HAP 
were used in identifying the draft list of new area source categories 
for which standards will be addressed in the future as required by 
section 112(c)(3) and 112(k)(3)(B)(ii). The entire list of 33 HAP will 
be used to guide actions to meet the requirements of section 
112(k)(3)(C).
    We are taking comment on the criteria we used in developing the HAP 
list including whether it is appropriate for us to include multipathway 
exposures as part of this determination; whether it is appropriate to 
include more than those HAP with significant contribution from area 
sources; and if we should expand the list to include a broader 
representation of HAP.

III. Plan for the Area Source Strategy

    This section discusses how we intend to use the information 
collected in the emissions inventory development and HAP ranking 
assessment efforts to address the requirements of section 112(c)(3) and 
112(k)(3) to regulate emissions of air toxics from area sources. It 
reviews the process of establishing a list of source categories, 
identifies those source categories we intend to subject to further 
emission standards, and discusses the significance of the listing 
processes.

A. How does EPA plan to address area sources of HAP?

    One component of the integrated urban air toxics strategy will 
address the provisions of section 112(k). The basis for the draft area 
source component of the integrated urban air toxics strategy is our 
draft list of HAP that, as a result of emissions from area sources, 
present the greatest threat to public health in urban areas. Section 
112(k)(3) requires that we assure that area source categories or 
subcategories accounting for at least 90 percent ``of each of the 30 
identified hazardous air pollutants are subject to standards pursuant 
to subsection [112](d).'' In addition, section 112(c)(3) specifies that 
we list source categories or subcategories representing 90 percent of 
area source emissions of the 30 HAP.
    These provisions of the 1990 Amendments reflect Congress's judgment 
that there are significant health risks from air toxics in urban areas 
that should be expeditiously reduced. In addition, these provisions 
reflect an understanding that available information is in many cases 
insufficient to quantify risks from air toxics. Therefore, we are 
directed to identify the pollutants from area sources that, in a 
relative sense, present the greatest threat in urban areas and to set 
achievable standards to reduce overall emissions of these priority 
pollutants of concern. By requiring 90 percent of the emissions of each 
of the identified HAP to be subject to regulation, the statute directs 
us to seek opportunities for emissions reductions in many industry 
sectors. However, the statute provided us with significant flexibility 
to determine the stringency of the sector-based standards (i.e., MACT 
or GACT standards) and to ensure that they are achievable and 
reasonable. To provide compliance flexibility, standards are to be 
performance-based (i.e., in the form of numerical emissions limits) 
except where infeasible. We will also consider the use of incentives, 
nonregulatory programs and other innovative approaches in seeking ways 
to reduce emissions and risks from area sources, as well as other 
sources addressed by the integrated strategy.
    The following presents the analysis of the area source categories 
that we are considering listing to meet the requirements of section 
112(c)(3) and 112(k). Because this section of the Act imposes 
requirements that are specific to area sources, this discussion did not 
include an analysis of major or mobile source categories. Any 
regulatory

[[Page 49249]]

activities for those categories will be addressed under other Act 
authorities.

B. What is a ``listing''?

    When we list a source category under the authority of section 
112(c), we publicly identify it for regulatory action under section 
112(d). As discussed earlier, the details of that regulation, such as 
what kinds of controls will be imposed or emission reductions 
accomplished, are determined in the subsequent regulatory development 
process and cannot be predicted at the time of listing. This strategy 
is not considered a rule and does not by itself affect the interests of 
any party in a direct or quantifiable manner. Any standards that result 
from this listing, however, will undergo full public notice and 
comment. We believe that this is consistent with section 112(e)(4) of 
the Act which states:

    Notwithstanding section 307 of this Act, no action of the 
Administrator adding a pollutant to the list under subsection (b) or 
listing a source category or subcategory under subsection (c) shall 
be a final agency action subject to judicial review, except that any 
such action may be reviewed under such section 307 when the 
Administrator issues emission standards for such pollutant or 
category.

At the time we propose new emission standards for a source category or 
subcategory identified in the final strategy, we intend also to request 
comment on the section 112(k)(3)(B)(i) listing of the specific 
pollutants that serve as the basis for the listing of that category or 
subcategory.

C. What is EPA's goal in area source listing?

    The stated purpose of section 112(k) of the Act is ``to achieve a 
substantial reduction in the emissions of hazardous air pollutants from 
area sources and an equivalent reduction in the public health risks 
associated with such sources.'' In addition to assuring compliance with 
the requirements of section 112(c)(3) and 112(k), our goal in this 
draft listing action is to meet the purpose of the urban area source 
program in the most effective and least burdensome way possible.

D. What does ``subject to standards'' mean?

    In order to subject a source category to standards, we plan to 
conduct an evaluation of the source category, then, based on that 
evaluation, make rulemaking decisions as to what are the most 
appropriate controls or other requirements for that area source 
category and publish our findings or promulgate a rule, as appropriate. 
This process will take place after publication of the final list of 
newly identified source categories. That is, source categories listed 
under section 112(c)(3) and (k)(3) will be ``subject to standards'' 
under section 112(d), but the appropriate controls and resulting 
emission reductions will not be known until an area source standard is 
subsequently proposed and promulgated.

E. Which area source categories are to be listed?

    The following table summarizes which of the additional source 
categories EPA intends to list in the final strategy. These categories 
are in addition to those already listed for which standards have been 
published or are being developed. Attached as an appendix is a table 
for each HAP showing the source categories listed. We are requesting 
comment on the list of area source categories identified below.

 Table 1.--Draft List of Source Categories for Regulation Under Section 
                                 112(k)                                 
------------------------------------------------------------------------
                                                                        
-------------------------------------------------------------------------
Abrasive Grain (Media) Manufacturing.                                   
Acrylic and Modacrylic Fiber Production.                                
Agricultural Chemicals and Pesticides Manufacture.                      
Manufacture of Nutritional Yeast.                                       
Cadmium Refining and Cadmium Oxide Production.                          
Chemical Manufacturing: Chromium Compounds.                             
Electronic and other Electric Equipment Manufacturing (SICs combined).  
Food Products (SICs combined) manufacturing.                            
Gasoline Distribution Stage I.                                          
Hospital Sterilizers.                                                   
Industrial Inorganic Chemical Manufacturing.                            
Industrial Machinery and Electrical Equipment (SICs combined).          
Industrial Organic Chemicals Manufacturing.                             
Instruments and Related Products (SICs combined).                       
Iron and Steel Foundries: Steel Foundries.                              
Landfills (excluding Gas Flares).                                       
Mineral Wool Manufacturing (includes Wool Fiberglass).                  
Miscellaneous Manufacturing (SICs combined).                            
Mobile Homes Manufacturing.                                             
Nonclay Refractories.                                                   
Oil and Gas Production: Glycol Dehydrators.                             
Paint Application (no spray booths).                                    
Pharmaceuticals Preparations and Manufacturing (SICs combined).         
Plastics Materials and Resins Manufacturing.                            
Plastics Products Manufacturing.                                        
Primary Copper Smelting.                                                
Primary Metal Products Manufacturing (SICs combined).                   
Publicly Owned Treatment Works (POTWs).                                 
Reconstituted Wood Products.                                            
Sawmills and Planing Mills, general.                                    
Secondary Copper Smelting.                                              
Secondary Smelting and Refining of Nonferrous Metals.                   
Storage Batteries Manufacturing.                                        
Textiles (SICs combined).                                               
------------------------------------------------------------------------

F. How were the source categories selected for listing?

    The language about selecting area source categories in section 
112(c)(3) and section 112(k)(3)(b) differs somewhat. Section 112(c)(3) 
requires us to list sufficient categories ``to ensure that area sources 
representing 90 percent of the area source emissions of the 30 [listed] 
hazardous air pollutants'' are subject to regulation under section 112. 
That would seem to allow us to regulate either 90 percent of the 
combined emissions of all of the 30 HAP or 90 percent of the emissions 
of each of the 30 HAP. By contrast, section 112(k)(3)(B) requires us to 
identify sufficient categories to ``assure that sources accounting for 
90 percent or more of the aggregate emissions or each of the 30 
identified hazardous air pollutants'' are subject to standards under 
section 112(d). That language explicitly requires us to regulate 90 
percent of the emissions of each of the 30 HAP. Consequently, we 
selected the interpretation that allows us to read the two provisions 
consistently. In other words, we assembled a draft list of area source 
categories sufficient to cover 90 percent of the emissions of each of 
the 30 HAP.
    We ranked area source categories in the 1990 area source emission 
inventory (described earlier) on a HAP-by-HAP basis. That is, area 
source categories were ranked for each of the 30 urban HAP (30 separate 
rankings) by mass of annual emissions (greatest tons per year to least 
tons per year). For each HAP, we included emissions from those area 
source categories which are already regulated or listed for regulation. 
We then selected the greatest-emitting source categories until 
emissions added up to 90 percent of the total emissions of that HAP. 
All source categories selected in this process but not already listed 
under section 112 are then to be listed for regulation.
    It is important to note that for POM, we identified source 
categories based on the 7-PAH surrogate. Because the available data for 
the 7-PAH form are most amenable to risk analysis, we intend to apply 
additional emissions standards only to the sources of emissions of this 
form of POM.

[[Page 49250]]

However, we are seeking comment on the appropriateness of this 
approach.

G. If my source category is already subject to MACT, will section 
112(k) mean any changes to my requirements?

    Additional requirements, if any, for new or existing standards may 
follow after we conduct further assessments under section 112(f) of the 
Act to determine residual risks after the implementation of MACT 
standards set under section 112(d) and/or whether further actions under 
section 112(k) and other Act authorities are needed to achieve risk 
reduction goals. Because these elements of the program are not yet 
developed, it is difficult to determine what, if any, changes will be 
necessary. Section 112(k) requires that we ensure that 90 percent of 
the aggregate emissions are subject to standards. If your area source 
category is subject to a standard that has already been promulgated, 
then that standard has been considered in the 90 percent and thus would 
not require further listing under section 112(k). Where standards have 
not yet been promulgated for your category, area sources may be made 
subject to further requirements in order to assure the 90 percent 
requirement is met.

H. Are changes to the list possible after the strategy is final?

    It must be emphasized that, since the emissions inventory is likely 
to change as new information becomes available from public comments, as 
well as new data obtained in the regulatory development process, the 
source categories selected for listing to meet the 90 percent emissions 
requirement may also change. We expect to make revisions to this 
regulatory listing based on new emissions information where it is more 
accurate and effective to do so.

IV. Near-Term Actions To Implement the Strategy

    This section discusses actions that we intend to take within the 
next 2-3 years to address air toxics from all sources, including 
decisions on the need for, and feasibility of, standards for motor 
vehicle fuels and emissions, development of standards for area sources, 
improvement in air quality and emissions databases, development of 
analytical tools, and initiating collaboration with State and local 
governments. It also provides summary information about what EPA and 
State programs are currently in place to reduce risks from exposure to 
HAP in urban areas.

A. How will EPA develop motor vehicle and/or motor vehicle fuel 
standards?

    As previously discussed, under section 202(l)(2) of the Act, we 
will promulgate appropriate national regulations controlling HAP from 
motor vehicles and their fuels. The standards will be based on the 
updated analyses of the Motor Vehicle Related Air Toxic Study published 
in 1993 under section 202(l)(1) of the Act, which analyzed the need 
for, and feasibility of, controlling emissions of toxic air pollutants 
which are associated with mobile sources. The section 202(l)(2) 
regulations will reflect the greatest degree of emissions reductions 
that can be achieved considering various factors including availability 
and cost, and will at a minimum, address benzene and formaldehyde 
emissions. We will examine mobile source contributions to urban air 
toxics health risks and any new national mobile source regulations will 
be established by 2000. We envision that work done in the early stages 
of strategy implementation will serve to facilitate the important 
comparisons of various emissions sources in the urban areas and allow 
comparisons of control authorities to provide the best relative 
reduction of risk to the urban public. Although the study of mobile 
source emissions will be completed soon, and the rules may be among the 
earliest activities of the strategy, we expect to continue our efforts 
to ensure coordinated use of our authorities to address priority risks.
    We expect to complete activities required by section 202(l) 
according to the following dates, consistent with the consent decree:

1998: Complete the updated analysis of risks from mobile sources, 
including addressing comments received from review of that study to 
provide better estimations of mobile source emissions projected in the 
future; estimate the exposure and predict risk to the public from motor 
vehicle toxic emissions in 9 urban areas to better quantify the 
magnitude of the health risks; and, assess available motor vehicle and/
or fuel technologies, and the impact or cost effectiveness of those 
technologies to achieve the greatest reduction in public health risks 
from air toxics under section 202(l).
1999: Issue a notice of proposed rulemaking for mobile source standards
2000: Issue final rulemaking on mobile source standards

B. How will EPA develop area source standards?

    As discussed in section III, we must ensure that 90 percent of the 
aggregate emissions of each of the area source urban HAP are subject to 
regulation. Earlier, we presented the draft list of source categories 
that must be included in addition to the existing MACT regulations to 
achieve this requirement. We intend to ensure that the regulations that 
result are both efficient and warranted for protection of public 
health. In this notice, we are requesting comment on the following 
approach to developing the regulations necessary to meet this 
requirement.
    We intend to focus MACT on those area sources where the impact is 
greatest and where the technology applicable to major sources is also 
appropriate to area sources. However, there are likely to be 
circumstances where GACT might be more appropriate than MACT. In 
establishing the basis for emission standards under section 112(d)(5), 
Congress provided for GACT for area sources in lieu of MACT. That 
provision does not define GACT, but only states that the Administrator 
may elect to promulgate ``standards or requirements * * * which provide 
for the use of generally available control technologies or management 
practices by such sources to reduce emission of hazardous air 
pollutants.'' For instance, there may be important differences in the 
processes involved or the costs of control that might make it 
infeasible for area sources to comply with MACT.
    Although the primary focus of the specific requirements of section 
112(c)(3) and 112(k) is to ensure that at least 90 percent of the 
aggregate emissions of each of the 30 urban area source HAP are subject 
to standards, we anticipate that area sources may be further addressed 
in the strategy, as would major sources and motor vehicles, if we 
determine that they continue to present significant public health risks 
either on a national or local level once we have conducted analyses of 
the estimated reduction of cancer and noncancer health risks.
    We are seeking comments on the following schedule for developing 
the urban area source standards:

1999: Finalize the Integrated Urban Air Toxics Strategy; Initiate the 
development of additional area source standards
2002: Promulgate 50 percent of the area source standards
2004: Promulgate an additional 25 percent of the area source standards
2006: Promulgate final 25 percent of the area source standards

[[Page 49251]]

2008: Submit Report to Congress
2009: Require compliance with the urban air toxics standards

    This schedule was established considering the facts that we are 
currently engaged in significant efforts to develop standards for 
stationary sources that were previously listed under section 112(c), 
and that realistic schedule and resource constraints suggest that our 
efforts to develop additional standards should be phased in over time.

C. What role do major stationary sources play in the strategy?

    As previously discussed, section 112(k)(3)(b) requires that we 
ensure that area sources accounting for 90 percent of the aggregate 
emissions of the 30 112(k) HAP are subject to standards. Thus, major 
sources are not affected by the requirements of this subsection.
    However, in achieving required reductions in estimated cancer risk 
and substantial reductions in health risks in general, section 
112(k)(3)(C) permits us to consider reductions in public health risks 
resulting from actions to reduce emissions from ``all stationary 
sources and resulting from measures implemented by the Administrator or 
by the States under this or other laws.'' We interpret the language of 
this section to include reductions in major stationary source emissions 
as well as area source emissions. Therefore, any reductions resulting 
from MACT, the national ambient air quality standards, and other 
programs that achieve reductions in HAP can be included in the 
assessment of reductions in risks. In addition, in future stages of the 
strategy, if it is determined that a source category or an individual 
source is presenting a significant health risk, then it will be 
addressed under the appropriate regulatory authority. For example, if a 
source category is currently subject to MACT and it is found to pose a 
significant remaining risk, then that risk could be addressed through 
section 112(f) residual risk standards. Similarly, if a specific source 
is contributing to a local risk problem, then the State or local 
program may be more appropriate to address that risk. Finally, it is 
important to note that while additional actions may be required to 
address risks in the future, the baseline for evaluating what is needed 
to achieve a 75 percent reduction in cancer incidence remains at the 
1990 level.

D. How will EPA review and expand monitoring networks?

    In order to better characterize the risks from HAP in urban areas, 
it is important that we improve our ability to measure HAP in the urban 
areas. To that end, we are working to improve our monitoring networks 
for HAP in the urban areas over the next several years. The first step 
in this effort is to improve our knowledge of where the State and local 
agencies are currently monitoring HAP. We are currently conducting a 
study to determine the coverage, comparability, and relevance of 
existing monitoring networks. Further, recognizing competing resource 
needs, we are encouraging the State and local agencies to tailor their 
monitoring programs to address their most pressing air toxics issues 
and local needs. However, we are requesting the State and local 
agencies to work with us to develop a monitoring network distribution 
that capitalizes on existing efforts and capabilities. We expect to add 
17 new monitoring sites to the network in 1999. This will include one 
new site in the major metropolitan areas of each of the ten EPA Regions 
and an additional site in each of the seven areas with existing 
Photochemical Air Monitoring System networks. In addition, we are 
expecting to increase that number by up to 40 additional sites in 2000.

E. How will the consolidated emissions reporting rule fit in the 
strategy?

    In addition to expanded monitoring, we recognize the need for 
improved emissions information to support air quality, modeling and 
risk assessments. We are in the process of developing a consolidated 
emissions reporting rule whose purpose is to simplify reporting, offer 
options for data exchange, and unify reporting dates for various 
categories of inventories. This action is expected to consolidate the 
numerous emissions inventory reporting requirements found in various 
parts of the Act and is being taken at the request of numerous State 
and local agencies. Consolidation of reporting requirements will enable 
these agencies to better explain to program managers and the public the 
necessity for a consistent inventory program, increases the efficiency 
of the emissions inventory program, and provides more consistent and 
uniform data.
    As discussed earlier, modeling is one of the primary tools that 
will be used to estimate the exposure and risk from HAP. We will 
continue to develop modeling tools and guidance for assessment of risks 
on both the national and local scales.

F. What is the schedule for conducting risk assessments and assessing 
progress toward the risk goals?

    In addition to the emission standards called for by section 
112(k)(3)(B), and to addressing the risk reduction goals described in 
section 112(k)(3)(C), we expect to conduct assessments and make the 
determination of whether additional risk assessment and risk management 
activities are needed on an ongoing basis. However, the schedule for 
conducting the risk assessments will be influenced by the Agency's 
goal-setting and strategic planning processes and by the schedules set 
forth in applicable provisions of section 112, including schedules for 
the Reports to Congress required by section 112(k)(5). There are a 
number of interim milestones that must be met in order to conduct these 
assessments, particularly in the area of developing and refining the 
modeling tools to conduct these assessments. They include:

1999:
    (1) Initiate analyses of risks in urban areas; conduct assessment 
of the emissions reductions from 1990 level due to current programs and 
activities;
    (2) expand monitoring network to 17 additional urban areas;
2000: Complete the national scale screening model (CEP2)
2001: Complete the local scale risk assessment model (TRIM);

    Schedules for conducting more site-specific risk assessments will 
be established based on the outcome of our efforts to develop, enhance, 
and support State and local programs in the managing urban air toxics 
risks.

G. Coordinate with State and local governments to develop or strengthen 
risk-based air toxics programs.

    In order to achieve our risk reduction goals, we will need to look 
at ways to address public health risks not only on the national level, 
but also on the local level because many of the factors that influence 
risks, such as the types of sources, activity patterns, and 
meteorology, vary from city to city. Much of what has been previously 
discussed pertains to the tools and programs that can be employed on 
the national level to address emissions and risks that occur uniformly 
across the country. However, in order to achieve risk reductions at the 
local level, it is important that the strategy provide for a strong 
State or local role. We intend to work with the State and local air 
program agencies to refine this aspect of the strategy. The following 
is a discussion of some of the key elements

[[Page 49252]]

to developing the nature and scope of the State and local program.
    One of our goals in the strategy will be to encourage and support 
the State and local agencies in reducing public health risks (cancer 
and noncancer--chronic and acute) in individual urban areas. Because 
many of these risks are associated with specific local considerations, 
such as clusters of sources, local meteorology, local fish and other 
food consumption patterns, industrial make-up, and motor vehicle 
density and activity in the specific urban area, we believe State and 
local regulatory avenues are the most appropriate authorities to 
address these risks. To that end, we envision a process that will 
provide regulations, technical support and guidance, and/or other 
support as necessary to State and local agencies to ensure that there 
are substantial reductions in the public health risks in each urban 
area. The process is expected to provide flexibility for local planning 
and allow the development of city specific solutions to localized urban 
risks. We envision our role in this program to include providing 
guidance on important elements such as monitoring, emissions inventory 
development, modeling and risk assessment, control techniques, and 
enforcement provisions. As in the national elements of the program, we 
envision a process that will include periodic review of the risks 
associated with HAP emissions in the urban areas, and reductions 
achieved to ensure that the program goals are met. In addition, because 
the goal of the integrated strategy is to achieve public health risk 
reductions, we believe that the State and local programs should be able 
to address all emissions sources as appropriate to address the 
aggregate risks in the area. For instance, if the largest contributor 
to cumulative risk in an area is a cluster of MACT-controlled sources, 
then the State may find that controls beyond MACT or those imposed by 
residual risk are required. Likewise, if the risks are largely due to 
mobile source emissions based on vehicle activity, then the State or 
local Agency may consider transportation related measures to address 
the risk.
1. What are the principles used in developing the State and local 
program?
    Based on our early discussions with a number of State and local 
agencies, we developed and intend to employ the following principles in 
developing provisions for use by State and local programs:
     Provide a mechanism to encourage the development of State 
and local requirements and programs;
     Provide flexibility in implementing the national 
standards;
     Provide a balance between the need for flexibility for 
States and local agencies with existing programs and the need to 
provide a program for those States where Federal requirements are 
necessary to enable addressing risks from the HAP.
    We would like your comments on these principles, including the need 
for other or different operating principles.
2. What are the key issues that must be addressed in developing the 
State and local program?
    Again, based on our discussions with State representatives, there 
are a number of key issues that must be addressed which will determine 
the nature and scope of the State/local programs. They include:
     Should the program be mandatory?
     If the program is required in some way, should the State 
requirements be federally enforceable and, if so, by what mechanism?
     Should the State and local program include elements to 
address risk from all emission sectors (area source, major sources and 
mobile sources)?
    We would like your comments on these questions, including important 
legal, technical, or other factual information in support of your 
comments.
3. What might these programs include?
    State and local representatives working with us developed a number 
of preliminary ideas of how the program might work. We are requesting 
comment on these ideas and on other ideas in developing the State and 
local programs.
    One suggested approach might be a control strategy approach where 
we would set an urban areawide risk reduction target, considering risk 
from all pathways, which the States could develop control strategies 
and requirements for achieving those targets. These control strategies 
would supplement the national MACT program and might include emissions 
controls or other innovative strategies to address specific local 
health risks from HAP. Another suggested approach might include States 
that would be setting technology requirements for sources that 
contribute to risks above a given level. This would be similar to 
programs already in place in California, Maryland and other States. 
Some State and local programs may be more effective if the strategy 
provides for a purely voluntary program where we would provide Federal 
guidance and information for reducing risks from urban HAP to the 
State/local agencies and leave the program design to each individual 
State or local program to develop and implement. Another approach would 
be for us to set a HAP ambient concentration level and require/
recommend actions from the States where these levels were exceeded for 
a specified duration and frequency. Another approach may be to use 
combinations of these options. These options are not mutually exclusive 
and other ideas might be developed or expanded upon in the future. We 
are requesting input from you on the feasibility and desirability of 
these options and on what the appropriate level of State and local 
involvement should be. We expect to undertake some or all of the 
following activities under section 112, depending on the outcome of 
this process:
     Development or strengthening of State and local programs;
     Development of regulations necessary to provide authority 
to implement the program (if appropriate);
     Development of implementation guidance including 
information on risk assessment, monitoring, modeling, emissions 
inventory, potential control options; and,
     Development of risk assessment tools for local planning. 
While in the near term we intend to initiate discussions with the 
States to further refine the program, most of these activities will be 
longer-term activities. We expect to provide you with further 
information and opportunities to comment as these elements are 
developed or refined.

H. How does EPA intend to address special concerns about Environmental 
Justice in the Urban Areas?

    As discussed previously, we are particularly concerned about the 
potential for disproportionate risk in low-income minority communities. 
The Federal Government has not traditionally sought involvement from 
these communities in environmental program development and have voiced 
significant concerns about the difficulties and disadvantages they face 
when attempting to participate in decisions affecting their 
communities. We believe that the integrated urban air toxics strategy 
should evaluate the potential links between toxic exposure and health 
effects in disproportionately exposed populations, and should address 
any significant resulting risks. Concurrently, we will consider 
economic development and employment-related issues to ensure 
sustainable economic development while addressing unacceptable levels 
of

[[Page 49253]]

risk. In order to facilitate the development of a strategy which will 
be responsive to these environmental justice concerns, we are actively 
encouraging community groups not only to comment on the strategy, but 
also to work actively with us in developing a program that can address 
their concerns.

I. What EPA or State programs are currently in place to address the 
risk posed by these HAP?

    There are a number of activities that will take place prior to 
risk-based goal setting envisioned in the national air toxics program 
that will achieve significant early emissions reductions. They include 
actions to reduce emissions from mobile, major, and areas sources, both 
as a direct result of the Act requirements for control of air toxics 
described above, and requirements under programs (e.g., the national 
ambient air quality standards) which achieve significant coincidental 
air toxics benefits. As discussed above, the strategy called for under 
section 112(k)(3) is to achieve reductions in public health risks 
through emissions control ``measures implemented by the Administrator 
or by the States under this or other laws.'' The following presents a 
summary of Federal and State and local programs that are currently 
achieving HAP emissions reductions. This information will be considered 
in our assessments of reductions in public health risks which have been 
achieved as we evaluate the need for additional regulations.
1. Federal Regulatory Authorities
    Clean Air Act, Section 112 Authorities: Under section 112 of the 
1990 Amendments to the Act, there are many provisions, authorities, and 
programs that are reducing, and will continue to reduce, HAP emissions, 
exposures and health risks. Several of the major programs are discussed 
below. Further information is available from the ``Second Report to 
Congress on the Status of the Hazardous Air Pollutant Program under the 
Clean Air Act,'' EPA-453/R-96-015, October 1997.
    Section 112 established a procedure for developing and requiring 
performance-based emission standards for sources of HAP following a 
detailed 10 year schedule for action. These standards of control 
technology, required by section 112(d), are known as MACT standards and 
GACT standards. We are required to list categories and subcategories of 
major and area sources of HAP and then, according to a 10 year 
schedule, establish control requirements to assure that all major 
sources of HAP achieve the level of control already being achieved by 
the best performing sources in each category (i.e., MACT standards), 
and ensure that listed categories of area sources are subject to MACT 
or, alternatively, to GACT standards, which are controls that are 
generally available across the industry. As required by section 
112(c)(1), we published an initial list of source categories in 1992 
(57 FR 31576). Revisions made thus far have included adding and 
deleting source categories, combining categories for purposes of 
efficiency, and making other relatively minor changes and corrections. 
The list currently contains 175 categories, of which 167 are for major 
sources and eight for area sources (61 FR 28197). Note that some 
categories include both major and area sources. The schedule, initially 
published in 1993 (58 FR 63941), specifies source categories for which 
standards are to be promulgated within 2, 4, 7 and 10 years following 
November 15, 1990, such that standards are promulgated for 25 percent 
of the listed categories in the first 4 years (i.e., by November 15, 
1994), an additional 25 percent by November 15, 1997, and the remaining 
50 percent by November 15, 2000.
    We have thus far promulgated standards for all 47 source categories 
listed in the 2 and 4 year groups, which is approximately 25 percent of 
the 175 listed source categories. We estimate that these major and area 
source regulations will reduce air toxics emissions by approximately 
980,000 tons per year. Additional MACT and/or GACT emissions standards 
for the remaining listed source categories are scheduled to be 
promulgated by November 15, 2000. These standards are expected to 
obtain substantial additional reductions in air toxics over the next 
several years and will decrease exposures and risks due to air toxics 
in urban areas.
    Under the Residual Risk Program established by section 112(f), we 
will be assessing public exposures to HAP following MACT standard 
promulgation to assess the remaining public health and environmental 
effects of HAP and issue standards to provide an ample margin of safety 
to protect public health, if necessary. The residual risk provisions 
apply to all MACT standards and, therefore, focus primarily on major 
sources. We have the discretion to apply residual risk provisions to 
MACT standards that affect area sources as well.
    Under section 112(r), we published a final risk management program 
rule for the Prevention of Accidental Releases on June 20, 1996 (61 FR 
31668). Along with the final rule, we published guidance to assist the 
owner or operator of processes covered by the risk management program 
rule in the analysis of offsite consequences of accidental releases of 
substances regulated under section 112(r) of the Act. The list of 
regulated substances with threshold quantities was published on January 
31, 1994 (59 FR 4478). Of the 140 chemicals (77 acutely toxic 
substances and 63 flammable gases) regulated under section 112(r), 18 
are HAP under section 112(b) and eight are on the draft list of urban 
HAP presented in this notice for public comment. Section 112(r) also 
requires the source to assess each process to ensure they are safe and 
will not accidently release HAP. By preventing accidental releases, the 
section 112(r) rule will help reduce or prevent emissions of these HAP 
in the future.
    Requirements associated with the Act in section 112(g) and 
112(i)(5) are also expected to yield reductions in emissions of HAP in 
urban areas. The Construction and Reconstruction Rule required by 
section 112(g) of the Act was issued in final form on December 27, 1996 
(61 FR 68384). The rule requires, as of July 1, 1998, MACT controls for 
any new or reconstructed major source of HAP and major HAP-emitting 
production units at existing facilities. Section 112(i)(5), early 
reductions rules, provide incentives for sources of HAP to reduce 
emissions by 90 percent (95 percent for particulates) from 1990 levels 
prior to the proposal of MACT for that source category. Eligible 
sources may be granted a 6-year extension from compliance with the 
later promulgated MACT, during which time they must meet alternative 
emissions limitations which reflect the early reductions. Approximately 
27 permit applications have been received, representing HAP reductions 
of over 6,800 tpy. Approximately six permits have been issued to date.
    Other CAA authorities: In addition to authorities under section 
112, there are several other Act sections, the implementation of which 
may contribute or has already contributed to reductions in air toxics 
in urban areas. For example, state implementation plans developed to 
attain compliance with the national ambient air quality standards (set 
under section 109) are expected to provide incidental, but potentially 
significant, reductions in HAP in addition to their intended result of 
reducing levels of criteria pollutants (e.g., particulate matter, 
ozone, etc).
    The Act's mandated acid rain program may also provide HAP 
reductions in urban areas in addition to the intended

[[Page 49254]]

result of sulfur dioxide and nitrogen oxides emissions reductions.
    Section 202(l) is a critical part of the national air toxics 
program and will be very important to the success of the Urban Air 
Toxics Strategy because efforts to respond to section 202(l) will 
address exposure to HAP from motor vehicles and motor vehicle fuels. 
However, section 202(l) is just one example of the Act's authorities 
regarding mobile sources. Other provisions which may affect reductions 
in urban air toxics from mobile sources include sections 211 (fuel 
requirements), 213 (emission standards for nonroad engines and 
vehicles), and 219 (urban bus standards).
    Performance standard setting for solid waste incineration units and 
landfills under section 129 of the Act, which has been completed for 
two of the four categories (municipal, medical, industrial and 
commercial, and other categories of incinerators), is estimated to 
result in substantial reductions in total HAP emissions (>50,000 tons/
yr), much of which may be in urban areas. Under section 129, specific 
numerical emission limitations are required for various pollutants 
including lead, cadmium, mercury, and dioxins/furans, all of which are 
included on the draft list of urban HAP. Like the MACT standards, 
residual risk applies to section 129 standards and thus potential 
additional reductions may be possible in these areas.
    Title VI of the Act directs us to protect the stratospheric ozone 
layer through the reduction or elimination of certain chemicals. These 
ozone-depleting substances include three HAP (carbon tetrachloride, 
methly chloroform, and methly bromide), one of which, carbon 
tetrachloride, is included in the draft list of urban HAP in addition 
to the better known chlorofluorocarbons (CFC). We are implementing 
title VI through a number of regulatory and voluntary programs which 
have been successful in reducing production, use, and emissions of many 
CFC and other ozone depleting chemicals. Production and import of 
carbon tetrachloride and methyl chloroform were phased out as of 
January 1, 1996 and the third is expected to be phased out by 2001. 
Related regulations restrict uses to minimize the potential for these 
chemicals to get into the atmosphere.
    Other Federal laws: There are a number of other authorities, laws, 
rules, and programs that will also help reduce emissions of HAP and 
consequent exposures and risks. Some of these are discussed below. We 
are currently evaluating the appropriateness of these statutes for 
controlling emissions of HAP as described under section 112(k)(3) and 
intend to take further actions under these statutes as appropriate.
    Under the Toxic Substances Control Act (TSCA), chemicals produced 
or imported into the United States are evaluated as to toxicity to 
human health and the environment. To prevent adverse consequences of 
the many chemicals developed each year, TSCA requires that any chemical 
that will reach the consumer marketplace be tested for possible toxic 
effects prior to commercial manufacture. Any existing chemical that is 
determined to pose health and environmental hazards is tracked and 
reported under TSCA. Procedures also are authorized for corrective 
action under TSCA in cases of cleanup of toxic materials contamination. 
The TSCA is a complementary authority to the Act and has contributed to 
decreased emissions of several HAP. For example, concern over the 
toxicity and persistence in the environment of polychlorinated biphenyl 
compounds (PCB) led Congress to include in TSCA (see section 6(e) of 
TSCA), prohibitions on the manufacture, processing, and distribution in 
commerce of PCB. In 1990, TSCA authority was relied upon to eliminate 
chromium use in and emissions from comfort cooling towers, i.e., 
industrial process cooling towers used exclusively for cooling, 
heating, ventilation, and air conditioning systems.
    There are several provisions of the Resource Conservation and 
Recovery Act (RCRA) and its amendments which may yield reductions of 
urban air toxics. One impact evidenced in the 1990's is increased 
recycling and recovery of hazardous waste, including solvents which 
through volatilization contribute to HAP emissions. The RCRA's section 
3004(n) has been the basis of a three-phased regulatory program to 
control air emissions from hazardous waste treatment, storage and 
disposal facilities. The third phase will address any risks remaining 
after implementation of the control regulations issued in 1990 and 
1994, which were estimated to reduce HAP emissions by more than one 
million tons per year. Any resulting emissions and risk reductions can 
be considered in assessing progress in achieving the 75 percent 
reduction in cancer incidence from the 1990 base year.
    Under the Comprehensive Environmental Response, Compensation and 
Liability Act, commonly known as Superfund, the clean up of abandoned 
hazardous waste sites may also reduce emissions of HAP. Where 
significant health risks from chemical releases to the air have been 
identified at Superfund sites in urban areas, clean-up will reduce 
risks from urban air toxics.
    Under the Clean Water Act (CWA), States are required to adopt water 
quality standards for those section 304(a) priority pollutants which 
may be interfering with their water bodies' designated uses. In 
response to the CWA, we identified 126 priority pollutants for action. 
The CWA authorities provide for the regulation of discharges of these 
pollutants in order to meet applicable water quality standards. Among 
these pollutants, many are on the draft list of urban HAP. We are 
exploring how the CWA and the Act tools can be used together to reduce 
HAP.
    The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) 
provides Federal control of pesticide distribution, sale, and use. 
Several HAP have been used as pesticides. An EPA registration is 
required of all pesticides sold in the United States and is intended to 
ensure that pesticide use, when in accordance with label specifications 
regarding acceptable uses, does not cause unreasonable harm to people 
or the environment. It is a violation of FIFRA to use a pesticide in a 
manner inconsistent with its label. Registered pesticides classified as 
``restricted use'' may only be used by registered applicators who have 
passed a certification exam. This restricted use requirement minimizes 
the number of persons having access to certain pesticides. The FIFRA 
regulations may also reduce emissions and exposures by banning 
(canceling or denying registration) or severely restricting pesticide 
use. Seven individual HAP and members of three HAP compound groups have 
been banned or severely restricted in their use as pesticides.
    Two other Federal laws, the Emergency Planning and Community Right-
To-Know Act (EPCRA) of 1986 and the Pollution Prevention Act (PPA) of 
1990, while not directly regulating air emissions of HAP, may influence 
decisions regarding chemical usage and storage and yield significant 
reductions in air toxics risks in urban areas. The goal of EPCRA is to 
reduce risks to communities through informing communities and citizens 
of chemical hazards in their areas. Sections 311 and 312 of EPCRA 
require certain facilities to report the locations and quantities of 
chemicals stored at their facilities to State and local governments. 
This information is used by State and local agencies in preparing for 
and responding to chemical spills and similar emergencies.

[[Page 49255]]

    Through EPCRA, Congress mandated that a Toxics Release Inventory be 
made public. The TRI provides citizens with accurate information about 
potentially hazardous chemicals stored, manufactured and used in their 
community so that they have more power to hold companies accountable 
and make informed decisions about how toxic chemicals are to be 
managed. Section 313 of EPCRA specifically requires certain 
manufacturers and all Federal facilities to report to EPA and State 
governments, all releases of any or more than 600 designated toxic 
chemicals to the environment (including most of the 188 HAP). Each 
year, more than 20,000 manufacturing facilities and 200 Federal 
facilities submit information to us on the releases of chemicals to the 
environment. We compile these data in an on-line, publicly accessible 
national database, which is a significant source of information 
regarding HAP emissions. Reporting requirements for TRI became more 
comprehensive in 1991, highlighting the importance of pollution 
prevention. It is expected, and has been observed for some chemicals, 
that this public accounting for use and disposal of toxic chemicals may 
lead to reductions in their environmental release.
    The passage of the Pollution Prevention Act (PPA) established an 
environmental hierarchy that establishes pollution prevention (P2) as 
the first choice among waste management practices and was adopted as 
national policy. Traditionally, much environmental protection has 
involved controlling, treating or cleaning up pollution which, in many 
cases, we continue to create. Pollution prevention, which eliminates or 
minimizes pollution at the source, is most effective in reducing health 
and environmental risks because it: (1) Eliminates any pollutant 
associated risks; (2) avoids shifts of pollutants from one medium (air, 
water or land) to another, which can result from certain waste 
treatments; and (3) protects natural resources for future generations 
by cutting wastes and conserving resources. For waste that cannot be 
avoided at the source, recycling is considered the next best option. A 
waste generator should turn to treatment or disposal only after source 
reduction and recycling have been considered. Pollution prevention 
strategies include redesigning products, changing processes, 
substituting raw materials for less toxic substances, increasing 
efficiency in the use of raw materials, energy, water, land and other 
techniques. This is done in several ways, such as using voluntary 
pollution reduction programs, engaging in partnerships, providing 
technical assistance, funding demonstration projects and incorporating 
cost-effective pollution prevention alternatives into regulations and 
other initiatives.
    In addition, in 1994, we developed the Waste Minimization National 
Plan, a voluntary, long-term effort to reduce the quantity and toxicity 
of hazardous waste through waste minimization. The plan calls for a 50 
percent reduction in the presence of the most persistent, 
bioaccumulative and toxic (PBT) chemicals in hazardous waste by 2005. 
To assist in implementing this plan, we are developing a software tool 
to prioritize PBT chemicals to focus national waste minimization 
efforts and methods to track progress in reducing the presence of PBT 
chemicals in waste and the volume of hazardous waste streams containing 
PBT chemicals.
    The starting point for selecting chemicals for the national waste 
minimization list is EPA's Waste Minimization Prioritization Tool, a 
software program which provides a screening-level assessment of 
potential chronic risks chemicals pose to human health and the 
environment, based on their persistence, bioaccumulative potential, and 
human and ecological toxicity. This software program contains full or 
partial PBT data for approximately 4200 chemicals. The draft Waste 
Minimization Prioritization Tool was released for public comment in 
June 1997 (62 FR 33868, June 23, 1997) and a revised version is 
expected to be released in early 1999.
    In addition to PBT data from the Waste Minimization Prioritization 
Tool, we are considering a number of other factors in selecting 
chemicals for the national waste minimization list, including 
information about the quantity of chemicals in hazardous waste, the 
number of facilities generating or handling the chemicals in waste, the 
extent to which the chemicals have been found in the environment, and 
the significance of the chemicals to the RCRA program, other Agency 
programs, and States.
    We are requesting comment and specific information on other Federal 
programs, such as the Oil Pollution Act of 1990, that should be 
considered for potential reductions in risk from HAP.
2. Summary of State and Local requirements
    The Act requires that the strategy reduce cancer incidence by 
actions under ``this or other laws * * * or by the States.'' By 
including this language, Congress acknowledged that there are many 
State programs achieving HAP emissions reductions and therefore, 
reducing the chance for exposure and health risks including cancer. For 
example, before the Clean Air Act was amended in 1990, many State and 
local governments developed their own programs for the control of air 
toxics from stationary sources. Some of these State and local 
government programs have now been in place for many years and, for some 
of the source categories regulated by Federal emissions standards under 
section 112 of the Act, the State or local government programs have 
likely reduced air toxics emissions and may have succeeded in reducing 
air toxics emissions to levels at or below those required by the 
Federal standards. It is clear that Congress intended State and local 
governments to be important partners in carrying out the mandates of 
the Federal air toxics program, and the strategy provides a mechanism 
to recognize the reductions made by them.
    Because of the varied nature of the emissions sources, legislative 
structures, and other factors, the State and local government programs 
address air toxics in a number of ways. For example, some States and 
local programs have enacted technology standards for source categories 
that require controls for specific HAP, much like the MACT program. 
Other State or local government programs apply a risk standard to 
sources that prohibit emissions beyond a certain level of risk. Other 
States use an ambient air standard for air toxics that is based on 
threshold or exposure levels. Still others may rely on reductions 
achieved through volatile organic compounds, particulate matter, or 
lead regulations developed under section 110 or subpart D of the Act 
that control emissions of HAP to meet national ambient air quality 
standards. Regardless of the approaches used to address air toxics, 
State and local governments have accomplished and continue to 
accomplish reductions of HAP. As we proceed to implement the strategy, 
we will work with the States to better characterize these reductions in 
emissions and the resulting reductions of public health risks, 
including risk of cancer.

V. Longer-Term Activities

    This section discusses longer-term activities we expect to take to 
address risks from air toxics in urban areas, including how we intend 
to initiate assessments of urban risk, residual risk standards, 
additional stationary source standards, and possible State program 
actions. It further discusses our research strategy to better 
characterize risk and to

[[Page 49256]]

assess progress toward the risk reduction goals of the strategy.

A. How will EPA assess improvements in health risks?

1. How will EPA assess the reduction in cancer risk?
    As discussed previously, in the integrated urban air toxics 
strategy, we expect to utilize qualitative assessments of cancer 
initially by determining the emissions reductions achieved since 1990 
and using these emission reductions as rough surrogates for risk. Over 
time, we intend to develop more quantitative estimates of risk or 
estimated cancer incidence associated with toxic air pollutants to 
measure progress toward the Act's goal of achieving a 75 percent 
reduction in cancer incidence from 1990 levels. This effort is still 
under development, and the final strategy will include more detailed 
text describing the cancer risk-reduction estimation methodology and a 
timeframe for carrying out the analysis.
2. How will EPA assess the reduction in noncancer risks?
    As discussed before, Congress also expressed concern in section 
112(k) about the noncancer health risks posed by HAP. While Congress 
did not provide a quantitative goal for noncancer risks, we believe 
that these risks are important to address. Several issues, however, 
complicate our ability to assess reductions in noncancer risks. A 
complication particularly relevant to urban air is our incomplete 
knowledge about the effect of multiple pollutants. At a more 
fundamental level, however, while we and other agencies have developed 
estimates of lifetime excess cancer risks associated with air exposures 
to many HAP, we do not have comparable quantitative ``risk per 
exposure'' measures for assessing health risks other than cancer. The 
reason for this is the assumption that there are thresholds associated 
with most noncancer health effects such that exposures below the 
threshold are considered unlikely to be harmful. Consistent with this 
reasoning, we and other entities charged with protection of public 
health, have identified ambient air levels for many air pollutants 
which are unlikely to pose health risks for persons (including 
sensitive sub-populations) who are exposed to that level over their 
lifetime. These levels do not, however, provide information on the 
exposure levels at which health effects are expected (i.e., the 
threshold). Moreover, these cancer and noncancer concern thresholds do 
not account for possible additive (i.e., synergistic) or antagonistic 
effects when there are mixtures of HAP, as in urban areas. The issues 
raised here necessitate the development of a noncancer risk reduction 
assessment methodology or selection from among existing methods which 
differs from that which we intend to follow for assessment of cancer 
risk reduction.
    We intend to address these issues as we proceed to set goals for 
noncancer risk reductions and provide a description of assessment 
methodologies, evaluating progress against the goal and identifying 
appropriate additional risk reduction actions. The final strategy will 
document our progress in addressing these activities.
3. How will EPA use modeling to assess risks?
    In general, two types of models are important to our ability to 
assess risk to the public from exposure to HAP: (1) transport, 
diffusion and/or dispersion models simulate the release and transport 
of pollutants, estimating concentrations at different points in time 
and space; and (2) Exposure models simulate human activity patterns to 
estimate the extent to which people may be exposed to pollutants and, 
therefore, experience some level of risk. Air quality simulation models 
have a long history of use in providing pollutant concentrations for 
use in specifying emission limits and assessing control strategies to 
attain ambient air quality standards. The Guideline on Air Quality 
Models was established to promote consistency in the use of models 
within the air management process.
    Our use of exposure models to estimate risks to the public from HAP 
in a meaningful and reliable manner has been more limited. As part of 
the integrated urban air toxics strategy, we are conducting a pilot 
modeling study for certain cities to better understand the potential 
public exposure to HAP. The use of existing modeling tools to estimate 
exposure potential for the urban air toxics strategy poses special 
challenges due to the large geographical scale in urban areas relative 
to the types of exposures which can produce adverse health effects, the 
large number and variety of sources to be modeled, the variety of 
pollutants to be considered, and variations in the exposure regimes of 
significance for estimating the likelihood of effects. For that 
purpose, we are developing a document describing suggested methodology 
for using air dispersion models in urban areas. The document 
illustrates the type of issues encountered when modeling two example 
urban areas and provides suggestions for State and local agencies to 
follow when modeling air toxics in urban areas.
4. How will EPA use ambient monitoring to assess risk?
    Ambient air quality data can provide valuable input into the 
assessment of the cancer and noncancer risks from air toxics in urban 
areas. First, ambient air quality data provide a measure against which 
any modeling of atmospheric HAP concentrations can be compared for 
evaluation or verification purposes. Ambient air quality data can also 
be used to evaluate differences in HAP concentrations from one urban 
area to another to determine geographic patterns and/or characteristic 
profiles based on demographic, economic or other attributes of these 
areas. Finally, trends analyses of ambient air quality data on toxics 
can provide a measure of the effectiveness of regulatory programs over 
time. In addition to chronic exposure data, short term exposure data 
may be important in various noncancer assessments. It is important to 
recognize that exposure data can include more than ambient air 
concentrations, and that microenvironmental exposure data can be 
important to achieve a distribution of the population exposures.
    As the goals for the program are established and the early 
activities are carried out, we will conduct appropriate analyses to 
determine the success of the program against the goals. If, in the 
assessment of risk reduction, we conclude that the reduction goals 
(e.g., 75 percent reduction in cancer risk) are not yet met, we expect 
to identify and implement additional activities necessary to meet those 
goals. These activities might include regulations to reduce stationary 
or mobile source emissions or implementation of specific State 
programs. Some examples of such actions are described below:
    a. Residual risk standards. Under section 112(f) of the Act, we are 
required to assess the risks remaining after the MACT standards are 
implemented. For some source categories, more stringent standards to 
achieve additional risks reductions from those standards might be 
necessary. We intend to count any resulting risks reductions in the 
urban areas toward the 75 percent reduction in cancer risks. However, 
it is important to remember that residual risk only applies to source 
categories for which there are MACT standards. Because MACT standard 
development has focused on major sources, the residual risk program 
will

[[Page 49257]]

primarily address risk from major sources.
    b. Additional stationary source standards. We will develop section 
112(d) standards (MACT/GACT) for the source categories listed 
previously to address the requirements of section 112(k)(3)(B). 
Emissions reductions from these standards are expected to reduce HAP-
associated health risks, thus providing early progress in achieving the 
risk goals required under section 112(k)(3)(C). However, it is 
important to recognize that in order to achieve the risk goals, we may 
need to go beyond source-category-by-source-category approaches because 
of concerns about cumulative risk from numerous sources. We believe 
that individual 112(d) standards may not adequately address those risks 
without further actions.
    c. State program actions. As discussed earlier, in order to achieve 
our risk reduction goals at the local level, it is important that the 
strategy provide for a strong State or local role. We believe that this 
will require significant ongoing efforts to develop and implement the 
program in the urban areas. We will work with the State and local air 
program agencies to refine this aspect of the strategy and we expect to 
provide further opportunities for comment on it.
    To address these issues and develop the necessary additional 
technical, policy and/or regulatory support, we expect to carry out 
additional efforts under the following schedule.

1999: Convene a State/local work group to better define the State and 
local program structure
2000: Complete work on program development
2001: Development of any regulations necessary to provide authority to 
implement the program (if appropriate)
2002: Develop implementation guidance concerning: risk assessment, 
monitoring, modeling, emissions inventory, potential control options
2006: Assess progress toward goals, including the Integrated Urban Air 
Toxics Strategy Report to Congress.
d. How will EPA address information and data gaps?
    Significant research and data needs must be addressed in order to 
achieve the goals of the strategy. Estimates of the reduction of cancer 
incidence and of other significant public health effects related to 
exposure to HAP targeted in this strategy will require:
     Additional knowledge of both cancer and noncancer health 
effects of these pollutants. This will include determinations of 
specific toxicities determined from animal and human studies as well as 
the development of models to extrapolate across species, across time 
and across routes of exposure with a special emphasis on the effects of 
HAP in children.
     Improved monitoring data for ambient levels of HAP to 
improve spatial characterization of exposure potential and act as a 
measure against which modeling concentrations can be compared for 
evaluation or verification purposes.
     Improved data to better understand the potential for 
disproportionate impacts on minority and low income communities.
     Improved emissions models to estimate and assess HAP 
emissions in a representative number of cities, and to extrapolate 
results to other locations, together with atmospheric transport and 
fate models.
     Improved exposure models that include multiscale air 
dispersion models (neighborhood, urban, and regional) and simulated 
microenvironments of exposure, to estimate inhalation exposures to 
urban HAP and their potential transformation products.
     Improved modeling and monitoring to assess noninhalation 
exposures to contaminated foods, such as fish, vegetables and beef, 
resulting from deposition of urban HAP.
     Measurement methods for many HAP for which none are 
currently available.
     Reference values such as inhalation reference 
concentrations, acute reference exposure values, and cancer unit risk 
factors for those among the HAP for which such values have not been 
developed to perform quantitative risk assessments that EPA plans to 
use as part of this strategy.6
---------------------------------------------------------------------------

    \6\ The use of These values is an essential part of EPA's 
current practices in conducting risk assessment. For further 
information about how the we conduct risk assessments please refer 
to the draft Residual Risk Report to Congress on the EPA website 
(www.epa.gov/ttn/oarpg/t3/report/rrisk.pdf) and the National 
Research Council (NRC). 1994 Science and Judgment in Risk 
Assessment. National Academy Press, Washington, D.C. and the 
Commission on Risk Assessment and Risk Management (CRARM). 1997. 
Risk Assessment and Risk Management in Regulatory Decision making. 
Final Report, Volume 2.
---------------------------------------------------------------------------

     Statistical methods for quantifying and reducing 
uncertainty in risk assessments.
     Cost-effective control technologies for all HAP and more 
effective controls developed for those pollutants predicted to have 
residual risk using currently available controls.
e. What is the schedule for addressing the research needs?
    Research needed to improve the quantitative risk assessment and 
risk management of pollutants addressed in the urban air toxics 
strategy will be identified in a separate research needs chapter of the 
Integrated Urban Air Toxics Strategy Report to Congress that will be 
provided to the public in June of 1999. Our current and near-term 
planned research activities will also be described.

VI. How will EPA communicate with the public on progress in meeting 
the strategy's goals?

    The Act requires us to report to Congress at intervals not later 
than 8 and 12 years after the date of enactment of the CAA Amendments 
of 1990. We expect to provide the first Report to Congress when we 
issue the final strategy on June 18, 1999. We anticipate updating the 
public periodically on the status of the activities to implement the 
work plan, as well as the status of the activities to reduce risks in 
urban areas. However, we also expect to report to the public annually 
on the air quality and emissions trends for air toxics in urban and 
other areas in our annual Air Quality and Emissions Trends Reports.
    Many of the activities identified in the strategy will require 
further public notice and comment, and we will be providing further 
opportunities as they are developed. The public will also be able to 
measure the progress of the strategy by tracking these milestones.

VII. Regulatory Requirements

A. General

    Today's notice is not a rule and does not impose regulatory 
requirements or costs on any sources, including small businesses. 
Therefore, the EPA has not prepared an economic impact analysis 
pursuant to section 317 of the Act, nor a regulatory flexibility 
analysis pursuant to the Regulatory Flexibility Act (Pub. L. 96-354, 
September 19, 1980), nor a budgetary impact statement pursuant to the 
Unfunded Mandates Act of 1995. Also, this notice does not contain any 
information collection requirements and, therefore, is not subject to 
the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.

B. Executive Order 12866 and Office of Management and Budget (OMB) 
Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), the 
Agency must determine whether a regulatory action is ``significant'' 
and therefore subject to OMB review and the requirements of the 
Executive Order.

[[Page 49258]]

The Order defines ``significant'' regulatory action as one that is 
likely to lead to a rule that may either: (1) have an annual effect on 
this economy of $100 million or more, or adversely and materially 
affect a sector of the economy, productivity, competition, jobs, the 
environment, public health or safety, or State, local or tribal 
governments or communities; (2) create a serious inconsistency or 
otherwise interfere with an action taken or planned by another Agency; 
(3) materially alter the budgetary impact of entitlement, grants, user 
fees, or loan programs or the rights and obligations of recipients 
thereof; or (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, this is not a 
``significant regulatory action'' within the meaning of the Executive 
Order. This notice was submitted to OMB for review. Any written 
comments from OMB and written EPA responses are available in the 
docket.

C. Regulatory Flexibility Act of 1996

    Today's action is not a rule that requires the publication of a 
general notice of proposed rulemaking. Thus, it is not subject to the 
Regulatory Flexibility Act of 1980, as amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996. In any case, as mentioned 
above, this notice does not impose any regulatory requirements. 
Instead, it merely provides a draft list of source categories and a 
draft schedule of specific actions. Consequently, this notice will not 
have any economic impact on small entities.

D. Executive Order 13084: Consultation and Coordination With Indian 
Tribal Governments

    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments. If the mandate is unfunded, 
EPA must provide to the Office of Management and Budget, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected and other representatives of 
Indian tribal governments ``to provide meaningful and timely input in 
the development of regulatory policies on matters that significantly or 
uniquely affect their communities.'' Today's rule does not 
significantly or uniquely affect the communities of Indian tribal 
governments because it is not a rule and does not impose regulatory 
requirements or costs on any sources. Accordingly, the requirements of 
section 3(b) of Executive Order 13084 do not apply to this rule.

E. Applicability of the E.O. 13045: Children's Health Protection

    (62 FR 19885, April 23, 1997) applies to any rule that: (1) Is 
determined to be ``economically significant'' as defined under E.O. 
12866, and (2) concerns an environmental health or safety risk that EPA 
has reason to believe may have a disproportionate effect on children. 
If the regulatory action meets both criteria, the Agency must evaluate 
the environmental health or safety effects of the planned rule on 
children, and explain why the planned regulation is preferable to other 
potentially effective and reasonably feasible alternatives considered 
by the Agency.
    This draft strategy is not subject to the Executive Order because 
it is not a rule, it is not economically significant as defined in E.O. 
12866, and the Agency does not, at this time, have reason to believe 
the environmental health or safety risks addressed by this action 
present a disproportionate risk to children.
    The public is invited to submit or identify peer-reviewed studies 
and data, of which the Agency may not be aware, that assessed results 
of early life exposure to any of the HAP of concern discussed in this 
notice.

F. National Technology Transfer and Advancement Act

    Section 12 of the National Technology Transfer and Advancement Act 
of 1995 (NTTAA) requires Federal agencies to evaluate existing 
technical standards when developing new regulations. To comply with 
NTTAA, the EPA must consider and use ``voluntary consensus standards'' 
(VCS) if available and applicable when developing programs and policies 
unless doing so would be inconsistent with applicable law or otherwise 
impractical.
    The EPA believes that VCS are inapplicable to this draft strategy. 
The section 112(k)(3) strategy and section 112(c)(3) listing are not 
regulatory actions that require the public to perform activities 
conducive to the use of VCS. Instead, the strategy and listing are 
actions performed by the Agency in anticipation of potential future 
standard-setting, research, and other related activities. The EPA may, 
however, find that VCS are available, applicable, and practical for 
regulations that are promulgated in the future pursuant to the strategy 
and listing. In any case, the Agency requests comments on whether any 
VCS exist that could be considered for inclusion in this strategy and 
listing.

    Dated: August 31, 1998.
Robert Perciasepe,
Assistant Administrator for Air and Radiation.
[FR Doc. 98-24335 Filed 9-11-98; 8:45 am]
BILLING CODE 6560-50-P