Order Code RL33807
Air Quality Standards and Sound Science:
What Role for CASAC?
January 19, 2007
James E. McCarthy
Specialist in Environmental Policy
Resources, Science, and Industry Division

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Air Quality Standards and Sound Science: What Role
for CASAC?
Summary
As the Environmental Protection Agency (EPA) completes its reviews of the
ozone and particulate matter (PM) air quality standards – the PM review was
completed in September 2006, and the ozone review is due for completion in early
2008 – the Clean Air Scientific Advisory Committee (CASAC), an independent
committee of scientists that advises the agency’s Administrator, has received some
notable attention as a result of its disagreements with EPA’s decisions.
CASAC was established by statute in 1977. Its members, largely from academia
and from private research institutes, are appointed by the EPA Administrator. They
review the agency’s work in setting National Ambient Air Quality Standards
(NAAQS), relying on panels of the nation’s leading experts on the health and
environmental effects of the specific pollutants. CASAC panels have a nearly 30-
year history of working quietly in the background, issuing what were called “closure
letters” on agency documents that summarize the science and the policy options
behind the NAAQS. The science and policy documents, written by EPA staff,
generally have gone through several iterations before the scientists were satisfied,
but, with the issuance of a closure letter, CASAC has in past years removed itself
from the process, leaving the final choice of standards to the Administrator.
In 2006, however, CASAC and its 22-member PM Review Panel forcefully
objected to the Administrator’s decisions regarding revision of the particulate
NAAQS. The committee took the unprecedented steps of writing to the
Administrator both after he proposed the standards in January, and after he
promulgated them in September. In the latter communication, CASAC stated
unanimously that the Administrator’s action “does not provide an ‘adequate margin
of safety ... requisite to protect the public health’ (as required by the Clean Air Act)
....” (Italics in original)
Within a month of CASAC’s September 2006 letter, the committee’s ozone
review panel approved EPA’s policy options Staff Paper, the next-to-last formal step
before the Administrator proposes to retain or revise the ozone NAAQS. In doing
so, the panel drew a firm line (“There is no scientific justification for retaining the
current primary 8-hr NAAQS”), and recommended a range far more stringent than
the current standard. The Administrator has until May 2007 to propose a decision.
At the same time that CASAC panels were speaking out, EPA was conducting
a review of CASAC’s role and other aspects of the NAAQS-revision process. A
December 7, 2006 EPA memorandum makes a number of changes in that process
that many argue will diminish the role of CASAC and agency scientists. CASAC has
not formally opposed these changes. However, a number of Senators have written
the EPA Administrator to express their opposition to the changes, and Congress is
expected to take up these issues through oversight hearings. This report discusses
these issues, focusing on the statutory and historical role of CASAC and various
proposals for change.

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Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The Role of NAAQS in Air Quality Regulation . . . . . . . . . . . . . . . . . . 1
CASAC and NAAQS Revision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2006: A Pivotal Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
History of the NAAQS-Setting Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Legislative History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Specifics of the Statutory Requirements . . . . . . . . . . . . . . . . . . . . . . . . 6
Standard-Setting in Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Early Reports / Memoranda Concerning the NAAQS Process . . . . . . . . . . . 9
EPA's 1979 CASAC Memorandum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Memos and Reports in the 1980s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2006 Agency Review of the NAAQS Process . . . . . . . . . . . . . . . . . . . . . . . 10
Current and Former CASAC Members’ Views of the NAAQS Process . . . 15
Criteria Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Closure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Public Comments and Transparency . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Timeliness and Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Distinguishing Scientific Judgments from Policy Choices and
Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
A Consensus Observation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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Air Quality Standards and Sound Science:
What Role for CASAC?
Introduction
The Role of NAAQS in Air Quality Regulation. Setting National Ambient
Air Quality Standards (NAAQS) is an action that is at the core of the Clean Air Act.
NAAQS apply to “criteria” pollutants – pollutants that “endanger public health or
welfare,” and whose presence in ambient air “results from numerous or diverse
mobile or stationary sources.”1 Six pollutants are currently identified as criteria
pollutants.2 The EPA Administrator can add to the list if he determines that
additional pollutants meet the act’s criteria, or delete them if he concludes that they
no longer do so.
NAAQS do not directly regulate emissions. Rather, the primary NAAQS
identify pollutant concentrations in ambient air that must be attained to protect public
health with an adequate margin of safety; secondary NAAQS identify concentrations
necessary to protect public welfare, a broad term that includes damage to crops,
vegetation, property, building materials, etc.3
In essence, NAAQS are standards that define what EPA considers to be clean
air. Their importance stems from the long and complicated implementation process
that is set in motion by their establishment. Once NAAQS have been set, EPA, using
monitoring data and other information submitted by the states, identifies a list of
areas that exceed the standards and must, therefore, reduce pollutant concentrations
to achieve them. State and local governments then have three years to produce State
Implementation Plans which outline the measures they will implement to reduce the
pollution levels in these “nonattainment” areas. EPA also acts to control many of the
NAAQS pollutants wherever they are emitted through national standards for products
that emit them (particularly mobile sources, such as automobiles) and emission
standards for new stationary sources, such as power plants.
CASAC and NAAQS Revision. Because the understanding of pollution’s
effects changes with new research, the Clean Air Act requires that EPA review
NAAQS at five-year intervals and revise them as may be appropriate. To ensure that
1 Authority to establish NAAQS comes from Section 109 of the act, and the procedures for
controlling NAAQS (or “criteria”) pollutants are found throughout Titles I, II, and IV of the
act. Pollutants that are less widely emitted are generally classified as “hazardous air
pollutants” and are regulated under a different section of the act (Section 112).
2 The six criteria pollutants are ozone, particulates, carbon monoxide, sulfur dioxide,
nitrogen oxides, and lead. All six were first identified as criteria pollutants subject to
NAAQS in the 1970s.
3 The Clean Air Act’s definition of welfare is found in Section 302(h) of the act.

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CRS-2
these reviews meet the highest scientific standards, the 1977 amendments to the act
required the Administrator to appoint an independent Clean Air Scientific Advisory
Committee (CASAC). CASAC has seven members, largely from academia and from
private research institutions, who generally serve for two consecutive three-year
terms. In conducting NAAQS reviews, their expertise is supplemented by panels of
the nation’s leading experts on the health and environmental effects of the specific
pollutants that are under review. These panels can be quite large. The recent
particulate matter and ozone review panels, for example, had 22 and 23 members,
respectively. CASAC, as well as the public, makes suggestions regarding the
membership of these panels, with the final selections made by EPA. The panels
review the agency’s work during NAAQS-setting and NAAQS-revision, rather than
conducting their own independent reviews.
CASAC panels have a nearly 30-year history of working quietly in the
background, advising the agency’s staff on NAAQS reviews, and issuing what were
called “closure letters” on the agency documents that summarize the science and the
policy options behind the NAAQS. Closure letters have been used by CASAC
panels to indicate a consensus that the agency staff’s work provides an adequate
scientific basis for regulatory decisions. The science and policy documents, written
by EPA staff, generally have gone through several iterations before the scientists
were satisfied, but, with the issuance of a closure letter, CASAC has in past years
removed itself from the process, leaving the formal proposal and final choice of
standards to the Administrator. Proposal comes in the form of a Federal Register
notice that triggers a formal public comment period, and the final choice is
promulgated in the Federal Register, as well, following the review of public
comments.
2006: A Pivotal Year. In 2006, the usual pattern of NAAQS reviews was
upset by three events. First, as EPA promulgated revisions to the particulate matter
(PM) NAAQS, CASAC and its PM Review Panel publicly objected both to the
Administrator’s decision not to strengthen the annual standard for fine particulates
(PM ) and to various aspects of his decision regarding larger particles (PM ).4 The
2.5
10
committee took the unprecedented steps of writing to the Administrator both after he
proposed the standards in January, and after he promulgated them in September. In
the latter communication, CASAC stated unanimously that the Administrator’s
action “does not provide an ‘adequate margin of safety ... requisite to protect the
public health’ (as required by the Clean Air Act) ....”5 (Italics in original.)
4 The decisions that CASAC objected to also failed to follow the advice of EPA’s Staff
Paper, which CASAC had endorsed in letters dated June 6, 2005, and September 15, 2005.
See letters of Dr. Rogene Henderson, Chair, CASAC, to Hon., Stephen L. Johnson,
Administrator, U.S. EPA, June 6, 2005, at [http://epa.gov/sab/pdf/casac-05-007.pdf] and
September 15, 2005, at [http://epa.gov/sab/pdf/sab-casac-05-012.pdf]. These letters did not
use the word “closure,” a point of controversy that will be discussed later in this report. For
many members of CASAC, the absence of closure in 2005 appears to have been the root of
the public controversy over the PM standard in 2006.
5 Letter of Rogene Henderson et al. of the Clean Air Scientific Advisory Committee to Hon.
Stephen L. Johnson, EPA Administrator, September 29, 2006, available at
(continued...)

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CRS-3
A month after CASAC’s challenge to the final particulate decision, CASAC’s
ozone review panel took an unusually strong stand regarding review of that NAAQS.
The panel approved EPA’s policy options paper (or “Staff Paper”), the next-to-last
formal step before the Administrator proposes revision of the ozone NAAQS, but
in doing so it stated, “There is no scientific justification for retaining the current
primary 8-hr NAAQS ...,” and it recommended a range for the revised standard that
would be substantially more stringent than the current standard.6 The Administrator
has until May 2007 to propose a decision, and February 2008 to finalize it.
These actions by CASAC and its ozone panel were followed in short order by
an EPA announcement, December 7, 2006, that it will modify the process for setting
and reviewing NAAQS. Under EPA’s new procedures, the agency’s political
appointees7 will have a role early in the process, helping to choose the scientific
studies to be reviewed, and CASAC will no longer have a role in approving the
policy Staff Paper with its recommendations to the Administrator. (The Staff Paper
will also be renamed, becoming a “Policy Assessment.”) CASAC will be relegated
to commenting on the paper after it appears in the Federal Register, during a public
comment period.
The goal, according to agency officials, is to speed up the review process, which
has consistently taken longer than the five years allowed by statute. “These
improvements will help the agency meet the goal of reviewing each NAAQS on a
five-year cycle as required by the Clean Air Act, without compromising the scientific
integrity of the process,”8 according to the memorandum that finalized the changes.
The changes caused concern among environmental groups and some in the scientific
community, however, because, they say, they give a larger role to the agency’s
political appointees and a smaller role to EPA staff and CASAC.
These three events (CASAC’s challenge of the PM NAAQS, its panel’s
unusually forceful stance regarding revision of the ozone NAAQS, and EPA’s
decision to change the NAAQS review process) have thrust CASAC, heretofore a
relatively obscure scientific committee, into the limelight. Hearings on CASAC’s
role are expected early in the new Congress. More broadly, the developments raise
5 (...continued)
[http://www.epa.gov/sab/pdf/casac-ltr-06-003.pdf]. Italics in original. For additional
discussion of the PM standard controversy, see CRS Report RL33776, Clean Air Act Issues
in the 110th Congress: Implementation and Oversight, by James E. McCarthy.
6 Letter of Rogene Henderson, Chair , Clean Air Scientific Advisory Committee, to Hon.
Stephen L. Johnson, EPA Administrator, October 24, 2006, available at [http://www
.epa.gov/sab/pdf/casac-07-001.pdf].
7 As in other executive branch agencies or departments, the senior management of EPA
consists of officials appointed by the President and confirmed by the Senate.
8 “Process for Reviewing National Ambient Air Quality Standards,” Memorandum of
Marcus Peacock, Deputy EPA Administrator, to Dr. George Gray, Assistant Administrator,
Office of Research and Development, and Bill Wehrum, Acting Assistant Administrator,
Office of Air and Radiation, December 7, 2006, p. 3, available at [http://www
.epa.gov/ttn/naaqs/memo_process_for_reviewing_naaqs.pdf].

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important questions regarding the role of science and scientists in the setting of air
quality standards.
To provide a better understanding of these issues, this report provides a history
of the NAAQS-setting process and the role of CASAC since its inception in the late
1970s. It also reviews various proposals for change that have been discussed,
including EPA’s recently announced modifications.
History of the NAAQS-Setting Process
Legislative History. Prior to enactment of the Clean Air Act of 1970, there
was no authority for the establishment of national ambient air quality standards.
Control of air pollution and standards for air quality were considered primarily a
state’s right and responsibility.
Beginning in 1963, however, Congress began establishing the framework for
what became the NAAQS-setting process. The Clean Air Act of 1963 (P.L. 88-206)
and the Air Quality Act of 1967 (P.L. 90-148) directed the Secretary of Health,
Education, and Welfare9 to “develop and issue to the States such criteria of air quality
as in his judgment may be requisite for the protection of the public health and
welfare.” These criteria were to be issued “after consultation with appropriate
advisory committees and Federal departments and agencies,” and were to “accurately
reflect the latest scientific knowledge useful in indicating the kind and extent of all
identifiable effects on health and welfare....”10 To provide scientific advice, the
Surgeon General established a National Air Quality Criteria Advisory Committee
(NAQCAC) in March 1968.11
Establishment of the NAAQS Process. The air quality criteria were
originally intended primarily to assist the states in establishing their own air quality
standards; but they survive today as the first step in the establishment of national
standards (NAAQS). NAAQS themselves were first required by the Clean Air Act
Amendments of 1970 (P.L. 91-604). The 1970 amendments directed the new
Environmental Protection Agency (which had taken over the air pollution functions
of the Health, Education, and Welfare Department) to promulgate NAAQS for each
pollutant for which air quality criteria had already been issued,12 and to promulgate
9 At the time, the Environmental Protection Agency had not been established.
10 Section 107 of the Clean Air Act (P.L. 88-206, 1963), as amended by the Air Quality Act
of 1967 (P.L. 90-148).
11 Morton Lippmann, “Role of Science Advisory Groups in Establishing Standards for
Ambient Air Pollutants,” Aerosol Science and Technology, Volume 6, 1987, p. 101.
12 Four months after enactment of this authority, on April 30, 1971, the EPA Administrator
established the first NAAQS, simultaneously promulgating standards for six categories of
pollutants: particulate matter, photochemical oxidants (principally ozone), hydrocarbons,
sulfur oxides, nitrogen dioxide, and carbon monoxide. With some modifications, these
NAAQS form the cornerstone of the agency's air pollution regulatory programs today, 36
years later. Three of the standards (for SO , NOx, and CO) have changed little. The PM
2
(continued...)

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CRS-5
NAAQS with respect to any additional air pollutant for which criteria would be
issued after the date of enactment.13
Primary NAAQS, as described in Section 109(b)(1), were to be “ambient air
quality standards the attainment and maintenance of which in the judgment of the
Administrator, based on such criteria and allowing an adequate margin of safety, are
requisite to protect the public health.” Secondary standards (which, in practice, are
often the same as the primary) were also to be based on the criteria and set at a level
“requisite to protect the public welfare from any known or anticipated adverse
effects” (Section 109(b)(2)). The Administrator was permitted to revise both types
of standards.
Establishing Formal Review Requirements: SAB and ERDDAA. To assist
the Administrator in setting criteria, the Advisory Committee established by the
Surgeon General in 1968 (NAQCAC) was transferred to EPA in 1970, as part of the
Reorganization Plan that established EPA, but it had no statutory authority.
According to Lippmann, a former Chair of CASAC and perhaps the man most
familiar with the history, “EPA did not necessarily feel obliged to follow the advice
of the Committee.”14
Beginning in 1974, EPA reorganized its science advisory structure several times,
ultimately abolishing NAQCAC over the strong objections of its chairman and
members, and reassigning the members to the agency's Science Advisory Board
(SAB). According to Lippmann, at the time it was abolished, “It had been surveying
the contents of all the CDs [Criteria Documents] and was drafting a final report that
recommended a complete review and revisions of all the air quality criteria
documents.”15 About this time, the House Science and Technology Committee held
hearings and produced an investigative report on a series of EPA studies that were
intended to provide an improved health basis for the NAAQS.16 The report led to
provisions in the Environmental Research and Development Demonstration
Authorization Act of 1978, enacted in November 1977 (ERDDAA, P.L. 95-155) that
required the SAB to review all scientific information on which air quality standards
are based.
12 (...continued)
and oxidant standards have been modified, both in the form and the specified concentration
of the pollutants, reflecting the developing understanding of the effects of PM and ozone
pollution, but the categories of pollution being regulated have not changed. The
hydrocarbon standard was revoked in 1983, but hydrocarbons continue to be stringently
regulated (as volatile organic compounds) in order for areas to meet the ozone NAAQS.
13 Only one additional NAAQs has been issued, for lead, in 1978.
14 Lippmann, previously cited, p. 101.
15 Ibid.
16 U.S. House of Representatives. Committee on Science and Technology. The
Environmental Protection Agency Research Program with Primary Emphasis on the
Community Health and Environmental Surveillance System (CHESS): An Investigative
Report. November 1976.

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1977 Clean Air Act Amendments: Deadlines and CASAC. The process
of establishing NAAQS, in Section 109 of the Clean Air Act, was also amended in
the Clean Air Act Amendments of 1977 (P.L. 95-95), adding two major dimensions.
First, in Section 109(d)(1), the act established a more formal requirement for review
and revision of the NAAQS, directing the Administrator to review the criteria and
standards by December 31, 1980, and at five-year intervals thereafter. For a variety
of reasons (lack of resources, inadequacies in draft documents, competing demands
on agency managers, and in some cases, a lack of political will), these reviews have
generally not taken place on the schedule mandated, but, by establishing a
nondiscretionary duty of the Administrator, the 1977 act has allowed citizen suits to
force the Administrator to undertake reviews.
Second, in Section 109(d)(2), the amendments required the EPA Administrator
to appoint “an independent scientific review committee” (to which EPA gave the
name CASAC), requiring that it also complete a review of the criteria and standards
by December 31, 1980 and at five-year intervals thereafter, and that it recommend to
the Administrator any new NAAQS and revisions of existing criteria and standards
as may be appropriate. While CASAC is directed to review the criteria and NAAQS
and make recommendations to the Administrator, the Administrator is not under a
legal obligation to follow CASAC’s advice. As noted below, however, Section
307(d) of the Clean Air Act requires the Administrator to explain the reasons for any
differences from CASAC's or the National Academy of Science's recommendations.
Thus, in the same year, 1977, Congress gave authority to both CASAC and the
SAB to review air quality criteria and NAAQS. EPA resolved this potentially
overlapping jurisdiction by making CASAC part of the Science Advisory Board.
There have been no changes to these legislative requirements since 1977.
Specifics of the Statutory Requirements. In Section 108, the Clean Air
Act requires the Administrator to provide specific information regarding criteria
pollutants, without specifying the form of any required documents. It describes at
some length what the criteria shall “reflect” and “include.” In response to this
language, EPA has developed what it has called a Criteria Document, whenever it has
reviewed or established a new NAAQS. The Criteria Document summarizes the
state of scientific knowledge regarding the effects of the pollutant in question.
A second document that EPA has prepared as part of the NAAQS-setting or
revision process, the Staff Paper, summarizes the information compiled in the
Criteria Document and provides the Administrator with options regarding the
indicators, averaging times, statistical form, and numerical level (concentration) of
the NAAQS. The Staff Paper has no statutory basis, but it is hard to imagine the
setting of a standard without some document or documents that would serve its
purpose.
Section 109 of the Clean Air Act makes clear that NAAQS are to be proposed
and promulgated as regulations, thus requiring their publication in the Federal
Register. The procedural requirements are addressed in Section 307(d), which
exempts NAAQS promulgation or revision from the requirements of the
Administrative Procedure Act, but establishes its own (in most cases, similar)

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requirements. Section 307(d) requires the establishment of a rulemaking docket; it
requires notice of proposed rulemaking in the Federal Register, accompanied by a
statement of the proposal’s basis and purpose, including a summary of the factual
data on which the proposed rule is based, the methodology used in obtaining and
analyzing the data, and the major legal interpretations and policy considerations
underlying the proposed rule. The statement is required to set forth or summarize
and provide a reference to any pertinent findings, recommendations, and comments
by CASAC and the National Academy of Sciences, and, if the proposal differs in any
important respect from any of these recommendations, provide an explanation of the
reasons for such differences.
Section 307(d) also requires that any drafts of proposed and final rules
submitted by the Administrator to the Office of Management and Budget (OMB)
prior to proposal or promulgation, all documents accompanying those drafts, and all
written comments thereon and EPA responses to such comments, be placed in the
docket no later than the date of proposal or promulgation.
The promulgated NAAQS, like the proposed rule, must appear in the Federal
Register. It must be accompanied by a statement of basis and purpose and an
explanation of the reasons for any major changes from the proposed rule, as well as
a response to each of the significant comments, criticisms, and new data submitted
during the public comment period.
Standard-Setting in Practice. In practice, NAAQS standard-setting has not
directly followed the path envisioned in the statute. Only one of the six standards
(for photochemical oxidants/ozone) was reviewed by December 31, 1980, and none
has been reviewed at five-year intervals since that time. Several reviews have been
begun, only to languish for years in limbo, with no criteria being issued and no
decisions as to standards being made. The agency has rarely had the resources to
conduct more than two reviews at a time. Citizen suits have generally been the factor
that sets the agency's priorities.
Role of CASAC. As discussed further in later sections of this report, the Clean
Air Scientific Advisory Committee has been one of the few exceptions to this record.
CASAC has provided much of the discipline to keep the NAAQS process moving
and has set high standards for agency reviews. As a result, the completed reviews
have generally elicited respect from the scientific community, and have generally
survived court challenge.
At the same time, CASAC’s role has been somewhat different than that
specified by the letter of the statute.17 Rather than conduct its own independent
17 CASAC's establishment by statute, and its modus operandi apparently grew out of the
experience of an ad hoc scientific advisory body that helped EPA develop the NAAQS for
lead in the 1970s. For the history of this, see Roger O. McClellan, “Comments on National
Ambient Air Quality Standards Review Process,” March 18, 2006, in U.S. EPA, NAAQS
Process Review Workgroup, Review of the Process for Setting National Ambient Air Quality
Standards, March 2006, Attachment 3-B, pp. 4-5, at [http://www.epa.gov
/ttn/naaqs/naaqs_process_report_march2006_attachments.pdf], hereafter referred to as
(continued...)

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CRS-8
reviews of a NAAQS, CASAC in practice has fulfilled its obligations by reviewing
and evaluating the adequacy of the key documents (the Criteria Document and Staff
Paper) prepared by EPA staff as they develop or review a NAAQS.
In conducting these reviews, CASAC has played an important role in the
decision-making process: in general, the Administrator has not proposed a revision
of a NAAQS until CASAC provides him (or her) what have been called “closure
letters,” stating its consensus that the Criteria Document and Staff Paper provide an
adequate scientific basis for regulatory decisionmaking. The closure letter is not
statutorily required; it dates from a June 1979 memorandum presented to CASAC by
key officials in EPA's Office of Research and Development, Office of Air Quality
Planning and Standards, and the CASAC staff officer.18 Until the PM review just
completed in 2006, however, every NAAQS review resulted in closure letters before
the Criteria Document and Staff Paper went to the Administrator for decisions on
NAAQS revision. As will be discussed further below, this departure from past
practice in the 2006 NAAQS for PM was opposed by numerous current and former
CASAC members in comments to EPA.19
Staff Paper Recommendations. The recommendations in Staff Papers have
tended to provide a range of options, so that the Administrator's choice often fell
somewhere within the range discussed. For example, in 1997, when EPA revised the
PM standard, the Staff Paper recommended a 24-hour PM standard somewhere in
2.5
the range of 20 to 65 µg/m3. The Administrator chose 65 µg/m3 as the standard. The
Staff Paper also recommended an annual standard of 12.5 to 20 µg/m3. The
Administrator chose 15 µg/m3.
On several occasions, the Administrator took no action, despite a Staff Paper
recommendation. For example in 1990, a Staff Paper on revision of the lead standard
recommended a range of standards from 0.5 to 1.5 µg/m3 (vs. the existing standard
of 1.5 µg/m3), a monthly rather than quarterly averaging period, and more frequent
sampling. EPA took no action on the recommendations, however, and never
formally published a decision.
The sulfur dioxide review completed in 1996 provides a slightly different
example in which the agency deviated from Staff Paper recommendations. In this
case, the Staff Paper recommended three possible regulatory alternatives: 1) establish
a new 5-minute NAAQS; 2) establish a new regulatory program under the general
17 (...continued)
“Workgroup Report Attachments.” Dr. McClellan chaired the ad hoc lead committee in the
late 1970s and has served on or chaired CASAC or its review panels for much of the time
since then.
18 See “Recommended Practices for Involving the Clean Air Scientific Advisory Committee
(CASAC) in the Review Process for National Ambient Air Quality Standards,”
Memorandum from Lester D. Grant, Ph.D., Joseph Padgett, and Terry F. Yosie, p. 2. Memo
is undated, but was presented to CASAC June 15, 1979.
19 See the comments of Dr. Philip K. Hopke, Dr. Morton Lippmann, Dr. Joe Mauderly, Dr.
George T. Wolff, and Dr. Roger O. McClellan in Workgroup Report Attachments, pp. A-17-
18, A-20, A–23, A-27, and McClellan letter pp. 5-6.

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authority of Section 303 of the Clean Air Act; or 3) retain the existing suite of
standards, but augment their implementation by focusing on those sources likely to
produce high 5-minute peak SO levels. EPA retained the existing standard but has
2
not addressed the augmentation issue.
Early Reports / Memoranda Concerning the NAAQS Process
After the last statutory changes to the NAAQS-setting process in 1977,
numerous reports and memoranda discussed CASAC's role and the standard-setting
process in general. This section briefly reviews these reports and memoranda, before
we turn to the 2006 revisions to the process in the next section.
EPA's 1979 CASAC Memorandum. In a 1979 memorandum entitled
“Recommended Practices for Involving the Clean Air Scientific Advisory Committee
(CASAC) in the Review Process for National Ambient Air Quality Standards,” key
officials in EPA's Office of Research and Development and Office of Air Quality
Planning and Standards and the CASAC staff officer laid out procedures “to define
what CASAC should review, the type of output to result from such reviews, and how
these reviews can be accomplished consistent with Congressionally mandated time
schedules.”20 The memo identified six phases of a NAAQS review (planning,
preparation of a draft report, internal review, public review, document revision, and
CASAC closure); it estimated the time needed for each phase (a total of 285-360
days for all six phases); and it identified where in the process CASAC review and
closure would occur. According to CASAC staff, this memorandum was never
formally approved, but the procedures, including CASAC “closure” on Criteria
Documents and Staff Papers, grew out of its recommendations.21
Memos and Reports in the 1980s. In the 1980s, as EPA began conducting
the NAAQS reviews mandated by the 1977 amendments, and as CASAC developed
its procedures for NAAQS review, a number of reports and memoranda discussed
those procedures. In March 1981, the National Commission on Air Quality, a
Congressionally-mandated 13-member bipartisan and multi-stakeholder commission,
discussed the setting and revision of NAAQS in its final report.22 In September 1981,
CASAC itself completed a report with recommendations concerning the NAAQS
standard-setting process.23 A draft report prepared for EPA's Office of Research and
Development in August 1984 focused on the structure of the Criteria Document.24
20 Grant, Padgett, and Yosie memo, p. 2, previously cited.
21 Personal communication, Vanessa Vu, Director, Science Advisory Board Staff Office,
U.S. EPA, April 24, 2006.
22 U.S. National Commission on Air Quality, To Breathe Clean Air, Final Report,
Washington, D.C., March 1981. The Commission was established by Congress under the
Clean Air Act Amendments of 1977 “to make an independent analysis of air pollution
control and alternative strategies for achieving the goals of the act.”
23 U.S. EPA, Clean Air Scientific Advisory Committee, “Setting Ambient Air Quality
Standards: Improving the Process,” September 1981.
24 R.M. Dowd & Company for U.S. EPA Office of Research and Development,
(continued...)

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CRS-10
And, in July 1985, CASAC issued an update report, noting that many of its 1981
recommendations had been successfully implemented, but identifying additional
issues to further improve the NAAQS process.25
These reports and memos made a number of recommendations that have
resurfaced in the December 2006 revisions to the NAAQS review process. These
include repeated conclusions that the Criteria Documents are too long or too
encyclopedic and need to be focused on key scientific issues. To improve the focus,
CASAC, as early as 1981, called for the identification of critical scientific issues and
greater public involvement in the early stages of the NAAQS review process.
CASAC, both in 1981 and 1985, also called for increased efforts to develop and
incorporate risk assessment methodologies in order to better evaluate and
communicate the uncertainties inherent in the analyses.
2006 Agency Review of the NAAQS Process
After the mid-1980s, there was little further discussion of changes to the
NAAQS review process until December 2005, when EPA’s Deputy Administrator
asked the Assistant Administrator for Research and Development and the Acting
Assistant Administrator for Air and Radiation to “conduct a top-to-bottom review of
the NAAQS process” to determine whether its discretionary (as opposed to statutory)
aspects “reflect the most rigorous, up-to-date, and unbiased scientific standards and
methods.” The letter set forth a series of specific questions regarding the timeliness
of the process, consideration of the most recent available science, the distinction
between science and policy judgments, and whether changes were necessary to better
identify and communicate uncertainties.26 The two Assistant Administrators
established a Workgroup of EPA staff to conduct the review and make
recommendations.
The review was essentially completed by April 3, 2006, when the two Assistant
Administrators sent the Workgroup’s report to the Deputy Administrator.27 The
report led to further discussions with CASAC and a public meeting, before the
24 (...continued)
“Recommendations to Improve the Process of Preparing Air Quality Criteria Documents,”
Draft, August 1984, 17 p. Richard Dowd served as principal science advisor to the EPA
Administrator from 1977 to 1981 and was acting Assistant Administrator for Research and
Development in 1980 and 1981.
25 U.S. EPA, Clean Air Scientific Advisory Committee, “Report of the Clean Air Scientific
Advisory Committee (CASAC) on Improving the Process for Setting National Ambient Air
Quality Standards: An Update,” July 1985.
26 See Letter of Marcus Peacock, Deputy Administrator, U.S. EPA, to Dr. George Gray,
Assistant Administrator for Research and Development, and Bill Wehrum, Acting Assistant
A d m i n i s t r a t o r f o r A i r a n d R a d i a t i o n , D e c e m b e r 1 5 , 2 0 0 5 , a t
[http://www.epa.gov/ttn/naaqs/naaqs_process_report_march2006_attachments.pdf].
27 U.S. EPA, NAAQS Process Review Workgroup, Review of the Process for Setting
National Ambient Air Quality Standards, March 2006 (hereafter, “EPA 2006 Review”) at
[http://www.epa.gov/ttn/naaqs/naaqs_process_report_march2006.pdf].

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CRS-11
Deputy Administrator announced a decision, December 7, 2006, that the Agency
would revise the NAAQS process, largely along the lines suggested in the report.
The Workgroup report reached many of the same conclusions as the 1980s’
reviews. As the Executive Summary noted:
Past reviews of the process have addressed a number of issues, including the
difficulty EPA has had historically in completing NAAQS reviews at five-year
intervals as required by the CAA, resulting in litigation-driven review schedules;
the statutory role of the Clean Air Scientific Advisory Committee (CASAC) in
providing scientific and policy-relevant advice to the Administrator; concerns
about the “encyclopedic” nature of EPA's science assessment documents
(referred to as “Criteria Documents”) and support for a more integrative
synthesis of the science; and general support for the introduction and subsequent
evolution of a policy-oriented “Staff Paper” to help bridge the gap between the
science presented in the Criteria Document and the policy judgments required of
the Administrator in reaching decisions on the NAAQS. While many
improvements have come about as a result of these past reviews, some of the
same issues remain relevant today, and are addressed again in this process
review.28
The report recommended:
! combining planning activities for the Criteria Document (CD),
risk/exposure, and policy assessment into one integrated planning
document;
! restructuring the CD to be a more concise evaluation, integration,
and synthesis of the most policy-relevant science, and writing it in
language more accessible to policy-makers, “perhaps in the form of
a ‘plain-English’ executive summary”;
! developing a continuous process to identify, compile, characterize,
and prioritize new scientific studies;
! developing a more concise risk/exposure assessment document
(similar to the risk/exposure chapter(s) now included in Staff
Papers);
! to the extent that the recommendations above are implemented,
replacing the Staff Paper with a more narrowly focused policy
assessment document; and
! working with SAB staff to consider the formation of a CASAC
subcommittee on risk/exposure assessment, examining additional
measures that can be taken to orient new CASAC panel members,
28 Ibid., p. E-1.

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CRS-12
and giving further consideration to the issue of CASAC closure in
its review of key documents.29
The first five of these recommendations were adopted in the December 7, 2006
decision memorandum with little change. Most were relatively non-controversial,
although some, such as the continuous process for review of new scientific studies,
could require additional resources. Also non-controversial would be better focus of
the Criteria Document (renamed the “Integrated Science Assessment”), a
recommendation made by virtually every group that has reviewed the subject over the
last 30 years.
One of CASAC’s major suggestions, stated in letters to the Administrator dated
May 12, 2006 and July 18, 2006, was that the initial step in the review process be the
convening of a “science workshop,” at which an invited group of expert scientists
would “identify important new scientific findings regarding the pollutant in
question.”30 EPA staff, CASAC members, and the public would be invited to the
workshop, and, prior to it, “CASAC would provide input to the Agency to identify
subject-matter experts and key new scientific studies and findings to be discussed.”
The December 7 decision memorandum accepted this CASAC suggestion, and, as
a result, press reports indicate that CASAC is generally pleased with the final
decisions.31
One potentially more controversial change is the preparation of a separate
risk/exposure assessment, and a related recommendation that CASAC consider
formation of a separate subcommittee on risk/exposure assessment. In the
Workgroup report released April 3, 2006, these recommendations were presented as
measures that “could enhance the efficiency and timeliness of the overall NAAQS
review process.”32 In calling for better risk assessment, the 2006 review echoed the
recommendations of both the 1981 and 1985 CASAC reviews. Better risk
assessment would presumably clarify the policy choices the Administrator faces in
making NAAQS decisions. At the same time, it is difficult to see how adding a third
29 Ibid., pp. E-3-4. A more complete discussion of the conclusions and recommendations
is found on pp. 30-33.
30 These questions would include “low-concentration effects [of the pollutant] on both
public health and public welfare; current trends in atmospheric chemistry and pollutant
distributions; characterization of both anthropogenic and natural sources of pollutant or
precursor emissions; and appropriate risk assessment approaches for this particular
pollutant.” See letter of Dr. Rogene Henderson, Chair, CASAC, to Hon. Stephen L.
Johnson, Administrator, U.S. Environmental Protection Agency, July 18, 2006, at
[http://www.epa.gov/sab/pdf/casac_input_epa_naaqs_process_rev_july_2006_final_ltr.pdf].
31 Dr. Rogene Henderson, CASAC’s Chair, for example, was quoted by InsideEPA as
“pleased that EPA accepted two recommendations from CASAC as part of changes to the
NAAQS review process” – the two changes being the science workshop at the outset of the
review and the preparation of a more concise science assessment document, supplemented
by an electronic database with more detailed information. See “EPA Adviser Downplays
Democrats’ Criticism over New NAAQS Changes,” InsideEPA Clean Air Report, December
14, 2006.
32 EPA 2006 Review, p. 26.

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CRS-13
significant document to the process would enhance its timeliness, as stated in the
report. In its May 12, 2006, letter to the EPA Administrator, CASAC raised this
point. Noting that CASAC would now have to “double up” the scientific subject
matter to be considered at certain meetings, the CASAC Chair wrote:
Therefore, it was not apparent to us how the suggested alterations would make
the NAAQS process more efficient or streamlined. On the contrary, EPA’s
proposed process appears to be no less time-consuming and likely more
resource-intensive than the current process. Indeed, rather than helping the
Agency more-easily achieve its NAAQS reviews for the six criteria air pollutants
within the statutorily-mandated five-year period (i.e., per the Clean Air Act
Amendments of 1977 codified at 42 U.S.C. § Sec. 7409), the proposed process
would seemingly ensure that court-ordered completion dates — the result of
external litigation — would continue to be the principal “driver” for key
milestones in these NAAQS reviews.33
The December 7, 2006 decision memorandum retained the recommendation for
a risk/exposure assessment document, but, rather than call for formation of a separate
CASAC subcommittee on risk/exposure assessment (which CASAC “emphatically”
opposed in its July 18 letter), agreed to CASAC’s suggestion that risk assessment
experts be added to future CASAC review panels.
The Workgroup report’s recommendations concerning the Staff Paper (renamed
the “policy assessment document” in the report) are difficult to evaluate. Although
the language is somewhat vague, the report’s cover memo appears to recommend the
removal of EPA staff and CASAC from the document’s final review, making it a
reflection of EPA senior management views instead. The memo says, “We have
concluded that it is appropriate for the policy assessment document to reflect the
Agency's views, consistent with EPA practice in other rulemakings.”34 This
presumably means the views of the agency's senior management rather than its staff.
On the other hand, the Workgroup report stated:
We recognize that important and complex issues are involved in deciding
the scope of such a document, as well as deciding whether such a
document would continue to reflect staff views, EPA senior management
views, or both, and how that choice may affect the process by which such
a document would be reviewed by CASAC and the public.35
33 Letter of Dr. Rogene Henderson, Chair, CASAC, to Hon. Stephen L. Johnson,
Administrator, U.S. Environmental Protection Agency, May 12, 2006, at
[http://nsdi.epa.gov/sab/pdf/casac_initial_comments_epa_naaqs_proc_rev_2006_final_lt
r.pdf].
34 See “Review of Process for Setting National Ambient Air Quality Standards,”
Memorandum from George Gray, Assistant Administrator, Office of Research and
Development, and William Wehrum, Acting Assistant Administrator, to Marcus Peacock,
Deputy Administrator, U.S. EPA, April 3, 2006. The memo is available at [http://www
.epa.gov/ttn/naaqs/naaqs_process_report_march2006_cover.pdf].
35 EPA 2006 Review, p. 32.

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CRS-14
The December 7, 2006 decision memorandum reiterates the language of the April 3
recommendation, in stating:
... the Agency will develop a policy assessment that reflects the Agency’s views,
consistent with EPA practice in other rulemakings. ... This policy assessment
should be published in the Federal Register as an Advance Notice of Proposed
Rulemaking (ANPR), with supporting documents placed in the rulemaking
record as appropriate. The use of an ANPR will provide an opportunity for both
CASAC and the public to evaluate the policy options under consideration and
offer detailed comments and recommendations to inform the development of a
proposed rule.36
A number of observers have interpreted this language to mean that CASAC will
review the policy options after completion of the document rather than before,
diminishing its role in the NAAQS-review process. In its July 18, 2006 letter to the
Administrator, CASAC said that it wished to review both a first and second draft
version of the policy assessment (PA) document before the issuance of a Notice of
Proposed Rulemaking. The December 7 decision memorandum does not address this
wish directly, but its choice of language appears to have rejected CASAC’s request.
One press account quoted the CASAC Chair as saying, “They will come out with
their policy before we have a chance to comment on it.” But she added, “They
weren’t taking our advice” even under the old process, at least in the recent PM
decision.37 In another press account, she appeared less concerned about the changes
to the NAAQS process, however, reportedly saying: “I see it as the role of the
CASAC to advise the administrator on which levels will be health protective with an
adequate margin of safety. That we have done and that we will continue to do.”38
A general theme in the April 3 recommendations and the December 7 final
decision seems to be that the role of EPA senior management in the NAAQS-setting
process should be heightened, and that of CASAC lessened. The recommendation
for preparation of a single integrated planning document, for example, “would
provide an opportunity for early involvement of EPA senior management and/or
outside parties in the framing of policy-relevant issues,” according to the Review
Workgroup’s March 2006 report.39 The new policy assessment document would be
reviewed after the document's publication, despite CASAC’s recommendation that
it review a first and second draft. The March 2006 report also suggests: 1) a single
CASAC review of the policy assessment document, as opposed to the current
iterative process; 2) the apparent discontinuation of CASAC closure on the
36 “Process for Reviewing National Ambient Air Quality Standards,” Memorandum of
Marcus Peacock, Deputy EPA Administrator, to Dr. George Gray, Assistant Administrator,
Office of Research and Development, and Bill Wehrum, Acting Assistant Administrator,
Office of Air and Radiation, December 7, 2006, pp. 2-3, available at [http://www
.epa.gov/ttn/naaqs/memo_process_for_reviewing_naaqs.pdf].
37 Rogene Henderson, CASAC Chair, as quoted in “Greater Role for Nonscientists in EPA
Pollution Decisions,” New York Times, December 8, 2006, p. A22.
38 Inside EPA Clean Air Report, December 14, 2006, previously cited.
39 EPA 2006 Review, p. 31.

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CRS-15
document; and 3) CASAC’s comments to be solicited along with those of the
public.40
Three recommendations regarding CASAC in the Workgroup report also
suggested a less independent role for the Committee. These were:
! that EPA prepare more comprehensive guidance on CASAC’s
statutory role, to enhance the orientation of panel members and
“increase awareness of the importance of maintaining the distinction
between science and policy judgments” in CASAC’s
recommendations;
! that further consideration be given by EPA and “perhaps
communication with CASAC” regarding the issue of CASAC
“closure” on EPA documents; and
! that EPA's SAB Staff Office consider issues related to the selection
and management of CASAC NAAQS review panels.41
These recommendations may have arisen simply from concerns for effectiveness –
i.e., they may represent only a concern that the agency better orient new members,
make the selection process for review panels more transparent, and review the issue
of closure, which was raised by several current and former CASAC members in
comments they submitted to the workgroup. But coming in the context of the other
recommendations, they raised the possibility that EPA intended to weaken the
independence and power of CASAC through a variety of means.
Current and Former CASAC Members’ Views of the NAAQS
Process
As part of the 2006 NAAQS process review, EPA solicited comments from
current and former CASAC members and from stakeholder groups. EPA summarized
these comments on pages 15-20 of the Workgroup’s March 2006 report; the full text
of written comments from 12 current or former CASAC members was provided in
Attachment 3 to the report; and 4 letters from interested parties (states, environmental
groups, and the American Petroleum Institute) appeared in Appendix 4.
The most consistent comments concerned the need to improve the focus of
Criteria Documents and the need to reinstate the “closure” procedure.
Criteria Document. Commenters generally agreed that CDs are too
encyclopedic, take too long to compile, are too difficult to read, and are not
sufficiently focused on research that would inform the NAAQS review process.
Commenters had a number of suggestions for improving the process, which are
reflected in the workgroup's recommendations. EPA's latest CD, on ozone, was
40 Ibid., p. 28.
41 Ibid., p. 29.

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CRS-16
mentioned by several commenters as a vast improvement and a model for future
efforts.
Closure. The “closure” issue was raised by 7 of the current or former CASAC
members, who generally felt that the lack of closure on the latest PM Staff Paper
(completed in 2005) was a serious and unwarranted break with precedent, and has
contributed to the controversy over the proposed annual PM standard. CRS
2.5
contacted EPA staff to ask for background concerning the change in policy on
closure. In particular, EPA was asked if there were a memorandum or guidance
document, either from CASAC or from the agency, that explained the new policy.
EPA’s response was that there was, in fact, no change in policy. The current
CASAC chair, who assumed the Chairmanship in 2005, simply stopped using the
term “closure,” according to the Director of the Science Advisory Board Staff Office.
“She is trying to get away from the implication that CASAC ‘approves’ of the
document. It’s a semantic difference.”42
CASAC commenters appeared to strongly disagree with that assessment. Dr.
George Wolff, for example, said:
The recent decision by the Agency to eliminate the need for CASAC closure will
shorten the process, but, in my opinion, was a bad decision, and I fear that quality
will suffer. The iterative review process leading to closure gave the Agency
incentive to produce a document that CASAC would approve. Removing that
incentive could lead to inferior products.43
Dr. Morton Lippmann stated:
... it is important that any changes made in the process do not weaken the
long-established integrity, objectivity, and credibility of the process to the
scientific community and interested stakeholders. This needs to be explicitly
considered in light of the recent changes in SAB Staff management of CASAC’s
modus operandi in relation to its demands for discontinuing the issuance of a
formal ‘CASAC closure letter’ on Air Quality Criteria Documents (CDs) and
Staff Papers (SPs) from the CASAC review process. This management decision
was unwise ....44
Several of the statements regarding the closure decision show the strong feelings it
generated among CASAC members. Dr. Joe Mauderly stated:
One of the reasons given for the recent (apparently successful) move by EPA to
relegate CASAC to a reviewer, rather than an approver, of documents is that it
slows the process. That is pure balderdash. I cannot recall a single instance over
my 15 years of experience with the Committee that CASAC was truly the root
42 Telephone contact, Vanessa Vu, U.S. EPA, April 24, 2006.
43 Wolff, in U.S. EPA, NAAQS Process Review Workgroup, Review of the Process for
Setting National Ambient Air Quality Standards, March 2006, Attachments, p. A-27, at
[http://www.epa.gov/ttn/naaqs/naaqs_process_report_march2006_attachments.pdf].
44 Lippmann, in Workgroup Report Attachments, p. A-20.

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CRS-17
cause of significant delay. On the other hand, I can recall multiple instances in
which, if CASAC had not the prerogative to “close” on documents, EPA was
clearly on track to ignore scientific advice and move forward with inadequate
documents or incorrect conclusions.45
Dr. Bernard Goldstein added: “EPA’s recent decision tells the scientific community
that it is not worth our time to be involved in the EPA advisory process.”46
CASAC’s July 18, 2006 letter to the Administrator attempted to resolve the
“closure” issue by saying that, in order to avoid any implication that closure meant
“approval,” the Committee would go back to the original wording of the 1979 memo
in which the term closure was first used. “When the CASAC thinks that the science
presented in a particular document is adequate for rulemaking, it will affirmatively
state so in the closing paragraph of the final letter to the Administrator regarding the
review of that document.” This issue was not addressed in EPA’s December 7, 2006
decision memorandum.
Public Comments and Transparency. A third issue raised by several
commenters was a sense that EPA and CASAC do not adequately consider public
comments during the preparation of the Criteria Document and Staff Paper, in large
part because of the lack of a deadline for submission. For example, Dr. George
Wolff stated:
Over the years there have been numerous excellent scientific comments produced
by various organizations. Unfortunately, they typically arrive a day or two before
the CASAC meeting, which gives the members insufficient time to digest them.
... Some Agency response to the public comment documents should be prepared
and provided to CASAC.47
On a related note, Dr. Roger McClellan complained that too many of CASAC’s
meetings are now being scheduled as teleconferences, of which only a summary (no
transcript) is later made available.
Timeliness and Efficiency. There was general agreement that the biggest
obstacle to more timely completion of NAAQS reviews was the poor quality of initial
CD and Staff Paper drafts that EPA presented to CASAC for review. The net result
is an iterative (“ping pong”) process in which CASAC requests improvements to the
documents and EPA revises them, until, after several iterations, CASAC finally
closes on the documents’ adequacy.
Distinguishing Scientific Judgments from Policy Choices and
Values. Another area in which EPA asked for comments was on the issue of how
to distinguish more clearly scientific conclusions and advice from policy judgments
and recommendations. This question produced no consensus. On one hand, Dr. Ellis
Cowling and others noted that CASAC is required by the statute to “recommend to
45 Mauderly, in Workgroup Report Attachments, p. A-23.
46 Goldstein, in Workgroup Report Attachments, p. A-12.
47 Wolff, in Workgroup Report Attachments, pp. 27-28.

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CRS-18
the Administrator any new ambient air quality standards.” As Dr. Hopke noted, in
distinguishing between science and policy judgments:
I hearken back to the law which asks the Committee to recommend a standard.
CASAC has typically left the recommendation to the staff through closure on the
SP. Now since closure has been eliminated, it becomes incumbent on the
Committee to make a formal recommendation and this will clearly include more
than the science. The loss of closure has helped to blur the line between scientific
advice and clearly leads to the Committee taking a more active policy role.48
On the other hand, Dr. Wolff argued that, particularly in its January 17, 2006
letter regarding the proposed PM standards, “CASAC has clearly overstepped their
boundaries and ventured into the policy arena.”49
Somewhere between these views are the comments of Dr. Rogene Henderson,
the current Chair of CASAC, who states:
The Agency should make clear to CASAC what they require in terms of
scientific advice and what they consider to be policy issues, on which they do not
need advice. The line between science and policy is not always apparent, and this
difference should be made clear in the charge questions given to CASAC.50
A similar point is made by another long-time CASAC member, Dr. Joe Mauderly:
Neither scientists nor policy makers want to draw the line, or to define it or admit
to it. CASAC meetings are rife with discussions about how its pronouncements
will affect policy, and scientist advocates (on CASAC and its panels, as well as
others) game the system to achieve their ideological policy goals. When EPA
proposes or promulgates standards, it is reluctant to state clearly how science and
policy enter into the decision – it wants to portray that all is based on science.
These behaviors are absolutely understandable – most scientists are convinced
that they know what’s best for the country, and EPA Administrators don’t want
to admit to any motive other than the “best science”....
At present, my only suggestion is that the Administrator make explicit (much
more so than at present) just how science and policy separately bore on the
proposed standard, and how the two were integrated.51
A Consensus Observation. In reviewing the many comments on the
NAAQS process, much was found to criticize or to recommend, but perhaps more
striking than the criticism was the degree to which commenters appear to believe that
the system has worked. As stated by Dr. Bernard Goldstein, a former Chair of
CASAC and a former Assistant Administrator of EPA’s Office of Research and
Development, “... in my teaching of environmental health policy to both public health
students and to law students, I routinely present the NAAQS standard-setting process
48 Hopke, in Workgroup Report Attachments, p. A-19.
49 Wolff, in Workgroup Report Attachments, p. A-28.
50 Henderson, in Workgroup Report Attachments, p. A-14.
51 Mauderly, in Workgroup Report Attachments, pp. A-24, A-25.

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CRS-19
as one that represents an ideal interface between science and regulation.”52 Dr. Roger
McClellan, who, in some respects was critical of the process, stated:
Without question, the CASAC has played a critical role in ensuring that the
‘final’ criteria documents were of high scientific quality. ... The activities of the
CASAC, in my opinion, have been in accord with the language and intent of the
Clean Air Act (1977) and consistent over time with the evolution of CASAC
practices that have received substantial public and legal scrutiny. The modus
operandi has proved successful in helping to ensure that the NAAQSs are
science-based.53
Dr. Lippmann asked:
Can the Process for Setting NAAQS be Strengthened?
The easy answer is of course it can, and I will address how it can in text that
follows. However, it is important that any changes made in the process do not
weaken the long-established integrity, objectivity, and credibility of the process
to the scientific community and interested stakeholders.54
Conclusion
Sections 108 and 109 of the Clean Air Act establish statutory requirements for
the identification of NAAQS (or “criteria”) air pollutants and the setting and periodic
review of the NAAQS standards. But the process used by EPA is as much the result
of 36 years of agency practice as it is of statutory requirements. In Section 109, for
example, the statute establishes the Clean Air Scientific Advisory Committee to
make recommendations to the Administrator regarding new NAAQS and, at five-year
intervals, to make reviews of existing NAAQS with recommendations for revisions.
In practice, EPA staff, not CASAC, have prepared these reviews, drafting Criteria
Documents, which review the science and health effects of criteria air pollutants, and
Staff Papers, which make policy recommendations. CASAC’s role has been to
review and approve these EPA documents before they went to the agency’s political
appointees and the Administrator for final decisions.
Under EPA’s new procedures, EPA’s political appointees will have a role early
in the process, helping to choose the scientific studies to be reviewed, and CASAC
will no longer approve the policy Staff Paper with its recommendations to the
Administrator. CASAC’s iterative role that refined the EPA Staff Paper conclusions
could be eliminated, and the Committee relegated to commenting on the policy paper
after it appears in the Federal Register, during a public comment period. The goal,
according to agency officials, is to speed up the review process, which has
consistently taken longer than the five years allowed by statute. “These
improvements will help the agency meet the goal of reviewing each NAAQS on a
five-year cycle as required by the Clean Air Act, without compromising the scientific
52 Goldstein, p. A-11, in Workgroup Report Attachments.
53 McClellan, p. 5, in Workgroup Report Attachments.
54 Lippmann, p. A20, in Workgroup Report Attachments.

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CRS-20
integrity of the process,”55 according to the memorandum that finalized the changes.
The changes have caused concern among environmental groups and some in the
scientific community, however, because, they say, they give a larger role to the
agency’s political appointees and a smaller role to EPA staff and CASAC.
If Congress chooses to review these new procedures, one issue that it may wish
to focus on is the statutory role of CASAC: whether it should play some formal role
in approving the Administrator’s choice of standards. Under current law, CASAC’s
role is purely advisory. EPA is not required by the Clean Air Act to follow
CASAC’s recommendations; the act (in Section 307(d)(3)) requires only that, when
the Administrator proposes a new or revised NAAQS in the Federal Register, he set
forth any pertinent findings, recommendations, and comments by CASAC (and the
National Academy of Sciences), and, if his proposal differs in an important respect
from any of their recommendations, provide an explanation of the reasons for such
differences.
CASAC, in practice, has tended to play a larger role, evaluating EPA staff’s
analysis of the science and its policy recommendations and withholding formal
“closure” on the agency documents until it was satisfied that the documents
accurately reflected the state of the science. The statute has never required EPA to
have CASAC’s approval before proposing or promulgating NAAQS revisions, but,
in practice, the need to build a record that it could defend against court challenges has
generally led EPA to promulgate standards within the range of CASAC’s
recommendations.
In 2006, for the first time, the Administrator promulgated standards outside of
that range,56 and CASAC, in a written response, made clear that it felt the standards
did not meet the statutory requirements. That may be the role Congress intended for
CASAC, or it may not. On one hand, Congress could conclude that CASAC has
overstepped its bounds, in essence judging an Administrator’s final decision in
contrast to its statutory mandate to make recommendations beforehand. On the other
hand, Congress might conclude that the Administrator’s judgment should have been
constrained to the range of options that CASAC established as being supported by
the science.
The courts are likely to play a role here, as well. Thirteen states, the District of
Columbia, electric utilities and other industry groups, groups representing farmers
55 “Process for Reviewing National Ambient Air Quality Standards,” Memorandum of
Marcus Peacock, Deputy EPA Administrator, to Dr. George Gray, Assistant Administrator,
Office of Research and Development, and Bill Wehrum, Acting Assistant Administrator,
Office of Air and Radiation, December 7, 2006, p. 3, available at [http://www.epa
.gov/ttn/naaqs/memo_process_for_reviewing_naaqs.pdf].
56 In the Administrator’s judgment, the science underlying CASAC’s recommendation
(regarding the PM2.5 NAAQS) was not sufficient, relying primarily on two studies, neither
of which “provide[s] a clear basis for selecting a level lower than the current standard....”
The Administrator agreed with CASAC that the science shows a relationship between higher
levels of PM and an array of adverse health effects, but he maintained that there was too
2.5
much uncertainty in the analysis to justify lowering the annual standard. See discussion
beginning at 71 Federal Register 61172, October 17, 2006.

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and ranchers, and several environmental groups have challenged the PM standards
in court. Legal challenges to NAAQS are not unusual. In reviewing EPA regulations
in the past, courts have often deferred to the Administrator’s judgment on scientific
matters, focusing more on issues of procedure, jurisdiction, and standing.
Nevertheless, CASAC’s detailed objections to the Administrator’s decisions and its
description of the process as having failed to meet statutory and procedural
requirements could play a role as these standards are reviewed in court.
Although the new NAAQS review procedures will change the role that CASAC
has historically played, CASAC itself appears less concerned with the changes than
some who are advocating on its behalf. The committee does not plan to issue a
formal response to the December 7, 2006 decision memorandum. As noted above,
in its response to the Workgroup report released in April 2006, the committee made
a number of suggestions, some of which, such as the convening of a science
workshop at the outset of the process to better focus the review, were incorporated
into the decision memorandum. The memorandum also addressed another of
CASAC’s major concerns, that the old process spent too much time compiling an
encyclopedic review of the literature, much of which had little relevance to the policy
questions that needed to be addressed. With respect to EPA taking comments from
CASAC at the same time that it considers comments from the public, CASAC’s
Chair is reported to have said, “(S)ome of the members were concerned but most are
not, because it doesn’t change CASAC’s ability to comment.”57
Reaction elsewhere has been stronger. Responding to the announced changes,
the incoming Chair of the Environment and Public Works Committee, Senator
Barbara Boxer, called them “unacceptable,” and said the committee plans to make
them a top priority for oversight in the 110th Congress.58 Seven Democratic members
of the committee, including Senator Boxer, wrote EPA Administrator Johnson,
December 21, 2006, to express their strong opposition to the changes and to ask him
to “abandon” them.59 Thus, the role of CASAC in NAAQS reviews is expected to
be the subject of hearings early in the 110th Congress.
Simultaneously, EPA is moving ahead with two more NAAQS reviews: an
ozone review, the results of which are required to be formally proposed in May 2007;
and a lead review, whose results are to be proposed early in 2008. The agency’s
actions in reviewing these two standards will be closely watched for indications of
CASAC’s role and for the degree to which the Administrator’s decisions reflect
CASAC’s recommendations.
57 Comment of Dr. Rogene Henderson, CASAC Chair, in “EPA Adviser Plays Down
Democrats’ Criticism over New NAAQS Changes,” Inside EPA Clean Air Report,
December 14, 2006.
58 Office of Senator Barbara Boxer, “Boxer Statement on EPA’s Politicization of Clean Air
Health Standards,” Press Release, December 8, 2006, at [http://boxer
.senate.gov/news/releases/record.cfm?id=266781].
59 Office of Senator Barbara Boxer, “Democratic Members of Senate EPW Committee Warn
EPA on Air Rollbacks,” Press Release, December 21, 2006, at [http://boxer
.senate.gov/news/releases/record.cfm?id=267092].

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