UNITED ST ATES E N VI RON M E N T A L PR OTE C TION AGE NCY
WASHING T O N D. C. 2046 0

OFFI CE OF THE A D M I N ISTR A T OR SCI E NCE A D VI SORY BO A RD

January 22, 2008

EPA-CASAC-08-007

Honorable S t ephen L. Johnson
Adm i nistra tor U.S. Environm ental Protection Agency 1200 Pennsylvania Avenue, NW Washington, DC 20460

Subject: Clean Air S c ientific Advisory Comm ittee’s (C ASAC) Review of the Advance Notice of Proposed Rulem a king (ANPR) for the NAAQS for Lead

Dear Adm i nistrator Johnson:

The Clean Air Scientif ic Advisory Comm ittee (C ASAC or Comm ittee), a u gm ented by subjec t-m a tter-exp ert Pa nelis ts — co llec tive l y r e f e rred to as the CASAC Lead Revie w Panel (Lead Panel) — m e t on Decem ber 12–13, 2007, in W a shington, DC, at the request o f EPA’s Office of Air and Radiation to review the Ag ency’s Advance Notice of Proposed Rulem a king (ANPR) for the National Am bient Air Quality Standards (NAAQS) for Le ad. The Panel also reviewed and provided comm ents on EP A’s Final Lead Staff Paper and the Human Ex posure & Health Risk Assessment (Full-Scale) Document (Final Lead Risk Assessm e nt). The Lead Panel roster is attached as Appendix A, and Panelists ’ individual comm ents are found in Appendix B.

The CASAC is quite p l eased with the conten t and conclusions of the Final Lead Risk
Assessm ent and Final Lead Staff Paper. The Committee unanimously an d fully supports Agency staff’s scientific analyses in r ecommending the need to substantially lower the level of the primary (public-health based) Lead NAAQS, to an upper bound of no higher than 0.2 μg/m 3 with a monthly averaging time. The CASAC is also un animous in its recommendation that the secondary (public-welfare based) standard for lead needs to be substantially lowere d to a level at least as low as the recommended primary NAAQS for Lead . However, th e CASAC finds th e ANPR for the Lead NAAQS to be both completely unsu itable and inadequate as a basis for rulemaking , in that it does not provide the underlyi ng scientific justification f o r the range of options for standard-setting that the Agency is currently considering.

In the Comm ittee’s la st two letters to the Adm i nistrator on this topic (EP A -CASAC-07- 003, dated March 27, 2007; and EPA-CASAC- 07-007, dated Septem ber 27, 2007), the CASAC acknowledged that the Agency wished to m ove forward with the implem entation of the revised NAAQS review process, and that this imple m en tation would begin in the m i ddle of EPA’s cur-2 rent review cycle of the lead standards — thus resulting in a “ hybrid” process, blending elements of the old and the new NAAQS processes. Thus far, the Panel has reviewed two drafts of the air quality criteria document (AQCD) for Lead — a key component of the Agency’s former review process that has been replaced by an Integrated Science Assessment (ISA) for subsequent criteria pollutant NAAQS reviews — and then received a stand-alone risk/e xposure assessment document in keeping with the new process, which has also twice undergone CASAC review. As the final major step in the NAAQS review process, EPA asked the Committee to review the ANPRfor the Lead NAAQS. As noted in the December 7, 2006 memorandum from EPA Deputy Administrator Marcus Peacock entitled, “Proce ss for Reviewing National Ambient Air Quality Standards,” the Staff Paper would be replaced by a policy assessment to be published as an ANPR. Nevertheless, the CASAC was particularly pleased to note that, pursuant to a Federal court order, EPA was required to produce a Fina l Lead Staff Paper for CASAC and public review in addition to an ANPR for the Lead NAAQS . On November 1, 2007, the Agency released the Final Lead Staff Paper and the Final Lead Risk Assessment report. On December 5, 2007, EPA released the ANPR for the Lead NAAQS, which was published in the Federal Register on December 17, 2007 (72 FR 71488).

Overall, the Lead Panel judged that the Agen cy’s Final Lead Risk Assessment report is responsive to the CASAC’s comments in the previ ous review and, with the incorporation of the few suggestions listed below, was considered ad equate for use in rulemaking. Likewise, EPA’s Final Lead Staff Paper, with some exceptions also noted in this letter, was considered to be an excellent document that clearly laid out the scien tific evidence for options for the indicator, level, averaging time and statistical form of a new ai r-lead standard. EPA st aff are to be commended for their careful, scholarly approa ch to the development of the Final Lead Staff Paper, which the
Panel also considered to be adequate for use in rulemaking.

By sharp contrast, the CASAC found the Advance Notice of Proposed Rulemaking for the Lead NAAQS — the first such document of this type to be issued under EPA’s revised NAAQS review process — to be entirely unsuitable and i nadequate for use in rulemaking . The notable shortcomings of this ANPR are the timing in th is review cycle for the Lead NAAQS and the absence of substantive information found in th e ANPR document itself. The Agency chose to employ an ANPR as the regulatory vehicle for soliciting broad-based CA SAC and public input on the full range of available policy options for the lead standards at this late stage in the process. To the CASAC’s understanding, the EPA had not pr eviously used an ANPR in its NAAQS rulemaking activities. Having now seen the structure and content of an Agency ANPR, the members of the Committee think that it is a regulator y tool more appropriately-suited to the beginning of the process for reviewing a NAAQS. Even more fundamental, the information contained in this ANPR fell far short of what the CASAC expecte d, per the EPA’s own implementation guidance.

Specifically, as noted in the Deputy Admi nistrator’s December 2006 memo, a key element of the Agency’s revised NAAQS revi ew process was for EPA to develop a policy assessment in lieu of a staff paper, in order to prope rly reflect the views of Agency management, consistent with other EPA rulema kings, and publish this in the Federal Register as an ANPR. This policy assessment was described in the Deputy Ad ministrator’s memo as a document that would “identify conceptual evidence- and risk-based approaches for reaching policy judgments, discuss what the science and risk/exposure assessments say about the adequacy of the current standards,3 and present any preliminary risk/e xposure information associated with alternative standards.” Importantly, this policy assessment would also “ describe a range of opti ons for standard setting, in terms of indicators, averagi ng times, [statistical] form, and ranges of levels for any alternative standards, along with a descript ion of the alternative underlyi ng interpretations of the scientific evidence and risk/exposure information that might support such alternative standards and that could be considered by the Ad ministrator in maki ng NAAQS decisions ” (emphasis added). In addition, we read in that me mo that “such [a policy] assessm ent should help to ‘bridge the gap’ between the Agency’s scientific assessment and the judgments required of the Administrator in determining whether it is appropriate to reta in or revise the standards” — a description that is virtually identical to what has heretofore been used in reference to EPA’s staff papers for its NAAQS reviews (see, for example, the November 29, 2006 Federal Register notice announcing the Agency’s release of the 1 stDraft Staff Paper for Lead [71 FR 69117]). Therefore, the Committee had every reason to expect that this policy assessment to be released and published in the form of an ANPR would contain the breadth and depth of information and analyses that were previously contained in the Final Staff Paper for a given cr iteria air pollutant.

However, the ANPR for the Lead NAAQS did not contain any such “policy assessment” as described above. Rather, this ANPR simply laid out all policy options for the CASAC’s and the public’s consideration while omitting the underly ing scientific rationale for many of them. Indeed, only EPA’s Final Lead Staff Paper provide s the scientific justif ication for each of the options that Agency staff presented for consider ation in the rulemaking process. The Committee had anticipated that having both the ANPR and th e Lead Staff Paper would provide an opportunity to compare the approach and content of th e two documents — and also, not insignificantly, to assess the consequences of replacing the Staff Paper with the ANPR. As it turned out, without the Lead Staff Paper, the CASAC would not have had the data and supporting analyses necessary to make scientifically-informed recommendati ons to the EPA Administrator concerning the adequacy and basis of the Lead NAAQS, as required by the Clean Air Act (CAA)

.

The Agency’s ANPR for the Lead NAAQS thus represented a remarkable weakening of the scientific foundation of th e NAAQS review process. Far from improving the efficiency of the review, the ANPR essentially reversed the process. After describing the scientifically-based advice and recommendations of th e CASAC — and the similar, sc ientifically-gr ounded choices of Agency staff (which agreed almost completely with the Committee’s findings) — the ANPR opened up the discussion of options that had al ready been considered in open public advisory meetings and dismissed on scientific grounds by both the CASAC and EPA staff. For example, the ANPR solicited additional public comment on whet her lead should be de-l isted as a criteria pollutant. However, the Agency had alre ady requested this evaluation in the 1 st Draft Lead Staff Paper (December 2006), along with an accompanying assessment as to whether revocation of the Lead NAAQS is an option appropriate for the EPA Administrator to consider, in light of the currently-available scient ific information. In its March 2007 lett er to the Administrator from its review of that document (reiterated in the Committee’s September 2007 letter), the CASAC unambiguously concluded that the option of de-listing lead as a criteria air pollutant was scientifically indefensible . As an example of the Committee’s scien tific rationale for this recommendation, the CASAC noted that, although over the past three decades, ambient air exposures and therefore blood lead (blood Pb or PbB) c oncentration levels in the U.S. population have drastically declined (primarily due to the elimination of l ead from gasoline), much more is now known about4 the adverse human health effects of even low leve ls of environmental lead exposure, and of corresponding PbB concentrations levels < 10 μg/dl, part icularly in children. Yet in spite of this, EPA’s ANPR effectively disregarded the CASAC’ s prior discussions and recommendations and reopened this issue. Numerous other examples of the inadequacy of this ANPR are furnished below in the Committee’s responses to specific sec tions of the document, as are more detailed comments on the EPA’s Final Lead Staff Paper and the Final Lead Risk Assessment report.

While this letter will focus specifically on the ANPR for the Lead NAAQS, the CASAC intends to send a separate letter to the EPA Admi nistrator in the near future to address our concerns and elaborate on the deficiencies in the Agency’s revised NAAQS re view process that the Committee has identified in light of the structure and content of this ANPR.



### CASAC’s Comments on EPA’s Final Lead Risk Assessment and Staff Paper

General Comments

The members of the CASAC Lead Review Pa nel were unanimous in their praise of
EPA’s Final Lead Risk Assessment and Final Lead Staff Paper. The Final Risk Assessmentreport captures the breadth of issues related to assessing the potential public health risks associated with lead exposures; it competently doc uments the universe of knowledge and interpretations of the literature on lead toxicity, exposures, blood lead mode ling and approaches for conducting risk assessments for lead. The Final L ead Staff Paper is also a very well-crafted summary of the important issues associated w ith interpreting the results from the Final Risk Assessment. The Staff Paper captures the scientific issues and discusses the uncertainties associated with the various assumptions made in the risk assessment. The Staff Paper also conducts a thorough and logical analysis of various optio ns for the NAAQS. The CASAC agrees with the vast majority of the scientific interpretations made in the Staff Paper.

Brief synopses of the Final Lead Risk Assessment and the Final Lead Staff Paper, and a few specific issues that the Panel raised with each of these documents, are highlighted below.

Synopsis and Specific Comments on EP A’s Final Lead Risk Assessment

Synopsis:

The Agency’s Human Exposure & Health Risk A ssessment (Full-Scale) Document (Final Lead Risk Assessment report) describes the quantitative human expo sure and health risk
assessments conducted to inform EPA’s current review of the Lead NAAQS. This document represented an update the Agency’s Lead Human Exposure and Health Risk Assessments for Selected Case Studies, Draft Report (2 nd Draft Lead Exposure and Risk Assessments, July 2007) that was reviewed by the Committee in August 2007, and has been updated in response to the CASAC’s advice and recommendations in its letter to the Administrator on this topic (EPA-CASAC-07-007, dated September 27, 2007). As noted in the introduction to this Final Lead Risk Assessment report, “risk results are provided in this docum ent without substantial interpretation. Rather, interpretative discussion of these results is provided in the [Final Lead] Staff Paper.”5 Specific Comments:

The Final Lead Risk Assessment document notes uncertainties associated with the analyses. One major uncertainty that is not discus sed well is that associat ed with quantifying the types of exposures that result in the higher (> 5 μg/dL) PbB levels among children in the U.S. The current approach used in the Final Lead Risk Assessment relies on using the Integrated Exposure Uptake Biokinetic (IEUBK) model for l ead in children to estimate the mean and median blood lead levels associated with the various scenarios and th en applying a geometric standard deviation (GSD) to quan tify plausible variability associat ed with the distribution of PbB levels for a given exposure scenario. The Lead Pane l notes that there is a need for better characterization of the uncertainties associated with the model assumptions re lated to children’s exposures at the upper end of th e blood lead distribution ( i.e. , the higher percentile) and how those exposures may differ from those of the mean/ median percentile. See also the individual written comments of Lead Panel member Mr. Sean Haye s attached in Appendi x B of this letter.

Synopsis and Specific Comments on EPA’s Final Lead Staff Paper

Synopsis:

EPA’s Final Lead Staff Paper concluded that the overall body of ev idence on lead health effects clearly calls into ques tion the adequacy of the current primary Lead NAAQS, and provides strong support for consideration of a lead st andard that would provide greater health protection for sensitive groups, especially for ch ildren. Additionally, the Staff Paper recommends
that EPA not remove lead from the list of six criteria pollutants and also not revoke the NAAQS for lead. Instead, Agency staff recommende d that the EPA Administrator consider appreciably lowering the level of the current prim ary standard for lead from the current level of 1.5 micrograms per cubic meter (μg/m 3 ). Specifically, the Final Lead Staff Paper recommends consideration of a range of levels, from levels that are currently seen in many urban areas across the U.S. (approximately 0.1–0.2 μ g/m 3 ) to the lowest levels evaluated in the Exposure and Health Risk Assessment (0.02–0.05 μ g/m 3 ). In addition, EPA staff recomme nds either revising the averaging time to monthly or retaini ng the current averaging time of a calendar quarter.

Specific Comments:

Consistent with the CASAC’s previously r ecommendations to the Administrator in our letter from the Lead Panel’s review of EPA’s 1 st Draft Lead Staff Paper and the Draft Lead Exposure and Risk Assessments documents (E PA-CASAC-07-003, dated March 27, 2007), and reiterated in the Committee’s September 27, 2007 letter (EPA-CASAC-07-007) on the 2 nd Draft Lead Human Exposure and Health Risk Assessments Document, the CASAC unanimously affirms EPA staff’s recognition of th e need to substantially lower the level of th e primary NAAQS for Lead, to an upper bound of no higher than 0.2 μg/m 3 with a monthly averaging time.

With regard to the secondary Lead NAAQS, the Final Lead Staff Paper concluded that the overall body of evidence of l ead effects on the environment calls into question the adequacy of the current secondary standard. However, Agency staff also concluded that EPA lacks the relevant data to provide a clea r, quantitative basis for setting a secondary lead standard that differs from the primary standard in terms of i ndicator, averaging time, level or form; thus, the Staff Paper recommends that the EPA Administrator consider sett ing the secondary standard forFurthermore, the Final Lead Staff Paper propos es a possible approach of enumerating the number of children above certain blood lead conc entrations, similar to th at used by the Agency in 1978. Such an approach is inferior to EPA’s associated lead risk assessment and would tend
to obscure the health benefits of reducing blood lead levels within categories. If used, this underestimation of health risk should be noted, and the CASAC recommends th at a threshold of 2 μg/dL be used as the cut-point, because of th e evidence of adverse effects at higher levels.

6 lead equal to a strengthened primary standard to provide in creased protection against adverse environmental effects. The CASAC had also note d in its previous letters to the Administrator that the level of the secondary Lead NAAQS shou ld be at least as low as the lowest-recommended primary lead standard, such that there is no reversal of the current downward trend in lead concentrations in the environment.

The Staff Paper also recommende d that the EPA Administrator consider retaining lead in total suspended particulates (TSP-Pb) as the indi cator for lead. The Lead Panel raised issues with the use of TSP or PM 10 monitors for quantifying concentrati ons of lead in air. While, historically, the Lead NAAQS has relied on TSP sa mples for quantifying ambient lead concentrations, the Lead Panel was unanimous in r ecommending that EPA should transition to PM 10 sampling for quantifying ambient lead concentrations. PM 10 is a much more accurate and preciselymeasured indicator and represents the fraction of l ead that is more relevant for human exposures. In addition, there is a gr eater availability of PM 10 samplers throughout the U.S. More detailed recommendations on this topic are provided in our comments in the ANPR monitoring section.



### CASAC’s Comments on the Agency’s ANPR for the Lead NAAQS

Synopsis and General Comments on ANPR for the Lead NAAQS

Synopsis:

The Agency’s ANPR for the Lead NAAQS i nvited public comment on: scientific evidence concerning the health and welf are effects of current and past air emissions of lead that may be found in ambient air, indoor dust, and outdoor soil; current lead exposures and health risks associated with such exposures; and, importantly, policy options for addressing lead air-related exposures and associated risks. Specifically, th e Agency indicated that, with this ANPR, it was soliciting comment on the adequacy of the current lead NAAQS, on potential revisions to the standard, and on questions that have been raised with regard to maintaining a NAAQS for lead — that is, whether it is appropriate to revoke the lead standard or to remove ( i.e.

, de-list ) lead from the list of criteria pollutants. In addi tion, the ANPR invited comm ent on issues regarding ambient air quality monitoring for lead, to incl ude sampling and analysis methods, network design, sampling schedule, and data handling methods . The Agency noted that it will consider CASAC recommendations and comments receive d from the public on the ANPR in developing EPA’s proposed decision on the adequacy of the current standards and on any revisions to the Lead NAAQS that may be appropriate; and, furt hermore, that the Agency will propose whether to revise or retain the current lead standards by no later than May 1, 2008 (with a target date of March 2008), and take final action by Septem ber 1, 2008, pursuant to a Federal court order.7 General Comments:

The CASAC notes that the ANPR for the Lead NAAQS adds no new information — and certainly no rigorous analyses of the various op tions that the Agency is considering — beyond what has already been presented in the Final Lead Staff Paper and the Final Lead Risk Assessment. Furthermore, contrary to the original inte nt of the review of EPA’s NAAQS-setting process, as set forth in the Deputy Administra tor’s memo of December 15, 2005, the ANPR also failed to “ensure that the best available scien ce [will] guide and inform Agency decision making”
— nor does the ANPR adhere to the “highest scientific standards” as stated in the Deputy Administrator’s memo of December 7, 2006 (and esse ntially reiterated in his April 17, 2007 memo) that “the Agency’s decisions would be inform ed by the best availabl e science .... without compromising the scientific integrity [ i.e. , soundness and transparency] of the process.” Finally, rather than making EPA’s NAAQS review process more efficient, as envisioned by the Deputy Administrator, the ANPR actually results in a slowing of the process by opening up a discussion of options that were already vetted in public and found not to be feasible by both CASAC and Agency staff. As noted above, the ANPR, in effect, puts the NAAQS review process in reverse

.

Specific Comments on ANPR Sect ions on Primary Lead NAAQS

Sections III.A (Health Effects Information) & III.B (Human Exposure and Health Risk Assessments):

These sections of the ANPR on the Primary Lead NAAQS contain much good discussion drawn from the Lead Staff Paper, and provide much of the data needed to understand sources of human lead exposure and the use of IQ loss in ch ildren as the metric for assessing the effects of lead in this sensitive subpopul ation. In the proposed rule fo r the Lead NAAQS that will follow — or, for that matter, in any ANPR for the NAAQS for a different criteria pollutant — greater emphasis should be placed on including tabular and gr aphical data of the scientific results that support or underpin the points be ing discussed. For example, th e “roll-up” scenario helps the reader interpret the incremental risks associat ed with sticking with the current NAAQS and any alternative NAAQS. Th e incremental risk ( i.e. , reflected by change in IQ loss) approach helps the reader assess the impact of th e various options that are under consideration for a Pb NAAQS.

However, there were several problems identifi ed in the discussion of the primary Lead NAAQS. The ANPR devoted too many pages to desc ribing an alternative to the Agency’s peerreviewed risk assessment, using instead the ap proach of 1978. In 1978, ev idence on the effects of lead on cognitive function was limited to a fe w studies that showed lower cognitive function in children with “high” lead levels. Reasonably, EPA set the NAAQS with a goal of limiting the number of children with “high” blood lead leve ls. Necessarily, such an approach recognizes no benefits to lowering blood lead levels within the “not high” category. As described by the Agency’s Final Lead Staff Paper and affirmed by the CASAC Lead Review Panel, much more is now known about the dose-response between blood lead and IQ th an in 1978. While there is always uncertainty in the dose-re sponse relationship, it should be noted that uncertainty about the slope is not the same as uncertain ty that the slope is not zero. Mo reover, it is clear that the adverse effects of lead are demonstrable at blood lead levels even lower than 5 μg/dL, as documented by the EPA peer-reviewed risk assessment and by empirical studies.8 For example, the ANPR suggests that the slope below 7.5 μ g/dL is unreliable because it is based on data from 103 children from one st udy (Lanphear, 2005). This argument is undercut by several other studies confirmi ng that the relationship of le ad exposure is non-linear and persists at blood lead levels considerably lower than 5 μ g/dL (Lanphear, 2000; Wasserman, 2003; Kordas, 2006; Tellez-Rojo, 2006). In particular, Tellez-Rojo and co -workers reported that the slope of the association betw een 24-month blood lead and the 24-month Mental Development Index (MDI) for 294 children who had peak blood lead levels below 5 μ g/dL was negative (-1.7 points for each 1 μ g/dL increase in blood lead concentra tion, p=0.01). Collectively, these studies
indicate that there is sufficien t evidence to support the use of the dose-response relationship from the pooled analysis at blood lead levels < 5 μg/dL (Lanphear, 2005) , as described in the Final Lead Staff Paper and previously recommended by CASAC.

The Lead Panel was concerned that the ANPR pr esented analytical choices, as described below, that may underestimate risks for the advers e effects of lead and th e benefits of reducing the Lead NAAQS. In isolation, each of these de cisions may not be substantial, but the cumulative impact could result in substa ntially underestimating the adverse effects of lead and the benefits of lowering the NAAQS for lead. Similarly, these choices would fail to provide an adequate margin of safety, as required by law. The follo wing examples illustrate the major ways that the
ANPR underestimated the lead effects and the be nefits of alternativ e lead standards:

• The Clean Air Act requires special attention to susceptible populat ions. The ANPR notes that there is evidence of increased susceptibi lity in African Americans and persons with certain genotypes ( e.g. , ALAD [aminolevulinate, delta-, deh ydratase] variants), but it is not apparent that these suscep tible populations were consider ed in EPA’s risk assessment.

• Members of the Lead Panel reiterate their previous advice to th e Administrator (EPACASAC-07-007, dated September 27, 2007) that the Agency use the two-piece linear function for relating IQ alterati ons to current blood lead leve ls with a slope change or “hinge” point closer to 7.5 μg/d L rather than the log-linear with low-exposure linearization (LLL) concentrati on-response function at 1 μ g/dL, as recommended in the ANPR. The ANPR argued, on the one hand, that there we re too few children to extrapolate below
7.5 μ g/dL. As noted above, the Lead Panel disagrees. On the other hand, the ANPR argued that it was not reasonable to see such a dramatic decrement in IQ scores at the lowest levels of exposure ( e.g. , < 1 μ g/dL). Use of the two-piece linear below 7.5 μ g/dL, which is based on empirical data, would reso lve the concern about steep slope observed with the log-linear results and require fewer assumptions or uncertainties.

• Lead found in “past air” is treated as part of background lead rather than as a component of policy-relevant (air) lead in the risk a ssessment. This will tend to underestimate the benefits of lowering the NAAQS for lead.

Section III.C (Considerations in Review of the Standard)

In its consideration of th e Primary Lead NAAQS, the ANPR combines, presents, and
solicits both scientific and policy considerations, and in several areas tends to obscure the transition from science to policy. As discussed above , the approach taken in the ANPR for the Lead NAAQS draws heavily from, repeats, or summari zes information by reference only to the EPA’s9 Final Lead Risk Assessment report and Final Lead Staff Paper, as we ll as the letters/reports that the CASAC previously sent to th e Administrator during this current review cycle for the Lead NAAQS. However, the ANPR fails to convey the scientific basis of the analyses, findings and
conclusions contained ther ein. In its review of the available scientif ic information, the ANPR should have indicated that: (1) l ead would be retained as a crite ria air pollutant; (2) the lowering of the Lead NAAQS substantially below the current value is fully-justified; and (3) as discussed below in the section on “Lead Ambient Air Mon itoring and Sampling,” a new indicator for lead needs to be developed. The po licy implications and the Agency’s view of these conclusions should then have been discussed in a transparen t manner and presented in a strong policy statement.

Rather, the ANPR for Lead tends to undermine the scientific proce ss in EPA’s consideration of the primary lead standar d. The ANPR frequently notes “l imitations and uncertainties” in the available data, analyses, and assessments. Agency staff, on the other hand, recognized these difficulties throughout the Lead NAAQS review pr ocess and addressed these unknowns in a scientifically-defensible manner. CASAC has carefu lly reviewed these analyses, and concurs with the conclusions in the Agency’s Final Lead Staf f Paper. However, the ANPR fails to carry the discussions and cautions forward and suggests that areas of uncertainty become purely policy issues. While the treatment of uncertainty in policy decision-making should be consistent with the development of those uncertainties in the scie ntific assessments and be incorporated in an adequate margin of safety, as required by th e CAA, the ANPR contains no discussions summarizing either the scientific treatment of un certainty, the manner in which reviewers should consider those uncertainties, or how EPA intends to address these uncertainties in a margin of safety protective of public health.

Section III.C of the ANPR also conveys no substantive comparative assessmentof alternative primary lead standards — that is, the point to which the established and vetted scientific evidence should lead — but merely indicates th at additional input from anyone would be welcome, without specifying whether that input should be additiona l data, scientific evaluations, opinions or policy analyses. At best, as twice-noted above, this is moving the process of developing the NAAQS for lead backwards

, i.e. , away from an established scientific foundation, with the ANPR seeming to undermine the clear intent of the Clean Air Act in what it specifies as the particular role of the CASAC.

In regard to the ANPR solicitation of additiona l public comment as to the sufficiency of the data to warrant the de-listing of lead as a criteria air pollutant, the EPA takes note that all current measurements are below the present ambient standard of 1.5 μg/m 3 . However, in light of evidence identified by the Agency in the 1990 review , the current lead stan dard is clearly not health-protective. Additionally, this is clearly no guarantee that future air lead levels will remain low. The ANPR also solicits comments on whethe r a broad range of current Federal and State lead control programs might render the NAAQS u nnecessary. The evidence evaluated, and the position of CASAC, clearly indi cate that the hazardous air pollutants (HAP) standards under Clean Air Act Section 112 are not appropriate, as these generall y apply to individual point sources. Lead is a ubiquitous pollutant, derived from numerous sources, presenting significant air-related exposures in multiple media; and thus is better regu lated under CAA Section 108 as a “priority” pollutant. As mentione d above, this issue of de-listing lead was previously considered10 by the CASAC on two occasions, and in its summary letters to the Administrator for the associated reviews the Committee unanimously indicated th at there is absolutely no scientific justification for an action to de-list. To the contrary, the CASAC has strongly indicated that the current
standard needs to be substantially lowered (and, in fact, should have b een lowered on the basis of existing data many years ago).

Furthermore, the ANPR for the Lead NAAQS co ntemplates that the U.S. Centers for Disease Control and Prevention (CDC) “ac tion” level for blood lead of 10 μ g/dL be considered as an acceptable risk level by the EPA Admini strator, either as a mean or as a not-to-exceed level. The Lead Panel finds any suggestion of using blood lead action levels as a starting point for a risk assessment to be particularly tr oubling, in that it begs the questi on as to why the Agency would even consider allowing children to be sufficientl y-exposed to ambient lead to permit PbB levels that require intervention. Sure ly such an approach — which ignores both the CDC and CASAC
determinations that there ar e adverse health effects at lower blood lead levels — does not allow protection of public health with an adequate marg in of safety as required by the plain language of Section 109 of the Clean Air Act. Therefore, the Lead Panel concludes that the ANPR document misapplies both the nature and purposes of the CD C’s advisory statement on measures to prevent childhood lead poisoning. Speci fically, the CDC level of 10 μ g/dL PbB is an “action” level, which recommends the initiation of secondary prevention measures, not a “risk” level. The CDC, in its most recent statements (CDC 2005, 2007) , explicitly declares that adverse health
effects of lead occur at PbB concentrations below 10 μ g/dL, but that effective response to sub10 μ g/dL blood lead levels requires primary prevention methods — which can only occur by significant reductions of ambient air lead levels pursuant to EPA regul ations via the NAAQS. Neither of the CDC’s lead-related st atements indicates that, at sub-10 μ g/dL levels, adverse
health effects are either non-existe nt or trivial. Rath er, the Center’s stat ements present action levels for the purpose of prioritizing secondary prevention methods: screening, identification of exposure, and intervention after identification. Nowhere in the CD C statements are action levels defined as a “threshold” of blood Pb levels be low which there is no harm. Indeed, there are several peer-reviewed papers — with results li mited to children whose blood lead was alwayslower than 10 μg/dL and, in one case, always lower than 5 μg/dL — that report significant associations.

Finally, with regard to the indi cator, level, averaging time, and statistical form of a proposed NAAQS for lead, the ANPR fails to either ta ke any position or provide sufficient detail of the position of Agency Staff or the CASAC that would permit a member of the public to understand or evaluate the scientif ically-informed decision process by which the Administrator will select from a range of options for the lead stan dards. The ANPR simply mentions that EPA Staff and the Committee have fulfilled their responsibilities in the process to date and solicits further input on each component. There is no indicati on that the scientific validity of any evidence presented will be vetted, nor whether potential co nflicts of interest am ong prospective reviewers will be ascertained. Thus, this ANPR fails as a rigorous policy assessment doc ument that would stand alone as a summary of the current scient ific data, and provides no discussion of the range of alternatives for the Lead NAAQS as offered by the Final Lead Staff Paper, and therefore does not provide an adequate basis from wh ich to make sound policy decisions.11 Comments on ANPR Sections on Secondary Lead NAAQS

The Lead Panel unanimously reaffirms its ear lier judgments that, as with the primary (public-health based) Lead NAAQS, the secondary (public-welfare based) standard for lead also needs to be substantially lowered. As previously noted, it is cr itical that the secondary Lead NAAQS be set at a sufficiently-stringent level so as to ensure that there is no reversal of the current downward trend in lead conc entrations in the environment. Therefore, at a minimum, the level of the secondary Lead NAAQS should be at least as low as the level of the recommended primary lead standard. Moreover, the Agency need s to give greater prior ity to the monitoring of environmental lead in the ambient air, as discussed more extensively in the section of this letter that immediately follows. As noted in the ANP R, these conclusions are also fully-supported by EPA staff in the Agency’s Final Lead Staff Paper.



### CASAC’s Comments on Lead Ambient Air Monitoring a nd Sampling Issues in the Agency’s ANPR for the Lead NAAQS

The Lead Panel provides the following comments on the monitoring section of the ANPR for the Lead NAAQS with respec t to: (a) sampling and analysis method; (b) network design; (c) sampling schedule; and (d) mon itoring for secondary standard.

Sampling and Analysis Method . In its previous comments on EPA’s AQCD for Lead, the 1st Draft Lead Staff Paper, and now in th is review of the ANPR for the Lead NAAQS, the Panel unanimously recommends that the Agency re vise the indicator for lead sampling from TSP
to PM 10 , as measured with a low-volume sampler and analyzed with low-cost multi-elemental analytical methods such as X-Ray Fluores cence (XRF), Inductively Coupled Plasma–Mass Spectroscopy (ICP-MS), or other techniques that offer improved detection limits at the lower concentrations typical of today’s ambient air. The detailed rationale for this recommendation is provided in the CASAC letters to the Administrator dated March 27, 2007 and September 27, 2007 (EPA-CASAC-07-003, EPA-CASAC-07-007). See also the individual written comments from Lead Panel members Dr. Barbara Zielinska, Mr. Rich Poirot, and Dr. Donna Kenski found in Appendix B of this letter.

The Agency should also seize this oppor tunity to transition from TSP to PM 10 , since the current review indicates a need for a substantia l lowering of the lead NAAQS. If a standard is lowered by a factor of 10 to 100, it is unimportant if the indicator measures 10% or 15% less than the indicator selected 30 years ago. The Cavender & Schmidt (2007) analysis does indicate some variability in the average ratios of PM 10 -Pb to TSP-Pb. However, it also shows average ratios of > 0.60 at all sites, > 0.75 at 20 of 24 site s, and > 0.80 at 18 sites. Rather than needing to arduously establish a la rge series of site-specific PM10-Pb to TSP-Pb ratios (which would, in essence, constitute “fitting good data to bad”), it would be well within EP A’s range of discretionary options to accept a slight loss of ultra-coarse lead at some monitoring sites by selecting an appropriately conservative level for the revise d Pb NAAQS. Conversely, it would be a mistake to hold up the old TSP metric as the “gold stan dard” and only allow newe r, better technology if it can reproduce the old, and seriously -flawed, sampler performance. To further explore and discuss these issues, Agency staff and the EPA Scie nce Advisory Board Staff Office are currently discussing a near-term meeting of the CASAC Ambient Air M onitoring and Methods (AAMM) Subcommittee.12 In response to the Agency’s concerns that the new PM 10 indicator must be tied explicitly to the historic TSP health data, it is the opini on of the Lead Panel that the above arguments may be one way to justify the change, especially given that any minor e ffect of losing coarse particles is dwarfed by the change in th e level of the standard. The Panel unanimously supported the
selection of an indicator that ca n be more robustly measured and thus would be more representative of actual population exposures. (It is also important to note that studies of the health effects of lead are not based on ambient monitoring at all, but rather are based on internal biomarkers of dose, such as blood lead and bone lead.) Finally, a more accurate and precise Pb-PM 10 indicator would provide a more stable determination of compliance with the new lower Lead NAAQS.

Network Design : The Lead Panel finds the existi ng Pb-TSP network inadequate in its ability to characterize population exposures, cond itions around large sources, and concentrations at typical ambient concentrations in many parts of the county. Th e issue of how best to design a lead monitoring network that would serve the many goals of air monitoring data collection (while balancing limited resources) is more comp licated than the Panel can do justice to in this meeting. Rather, it deserves thorough analysis a nd is a task that could more appropriately be assigned to the CASAC AAMM Subcommittee. Th e Lead Panel agrees that the current PM 10 and National Air Toxics Trends Sites (NATTS) networks could be integrated into a new lead monitoring network, while rec ognizing that most existing PM 10 monitors are high-volume samplers that use quartz filters. These samplers are preferable to high-volume TSP, but they have less precise cut-points than low-volume samplers, and the filt ers are not as clean as Teflon or as amenable to surface beam analytical tec hniques. Again, the Panel does not recommend any effort to develop site-specific or region-specific adjustment fact ors to make these measurements more “TSP-like.” The one place where Panel me mbers think continued TSP sampling (or more helpfully, collocated TSP and PM 10 ) would be appropriate is n ear large sources, where ultracoarse particles are most likely to contribute significant mass. Multiple size fractions can provide a better understanding of e xposures, of lead’s movement from a source through the environment, and the influences of various source ty pes and meteorological c onditions on the distribution and deposition of lead.

Sampling Schedule: If the form of the lead standard is changed to a monthly averaging time, the sampling frequency should be increased to once every three days (1-in-3) or even more often (another point in favor of PM 10 , which can be collected with automated sequential samplers). However, in the interest s of reducing filter-sampling effo rts, sampling frequency could be adjusted depending on concentrations; sites with consistently low concentrations could operate on a one-in-six-day (1-in-6) sche dule, and sites that are closer to the Pb NAAQS could sample more frequently to better characterize the mea n. The Lead Panel discourages the use of longer sampling times (48 or 72 hours) or compositing of samples, since th ese actions limit the utility of the data for other purposes.

Monitoring for the Secondary NAAQS : The Lead Panel supports the excellent idea of supplementing the rural/remote PM 2.5 Pb measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) netw ork with a smaller “sentinel” network of PM 10 -Pb samplers. The IMPROVE program already collects PM 10 samples and these samples — from a subset of sites that might be periodically rotate d — could be at least subject to multi-elemental13 XRF analysis that would provide useful informati on on both fine and coarse lead as well as other components of coarse particle composition.

In closing, the CASAC acknowledges the dist inction between scienc e and public policy in the NAAQS-setting process. However, it is essential that policy ch oices be based both on sound scientific data and supporting analyses and on independent, expert assessment thereof.Additionally, the process for the review of the NAAQS policy options and the associated information must be open and transparent — and should cer tainly reflect the results of the analytical efforts of the Agency’s own scientif ic and technical staff. In the past, this in-depth analysis has been presented as a policy assessment in the Agency’s Final Staff Paper. The Committee still needs this rigorous policy asse ssment of scientific and techni cal information, both now and in the future, to be able to properly advi se the EPA Administrator on the NAAQS. Accordingly, the CASAC looks forward to working with the Agency to effectively and appropriately implement a suitable process for NAAQS review that is scien tifically-sound and transp arent and will enable the Committee to properly fulfill its statutory oblig ations under the Clean Air Act, with the goal of protecting public health with an adequate margin of safety and protecting the public welfare.

Sincerely,

/Signed/

Dr. Rogene Henderson, Chair Clean Air Scientific Advisory Committee

Appendices14 

### NOTICE

This report has been written as part of the activities of the U.S. Environmental Protection Agency’s (EPA) Clean Air Scie ntific Advisory Committee (CASAC), a Federal advisory committee administratively -located under the EPA Science Advisory Board (SAB) Staff Office that is chartered to provide extramural sc ientific information and advice to the Administrator and other offici als of the EPA. The CASAC is structured to provide balanced, expert assessment of scie ntific matters related to issue and problems facing the Agency. This report has not been reviewed for approval by the Agency and, hence, the contents of this report do not n ecessarily represent the views and policies of the EPA, nor of other agencies in the Execu tive Branch of the Federal government, nor
does mention of trade names or commercial products constitute a recommendation for use. CASAC reports are poste d on the SAB Web site at: http://www.epa.gov/sab

.

### Appendix A – Roster of the CASAC Lead Review Panel

U.S. Environmental Protection Agency Science Advisory Board (SAB) Staff Office Clean Air Scientific Advi sory Committee ( CASAC)

CASAC Lead Review Panel

CASA C MEMBERS Dr. Rogene Henderson (Chair) , Scientist E m eritus, Lovelace Respiratory Research Institute, Albuquerque, NM

Dr. Ellis Co wling , University Distinguished Profess or At -Large, E m eritus, Colleges of Natural
Resources and Agriculture and Life Sciences, No rth Carolina State University , Raleigh, NC

Dr. Jam es D. Crapo [M.D.] , Professor, Depart ment of Medicine, National Jewis h Medical and Resear ch Center, Denver, CO

Dr. Douglas Crawford-B rown , Direct or, Carolina Environm ental Program ; P r ofessor, Environm ental Sciences and Engineering; and Professor, Public Po lic y, Depart m e n t of Environmental Scien ces and Engineering, University of North Caro lina at Chapel Hill, Chapel Hill, NC

Dr. Donna Kenski , Direct or of Data Analy s is, Lake Michigan Air Directors Co nsortium (LA D CO),
Rosem ont, IL

Dr. Ar mist e a d (Ted) Rus sell , Georgia Power Distinguished Profe ssor of Envir onm ental Engineering, Environm ental Engineering Group, School of Civil a nd Environm ental Engineering, Georgia Institute of Technolog y, Atlanta, GA

Dr. Jonathan Samet [M.D.] , Professor and Chairman, Depart m e n t of Epidem iology , Bl oom berg School of Public Health, Johns Hopki ns Univer sity , Baltim ore, MD

PANEL MEMBERS

Dr. Joshua Cohen , Research Associ at e Professor of Medicine , Tufts University School of Medicine,
Institute for Clinical Research and Heal th Polic y St udies, Center for the Evalua tion of Value and Risk, Tufts New England Medic a l Center, Boston, MA

Dr. Deborah Cory-Slecht a , Professor, Depart ment of Environm en tal Medicine, University of Rochester School of Me dicine and Dentistry, Roch ester, NY

Dr. Bruce Fowler , Assistant Director for Science, Division of T o x i colog y an d E nvironm ental Medicine, Office of the Director, Age n cy for Toxic Substa nces a nd Disease R e gistry , U.S. Centers for D i seas e Control and P r evention (ATSDR/CDC), Cham blee, GA

Dr. Andrew Friedland , Professor and Chair, Environmental Studies Progra m , Dart m outh College, Hanover, NH

A-1Dr. Robert Goyer [M.D. ] , Emeritus Professor of Pathology, Faculty of Medicine, University of Western Ontario (Canada), Chapel Hill, NC

Mr. Sean Hays , President, Summit Toxicolog y , Allen s park, CO

Dr. Bruce Lanphear [M.D.] , Sloan Professor of Childre n’ s Environm ental H e a lth, and the Director of the Cincinnati Children’s Environm ental Health Cen t er at Cincinnati Children’s Hospital Medical Center and the University of Cinc innati, Cincinnati, OH

Dr. Samuel Luoma , Senior Resear ch Hy drologist, E m eritus, U. S. Geological Surve y (USGS), Menlo Park, CA

Dr. Frederick J. Miller

, Consultant, C a ry , NC

Dr. Paul Mushak , Principal, PB Associ ates, and Visi ting Prof essor, Albert Einstein College of Medicine (New York, NY), Durha m , NC

Dr. Michael New m an , Professor of Marine Science, School of Marine Sciences, Virginia Institute of Marine Science, College of William & M a ry , Gloucester Point, VA

Mr. Richard L. Poirot , E nvironm ental Analy s t, Air Pollutio n Co ntrol Divisio n , Departm e n t of Environm ental Conservation, Verm ont Agency of Natural Resour ces, Waterbur y, VT

Dr. Michael Rabinowitz

, Geochem i st, Marine Biological Laborator y , Wo ods Hole, MA

Dr. Joel Schwartz , Profes sor, Environmental He alt h , Harvar d University School of P ublic Health, Boston, MA

Dr. Frank Spei z er [M. D .] , Edward Kass Professor of Medicine, Ch anning Laboratory , Harvard Medical School, Bost on, MA

Dr. Ian von Lindern , Senior Scientist, TerraGraphics Envir onm ental Engineering, Inc., M o scow, ID

Dr. Barbara Zi elinska , Research Professor, Division of Atm o sphe r i c Science, Desert R esearch Institute, Reno, NV

SCIEN C E A DVIS O RY B O AR D STA FF

Mr. Fred Bu tterfield , CASAC Designated Federal Officer , 1200 P e nnsy l vania Avenue, N.W., Washington, DC, 20460 , P hone: 2 02-3 4 3 -999 4, Fax: 202-2 33-0 6 4 3 ( butterfield. fred@epa.gov )

A-2

### Appendix B – Written Comments from Individual CASAC Lead Re view Panel Members

This appendix contains the prelim inar y and/or final written comments of the individual mem b ers of the Clean Air Scie ntific Advisory Committee (C ASAC) Lea d Review Panel who submitted such comments electronically. The co mments are inclu d ed here to provide both a full perspective a nd a range of individual views expressed by
Panel m e m b ers during the review process. These comments do not repres ent the v i ew s of the CASAC Lead Re view Panel, the CA SAC, the EPA Science Advisory Board, or the EPA itself. The views of the CASAC Lead Review Panel and the CASAC as a whole are contained in the text of the letter to which this a ppendix is attached. Panelists providing w r itten comments are listed on the ne xt page, and their i ndividual comm ents f

o llow.

B-1Panelist Page #

Dr. Deborah Cory-Slechta.............................................................................. B-3

Dr. Ellis Co wling......................................................................................... B-4

Dr. Jam e s Crapo..............................................................................................B-12

Dr. Douglas Crawford-Brown.......................................................................... B-14

Mr. Sean Hays.............................................................................................. B-17

Dr. Donna Kenski .......................................................................................... B-19

Dr. Bruce Lanphear....................................................................................... B-22

Dr. Paul Mushak ........................................................................................... B-24

Mr. Rich Poirot .......................................................................................... B-34

Dr. Michael Rabinowitz .................................................................................B-42

Dr. Ar m i stead (Ted) Russell.............................................................................B-43

Dr. Jonathan M. Sam e t

................................................................................. B-44

Dr. Joel Schwartz ........................................................................................B-45

Dr. Frank Speizer ........................................................................................B-49

Dr. Ian von Lindern ....................................................................................... B-51

Dr. Barbara Zielinska ................................................................................... B-62

B-2

### Dr. Deborah Cory-Slechta

These comm ents in regard spec if ica lly to the A N PR concur with those offered by other Panel

m e mbers on the content of the docum ent.

1. First, no specific options are ever proposed that could elicit serious sy s t ematic d e lib era tions
from the community at large, as p e r the stated intent of the change in process that has been evoked.

2. Nor is it clear how the infor m ation that would be obtained from this new process would be used and judged. W ould inform ation from non-expe rts be given the sam e weight as those of experts in the field? Does preponderance of opinion count? My service as a Panel m e m b er on the Lead NAAQS Panel is p r em ised on lack o f conf lict of inte rest. W ill inf o rm ation obtained from sources who m i ght ha ve f i nancia l inte rest in th e outcom e be given the sam e weight as those stakeholders who sustain the exp o sures ? The ANPR repeatedly m a kes reference to levels of uncertain ty in the effects of blood lead levels at <10 μg/dl, but w h at level of certainty would be sufficient? Si nce this would be a s ubjective judgm e nt, how

m i ght it be related to financ ia l conf licts of inte res t ?

3. It rem a ins difficult to consider how any loss of IQ could ever be accepta ble in the co ntext of
hum a n health protection and to be without public health signi f i cance. I rem a in of the m i nd
set th at th is is a slipp e ry slope and th at 20 yea r s f r om now, these docum ents will b e r ead by people wondering what on earth could th ese people have been thinking?

4. In addition, the lack of any full econom i c analysis of the costs associated with lead exposure and its consequences as a component of th ese docum e nts is a highly significant om ission. Such an analysis, which should include the co sts of all the health consequences, both f o r child ren and adults, and the long-term effects of early academ ic failure for children and its ability to res u lt in su stain e d academ ic failure shou ld be weighed in the deliberations. T h e focus strictly on IQ point loss is m i sleadi ng at best and thus does not allow a full
consideration of all of the conse quences of any policy decision.

5. The docum e n t conveys a bias in its request for inform ation. For exam ple, in its solicitation
of infor m ation on the prim ary standard, it requests comm ent on de listing, revocation and adequacy of the current standard, but does not specifically, in the sam e sentences, request comments on the inad eq uacy of the curren t standard, as consistent with CASAC

recomm end a tions and the OAQP S Staff paper.

6. It seem apparent that the inten t of the ch ange in process imposed during the Lead NAAQS review has been to downgrad e input and recommendations pr ovided by CASAC and t h ereby
dim i nish public health protecti on. It certainly leaves this pa nel m e m b er wondering why they are spending tim e providing any advice to the Ad m i nistrator. Likewise , th e current pro cess serves to underm ine the careful and consid ered deliberations of its own EPA staff.

B-3

### Dr. Ellis Co w ling

Ellis Cowlin g North Carolina State University January 3, 2008

Individual Comments Prepared in Connect ion w i th the December 1 2 and 13, 2007 CASAC Review of the Advanced Notice of Prop osed Rule Making (ANPR) and the November 2007 Staff Paper for P b NAAQS

Before dealing with m y specific assignm e nt with regard to the S econdary (public-welfare based) NAAQS Standards for Pb, perm it m e to offer the following general comm ents on: the importance of EPA’s role in help ing elim inat e childhood lead poison ing in the United States by 2010, and the s t ructure an d content of the ANPR for the Pb NAAQS in the contex t of the new processes and procedures for NAAQS reviews.

EPA’s role in “eliminat i ng childho od lead poisoning” in the United States

As indicated in m y individual comments on January 27, 2007 and again on July 23, 2007 regarding the USEPA’s implem entation of the Lead Renovation, Repair, and Painting Rule , it was an inspiration to learn that m a ny differe nt agencies of our federal Governm e nt had established a very noble goal for m u lti-a gency cooperation and collaboration in:
“elim inating childhood lead poisoning [in the United States] by the year 2010!”

At the sam e tim e, it was very disappointi ng to learn how little the USEPA had done during the several years after th is interagency goal was established during the early 1990s to do its part together with other federal agencies to help f u lf ill this ve ry no ble national goal.

As the m e mbers of our CASAC Lea d Panel look f

o rward to the tim e it will take f o r EPA to
implem ent its Lead Renovation and R e pair Rule , we could not help but wonder why it was not
until Feb r uary 2007 that CASAC wa s asked to review two separate docu m ents – the Draft Assessment Plan in Support of th e L e ad Renovation and Repair Rule and An Approach for Estimating Children’s Health Risk (IQ) Change s Associated with Dust Lead Generated by Renovation, Repair, and Painting Activities – when the goal of our governm e nt is “elim inating childhood lead poisoning by 2010” – then 3 ye ars away and now only 2 years away!

We comm end the pres ent adm i nistration of the USEPA for undertaking their presently renewed interest and actions with regard to lead pollution and pois oning and hope that the Agency will in fact now do its important and ap propriate part – togeth e rwith oth e r f e d e ral agencies – and thus help our country m a ke fu rther progress toward our self-declared national goal of “elim inating childhood lead poisoning – [hopefully] by 2010,” but if not by then “as soon
thereafter as possible. B e tter late th an never!

The references listed below describe importa nt parts of the reasons why the currently proposed actions and reports regarding lead poiso ning of children in the United States are so long overdue.

B-4References:
1) Childhood lead poisoning preven tion. Too little, too late. B P Lanphear. J Am er Med Assn. 2005 May, 293(18):2274-2276.

2) “Cater to the children”: The role of the lead industry in a public health tragedy, 1900-1955. G Markowitz and D Rosner. Am J Public Health. 2000 January; 90(1) :36–46.

General Comments on the Advanced Notice of Proposed Rulemaking for Pb NAAQS

As our CASAC Lead Pa nel gath ered in W a shington DC on Decem ber 12 and 13, 2007 to

m eet and discuss our individual review co mm ents on the Advanced Notice of Proposed
Rulem a king for the Pb NAAQS, once again we could not help but wonder if the form and
substance of the ANPR was in fact intended to f acilitate continuing delay and lack of tim ely action in fulfilling the n oble goal of “elim ina ting childhood lead poison i n g [in the United States].”

In this conte x t, perm it me to of f

e r th e f o llowing genera l comm ents on the ANPR for the Pb NAAQS and its relationship to two other sour ces of insight about the Pb NAAQS:

1) The detailed and firmly sta t ed conc lusions and recommendations w i th regard to both the Primary (public-health based) NAAQS for Lead and the Secondary (public-welfare based) NAAQS for Lead de veloped by the staff in EPA’s Office of Air Quality Plannin g and Standards (OAQPS) in their 2007 EPA Staff Paper for the Pb NAAQS , a nd

2) The similarly deta iled conclusio n s and recommendatio n s prepared over the past

tw o years by the CASAC Lead Panel a nd summariz ed in our tw o most recent letters to th e Administrator of EPA (EPA-CASAC-07-003 dated March 27, 2007 and EPA-CASAC-07-007 dated September 27, 2007) follo w ing careful Peer Review s of earlier assessment documents on these same P r imary and Secondary NAAQS for Lead.

I agree with the general comm ents made dur ing our CASAC m e eting on Decem b er 12 and 13 by essential all of m y expert colleagues on our CASAC Le ad Panel. We all are greatly puzzled and disturbed about:

1) The intent and purposes of these three separa te sources of insight about the adequacy (or inadequacy) of the present identical Pr im ary and Secondary NAAQS for lead, and possible changes in the indicator , lev e l, statistic f o rm , and averaging tim e of alterna tiv e NAAQS standards,

2) Presentation in the ANPR of the carefully re asoned and very congr uent science-based
conclusions and recommendations of both OAQPS and CASAC – as though both of these organizations were m e rely two additional “i nterested parties” in offering advice and counsel with regard to final decisions about the NAAQS for Pb and their important role
in “elim inating childhood l ead poisoning” and protecti ng ecosystem s from further poisoning by both current atm o spheric deposit ion and redistribution of historically deposited lead in the United States.

B-53) What is exp ected to be g a ined from ou r CASAC Lead Panel Review of the ANPR on
Decem ber 12 and 13 – beyond what has alr eady been communicated through CASAC’s

recen t letters to the Ad m i nistrator of EP A following careful Peer Reviews of earlier

assessm ent docum ents on these sam e Prim ary and Secondary NAAQS for Lead.

4) How the addition a l com m e nts receiv e d from the CASAC Lead Panel after our m e eting
on Decem be r 12 and 13, the already f i nalized con c lusions and recomm endations in the OAQPS Staff Paper for Pb NAAQS, and th e comments being solicited through the
ANPR from other federal, state, and local governm e nt agencies, public interest groups, industry and trade associations , and individual citizen will be weighed, evaluated, and assessed during the final rule m a king process.

Joel Schwartz summ arized our CASAC Lead Pa nel’s co llective puzzlements very well when he wrote: “I agree with the comments of Paul Mushak that this docum ent summ arizes the risk

assessm ent that OAQPS did, ... but then ignor es the recommendations of OAQPS, ...and
blith ely ask s f o r comm ents on a rang e of standards f r om zero to inf i nity. T h is is rea lly not accep tab l e. The Clean Air Act requires the ad m i nistrator to set standards for a pollutant that “m ay reasonably be anticipate d to endanger public he alth, ” using cr ite ria that “accurately reflect th e latest scien tif ic knowledge useful in indicating the kind and extent of all identifiable effects on public he alth and welfare which m a y be expected from the pres ence of a polluta nt in am bient air...”.

“The range of possibilities proposed for co mm ents ignores the comm ents of CASAC on what those effects are, at what levels, ignores the Staff Paper summ ar y of t hose effects at different levels, and igno res the risk assessm ent.”

Comments on Replacement of the OAQPS St aff paper w i th a Policy Assessment and Rulemaking document in the form of an Advanced Notice of Proposed Rule Making

In m y opinion, the ANPR for lead is not consiste nt with the hi gh scientific principles outlined in Deputy Adm i nistrator Marcus Peacock’ s original m e m o of De ce mber 7, 2006 (a nd repeated again in his follow-up m e m o of April 17, 20 07) wher e he outlined his high ho pes and prin cipled aspira tions f o r the new NAAQS review processes as follows:

“I believe these changes w ill help impr ove the efficiency of the NAAQS review

process w h ile ensuring that the Ag ency’s decis i ons are informed by the best available science and broad participatio n amo n g experts in the scientific community. These imp r ovements w ill help the Agency meet the goa l of review ing each NAAQS on a 5-year cycle as required by the Clean Air Act w i thout compromising the scien t ific in tegrity of th e pro cess. It is imperativ e that the NAAQS pr ocess continue to adhere to the highest scientific standard s to ensure adequate protection of public health and w e lfare.”

As outlined below, the ANPR for Pb is not c ons isten t with the Deputy Adm i nistrator’s hopes and written assertions about:

B-6“... ensurin g that the Agency’s decisions are inform ed by the best av ailable sc ience,” “... broad participation am ong expe rt s in the scientific com m unity,” “... without comp rom i sing the scientif ic integrity of the process,” and

“It is imperative that the NAAQS process cont inue to adhere to the highest scientific standards to ensure adequate protec tion of public health and welfare.”

The inf o rm ation con t ain e d in the A N PR f o r Pb is presented in two dis tin ctly d i f f

e rent ways:

1) Carefully reasoned analyses of scientific ev idence and insights developed since the last review to indicate if the current public-health based and current public-welfare based NAAQS f o r lead a r e ade quate, or if alte rnative le vels, ind i ca tors, sta tis tic a l f o rm s, and averaging tim e s are needed to protect public hea lth with an adequate m a rgin of safety and to protect public welfare.

(These parts of the ANPR are consistent wi th the public ly av ailab l e and well documented consensus findings and recomm endat i ons c ontained in the Novem b er 2007 OAQPS St aff Paper and in both the March 27, 2007 and September 27, 2007 CASAC letters to the
Adm i nistra tor of EPA.)

2) Much less carefully reasoned descriptions of uncertainties, alternative views, and/or possible alternative courses of action that m i ght be considered by the Administrator of
EPA in m a k i ng his final court-ordered deci sions about the current NAAQS for lead in Septem ber 2008.

(These parts of the ANPR are not consiste nt with the publicly available consensus findings and recomm endations contained in the N ovem b er 2007 OAQPS Staff Paper and in the March 27, 2007 and Septem ber 27, 2007 CASAC letters to the Adm i nistrator of
EPA and thus are not consistent with the high pr in ciple s of scientif ic integ r ity ou tlined in the Deputy Adm i nistrator’s m e m o randum s of Decem ber 7, 2007 and April 17, 200 7.)

Comments about My Specific Assignment

As requested by our CASAC Chair, Dr. Roge ne Henderson, my specific comments about the ANPR are focused prim arily on the six Areas in Which EPA Solicits Comments w i th regard to the Secondary (public-w elfare based) NAAQS Standard for Pb.

As we all are aware, EP A prom ulgated the pr ese n t iden tica l Prim ary (public -health b a sed) and Secondary (public-w elfare bas e d ) Nationa l Ambient Air Quality Stan dards for Lead on October 5, 1978. These standards were establishe d at a level of 1.5 m i crogram s per cubic m e ter of air, m easured as Pb in total suspended part iculate m a tter (Pb-TSP), not to be exceeded by the
arithm etic mean concen tration av erag ed over a calendar quarter.

The six Areas of EPA S o licitation d eal with the f o llowing is su es related to the Secon d ary NAAQS standard for Pb. My comments ar e presented in ordinary type (or in bold face i ta lic

B-7type in the case of impor tant quotations from pub lished docum ents) after each of these im portant Areas of Solicitation is presented in ordinary non-italic bold type

.

1) The questions of delisting and revocation.

These two questions have been very t horoughly considered and discussed by both CASAC in its March 2007 letter to Ad m i nistrator Johnson and also by OAQPS staff in their
Nove m b er 2007 Staff Pa per. In fact, the March 2007 CASAC letter contains a very detailed and carefully reasoned separate section titled “ Scientific Basis for Continuing or De-listing the Lead NAAQS.” This le tte r co ntains the f o llowing f i rm ly stated overall conclusions regarding the questions of delisting and revocation:

“ The unanimous judgment of the C A SAC Lead Pane l is that lead should not be de-listed as a criteria air pollu tant, as defined by the Clean Air Act, for which primary (publichealth based) and secondary (public-welfare based) NAAQS are established, and that both the primary and secondary NAAQS air stan dards should be lowered su bstantially.”

“It is a l so re commended that future monitor i ng of lead exposure be con d ucted with low volume PM 10 samplers r a ther than with tota l su spended particulate (TS P

) samplers, and that the averaging time be decrea sed from seasonal to mon t hly.”

“If lead were de-listed as a criteria air pollu tant, would it be appropriately regu lated under the Agency’s Hazardou s Air Pollutants (HAP) program? The answer is “No.” The HAP program regulates according to use of m aximu m achievab l e control tec h nology (M ACT) and is appro p riate for po int sources. However , the most wid e spread sou r ce of airbo r ne lead throughout the nation is the historical ly-deposited lead along roadways. Thus, this source of airborne lead could not be regulated u n der the HA P program.”

“The large environmen tal burden o f

histor ica l ly-deposited lead is currently decreasing. Accordingly, the goal sh ould be to set the secon dary Lead NAAQS such that there is no

reversa l of the current d o wnward trend in le ad concentrations in the environment. The limited funds availab l e f o r monitor i ng enviro nmental lead should be focused on this critical task. ”

Exactly these sam e questions of delisting and revocation also were very critically

exam ined in the OAQPS Nove m b er 2007 Staff Paper. The final carefully reasoned
conclusions of EPA staff are also stated very clearly:

“For reasons discussed above, staff concurs with CASAC with regard to consideration of Pb in the en vironmen t today and the adequacy of the current standard. Accordingly, we suggest that there is a n eed for the Administr ator to consider a revision of the current standard to provide increased protectio n against reasonably anticipated adverse
environmen tal effects.”

“In conclusion, staff concludes that in th e absence of information on which to base independent recommend a tions for th e secondar y standard consistent with a reduction in the level of the primary standard (S ectio n 5.5.4) would provide increased protection against adverse environmental effects. Accordingly staff recommends that the

B-8Administra t or consider a revised secondary sta n dard set id entica l to th e indica tor, averaging time, form, a n d level o f

a revised p r imary standa rd.”

2) Whether th e evidence s u ggests that adverse effects are occurring, particularly nea r point sources, under the current s t andard.

Here too both CASAC a nd OAQ PS staff have thoroughly cons idered the question of whether adv e rse effects are occu rrin g, particular ly near point sources. Both organizations agree that although there are few if any catas trophic dam a ges to aquatic or terrestrial ecosystem s that can be unequivocally be attribut ed specifically to Pb pollution, as opposed to Pb acting in concert with othe r stress factors, the general conclusion from the available scientific evidence is that adve rse effects are occurring, especially near point sources and that the current identical prim ary and seconda ry NAAQS for Pb need to be strengthen.

3) The role of deposition of Pb from current sou rces and th e availability of this Pb to ecological receptors.

Most air em issions from current Pb sources a r e dispersed into the environ m ent in the
for m of particulate m a tter that is transporte d over both short and long distances. Thus Pb particles are deposited onto the leaves, shoots, and stem s of agricultural crops, forest and shade trees, and natural vegetation at low and high elevations throughout the United States as well as d i rectly depos ited onto soils and surf ace waters in n a tural and m a n-m a de lakes,

stream s, ponds, reservoirs, and estuaries th roughout our country. From these initial deposition sites, Pb is generally absorbed, adsorbed, or chem ically bound to organic matter
from which it is only very sl owly transported deeper into soil layers and e v entually incorporated into sedim e nts. Thus air em issions from current sources ar e readily available to a wide variety of ecological recepto rs that include all the livin g plants, do m e sticated and wild
anim als, and both beneficial and harmful insect s and m i croorganism s as well as the physical

com ponents of both aquatic and terrestrial ecosystem s

.

Both CASAC and OAQPS staff have summ arized current scientific understanding of the
role of atm o spheric d e po sition of Pb f r om current sources and the ava ilab i lity of th is P b to ecological recepto rs and how this kn owledge sh o u ld be cons idered in relationship to the adequacy of the current secondary standard for Pb and needs for consideration of alternative indicator, averaging tim e, for m , and le vel of a revised secondary standard.

4) The adequacy of the cu rrent stand a rd and the rationale upon w h ich such view s are based.

Please no te once again the firm ly stated summ ar y conclusions of both CASAC and OAQPS staff (see the d i s c ussion und er Item 1 ab ove) with regard to the adequacy of the current secondary NAAQS standard for Pb a nd the recomm e ndation from both organizations that both the prim ary and secondary NAAQS air standards for Pb should be decreased substantially. The principal ra tionale for recommending that the secondary standard be set at leas t as low as the propo sed prim ary standard is that:

B-9“ The large environmental burden of historical ly-deposited lead is currently decreasing. Accordingly, the goal sh ould be to set the secon dary Lead NAAQS such that there is no

reversa l of the current d o wnward trend in lead concentrations in the environment. ”

5) The option of a reduction in the secondary standard consistent w i th any reduction of the primary standard that w o ul d pr ovide increased protection against adverse environmen tal effects.

As stated in the disc ussion under item 4 above, the principal rationale for recomm ending
that the seco ndary stand a rd be set at least as low and the proposed prim ary standard is that:

“ The large environmental burden of historical ly-deposited lead is currently decreasing. Accordingly, the goal sh ould be to set the secon dary Lead NAAQS such that there is no

reversa l of the current d o wnward trend in lead concentrations in the environment. ”

6) Additional information pertaining to a nd comment on the considerations described above, as well as on oth er view s w i th regard to the elements of a secon d ary standard for Pb, and the rationa l e upon w h ich such views are based.

The ANPR, CASAC’s March 27 and Septem ber 27, 2007 letters to Adm i nistrator Johnson, and the November 2007 OAQPS Staff pa per on the NAAQS standards for Pb are essentially congruent in that all th ree docum en ts summ arize com p elling s c ientific ev idence
that cu rren t atm o spheric lead conc en trati ons and deposition — co m b ined with a la rg e

reservo i r of historically -deposit ed lead in soils, s e dim e nts and surface waters — con t inue to cause advers e environm ental effects in aquatic an d/or terrestrial ecosyste m s , especially in th e vicinity of large em ission sour ces. Th ese effects p e rsis t in som e cases at lo cation s where

curren t airb orne lead co ncentration s are below the levels of the current identical prim ary and secondary lead standards.

Thus, from an environmental pers pective, th ere are convincing scientific reasons to both retain lead as a regulate d criteria air pollutant and to low er the level o f the current secondary s t andard.

Since concentrations of histor ically deposited lead in soil s throughout the U.S. (averaging 0.5 to 4 g/m 2 of land area) are changing only slowly — with a half -lif e exceeding a century
— these con centrated deposits of lead are expe cted to rem a in access i ble f o r exchange with
the atm o sphere and the rest of the biosphere in to the f o resee a b le f u ture. Fires, chang e s in land use, or clim atic events such as regional dust storm s could m ob ilize s i gnif i can t qu antities of lead that would be harmful both to hu m a n health and ecosystem s downwind. This potential for harm is not adequately recognized in the 1 st Draft Lead Staff Paper and th e Draft Lead Exposure and Risk Assessm ents technical support docum ent, but is a concern that warrants careful continued m onitoring in the future.

In addition, I recently reexam ined the m a gnitude of the reser voir of “historically deposited lead” and found that -- 0.5 to 4 gram s per square m e te r of land area translates into 4.4-35.7 pounds of lead that is available for poten tial redistribution from e v ery acre of land

B-10area in this country! This simp le recalculati on adds significance to the CASAC assertion in the March 2007 CASAC letter to Adm i nistrator Johnson that:

“Fires, cha n ges in land use, or climatic e vents s u ch as regio n al dust stor ms could mobiliz e signif icant quantities o f

lead that would be harmful both to human health and ecos y ste m s downwind.”

Am ong these several potential causes of atm o sphe ric redistribution of lead, wild fires in forest and grassland areas – which are occurri ng with increasing frequency and intensity in

recen t decad es in m a ny parts of the U S – are potentially very important for both hum an health and ecosystem health and stability.

The EPA is also encou r aged to iden tify th e necessary funds to support needed contin uing research on the ecolog i cal effects of airborne lead pollution and to consider developing alternative secondary standards su ch as critical loads for lead , which m a y be different from prim ary standards in indicator, averaging tim e, level or form

.

Finally, although the ANPR, CASAC’s Ma rch and Septem ber 2007 letters to
Adm i nistrator Johnson, and the Novem b er 2007 OAQPS Staff Paper for Pb do not provide a clear quantitative b a sis f o r iden tifyin g a speci fic lower level at which a more protective secondary P b NAAQS s hould be set, there are no reasons to exp ect that hum a ns are uniquely sensitive to lead pollu tio n am ong the m illions of plant, an im a l , insect, and m i croorgan i sm s with which we share our life on this planet. Therefore, at a minimum, th e level of the secondary Pb NAAQS should be at least as low as th e lowest-recommended primary P b standard.

B-11

### Dr. James Crapo

Review Comments: EPA’s Advance Notice of Proposed Rulem a king for the NAAQS for Lead

Jam e s D. Crapo, M.D. Professor National Jewish Medical and Research Center Denver, CO 80206

The ANPR for the NAAQS for Lead as released by the EPA Decem ber 1 7, 2007 is a severe disappointment and raises substa ntial questions regarding the viability of the revised NAAQS Review Process and th e inten t of the Agency to used this p r ocess to app r o p riately m eet the requirem e nts of the Clean Air Act. The ANPR for l ead failed to m eet the Agency’s obligation to consider the “best av ailable science” and provide an advance notice of, an d rationale f o r, a justifiable range of standards that the ag ency is considering for rule m a king.

The ANPR for Lead contained only a restatem ent of the Agency’s Final L ead Risk Assessm ent report and the Agency’s Staff Pape r along with the statem ent that the Agency would consider all options for its eventual rule m a king for this air criteria pollutant, including delisting lead. This
does not con s titu te an ad vance notice of the agen cy’s ass e ss m e nt of the scienc e in th is f i eld and its thinking regarding how the NAAQS for lead s hould be revised to confor m to the requirem e nts of

the Clean Air Act. One is lef t to assum e that the Agency plans to m a ke a closed door decision
on a final rule after the scient ific and public review is co m p leted, thereby ignoring their responsibility to conduct this process in a m o re open fashion and provide an advance notice of the agency’s assessm ent of the scientific and public policy issues that will fra m e the final
decision.

I would applaud the quality of the Agency’s wo rk on the Final Lead Risk Assessm ent docum ent and the Agency’s Staff Paper on Lead. Both were well done and correctly reflected the m a rked evolution of the science in the field of lead t oxicity. These docum ents correctly identified the
substantia l a dverse r i sk o f even low levels of lead on neuroco gnitiv e f unction in ch ildr e n and the obvious need for a m a rked tightening of the cu rrent lead standards. The docum ents also
identified th e central role that air lead plays in the m ove m e nt of lead between environm ental

reservo i rs a nd the need to m a intain a strict air q u ality stand a rd fo r lead as a central m echanism to

contro l expo sures of sens itiv e populations (i. e ., ch ildren). W h ile the ANPR lists find ings and conclusions found in the Agency’s Staff Paper, it does not provide any insight into the Agency’s

assessm ent of these findings and conclusions.

The current review of the Lead NAAQS is th e first tim e that the revised NAAQS is being
imple m ented. It is essential that this process be done correctly in order to establish credibility for the Agency and for th e process it will use to m eet its legal oblig ation s under the C l ean Air Act. I would recomm end that the Agency accep t the failure of the curren t Lead ANPR to m e et

even m i ni mum expectations and to redo this do cum e nt. The revised docum e nt should consider
the cr itica l s c ientif ic and policy issue s and pr ovide a range of standards that the Agency is actively considering for the eventual rule. This range of standards should be defended in the

B-12ANPR by showing that it can be supported by high quality scien ce and th a t it conside r s health
risks to sens itiv e populations as re quired by EPA’s legis l ative m a ndate.

B-13

### Dr. Douglas Cra w ford-Bro wn

Comments on the Lead Human Exposure and Heal th Risk Assessmen ts for Selected Case Studies (ANPR), Volu me I.

Doug Crawford-Brown, Decem ber, 2007

This rev i ew focuses larg ely on Section III B of the ANPR docum e nt and the assoc i a t e d Volum e I and appendices.

General Remarks

I am generally supportive of the approach taken by the authors in this assessm ent. The

m e thodologies used are sophisticated and comp le x, capturing the m a jor issues associated with what is perhaps the m o st difficult set of exposur e pathways to model of any of the NAAQS due to the wide range of sources of lead in the envi ro nm ent. Because of this com p lexity, I support th e idea of exam ining some selected case studies rath er than attemp ting to produce a distribution of risks in the entire U.S. populati on, and I support the particular cas es the authors have selected. The cases cover a reasonable range of exposure scenarios and include a significant number of people in the U.S.

I rem a in unclear as to ho w the results in the ta bles at the end of Sec tion III B – the resu lts concerning the NUMBER of people with a BLL or an IQ loss – are to be used by the Agency in

m a king a fin a l decision on the NAAQS. I suppose th e conclusion that can be drawn is that the

num b ers of people affected are by no m eans in significant (tending to be in the hundreds of thousands), and that these num bers would be even larger if the Agency were to perform the sam e kind of assessm ent over the entire U n ited States rath er than just for the case stud ies. And these

num b ers are presented in the context of ot her tables that report the m e dian and 95 th percentiles of the BLL and IQ loss, which provides a range of c onsidera tion s the Adm i nistr a to r m i ght take into
account in m a king a final decision. I simp ly was struck by the lack of any clearly stated decision
criter ia to be em ployed in inte rpre tin g the tab l es at the end of Section 3 II I, but can understand if those criteria are being left to the discretion of the Adm i nistrator. As the tables stand, they
dem onstrate that any d e cision will be m a de in the face of results th at show that the exis ting NAAQS is associa t ed with signif i can t IQ loss to a significant num b er of people in urban areas
and near sm elters located in diverse regions of the United States. It would im prove the ANPR to show not just num bers of people affected in the case studies, but the fraction affected.

However, there is a prob lem I see in inte rpre ting the resu lts o f the table s a t the end of this
section. W h i l e the risks appear si gnificant, the large m a jority of those risks m u st be due to
sources that are not impacted by th e NAAQS, or at le ast a r e n o t comp letely m odeled in the

assessm ent. The tables show what I believe to be very sm all reductions in the 95 th percentile IQ loss (or even m e dian IQ loss) as the NAAQS is progressively lowered all the way down to 0.02.
There ar e tw o possible in terpr e ta tions of this re su lt. The first is that a m o re string ent N AAQS will have little impact on improving public health because th e larg e m a jo rity of the risk is

com i ng fro m sources unaffected by a NAAQS (an i ndication of the success the Agency has had with past regulatory action). The oth e r in terp reta tion is tha t this finding is an artifact of the

B-14curren t inab ility to fully mode l the effect of lowered air c oncentrations on exposures th rough soil, indoor dust, etc. The claim could be m a de that the differences in the results as the NAAQS are lowered are significan tly understated in the tables (i.e., th at the benefits of regulation are understated). Both interpretations ha ve m e rit here. The problem is that the latter one, the one that would support a m o re stringent NAAQS for lead, can’t be determ ined one way or the other from
the current assessm ent. I will say that the autho r s have done a good job of pointing to this issu e in the docum ent, so it hasn’t simp ly been ignored. And I have no suggestions as to how the problem can be rem oved; it seem s to m e inherent in the cu rren t lim itations on the state of the science in modeling non-air exposur es resulting from past releases.

On the issue of the various exposure-response fu nctions, I can’t support th e use of the stratified analysis with two separate slopes. I understand the reason ing that there m i ght be two

m echanism s at play at two di fferent concentrations, but I ju st can’t find any biological justification for a discontinuous curv e. And as the curves currently st and, one is left with the odd situation (not called out in the text) that there is an interm ed iate range of exposures surrounding the cut-point where it looks as if a small increase in exposure leads to a decrease in IQ loss. This is an artifact of having the two separate slopes with no attemp t to provide a single m odel over the entire range of exposures . The issue is hidden in Figure 5-2 of Volum e I by the fact that the authors have chosen to force the two parts of the curve to m eet (in both the 7.5 and 10 μg/dL curves). But I am not sure that this is how the m o deling was done. Unless I am m i sreading that
Volum e , the C-R function used in the m odeling was actu a lly a piece-wis e model with an IFTHEN-ELSE structure (IF BLL<7.5, THEN slope = X, ELSE slope = y). So there seem s to m e to be a disconnection between the computationa l for m of the model and the picture shown in Figure 5-2. But absent having the code in front of m e , I can’t be su re th is is the case. I f it is, I suggest de-emphasizing this appr oach. I also suggest that Tabl es 3 and 4 contain a footnote letting the reader know which m ode ls const itute the Low and High C-R function estim a te.

On a related note, I am supportive of the claim s on pages 57 and 58 that the m odels that have undergone the extensive developm ent and statistical diagnoses should have top priority in the

assessm ent. At severa l p o ints in the ANPR, the authors th en m e ntion that the log

- lin e a r m odel
for m should enjoy greater “confidence”. I can ’t, h o wever, see any place in the assessment where the idea of “confidence” plays a ro le for m ally. A nd this m e ntion of increased confiden ce doesn’t

appear ag ain in the tables . So, I am not convi nced that this claim will have any impact on conclusions drawn by the reader or the Adm i nistrator. The author s m i ght consider som e way to give this judgm e nt of confidence m o re of a role in inte rpre tin g the tab l es of results.

This asses s m ent of I Q loss, and the claim that th ere is no threshold, places the as sess m e nt m o re in lin e with probabilis tic risk as sess m e nts such as for cancer rather than in the older n on-cancer, threshold, assessm ents. In the case of regulating f o r reduction of cancer ris k, there is a need to specify an u n acceptable level of risk

, giving rise to the “fuzzy bri ght line” concept that generally plays itself out as a range of target values between 1E-6 and 1E-4. I kept wondering throughout the ANPR what the analo gue is for IQ loss. The tables present estim ates of the num ber of people with an IQ loss above 1 and an IQ loss above 7, but I can ’t find a coherent explanation as to why
these are th e relev a nt values defi ning anything like a “fuzzy bright line”. I am not saying they are the wrong values, I just don’t unde rstand the implications of th ese values for anything like quality of life. In the case of cancer risk, the Agency did a reasonable job of looking at lifetim e

B-15excess in cid e nce of disease that is accepted in different occupati ons, and used this as basis for
estab lish i ng target lev e ls of risk to be deem ed unacceptab l e. S o m e thing ak in to th at is needed here, or at least will be n eeded when a num erical value fo r a NAAQS is established and presented for public comm ent.

The authors have chosen, in m y m i nd, the a ppropriate exposure m eas ure from the list of possibilities (concurrent, etc.). I doubt the results would change si gnificantly if the others were used, but it m i ght i m prove the docum ent by at leas t includ in g the resu lts of samp le calcula tions in which the sam e case study is assessed through th ese 4 different m easures (or at least the two that Lanphear et al found m o st pred ictive). This would help the read er see that the results are not

extrem ely se nsitiv e to this choice.

I rem a in supportive of the proporti onal roll-up and roll-down approach used in the assessm ent, although it will introdu ce errors due to the fact that th e im pact of a revised NAAQS on non-air pathways is not being m odeled directly. But given this caveat, the roll-up and roll-down procedures are the b e st availab l e at the m o ment.

I also rem a in supportiv e of the post-process i ng appr oach to incorporating in ter-sub ject variability
into the assessm ent. The choice of a lognorm a l dist ribution is appropriate, as it agrees reasonably well with ex isting d a ta o n variab ility of the bi ological param e ters going into the relationship between exp o sure and B LL. There rem a ins som e m i nor concern tha t they are assum i ng that the
“central ten d ency” valu es they calculate are eq u a l to the m e dians of a lo gnorm a l distribution, without any evidence that they are in fact m e di ans rather than m eans or just som e kind of “representative typical” v a lue (as is of ten the case in such regulatory assessm ents, typified by NATA). But that is a m i nor quibble and in any even t it is m a de routinely both in risk assessm ent in general and in EPA assessm ents in particular.

On the issue of uncertainty, the authors have chos en not to employ a form a l statistical approach, and have instead provided results under a range of different C-R m odels. I support this idea in principle, because it would not be feasible at pres ent to p l ace such a com p lex com putational system into a f u ll, neste d, uncertainty-variability f r am ework. However, I think th e un certainties in characterizing exposure, and in the exposure-to-BLL conversion, ar e at least as large as those associated w ith the C-R functions. As a resu lt, the docum ent should m a ke it clear that the uncertainties described are a lower bound estim at e on uncertainties (and then m a ke it clear that this uncertainty can cut both ways).

On Page 73 of the ANPR, the authors note that the uncertainties and lim ita tions in the Secondary Lead Sm elter case study are large. Th e closing sentences in this bulle t appear to suggest that this analysis should not be used. Is that what the authors intend to convey?

Finally, I note that the authors ha ve, for the m o st part, responded to all of my concerns with the
first draft as sessm ent, and m o st of the concer n s r a ised in the CASA C review overall. There

rem a in areas where the science needs to be impr oved, especially with resp ect to non-air exposure pathways that reflect “past” exposures, but the authors have done what I believe is the best

assessm ent possible g i v e n these current lim itatio ns and com p lexities. I was especially pleased to see the complete dropping of calculations at the 99.5 th percentile.

B-16

### Mr. Sean Hays

Individual R e view Comm ents By: Sean M. Hays Date: December 19, 2007

Comments on Final Lead Risk Assessment and EPA Staff Paper

I comm end t h e EPA for providing the incr em ental changes in blood lead levels associated w ith th e vario u s NAAQS scenarios. As I have commented before, the increm ental changes in blood lead levels are far more certain and inform a tive than the predicted absolute blood lead levels. In m y opinion, these incr em ental changes in blood lead (and thus IQ
decrem ents) between current levels and the va rious NAAQS options should be relied upon for setting the N AAQS.

Providing the “roll-up” scenar io is very helpful and inform ative for NAAQS decision

m a king. It is im portant to see what could happen if the NAAQS is set at a level that allows for levels of air lead to increa se above those occurring today.

The final ris k assessm ent notes m a ny uncertainties associated with the an a l yses. One

m a jor uncertainty that is not discus se d well is re lated to uncertainties as sociated with quantifying the types of exposures that resu lt in the higher (> 3 - 5 μg/dL) PbB levels am ong children in the United States. The current approach used in th e Final Lead Risk Assess m e nt relies on using the Integrated E xposure Uptake Biokinetic (IEUBK) m odel for lead in children to estim a te the

m ean/ m edian blood lead levels associated with the various scenarios and then applying a

geom etric standard deviation (GSD) to quantif y plausib l e variab ility ass o ciated with the distribution of PbB levels for a given exposure scenario.

The Final L ead Risk Assessm ent notes on pa ge 4-17 that “pathway apportionm ent of blood Pb levels for higher population percentiles is specified to be the sam e as that estim a ted using the central tendency estim a te of blood Pb in an exposure zone.” In other words, if air lead is thought to contribute ten percen t (10%) of total lead exposures for the centr al tendency of the U.S. population, this estim ate is also used for th e higher population pe rcentiles of PbB. Since the goal of any lead risk assessm en t will be to redu ce the blood le ad for the higher percentiles, knowledge of the exposure sources for these higher percentile PbB levels and the potential to
im pact these exposures via the Lead NAAQS is critically im portant. The current Final Lead
Risk Assess m e nt does not provid e a ny assessm ent or assu ran ces tha t the alte rnative NAAQS will
im pact the PbB levels among the upper percenti les beyond those predicted for the m e an/m edian percentiles. I still have un certainties about whether lo wering the NAAQS below current exposure levels will m eaningfully im pact the le vels of lead in childre n who already have blood lead levels above 5 μg/dL (the population of ch ildren m o st at risk of developing neurological effects). Sin ce it appears there are no data to fi ll this gap, th is issue s hould be identified and highlighted as a data gap and research need.

The other m a jor uncertainty that exists is the shape of the dose-response curve for children with blood lead levels below approximate ly 5 μg/dL. The EPA has provided a range of

B-17slopes (both linear and non-linear ) to help bound the variability or uncertainty in the doseresponse relationship relating childre n’s concurrent blood lead levels with IQ decrem ents. I agree with the use of the vari ous m odels as it is unclear which m ode l provides the best fit (since EPA was unable to independently validate the m odel fits to the data from th e Pooled International Analysis).

Comments on ANP R

Not having expertise in the policy aspect of setting the NAAQS, I find it difficult to
comment on the ANPR a s a tool for setting th e A N PR. Howe ver, I find the ANPR to read

som e what of a two-handed report. One the one h a nd it c a ref u lly summ arizes the EPA f i nal risk

assessm ent and staff paper, and then on the other ha nd it offers other altern atives and discussions of science that were already passed off as not being supported or supportable by the science as
deem ed by the risk assessm e nt, staff paper, a nd opinions of the CASAC. In addition, when discussing the various options, the ANPR fully ch aracterizes the uncertain ties noted by EPA and CASAC for the various issues with the risk a ssessm e nt, but does not fully characterize the uncertainties with the new options being offe red in the ANPR which were elim inated from consideration by EPA and CASAC. It is unclear how expanding the universe of options and
inte rpre tatio n s at th is late in the p r oc ess he lps to advance th e policy op tio ns f o r settin g the NAAQS.

Other spec if ic comm ents include :

• On page 118 of the ANPR, it is stated that CASAC recommended 1.0 – 1.4 μg/dL or lower to be considered as an estim at e of the non-air component of blood Pb. I do not agree with this estim a te nor do I unde rstand the basis for such an estim ate. This estim a te m a y be fine for the m e dian child, however it m a y grossly
underestim ate the non-air contribution am ong chi l dren with much higher blood lead levels. This distinct ion needs to be m a de clear.

• On page 65 of the ANPR, it is stated th at “inclusion of indoor lead Pb as a

com ponent of “other” indoor air (and cons equently as a component of “past air” exposure) represents a source of potentia l high bias in our prediction of total

exposure an d risk associated with p a st air becau se conceptu ally, exposure to indoor paint Pb is considered part of background exposure. ” I agree this biases the “past air” contribution to total Pb exposure. P b from paint should not be attributed to “past air”.

• On page 67 it is stated th at a “p robab ilis tic expos ure m odel” was used to generate distributions of blood lead concentrations for the various scenarios. The Agency should be careful not to characterize what they did as a probabilis tic effort. Use of a GSD on top of estim ates of the m ean does not constitute a probabilistic effort.

B-18

### Dr. Donna Kens k i

Co mm ents o n the NAAQS for Pb ANPR
Donna Kenski
Decem ber 11, 2007

As a new mem b er of CASAC, I ca m e to this pane l very late in the process of reviewing the Pb standard. My a priori view was that we’d m a de wonderful progress in controlling lead and that

m a ybe it was tim e to retire the standard, since EP A’s direction to the states has been to retire the
monitors. T h e Staff Paper quickly set m e straight. The new health effects data reviewed in that
docum ent make an absolutely c onv in cing cas e th at the standard m u st significantly low e red from the current level in order to protect at-risk populations. The ANPR, how ever, failed to convey the tone of the staff paper and also failed to present any concrete opt ions or preferences on EPA’s part for the direction of the rulem a king with respec t to antic ipated le vel or averaging tim e

. It seem s to h a ve summ ar ized m o st of the science and data analysis of the staff paper but failed to include the logical conclusions th at were, for the m o st part, pres ented there. Instead, it asks CASAC again for its opinions on issues we ha ve already weighed in on. Consequently, m y responses to the specific solicitations for comm ent below reiterate som e of the advice that panel

m e mbers have discussed and docum e n ted in their delibe r ation s and le tte rs to the Adm i nistr a to r (e.g., Henderson, Sept. 2007).

Monitoring considerations :

On the issu e of variab i lity of collection efficien cy of the high-volume TSP sampler : The
ANPR and t h e staff paper fail to m a ke a comp e lling case for continuing to use the high-volum e TSP sam p ler as the FR M. In ligh t of the clea rly estab lishe d need to lo wer the leve l of the
standard and m a ke m o re frequent m e asurem ents at additional sites, EPA should take this opportunity to m a ke low-volum e PM10 sam p ling on Teflon filters the n e w FRM. It offers significant improvem e nt s in precision, allows fo r sequential samp ling, allows for analyses of multiple spe c ies, and m a kes it pos sib l e to integ r at e Pb m easurem ents m a de in existing networks that are already m a king PM10 m e tal m easurem e n ts like NATTS and IMPROVE (not all of these
PM10 m easurem ents are currently low volum e).

The Staff Pa per and the Cavender/Schm idt m e mo m a de it clear that PM10 and TSP lead are generally highly correlated. The instances where they were n o t well co rre lated is m o st like l y due
to the inef f i cient and v a riable co llec t ion of la rge particles by the TSP sa mpler. Som e of these poorer relationships were based on a sm all num b er of data points, m a ny at concentrations close
to the detection lim it for the TSP FRM. Th e range of proposed levels (0.02 to 0.5 μg/m 3 ) is sufficiently broad that the selection of PM10 vs . TSP FRM has a m i nor impact in comparison. The average Pb-PM10/Pb-TSP ratio was 0.8, with a ll sites exam ined being above 0.6. So a level of 0.03 for PM10 would be as protective as a leve l of 0.05 for TSP at m o st sites. The sensible approach w ould be to choose a m o r e conservative (lower) level of the st andard and use a m e thod

to m onitor that, while c o llec ting s l ightly less Pb m a ss, offers significan t monitoring advantages
and m a kes it possible to colle ct th e a ddition a l hi g h -quality da ta necess a ry to m a ke stro nger

assessm ents of Pb im pacts on public health. The very la rge p a rticle s tha t will be m i ssed by the PM10 are the sam e ones collected with th e least reliability by the TSP m e t hod.

B-19Retain TSP or require around large sources? As stated above, I th ink reta ining TS P is

unnecessary because a P M 10 indicator could be sufficiently protec tive, b a sed on the data presented in the Staff Paper and Cavender m e m o , a nd offers num e rous adva ntages. That said, I like the idea of continuing to collect TSP (a lthough a low-volum e m e thod would be preferable) in a few places, includin g around large sources, because there is m u ch value in co llocated

m easure m ents of the various size fractions. Mu ltiple size fractions can give us a better understanding of exposures, of lead’s m ove m e nt from a source through the environm ent, and the influences of various source types and m e te orological conditions on the distribution and deposition of lead. More important than what kind of m onitoring is a requirem e nt for any monitoring—PM10 or TSP—around large sources (but see comments on network below).

Appropriateness of using Pb-PM10 data as a surrogate for Pb-TSP: As noted above, I think low volum e PM10 would be the appropriate indi cator, not T SP. Making PM10 a surrogate for TSP is m e rely trying to m a ke a m o r e precise an d well-defin e d m easurem ent m a tch a less p r ecis e and poorly defined m eas urem ent, which is the wrong approach.

Appropriate range of concentratio ns for an FEM demonstration: Clearly FEM
dem onstrations should be m a de across a range of concentrations that represent real-world
conditions. Presum ing a switch fr om TSP to PM10, a range of 0.01 μg/m 3 to 0.2 μg/m 3 should

cover cu rren t am bient Pb-P M10 concentrations.

Adequacy o f current lab analys is methods for use at altern ative NAAQS levels considered in Staff Pap er: A lower level of the standard, pref erably one with an accom panying PM10 indicator, should be supported with a change in lab analysis method, or a requirem e nt for a

m i ni m u m de tection lim it that perm its concentratio ns at typical am bient levels to be accurately quantified. At current ambient Pb-T SP or Pb -PM10 levels, a detec tion lim it of 0.01 μg/m 3 is too high. As noted in Sec. 2.3.2.5 of the Staff Pa per, 57 of 129 non-source-oriented m onitors reported m o re than 50% of their raw data below th e MDL. In order to su pport future reviews of the NAAQS and assess exposures to Pb, the m oni toring network m u st do a better job characterizing these low concentrations. A m e t hod like ICP/MS has a det ection lim it that is
suf f i ciently low and perm its the quantitation of multiple m e tal spec ies on the f ilter, an other
consideration that should be weighed in determ ining the appr opriate choice of indicator and
FRM.

Adequacy of current P b -TSP net w ork and ne ed for additional sites to determine compliance w i th current or rev ised Pb NAAQS : Serious d e ficien cies in the m onitoring network m u st be addressed. The fact that only 2 of the 27 largest Pb point sources have a monitor within 1 m ile is appalli ng. Two of the sources on the list of 27 reside in a state with no
Pb m onitors at all. How can this be??? By allowing the nation’s lead monitoring network to be
dism antled, EPA has m a de a grave error in judgm e nt. The new st andard could address this in part by requiring m onitoring around p o int sources (can th is be m a de a condition of operating

perm its?) E P A could conduct the necessary analyses to determ ine what facility size or em ission rate would require m onitoring and how far from t h e fencelin e is acceptable. Expanded monitoring f o r population exposure and to support future health risk assessm e nts is also necessary. EPA’s goals for m onitoring are m u ch broader than m e rely NAAQS determ ination.

B-20As stated in the recent P M Draf t Integrated Review Plan, “m onito ring networks provide data that serve a wide variety of purposes as part of an iterative p r oces s in m a naging air qua lity. These include: (1) determ ining com p lia nce with the NAAQS; (2) characte rizing air quality status; (3) supporting air quality an alyses us ed to conduct as sessm ents of exposure, h ealth risk s, and welfare effects; (4) dev e loping and evaluating em issions control strategies; and (5) m easuring overall progress for the air pollution contro l pro g ram

. ” All of these are necessary g o als th at nee d
to be accom m odated so that we don’t go th rough another NAAQS review with wholly inadequate data.

But expanded m onitoring has to be funded, and hopefully not at the expense of other monitoring program s. Yet another reason for moving to PM10, which would allow the NATTS monitors to take up som e of the burden. In ponde ring the question of where to m onitor for lead under a new NAAQS, I find that the issue of netw ork design is m o re com p l i cated than can be addressed adequately here. It deserves a m u ch more thorough an alysis and careful deliberation that could appropriately be assigned to th e CASAC Ambient Air Monitoring and Methods Subcomm ittee, as Rich Poirot has suggested. H a st y decisions are likely to be regretted.

Options fo r improving the c overage of the Pb netw ork : As noted above, there are m a ny,

m a ny options, and the design of an adequate netw ork that w ould provide sufficient infor m ation to support N AAQS determ inations and also suppor t exposure and risk assessm ents for the next review needs m o re attention than I can addre ss here. To do this properly requires careful analysis. Of the options laid out in the ANPR, none are wholly satisfactory. Som e combination of source monitors, population m oni tors, and rura l m onitors is needed, and taking advantage of the existing PM10 network would be great, alth ough m o st are not low-volum e sa m p lers.

Appropriateness of sampling opti ons and suggestions for others: The concept of a sam p ling frequency that increases as c oncentrations approach the NAAQS is clever. It reduces the

sam p ling burden (and expense) where concentrations are low, and assures that as concentrations approach levels of concern, we collect enough d a ta to assess concentrations accurately. I like this option best. Multi-day samp les (48-hr, 72- hr) and comp osited samp les are satisfactory for assessing attainm e nt but less so for suppor ting other potential uses of the data.

Conventions for interpreting NAAQS: The proposed conventions are f i ne.

Value and appropriateness of use of IMPR OVE Pb-PM 2.5 data for assessing trends: Yes, it is a great idea to analy ze som e of t h e IMPROV E PM10 filters for Pb (and other m e tals at the

sam e ti m e ). Adopting a PM10 indicator m a kes this a no-brainer.

Reference: Henderson, R. (Sept. 27, 2007) Letter from Dr. Rogene Henderson, Chair, Clean Air Scientific Advisory Committee, to Adm i nistrator Stephen L. J ohnson. Re: CASAC Review of
the 2 nd Draft Lead Hum a n Exposure and Health Risk Assessm e nts.

B-21

### Dr. Bruce Lanphear

Co mm ents o n ANPR Clean Air S c ientific Advisory Comm ittee December 12 th -1 3 th , 2007

The general tone of ANPR is one of comp lete dis r egard f o r the CASAC Panel

recomm endations and a failure to provide any margin of safety. Th e fact that “EPA is seeking comment and supporting inform ation about whether it would be appropriate to determ ine that Pb

em issions no longer contribute to air pollution th at m a y reasonably be anticipated to endanger public health or the extent to which reductions in the am bient air Pb standard would benefit public health” at this late st age (page 114), m a kes m e wonder why the CASAC Panel has been

m eeting for the past two years and providing ad vise to US EPA Adm i nistrator Johnson.

The ANPR also raises other f undamental issues about low-leve l lead toxicity that have large l y been resolved. F o r exam ple, the f act th at the ANPR is solic iting c o mm ents on the appropriateness of using a m ean or individual target blood lead value 10 μ g/dL as the f oundation for deriving a level for the prim ar y lead standard (see page 148) is troubling and m i sguided for a federal agency that purports to protect the pub lics’ health using m o st recent and relevant
scientific evidence. The CDC clearly recognizes that the 10 μ g/dL is an action leve l that is triggered for an individual child at the sam e tim e they clearly recognize that there is no evidence of a threshold for the adv e rse effects of lead on c h ildr e n’s intelle ctua l ability.

The ANPR consistently recomm ends alternatives that underestim ate the ef fect of lead or the benefit of reducing air lead standards, t hus failing to provide any m a rgin of safety.

• Consistent with the 1978 NAAQS, the CASAC Lead Review Panel considers that the prim ary lead standard should be set so as to protect 99.5% of the population from exceeding s ubstantive IQ loss (~1-2 IQ points) . Due to uncerta inties in estim ating th e 99.5% of the populations, the 95 th percentile is reported as th e estim ate of the high end of the distribution (page 122). W h ile it m a y not be possible to estim ate the 99.5%, relying on the 95 th percentile to m a ke decisions about the lead standard will inevitably fail to protect 99.5% of the population.

• The ANPR i gnored em erging but consistent rese arch indicating that sub-populations of children with various polym o rphis m s (e.g., DRD4 7-repeat) are m o re susceptible to lead toxicity than children without the DRD4 7-repeat (Froehlich, 2007).

• Using a ratio of 1:5 rather than 1:10 for air lead

• Use of the log-lin ear with lin ear ex trapolation at 1 μ g/dL rath er than the two-piece lin ear estim ate recomm ended by CASAC Panel. The ANPR argued, on the one hand, that there were two few children to extrapolate below 7.5 μ g/dL. On the other hand, they argued that it wasn’t reason able to see such a dram atic decrem ent in IQ scores at the lowest levels of exposure e.g., < 1 μ g/dL. A m o re logical choice would have been to use the two-piece linear below 7.5 μ g/dL because the linear ex trapo l ation was b a sed on actu al

B-22data. Moreover, as described below, th ere are other studies with over 200 children having blood lead levels < 5 μ g/dL that confirm the non-linear relationship (Tellez-Rojo 2006).

Page 58: The ANPR was concer n e d that the re la tively f e w children who had peak blood
lead levels less than 7.5 μ g/dL (n=103). Still, other studies corroborated the results of the pooled analysis (see, for exampl e, Tellez-Rojo 2006). More over, a host of other st udies confirm that the relationship at lower blood lead levels is non-linear (Lanphear, 2000; Canfield, 2003;
Wasserm an, 2003; Schnaas, 2006; K o rdas, 2006). Thus, we have considerable confidence that lead exposure is associated with adverse effects at the lowest m easurable levels of lead in blood; the only question is the size of the effect.

While the ef fect for each of these decisions in iso l ation would not resu lt in a larg e difference in the estim ated IQ reduction or the pr edicted benefit of alternatives NAAQS for Pb, it is troubling that the cumulative effect of the decisions describe d in the A N PR fail to provide a

m a rgin of sa fety.

On page 79, there is discussion about significan t uncertainty at lower blood lead levels (e.g., below 5 μ g/dL) for concurrent blood l ead levels. The uncertainty is not whether there are
effects belo w 5 μ g/dL or that there is an inverse associa tion of lead with IQ , but the size of the effect. Although it is reasonable to be concerned that the low-lin ear m o del m a y not be ideal at the lowest levels of exposure, the two-piece linear estim a te < 7.5 μ g/dL serves as a reasonable
estim ate that provides a built-in m a rgin of safety that is otherwise ignored in the ANPR.

It is im portant to consider di ffering opinions, but it is question able to treat the opinions of a
commentator that has a clear c onflict of interest (e.g., the Na tional Association for Battery Recycling) as equivalent to th e recomm endations of the CASAC Pa nel. In several places in the ANPR, it notes th at th ere are dif f

e ri ng opinions and that the dram atic reductions in air lead raise questions ab out whether it is still app r opria te to m a intain a NAAQS f o r lead or retain lead as a criteria pollutant. If these di ffering (and conflicted) views are tr e a ted a s equal with the CASAC Panel, it underm i nes the Federal Advisory Co mmittee Act that restricts m e m b ers who have conflicts of interests from serving on the CASAC Panel (see, for exampl e, p. 111, 129 and 131).

I was struck by the US EPA’s recogn ition that the r e ar e important lim itations in the d e sign of, and data and m e thods employed in, the exposure a nd risk analyses in a pa ssive voice. To be

comp letely candid with the public, it m i ght have read, “EPA recognizes that it has failed to generate studies and m onitoring data to ensure that the pub lic is protected agai nst lead toxicity.”

Page 146: I was struck by the comment that th ere is “increasing uncertainty with regard
to the m a gnitude and type of effects at levels below 5 μ g/dL”. This m a kes it sound like, despite
considerable evidence ab out adverse effects below 5 μ g/dL, we know less and less about the
effects belo w 5 μ g/dL. Or, if we only did less research th ere would be less uncertainly about the

m a gnitude and type of effect at blood lead levels bellow 5 μ g/dL. The evidence is quite clear that there is no apparen t thresho l d; th at is cer tain. It is also qu ite c l ea r th at the effects appear to be greater for a given increm ent in exposur e at the lower levels of exposure.

B-23

### Dr. Paul Mushak

PRE-MEE T ING COMMENTS: THE USE P A PB NAAQS ADVANCE NOTICE OF PROPOSED RULEM AKING (ANPR)

CASAC Pb NAAQS Pa nel Mem b er: Paul Mushak, Ph.D.
Decem ber 8, 2007

My comm ents, per the request to the Panel from Chairperson Dr. Henderson, deal with
the ANPR e x clusively. Per Dr. Henderson’s lead discussant assignm ents, I focus comments on Section III, The Prim ary Standard, a nd pa rticula r ly on Sectio n III.C of th e ANPR, Considerations in Review of the Standard.

I. GENERAL AND S E CTIONAL COMMENTS

A review of the ANPR and an accompanyi ng “Fact Sheet” allows a num b er of conclusions, notwithstanding the review being lim ited by the tim e constraints posed by late release of the ANPR relative to the C A SAC 12/12-13/07 m eeting in W a shington.

The ANPR r e presen ts an impressive effort on the part of m u ltiple g r oups. I do have a

num b er of comm ents about the docum ent’s poten tial for causing confusi on, however. First, the ANPR is not the notice of proposed rulem a king but m a ny in the public m a y not get the
distin ction from proposed rulem a king. It is, rather , a m u lti-part inv itation to the regulatory dance
for a m bient air Pb stand a rd rev i ew. The invitation, I fear, is organized in a way that will appear quite confusing to stakeholders , the general public, the m e dia, and those in the scientific community not directly involved in the Pb NAA QS review over the past several years.

The ANPR proposes no specific air Pb NAAQS or range of NAAQS for Adm i nistrator
selection. T h e section on the Prim ary Standard considerations, includi ng policy options, Sec. III.C, says a considerable am ount abo u t where th e overall process is, i.e., OAQPS expo sure/risk

assessm ents and CASAC Panel recommendations, but says n o thing exp l icit that p r ior itizes th e thinking of the Agency about what NAAQS selecti on options are really in the running. It only says where things m i ght go in a proposed rulem a king of a NAAQS.

Specifically, while ANPR m a de good use of the OAQPS Exposure/Risk Assessm ents and Staff Paper analysis, this docum ent did not pay appr opriate atten tion to the Staff Paper’s sets of
conclusions and recommendations. The ANPR docum e nt si mply indicated it was taking note of the OAQPS conclusions and recommendations. It di d so by b u rying th e re f e rence to it in the
docum ent. Reviewers or other readers can rightf ully ask “How m a ny EPAs are there?” One h a s produced a f u ll Staff Paper with recommendations for NAAQS selection, while the other has

seem ingly relega ted the OAQPS f u ll Staf f Paper to th e status of som e sort of subm ission from an interested party.

The ANPR r e quests com m e nt on a docum e nt wh ich structurally resem b les no regulatory

crea tion eve r seen bef o r e and a struc t ure th at like l y will no t a ppear as su c h again. The

B-24docum ent’s contents embody the transition from the conven t ional review process with its production of Staff Papers and CASAC Panel peer reviews to ANPRs which cut out the Staff Paper and attenuate the traditi onal role of CASAC Panels for criteria pollutants m a ndated by statute. Consequently, this Pb ANPR invites comm ents at a seem ing prelim inary level on

som e thing which has already m a tured to a Staff Paper and almost two years of CASAC Pb NAAQS Pa nel review subm issions to the Adm i nistrator.

I assum e it was the call of EPA’s po licy office to continue with a Pb NAAQS ANP R alongside a full Staff Paper m a ndated by court orde r rather than opting for the ordered Staff Paper and leaving the m a iden voyage of the ANPR approach to som e other criteria pollutant that has no court challenge and no deadline date ce rtain. Having issued both a Staff Paper and an ANPR, the Agency has two products which basically use the sam e infor m ation. The Agency is stitching an extra toe (A NPR) to an intact and fully functional foot (OAQPS Staff Paper and multiple CA SAC Panel reviews).

The health, scien tif ic an d br oader public, not to m e ntion the various stakeholders, will
f i nd it dif f i c u lt to reconc ile a p r elim inary ANPR th at only invites comm ent on Agency work and findings so far with a final Staff Paper th at says here are our NAAQS conclusions,

recomm endations, and options for air lead base d on (1) OAQPS’ extensive scien tif ic a nd policy considerations and (2) th e serial reco mmendations from exte nsive peer review by the principal reviewers, the CASAC Pb NAAQS Panel.

A critical concern is how an ANPR, howeve r well done, would play out in the overall NAAQS decision-m a king process w h en it com e s tim e to propose a Pb NAAQS or a range of NAAQS.

— In the present case, we have an A N PR whose extens ive an d reasonab l y well-prepared sections are such because they directly be nefited from the work done by o t hers v i a th e Staff Paper and the CASAC Panel reviews.

— To what extent does that continue in th e lead s t andard case after solicited comm ent s via ANPR a r e received and assim ilated?

— How m u ch relative wei ght will be given to the St aff Pap e r’s and CA SAC Panel’s

recomm endations versus recomm endations of non-Agency or non-CASAC Panel parties?
The ANPR does note th at thos e sub m itting comm ents will presum ably have to prov ide a
credib le bas i s f o r their co mments. Is it not app r op ria t e f o r EPA to spell o u t cle a r c r ite r ia for scientific support needed for outside partie s in offering their comm ents so they can be ranked with the sc ientif ic da tabase being used in the Agency efforts so far?

— In future criteria pollutant regulatory ru le m a king, will the associated A N PRs be as

comp rehensive and transparent as this one for Pb?

B-25II. SPECIF IC COMMENTS ON THE ANP R DOCUM ENT

The invitations for comm ent in the ANPR do so with an odd, repetitive sem a ntic style of
“Som e m i ght conclude...” “Som e m i ght not conclude...,” etc. This is a rather unusual style in m y experience with thes e matters, what ever the novelty of the A N PR a pproach in transition from the
classical m e thodologies for criteria pollutants. The style presents no ranking or weighting to be
accorded in put on the b a sis of expertise, freedo m from bias or official ro les in the N AAQS review process. It m a y be true that “Som e m a y s a y A, while som e m a y s a y B,” but B m a y be totally incorrect owing to lack of expertise, absence of arm s -length exercise of judgments, existence of an agenda, o rall three.

Nowhere in Sec. III.C do I find a coh e rent ta bular comp ilation

, with assoc i ated con t exts, rationales an d evidence, that lay s out even a broa d range of those Pb NAAQS offered in the final Staf f Paper and the two CASAC Panel’s Le tte rs to the Adm i nistrator. Such one-stop reading would help clarify things imm e nsely. These options on the basis of policy or whatever should not
be scatter e d and buried in the dense text. The re v i ewer or any other inte res t ed re ader w ill no t harvest a clu e , from the present langu age, about w h at EPA will eventu ally consider seriously even with in an extreme range of options. They may de-list; then again, they m a y not. They m a y keep the obs olete current standard ; th en again, they m a y not. They m a y adopt a fully protective stance with regard to IQ loss; then ag ain, th ey m a y not. And so forth down the line.

As noted already, a significant part of the ANPR draws heavily from , repeats, or summarizes inform ation in the OAQPS Risk Assessm ents, the OAQP S Staff Paper and the several CASAC Panel Adm i nistrator Letters and attachm e nts therein. These docum ents and the dependency on them in the ANPR would serve, collectively, to anticipate a strong argum e nt presented in the policy p a rt of Sectio n III.C for (1 ) retain ing Pb as a crite r ia po llutant and (2) lowering the Pb NAAQS substantiall y below the current value.

This has not occurred in Sec. III.C. T h er e is a se rious disconn ect be tween the new evidence an d its as sess m e nts and the relativ e tre a tm ent in Sec. III.C of th e various op tions for th e NAAQS. Se c. III.C conveys no real co m p arative assessm ent of alternative NAAQS v a lues in

term s of where the established and vetted scientific evidence should take the ANPR’s thinking.
For exam ple, Sec. III.C leaves open the opti on of delis ting an d, barring d e listing, keep ing the present air lead standard at 1.5 : g/m 3 averag ed q u arterly.

W ithin the ANPR are severa l item s on which I provide m o re detailed comment below.

A. Potential U.S. Child Health Consequences o f Retaining the Current Air Pb Standard

Retention of the current air Pb NAAQS as one of EPA’s eventual proposed options f o r action in th is prelim inary ANPR obliges EPA to c onsider the consequences to child health. The data are available to do so.

The CASAC Pb NAAQS Panel has already pres ented its con c lu sions in its Adm i nistrator
Lette rs abou t the issues of delis ting Pb as a criteria pollutant and the argum e nts for pr om ulgating a NAAQS much lower than the current one. I will quantify so m e of the concerns here.

B-26I am particularly con cern e d about th e ANPR not r u ling out an eventual NPR setting forth a rationale for keeping the current air Pb standard of 1.5 : g/m 3 . EPA has attem p ted to m odel through “proportional roll-up” m e thods the sim u late d consequences of air lead at the current NAAQS with respec t to f r actiona l distribu tio n s o f i mpacts. I agree with OAQPS’ Risk
Assessm ent effort that th ere is consid erable uncerta in ty assoc i ated with this . I do not agree that it is highly unlikely that general, am bient urban air Pb values will ever re-attain levels near or at
the current s t andard s i nce achiev e m e nt of such high levels would deri ve from point sources.

A better app r oach is a revisiti ng of the historical record. In this, I follow up and elaborate on Dr. Joel Schwartz’s earlier m eeting comments about the nature and extent of toxic lead exposures in U.S. children in earlier y ears. Th e Pb exposure record of past decades sho w s
reta ining the curren t stan dard would be potentially catastroph ic to the env i ronm ental a nd developm ental health of young U.S. children and th e health of other national risk groups.

— Setting standards for toxics such as lead in air cannot be based on what a particular national, regional, or stratified expression of that substance’s level in the environm ent happens to be at som e isolated tim e, nor on sim u lations of hypothetical returns to some previously high value. T h e process hinges on the full regulatory and public health record
for that subs tance. All Federal agencies en trusted with regulating toxic substances via diverse statutes have adhered to this prescriptive dictum

. Besides EPA, these include the FDA, HUD, and the USDA.

— Specifically, current air Pb levels in the U.S. cannot be taken as a permanent environm ental feature of U.S. air quality. Th ey are sim p ly a reflection of th e presen t processes for lead’s entry or reen try into th e am bient atm o sphere. As such, they are subject to abrupt changes in U.S. technologica l and/or industrial activ ity using lead. I do not agre e with the ANPR’s assum p tion tha t re tu rn to past air Pb levels w ould be highly unlikely. We should be m i ndful th at discussions of lead contro l in the 1920s, such as they were, did not anticipate the enorm o us a dverse child health co nsequences of the
introdu ction of leaded g a solin e in th e U.S.

— Re-promulgation of the current prim ary air Pb standard or prom ulgation of an even weaker one would sim p ly m ean there is no de-facto regulatory barrier to the introduction
or re-introduction of lead sources and am bi ent atmospheric em issions that would expose

m illions of Am erican children to lead at tox i c levels, as h a p p ened in th e 1970s.

— Alternative regulation of air Pb as a h azardous air po llutant under Sec. 112 of the CAA would not be as effectiv e for co ntrol as a criteria pollutant process. The CASAC Panel put f o rth re asons f o r this and m a de this explic itly cle a r in past communications to EPA.

— In the late 1970s, the nationwide U.S. air Pb values (as maxim u m qua rterly averages) for the years 1978 and 1979 were around or even below the current air P b standard, 1.5
: g/m 3 . The national values were 1.67 and 1.36 : g/m 3 respectively (see, e.g., USEPA, 1994).

B-27— In the period 1976-1980, corresponding to the above air Pb values, the NHANES II survey (Annest and Mahaffey/USDHHS, 1984, Table 4; US E P A, 1986 Cr iteria
Docum e nt, Ch. 11, Table 11-2, Maha ffey et al., 1982) showed that:

— The arithm etic and geom etric m eans of blood lead (Pb-B) for U.S. children 6 m o s. to 5 years of age were 16.0 and 14.9 : g/dl in the 1976-1980 tim e respectively. The great

m a jority, 87.8%, of children in this ag e band at that tim e had Pb-Bs of 10 : g/dl or higher. The tally of U.S. childre n in this age band was 17 m illion (rou nding), m eaning 15 m illion children had Pb-Bs at or above this value. A significant fraction of these children, 20.5%, had Pb-Bs at or above 20 : g/dl, or a total of 3,500,000 child ren (rounding).

— The arith m etic and geom etric m eans for black child ren 6 mos.-5 years o f age were 20.9 and 19.6 : g/dl, respectively, while this age block of whit e children showed 14.9 and
14.0 : g/dl, respectively. Virtually all U.S. black children (97.5%) had Pb-Bs at or above
10 : g/dl, while the corresponding percentage figure for white children w a s 85.5%. T h e tally of black children in this ag e band was 2,600,000 (rounding), m eaning over 2,500,000 black children had Pb-Bs at or above this value.

— For a total of 13,600,000 white children (r ounding), 11,600,000 of these had Pb-B at
10 : g/dl or higher. A majority of black children, 51.1%, had Pb-Bs 20 : g/dl or higher.
W ith a total base of 2,600,000, 1,340,000 black childre n had a Pb-B of 20 units or higher. White children had lower prevalence, 18.1%, of Pb-B 20 : g/dl or higher, but the m u ch greater population base m ean t higher tallies at 20 : g/dl and higher, i.e., 2,460,000 (rounding) white children.

— The m a jor source of the above-described grea tly elevated Pb-B values was direct and indirect air Pb exposures, the latter as dusts and f a llout onto soils. W e know this from the quantitative features of tim e tr end correlational analyses of am bient air Pb and declines in
Pb-B.

Illustrative Refs for 1970s Pb Exposures:

Annest JL, Mahaffey K. 1984. Blood lead leve ls for persons ages 6 m onths-74 years: United States, 1976-1980. Hyattsville MD: Nationa l Center for Health S t atistics, U.S. Departm e nt of Health and Hum a n Se rvices. Series 11, No. 233.

Mahaffey KR, Annest JL, Roberts J, Mur phy RS. 1982. National estim ates of blood lead levels: United States, 1976-1980: associ ation with selected dem ographic and
socioeconom i c factors. N. Engl. J. Med. 307: 573-579.

U.S. EPA. 1986. Air Quality Criteria for Lead, 4 Vols. EPA 600/8-83/028bF. Research Triangle Park, NC: Environm ental Protection Ag ency, Ch. 11, Vol. III.

U.S. EPA. 1994. National Air Quality and Em iss i ons Trend Report, 1994. Report No. EPA 454/R-95-014. OAQPS, RT P, NC . Append ix Table A-9.

B-28B. Gaps in Regulatory Policy Op tions in ANPR Sec. III.C.

The ANPR accepts that there is no d o cum e nted “safe” level for lead expo sures ind e xed as Pb-B in children. It accepts, as do virtually al l oth e r expert co nsensus pub lic docum ents on the topic, the huge database for hum a n populations showing lead is a non-threshold toxicant in children. Characterizatio n of lead as a non-threshold t oxicant has obvious regulatory policy
im plications f o r its con t r o l.

— The ANPR does not go the next obvious step and discuss the question of whether lead needs to be regulated the way EPA regulates other non-threshold toxi cants, for exam ple, the toxicants classified as likely or estab lished hum a n carcinogens. I am not saying that lead bears toxicological and m echanistic analogy with hum an carcinogens, only analogy with this cla ss of toxican ts in term s of the clear need for harmonization of regulatory
rationales and m e thodologies for all non-threshold toxicants.

— EPA m a y in fact tak e the view th at lead is th eo retically a th re shold toxicant but that threshold has not yet been revealed. However, the issue rem a ins: if lead is a threshold toxicant it has an extremely sm all window in which to exhibit this characteristic. The window is now so s m all that the potential ra nge f o r a claim e d threshold becom e s a doseresponse distinction without a toxicological diffe rence from non-threshol d toxicants.

— Regulation of lead in air or elsewhere as a non-threshold toxican t retains in a more stringent way the suite of policy questions of what non-threshold toxic endpoint and its

num e rical v a lue a r e to b e dete rm inative f o r c ontrol and at what risk m a nagem e nt level, i.e., what frequency of toxi c occurrence within a risk gr oup is to be acceptable.

— The upshot of the above that the nature of lead as a non-threshold toxicant clearly requires that any selected air Pb NAAQS be as low as possible.

C. Use of CDC Statements in the ANPR

The various CDC State m ents on childhood lead poisoning appear to occupy a central position in the general thinking in the ANPR, but EPA’s grasp of th ese Statem ents appears to b e tenuous at best. It is necessary to put CDC Statem ents in contex t in term s of their scope and purposes for use by regulatory agencies fo r lead control and to avoid m i suse.

CDC State m ents, contrary to implied or expres sed interpretations and roles given them in the ANPR, were and rem a in highly flexible pres crip tive instr u m e nts f o r addressing the problem of childhood lead poisoning in the U.S. and else w h ere. Every incarnation and iteration of the
CDC State m ents has m a de two char a c ter i za tions of the State m ents explic it. Fir s t, ther e was and is every exp ectation th at the natu re and advisory utility of the Statem ents would change as the science changed. For example, the CDC April, 1978 Statem ent, which was used in the derivation of the 1978 and current NAAQS prim ary standard of 1.5 : g/dl, stated that (p. 1, Introduction):

“The CDC r ecognizes that ther e will doubtless be further deve lopm ent in this field which

m a y alter or redefine our current understanding.”

B-29The 1985 Statem ent (p. 1, Introduction) noted:

“The revised recomm endations in this 1985 Statem ent reflect current knowledge concerning screening, diagnosis, treatm ent, follow up, and environm ental intervention for children with elevated blood lead levels.”

The second aspect of all Statem ents, incl uding the 2007 version, was the use of the
Statem ents to eventually effect prim ary lead poisoning prevention for children in the U.S. and elsewhere. Furtherm ore, this ultim ate goal of pr im ary prevention was presented in print to the public he alth and clin ica l comm unities f o r m o re than 30 years

. W e clearly see th is in th e evolution of the prescriptive language of successive Statem ents which sim p ly translates as ‘it is much easier to preven t th an to treat. ’

The 1978 Statem ent (p. 1, Introduction) notes:

“The ultim a te preven tive goal is iden tif ica ti on and rem oval of lead in the environm ent before it en ters the child

. Until th is o ccu rs, screening, diagno sis, treatm ent, and environm ental m a nage ment will continue to be necessary public he alth a c tiv ities.”

The 1985 Statem ent (p. 1, Introduction) notes:

“Clearly, the goal is to remove lead from th e environm ent of children before it enters
their bodies. Until th is g o al is reach e d, screen ing, diagnosis, treatm e nt, an d environm ental m a nage ment will continue to be necessary public he alth a c tiv ities.”

The 1991 Statem ent (pp. 1-4, Introduction) notes:

“Prim a ry prevention ef forts ( t ha t is, elim in ation of lead hazards before children are poisoned) m u st receive more empha sis as th e blood lead levels of concern are lowered [p.1].”

“Prim a ry Prevention. Ef forts need to be increasingly focused on preventing lead poisoning before it occurs. This will require communitywide environm ental intervention s, as well as educati onal and nutritio nal campaigns. [p.3] “

“The focus of prevention efforts, therefor e, m u st expand from m e rely identifying and treating individual ch ildren to include prim ary prevention....[ p.4]”

The 2005 Statem ent (p. ix, Preface) n o tes:

“The data demonstrating that no “safe” threshold for blood lead levels (BLLs) in young
children has been identified highlights the importance of preventing childhood exposures
to lead. It co nfirm s the need for a sys t em a tic and society wide effort to control or
elim inate lead hazard s in child ren’s environm en ts before they are exposed. This emphasis on prim ary prevention, although not entirely new, is highlighted here and is clearly the

B-30fore m o st action supported by the data presented in A Review of Evidence of Adverse Health Effects Associa t ed with Blood Lead Levels < 10 : g/dL in Children. “

The CDC 2007 Statem ent (MMW R 56: 11/2/07, p. 1), in advising how clinicians are to deal with Pb-B values < 10 : g/dl, essentially iterates parts of the 2005 Statem ent from which it drew considerable inform ation.

CDC presented the CDC Statem ents of 1975, 197 8 and 1985 as tabulated Pb toxicity risk advisories for secondary preven tion of childhoo d lead poiso ning. That is, the focus was to be on identification of the frequency and nature of lead exposures in U.S. children where the

m echanism s are post-hoc in nature: childre n are identified as to toxi c lead exposures after they have sustained such toxic lead exposures.

However, developm ental neurotoxic effects in children appear to be persistent and m a y be irreversible to som e significant extent. Once such effects are expressed, whether recognized or not, they are not easily reversed (R ogan et al., 2001; Rosen and Mushak, 2001).

Refs:

Rogan W J , Dietrich KN, W a re JH et al. 2001. The effect of chelation therapy with
succim e r on neuropsychological developm ent in children exposed to lead. N. Engl. J. Med. 344: 1421-1426.

Rosen JF, Mushak P. 2001. [Editorial]. Prim ary prevention of childhood lead poisoning-- the only solution. N. Engl. J. Med. 344: 1470-1471.

The October 1991 CDC Statem ent presented pres criptive language that was transitional in nature, combining elem ents of bot h secondary and primary prevention mechanisms . Prim ary prevention deals with prevention of the toxi c lead exposures in the first place.

The August, 2005 and Novem b er, 2007 Statem en ts clearly state that adverse health
effects in ch ildren occur below 10 : g/dl. These S t atem ents acknowledged the huge growth in the database for low-level lead poisoning in the gl obal literature from 1991 to the present. The 2005 and 2007 Statem ents render the 14 to 16 year s-old 1991 Statem ent irrelevant to doing quantitative health risk assessm en ts for lead in children now.

The latter two Statem ents preserved the value of 10 : g/dl as the action lev e l for earlies t intervention in term s of a prio ritization rationale. Nowhere in the 2005 and 2007 Statem ents does CDC say that effects in children below 10 : g/dl a r e tr ivial, merely that B LLs in this r a nge require primary prevention through the various agen cies entrusted with such prim ary prevention,
to include E P A.

More specifically, the C D C m a terial shows EPA needs to recognize one obvious fact about the need for prim ary prevention m e thods spelled out in the 2005 and 2007 Statem ents. Prim ary prevention m e thods to address th e toxic effects of lead at Pb-Bs <10 : g/dl require the
action s of regulato r y agencies such as EPA, not advisory agencies such as CDC. Ambient air Pb

B-31through direct and indirect pathways poses advers e health risk to children and EPA is in the business of regulating air lead so as to preven t such adverse health risks through the prim ary prevention modality of continue d ambient air Pb reduction.

D. Adequac y of CDC Statements in Meeting S ection 109, CAA Requirements The ANPR s eem s to dance around the issues of adequate health protection and adequate

m a rgins of s a fety expressed in Section 109 of the CAA with legalism s rather than convincing
health scien ce. It n eeds to address 10 9 with the la tte r.

Secondly, there is no ex plicit or causal quantitative linkage between values presented in
CDC State m ents and the requirem e nts of Sec. 109 in the Clean Air Act. The “action” levels of those earlier CDC Statem ents e mpl oying second ary prevention m e thods are not values that provide adequate protection of hum a n health with adequate m a rgins of s a fety. They were m eant to be and rem a in as triggers for prioritizi ng secondary lead poisoni ng prevention strategies: screening, diagnosis, treatm ent, and environm ental m a nage m e nt.

The CDC risk catego r ies, with their s u ccessiv e reductions in earliest levels of concern for Pb-Bs, do not scientifically sati sfy nor are they synonym ous with these Sec. 109 requirem ents.

Refs for CDC Use of Statem ents and Reference Values

U.S. DHEW/CDC. 1975. Increased L ead Absorp tion and Lead Poisoning in Young Children: A
Statem ent by the Centers for Diseas e Control. A tlanta, GA: U.S. Departm e nt of Health,
Education and W e lfare.

U.S. DHEW/CDC. 1978. Preventing Lead Poison ing in Young Children: A Statem ent by the Centers for Disease Con t rol. Atlanta, GA: U.S. Departm e nt of Health, Edu cation and Welfare. April.

U.S. DHHS/ C DC. 1985. Preventing Lead Poison ing in Young Children. A Statem ent by the Centers for Disease Con t rol. Atlanta, GA: U.S. Departm e nt of Health and Hum a n Services. January.

U.S. DHHS/ C DC. 1991. Preventing Lead Poison ing in Young Children. A Statem ent by the Centers for Disease Con t rol. Atlanta, GA: U.S. Departm e nt of Health and Hum a n Services. October.

U.S. DHHS/ C DC. 1997. Preventing Lead Poison ing in Young Children. A Statem ent by the Centers for Disease Con t rol. Atlanta, GA: Departm e nt of Health and Human Services.
Nove m b er.

U.S. DHHS/ C DC. 2005. Preventing Lead Poison ing in Young Children. A Statem ent by the Centers for Disease Control a nd Prevention. Atlanta, GA: Depa rtm e nt of Health and Hum a n Services. August.

B-32U.S. DHHS/ C DC. 2007. Interpreting a nd Managing Blood Lead Levels <10 : g/dL in Children
and Reducin g Childhood Exposures to Lead. R ecomm endations of CDC’ s Advisory Comm ittee on Childhood Lead Poisoning Prevention. MMWR 56: 1-14; 16.

B-33

### Mr. Rich Poirot

Post-Me e ting Comments on (mon i tor i ng section of) 12/07 Pb ANPR, R. Poirot, VT DEC

I was disappointed by the overall form and content of the Pb ANPR – bot h as a guide to policy
decision-m a king for revising the current (1978) P b standards, and m o re generally as a harbinger of how the new NAAQS review process m a y be c onducted in the future. Nearly as m u ch space is devoted to summarizing and justifying the l ogic and rationale for the 1978 standards and 1990 decision not to revise them, as is provided to sum m a rize and synthesize the new scientific
inform ation that is relevant to the current NAAQS review. In discussing the current review, the ANPR presents – and sp ecifically seeks comm ent on - such a broad range of policy options for all aspects of a revised (or de -lis ted) Pb NAAQS, that its d i f f i cult to see h o w it inf o rms the public on the Agency’s intentions for rule-m aking, or solicits useful new inform ation to inform
that rule-m a k ing. The resulting g e neral ‘pub lic o p inion surv ey’ also p r ovides an inherently difficult target for scientific review, and raises qu estions abou t the f u tur e role (if any) of CASAC review at this point in the NAAQS p r ocess.

Carefully considered, thoroughly docum e nted EPA staff recomm endations and associated CASAC comments are often presen ted as a sort of “extrem e” low bound to an open-ended range of policy options, for which alternative viewpoint s of “som e” or “others” are presen ted in the ANPR without docum e n tation, justif ication or attribution of au thorship. We learn that “questions have been raised” regarding the option of delisting Pb as a criteria pollutant, but not by whom or for what purpose. After explaining why the CDC action level of 10 μg/dL BPb is used to identify individual at-risk children fo r follow-up rem e dial action, and should clearly not
be “m isinterpreted as a d e finitiv e tox i colog i cal th reshold”, the ANPR then proceeds, b i zarrely, to request comm ents on the use of this screeni ng level as a (m isinterpreted) “foundation for deriving the level for the prim ary Pb standard”, because “som e” m i ght consider this appropriate.
The ANPR also featu r es a very heav y emphasis on ‘lim itatio n s and uncer tain ties ’ in a ll se ction s (the words “lim itations”, “uncer tainty” or “uncertainties” app ear a total of 136 tim es in the ANPR), but provides few if any quantitative asse ssm ents of these uncertainties for context.

By contrast, the final Pb Sta ff paper was clearly written, in telligently reasoned, thoroughly
docum ented, and should provide a useful basis for Agency decision-m aking. It was difficult to
im agine reviewing the current ANPR, without bene fit of this focused Staff Paper. Nor can I
im agine how future ANPRs - without benefit of preced ing Staff Papers - can effectiv ely present
the recommendations of technical staff and CASAC, along with the contrasting anonymous opinions of som e and others. If open-ended ANPRs of this nature are contemplated for future NAAQS reviews, they should be issued at the be ginning, rather than at the end, of the review process, and the Staff Paper should be retained as a critical step in the NAAQS review process.

Pb Indicator and Considerations for Ambient Monitoring In previous comments on the Pb CD and 1 st draft Staff Paper, the CASAC Pb Panel had encouraged the Agency to consider revising th e indicator for Pb samp ling from TSP t o low volum e PM 10 (with p r ovisions for lo w cost m u lti-elem ental analytical m e thods lik e XRF and ICP-MS). Reasons for this recomm e ndation (from Henderson, 2007) included:

B-34“Most other TSP sa m p ling was discontinued after PM 10 standards were prom ulgated in 1987.
TSP sa m p lers capture particles with an imprecise and variable upper particle cut size in the range of approxim a tely 30 to 50 m i crons on fi ber g lass f i lter s which are n o t well-suite d f o r analys is by inexpensive, multi-elem ental su rf ace beam techniques lik e particle-induced X-ray

em ission (PIXE) or X-ray fluorescence (XRF). Consequently TSP sa m p ling by imprecise

samp lers is prim arily conducted onl y for lead analysis and these f ilters are rarely analyzed for other species. If Lead NAAQS m oni toring was based on (low-volum e) PM10 samp ling on
Tef l on f ilter s , the re sulting data would be corr ela t ed with TS P lead, as su ggested by lim ited
data in the 1 s t Draf t Lea d Staf f Paper, but would have substantially im proved sam p ling precision. T h e Lead Panel recognizes that eith er monitoring system woul d be subject to variability based on location, particularly ne ar sources. Other adva ntages of low-volum e PM 10 sa m p ling include:

1. Focus on those biologically-relevant partic les that, when in hale d, are deposited in the thoracic region;

2. Larger spatial-scal e representativeness for population e xposures to m onitored particles which rem a in airborne longer;

3. Could utilize m o re widespread P M 10 and “air toxics” m e tals samp ling networks, leading to
collection of m o re data at lower costs;

4. Potential f o r inexpens ive m u lti-ele m ental anal ysis by XRF or PIXE would provid e usef ul supplem ental m e tals inform ation for health effects studies and source apportionm ent;

5. Potential for autom a ted sequential PM 10 sa m p lers (not available for TS P) would be especially useful if sampling frequency is increased from once every six days; and

6. W e ighing f ilter s would provi de us ef ul inf o rm ation on PM 10 m a ss; and, if collocated with
PM 2. 5 Federal Reference Methods (F RM), c ould provide needed inform a tion on PM 10–2. 5

m a ss and speciation.”

The Pb Panel had acknowledged that PM 10 samp ling could exclude som e ultra-coarse particle (>10 um ) Pb that had previously been capture d by TSP sa m p lers (and that m a y or m a y not becom e ingested), but that given the needs to sub s tantially re duce th e level of the standard and to
increase the samp ling frequency for a shor ter-term m onthly standard, the low volum e PM 10 Pb

m easure m ents, with greater a ccuracy and precision, lower de tection lim its, and potential for

autom a ted samp le collec tion with lo wer cost and m o re usef ul m u lti-e l em ental an alys is , would be a preferable m e thod for future m onitoring. The Pb panel also suggested that, if necessary, an “adjustm e nt factor” m i ght be appl ied to reduce th e level of a PM 10 standard to account for ultracoarse Pb no t captu red b y the PM 10 samp lers, as it was expected that PM 10 Pb would represent a large fraction of, and be hi ghly correlated with T SP Pb.

One m i nor criticism of the Final Staff Paper is that prior CASAC suggest ions on approaches the Agency m i ght consider in changing the Pb indicator from TSP to PM 10 are presen ted in the Staff Paper as “requirem e nts” rather than “recomm endations ”. For ex am ple, at the bottom of p 5-25

B-35and top of p. 5/26, it’s stated that “C ASAC recognized...that a scaling of the NAAQS level would be needed to accommodate the loss of very larg e coarse-m ode Pb particles, and that
concurrent P b -PM10 and Pb-TSP sampling would be needed to inform de velopm ent of scaling factors...” (emphasis added). I think the previous CA SAC intent was to suggest that such approaches could help infor m a judgm e nt about an appropriate revised indicator, rather to suggest th at a detailed qu antitative an al ysis would be a necessary prerequisite.

In the 12/07 ANPR and a ssociated support docum ents , the Agency presented an evaluation of the
lim ited available co llocated TSP and PM 10 Pb data (Cavander and Schm idt, 11/26/07) f r om which it is conclude d that no single PM 10 :TSP ratio could be developed that would accurately predict TSP Pb for all US locations, although it di d appear likely that such ratios m i ght be developed f o r indiv i dua l sites bas e d on f u ture site-spec i f i c measurem ents . An additio nal evaluation o f precision and bias of existing TSP Pb data (Cam ilier and Rice, 2007) d e m onstrated that the average precisio n of TSP Pb m easure m ents (averaging 12% + 19%) and samp ling bias were not substantially poorer than for som e other NAAQS FRMs (although it should be noted that this analysis exclude d 21% of measurem ents whic h were below MDL of 0.01 μg/m 3 , and also showed m u ch poorer relative precision at th e lower concentrations m o re typical of actual current population exposures.

Based on th ese analyses , the Agency continues to advocate retention of the TSP Pb indicator, although it does request comme nts on various related issu es and options, including:

• whether th e variab ility o f the TSP sampler wa rrants discontinuation of its usage as th e Pb indicator,

• the appropriateness of using Pb-PM 10 data as a surrogate for Pb-TSP,

• a perceived need to tighten the Pb FEM dem ons tration requirem e nts (which currently call for testing over a [1970s - type] range of Pb concentrations of 0.5 to 4 μg/m 3 ) to better reflect the much lower current concentrations,

• the need to a dd source-o r iented Pb m onitor i ng ne ar m a ny of the larg est P b em itters which are not currently m onitored,

• the desirability of various network options including population-ba sed sampling, sourceoriented sampling, a combination of these appr oaches, and/or utiliz ation of the current
PM 10 network if an acceptable regio n al or s ite-s pecific co rrelation of TSP-Pb and PM 10 - Pb can be established.

Regarding samp le frequency, the Agency sugge sts and seeks comments on a wide range of options including:

• 1-in-6 day, 1-in-3-day, 1-in-1 day sam p ling, pe rhaps with increased sample frequency for sites with higher concentrations,

• increased sample duration – from 24-hour to 48 or 72-hour or longer,

• allowing for samp le compositing (analyzi ng sequ entia l samp le s together), and

• allowing f o r

m u ltiple sa mplers at on e site.

Regarding P b m onitoring in rural areas to co m p are with secondary NAAQS - which is presum ed to be equal to the prim ary NAAQS ( w hat a surprise!), comments are requ ested on the appropriateness of using rural/rem o te PM 2. 5 Pb measurem ents from the IMPROVE network –

B-36possibly supplem e nted with a sm aller “sentinel” network of TSP-Pb or PM 10 -Pb samplers, to track spatial and temporal patterns of Pb c oncentration and deposition in non-urban areas.

I continue to strongly encourage the Agency to transition aw ay from TSP samplin g w i th the clear goal of using low

- volume PM 10 Pb sampling in the n e ar future . The Agency has

recen tly specified low v o lum e PM 10 sam p ling as a com ponent of the new FRM for coarse particle s (P M 10- 2. 5 ), and so there will be an expansion of population-oriented sites using this

m e thod and collecting (elem e ntally clean) Teflon filters am enable to low cost m u lti-elem ental analysis m e thods for Pb and other species indicative of em ission s ources and other health risks.
At the sam e tim e, the Agency and the States are also expanding their samp ling efforts for “toxic
air contam inants”, including Pb and other m e tals. The consensus m e thod for NAATS m e tals

samp ling is low volum e PM 10 with associated IC P-MS analysis. In addition to the large savings
in costs and hu m a n resources th at would be realized if Pb NAAQS sa m p ling were harm onized with these established and expanding program s, there are other good reasons why a transition to
PM 10 -Pb NAAQS sa m p ling would be tim ely.

The current Pb standard was established in 1978, and based on samp ling using 1950’s technology. Pb is som e what unique am ong the crit eria pollutants in that it has m o re or less “skipped” a m i d-term re view cycle. Twenty years ago, there was clea r evidence in the 1986-90 review to support both lowering the level of the 1978 NAAQS (from 1.5 to 0.5 to 1 μg/m 3 ) and also shortening the averaging tim e from quarterly to m onthly (adding further stringency). But as the Agency chose an alternative, ag gressiv e m u lti-m e dia Pb em ission red u ction s t rategy, am bient
air concentrations decl ined in m o st areas to well below the level of the antiquated NAAQS. Subsequently, Pb samp ling was di scontinued at m a ny sites, since it is labor intensive, provides
no useful inform ation on sources or other pollutant s, and revealed concentrations “safely” below the NAAQS. The current review provides co mp elling evidence of a need for a further substantial lowering of the standa rd, which in turn poses an especial challenge for m o nitoring, since the current network lacks sufficient size a nd orientation to focus on either populations or current sources. The continue d use of 1950’s sampling technology poses additional obstacles, as
TSP sa mp lers are no t su ited for au to m a ted sequential sam p ling, and the labor-in t ens i ve filter collections are not suitable to analyses for other p o llutants. Th e TSP sam p lers collect a variab le and unspecif i ed m i x of r e spirable air pollutant s and coarse m ode dust, and by inclusion of unknown fractions of ultra-coarse Pb contai ning particles, promote an FRM which – by definition – can’t represent population exposur es over areas extending m u ch beyond monitoring locations at any sites where TSP- Pb differs significantly from PM 10 -Pb. Measurem ents that are heavily influ e nced by ultra-co arse p a rt icles (where TSP-Pb differs from PM 10 -Pb) have m i croscale sp atial repres enta tiveness, and would be extrem ely sens itiv e to th e e x act he ight of the

samp ler inlet above the ground. It should also be noted that 2-m e ter separation requirem ents for TSP Hi-Vols, com b ined with the ab s e nce of sequ entia l TSP sam p lers (req u iring m u ltiple

sam p lers for m onthly m e ans) m a y render T SP-Pb samp ling impossible at m a ny existing monitoring s ites.

This would be an opportune tim e to m a ke or initiate a transition from TSP to PM 10 , since the

curren t rev i ew indicates a need for s u ch a subs ta ntia l lower i n g of the NAAQS - to the range suggested in the Staff Paper of between 0.1-0.2 μg/m 3 to as low as 0.02 to 0.05 μg/m 3 . If a standard is lowered by a factor of 10 to 100, it is unimportant if the indicator m easures 10% or 15% less than the indicator selected 30 year s ago. The Cavander & Schm idt (2007) analysis

B-37does indicate som e variability in the average ratios of PM 10 -Pb to TSP-Pb. However, it also shows average ratios of > 0.60 at a ll sites, > 0.75 at 20 of 24 sites, > 0.80 at 18 sites. S o m e of the

extrem e high or low individual sample ratio s (ranging from 0.04 to 11.9 at 1 site) or poor
correlations are not re flective of true PM 10 to TSP Pb ratios, but likel y the result of poor quality monitoring practices o r inaccu raci es in the TSP m easurem ents - which are generally > those for hi-vol PM 10 and >> those for low volum e PM 10 (not available for this an alysis ). Rath er than needing to arduously establish a la rge series of site-specific P M 10 -Pb to TSP-Pb ratios (f itting good data to bad), I think it would be well within the Agency’s range of discretionary options to consider a slight loss of ultra-co arse Pb at som e sites in select ing an appropriately conservative level for the revised NA AQS. C onversely, I think it would be a m i stake to hold up the old TSP

m e tric as the “gold standard” and only allow ne wer, better technology if it can reproduce the old, seriously flawed samp ler perform a nc e.

As observed in the ANPR, TSP sa mplers have a va riable and poorly charact erized upper particle cut size – of “between 25 and 50 um depending on wind speed and direction”. In Figure 1 below, I’ve plotted the Hi-Vol TSP collection e fficiency data reported by W e dding et al. (1977) cited in the ANPR. These wind tunn el m easuremen ts were ta ken with a single Hi-Vol at a wind speed of 4.6 m e ters, but with the slanted shed roof of the sa mpler at different orientations with respect to the wind direction. Th e lower blue curve represents samp ling with the ridge of the shed roof aligned parallel to th e WD, while the red curve represen ts samp ling with the ridge of the shed roof aligned perpendicular to the WD. Note both how poorly de fined (not sharp) the collection efficiency is for larger particles and how grea tly it varies with wind direction. At sites which have a high fraction of ultra-coarse Pb, the TSP Hi-Vol is a lousy way to m eas ure it.

Those relatively f e w site s that act ually have large contributions of ultra-coarse Pb also clearly have large, nearby coars e m ode (industrial p r oc ess or fugitiv e dust) em is sions, but ho w m u ch coarse Pb is m easured (and any m eas ure of th e sampling precision) is strongly dependent on wind speed and samp ler orientation. The Agency would be better off prescribing and enforcing specific control technologies for those large dus t sources, than requiring (& greatly expanding)

an extens ive national m o nitoring network to accomm odate the occas ion a l extrem e cases. Conversely, if ultra-coarse Pb is a widespread problem of concern, the Agency should develop appropriate m e thods to accurately ch aracterize th os e dust particles. “W ha te ver it is th at the TSP

sam p ler happened to collect today” is not a sufficiently clear definition.

B-38Figure 1. TSP Collection E fficiency vs. P a rticle Si z e and Sampler Or ientation at 4.6 m/s Wind Speed

It should also be noted that Pb in ultra-coarse particles is not deposited in the lower respiratory tract, and inefficiently deposited (especially duri ng nasal breathing) in the upper respiratory tract
– from whic h only a fraction is ulti mately inges t e d. Ultra- coa r se particles are also inef ficiently exchanged between outdoor and indoor air and so contribute less effectively to Pb loadings on indoor surfaces than does fine particle air lead. T h e Staff Paper argues (p. 5-25) that “nonrespirable Pb in the environm ent m a y, at so m e point, becom e respirable through weathering

or m echanical action.” But by this “logic”, we should also use TSP samplers to determ ine

comp liance with PM 10 and PM 2. 5 standards. The variability of TSP sa m p l e r cut size, the higher MDL associated with TS P-Pb samp ling, and th e relatively poor precision at lower Pb
concentrations all contribut e to va ria b ility in the T SP-Pb indicator. So a PM 10 -Pb indicator would have the added advantage of providing a more stable metric for compliance determ ination, as well as a more representative m e tric of population exposures to support future health studies
and risk assessm ents.

It is recogn ized that the Agency m a y lack th e tim e to develop a new Pb FRM for the curren t NAAQS review cycle. But at the sam e ti m e , it would be an unfortunate waste of scarce

B-39resources to require a large expansion of the TS P-Pb samp ling network. One option m i ght be for the Agency to simp ly designate low volum e PM 10 -Pb as an FEM – having first taken into
consideratio n the slight, occasion a l loss of ultra-coarse Pb in se tting the (slightly cons ervative) level of the standard. A nother possible variatio n on this m i ght be to require TSP-Pb sam p ling only at sites which exceed standards with the new PM 10 -Pb FEM. Another option might be to designate tw o separate P b NAAQS, one based on the current TSP-Pb FRM indicator and one based on a new PM 10 -Pb FRM indicator – allowing either m e thod to be used for attainm e nt

comp liance determ ination, but perhaps requiring both m e thods at sites which exceed either
standard. A lternatively, the Agency m i ght speci fy TSP sa mp ling at source-oriented locations
and PM 10 at population-oriented sites. The latter could be used for com p liance determ ination, while the form er m i ght be used to trigger a dditional m onitoring or c ontro l requ irem ents if “action levels” are exceeded. Possibly the Agen cy should seek advice fro m the CASAC AAMM Subcomm ittee to develop recomm endations for a ppropriate P b FRM, FEMs and network design strategies. That Subcommittee had previ ously reviewed EPA’s National Am bient Air Monitoring Strategy – at a tim e when the curren tly implied large expansion of a Pb sampling network was not envisioned. Un less new funds are provided, any new sampling needs to be paid for by reductions in existing program s.

Regarding the Agency’s request f o r comments on the suitability of using the cur r ent P M 10 network for Pb samp ling if adequa te regional or source-specif i c PM 10 -Pb/TSP-Pb correlations could be established – I would prefer this to a large expansion of the TSP-Pb network, regardless of whether acceptab l e co rrelations are develope d. However, a large fractio n of current PM 10 sites use hi vol PM 10 samplers, equipped with quartz filters. The particle cut size for these h i vol
PM 10 s is m u ch m o re clearly defined than for T SP, but is not as sharp as for low vol PM 10 , nor are the quartz filters as clean as Teflon or as am enable to surface beam analytical techn i q u es.

Regarding the request for comm ent s on changes to the Pb F E M certification requirem e nts, I agree that th ere should b e accuracy and precision perform a nc e specifications tested within a range of Pb levels m o re representative of toda y’s am bient concentrations than the 0.5 to 4 μg/m 3 range in the current FEM specs. B u t I think FE M certification need not (& should not) require statistical equivalency to the flawed TSP m e thod (or perhaps m i ght allow equivalency to be
determ ined under tes t co nditions wh ich do not in clude high levels of ultra-coarse Pb.

Regarding samp le frequency, the m ove to a m o nthly averaging tim e provides another reason to switch to P M 10 sam p lers, as they are available in au tom a tic sequential sam p ling configuration.
Sa m p le compositing o rs a m p le collection over prolonged m u lti-d a y perio d s is useful only for “brigh t lin e” comp liance determ inatio n (f or a polluta nt, in this case, for which there is no bright line for effects). But the aggregation produces in for m ation of lim ited value for source attribution or effects studies. I would also like to encourag e, however, that ev ery ef fort is m a de to avoid a need for hig h frequency, filter-based sam p ling. I would im agine a large p o rtion of the difference between m o nthly and quarterly aver ages could be described as a “s ta tistic al issu e.” T h at is there’s an average or m e dian ratio of m onthly m a x to quarterly m a x, and data from most sites will f a ll within a f a ir ly narrow rang e of that ra tio over tim e . Only a relatively f e w sites near

extrem ely e p isodic em ission sourc e s will have m onth/ y/qu arterly r a tios th at cons isten t ly f a ll well above the average. W h en concepts like the “2 nd highest m onthly m a x” and/or “the 3 year

average ” are introdu ced to provide so m e stability in the comp liance m e tric , the dif f

e re nce

B-40between m o nthly and quarterly is reduced to m o re of a scaling factor. I would think som e m e tric
ref l ective of the “ep isodicity” of the daily s a mp le values (perhaps the sta ndard deviation or ratio of the 98 th to 50 th percentile) could be used to supplem e nt a quarterly m ean in a way that sites with m u ch higher m onthly values could be targeted for increased sam p le frequency, w h ile a

m a jority of sites m i ght g e t by with 1

- in-3 sam p ling, or even 1-in-6 day sampling at sites that consistently fall below standards.

Regarding the request for comm ent s on Pb m o nito ring in rural areas to comp are with secondary NAAQS (and which would also help define regional background, tr ansport and trends), I think its an excellent idea to supplem ent the rural/remote PM 2. 5 Pb m e asurem e n ts from the IMPROVE network with a sm aller “sentinel” network of PM 10 -Pb samp l e rs (no TSP-Pb please), The IMPROVE program already collects PM 10 samp les and these samp les – from a subset of sites
that m i ght be period ica l ly rota ted – c ould be at le ast subject to m u lti- e l e m ental XRF analys is which would provide useful inform a tion on fine and coarse Pb as well as other components of coarse particle com position.

References

Ca m a lier, L. and J. Rice (2007) Estim ates of Pr e c ision and Bias for Lead in Total Suspended Particulate (TSP), Memo to Lead NAAQS Review Docket (OAR-2006-0735), 11/29/07.

Cavander, K. A. and S. M. Schm idt (2007) Re view of Collocated Lead in Total Suspended
Particulate Matter Less than Ten Microm eters, Mem o to Le ad NAAQS Review Docket (OAR2006-0735), 11/26/07.

Henderson, R. (2007) Letter from Dr. Rogene Hende rson, C h air, Clean Air Scientific Advisory
Comm ittee, to Steven L. Johnson. Re: Clean Ai r Scientific Advisory Co mmittee’s (CASAC) Review of the 1 st Draft Lead Staff Paper and Draft L ead Exposure and Risk Assessm e nts, 3/27/07

Wedding, J. B., A. R. M c Farland and J. E. Cermak (1977) L a rge Particle Collection Characte r is tics of Am bient Aerosol S a m p lers, Environ. Sci. Technol. 11: No. 4, pp 387-390.

B-41

### Dr. Mich ael Rabino w i t z

Review by Michael Rabinowitz of “Lead: Human Exposure and Health Risk Asse ssm e nts for Se lected Case Studies” and “Review of the National Am bient Air Quality Standards for Lead: OAQPS Staff Pape r” (October 2007)”

Nove m b er, 2007

General Comments: These two docum ents are the fruits of year s of labor of groups of well-funded and cocoordinated workers. In its current form I think it provides a sufficient basis for the
Adm i nistrator to set an appropria te air standard, taking into acc ount a vast am ount of older and newer inform ation. At this stage, I can think of nothing to add to or take out of the text, aside
f r om som e sm all item s below.

I would lik e to again str e ss that to achieve a lead-safe environ m ent not only m u st lead in air (and water) b e regulated, bu t the burdens of lead pa int, still in hom es, and lead accum u lated in outdoor areas, whether from old exhaust, paint, or industr ial sources, all need to be addressed.

Although I raise som e fairly m i nor points below, and I am wi thout the benefits of hearing from my panel colleagues, I see no reason not to appr o v e these do cum e nts in th eir present form

.

Minor Rem a rks Might this docum e nt have a useful “Executive S u mm ary”? pages 3-21 to 3-23 and 5-41-46

m i ght serve as a good start.

Page 2-8 line 3 Yes, indeed. You could actua lly point to a Feb 1972 pub lication of EPA’s fuel additive regulations which resulted in the reduction of lead in gasolin e which were to s t ar t in January 1977. {California lead the way}

Page 2-23 Figure 2-7 In m y draft th e m i ddle (average lines) were not visible.

Page 3-18 Section 4.4.2 I understand that th is section is suppose to show how lead can m a ke other health problem s worse. Bu t it was not clear to m e how lead m a kes diabetes worse. This section needs to be clarified and expanded or eliminated. Also, th e 3 groups of adults (hypertensives, diabetics, and kidney patients) m a y not be separate. Diabetes, hypertension, and kidney disease often co-occur in the sam e indi vidual. I suggest just focusing on hypertension, where the case is clearest.

B-42

### Dr. Armis t ead (Ted ) Russell

Comm ents of Dr. Ar m i stead (Ted) R u ssell Georgia Power Professor of Civil and Environm ental Engineering Georgia Institute of Technology, Atlanta, GA

on EPA’s Advance Notice of Proposed Rule mak i ng (ANPR) on the NAAQS for Lead

Decem ber 6, 2007

The lead staff paper is very responsive to our de liberations, and I was quite pleased w ith what is there. The ANPR, on t h e other hand, raises so m e concerns looking to a future where the ANPR replaces the Staff Paper. The ANPR says rather little new, but regurgita tes the findings of the Staff Paper and CASAC comments. I trust, and h ope we get reassurance, that the future ANPRs will r eally b e m o re like the curr ent Staf f Paper, not the cu rren t ANPR.

We also received a m e mo from Cave nder and Schm idt on the comp arison of PM10 and TSP lead
at collocated m onitors. I would like to thank th em for providing this inform ation. I must adm it,
the data raises som e que stions about the TSP m o nitoring, and m a kes m e wonder what is happening at som e of the TSP m onitors (I have a bias towards using PM10 in that I think the
inle t is be tte r char acte r iz ed, PM10 monitors are more ubiquitous, having the additional m e tals will prov ide more information in the long run, and they prov id e a be tter ch aracterizatio n of areawide lead exposures). I actually th in k that this a n alysis f u rther argues towards using PM10 monitoring as it m a kes m e a bit m o re leery of th e TSP m onitoring. I disagree with the idea of adding a delta (e.g., one standard deviation) to m a ke a cha nge to PM10 conservatively protective. I generally don’t like such arbitrary changes. Going to a tighter standard and going to PM10 at the sam e time will be bo th m o re pr ote c tive and better in the lon g run f r om a monitoring perspective. W h ile I m i ght prefer m onthly averaging, the difference betw een this and quarterly averaging is relative ly m i nor, so I m i ght just suggest we show a preference towards monthly, but not be overly emphatic about such.

In regards to the level of the standard, I view th at the staff paper has cap tured the rang e of where
I m i ght fall, and given that I will not be present for the final discussions I hesitate to be overly specific at this tim e as those discussi ons m i ght fi ne tune m y suggestions.

In regards to the secondary sta ndard, and what is said both th e ANPR and Staff Paper, I m i ght suggest th at we enshrine the various comm ents made by Rich [Poirot], [Dr

. ] Ellis [Cowling] and others about the lack of data how ever m a ny year s ago, and that little has been done to alleviate that inadequ acy. It is qu ite app a ren t that their words will b e just as app lic able f i ve yea r s f r om now. I trust that our furry, scal ed, leafed and single-celled frie nds will reap benefits f r om tightening of the prim ary standard in the m ean tim e.

B-43

### Dr. Jonathan M. Samet

Review Comments: EPA’s Advance No tice of Proposed Rulem a king (ANPR)

Jonathan M. Sa m e t, MD, MS Professor an d Chair Departm e nt of Epide m iology Johns Hopkins Bloom be rg School of Public Health

General Comments:

Having reviewed the staff paper and the ANPR for lead, I was left concerned by a process that
had left the ANPR as an isolated docum ent, lack ing any links to either the Crite ria doc um ent or the Staff Paper. Additionally, the peer rev i ew th at had been provided by CASAC, as well as comments by the public to date, were not acknowle dged to a sufficient extent. I recognize that this ANPR represen ts th e f i rst that th e Agency ha s developed and that it is linked s t ill to the pr ior process involving a Criteria Docum e nt and Staff Paper, now set aside in term s of the new ISA model. Nonetheless, this ANPR cannot stand as the m odel for developing a National Ambient Air Quality Standard (N AAQS).

The ANPR r eads as thou gh there was not sufficient cer tain ty with rega rd to the hea lth ef f

ects of
lead and the need for a standard that would be protectiv e of public health. Rather, it appears to
take a s eem ingly “neutral” stance, ap propriate on ly if the ev id ence were in equipoise, hardly the
case. The ro le of CASAC is dim i nished as a co mmenter, as is the Agency’s own staff which has synthesized the evidence through the Criteria Docum e nt and the St aff Paper. This ANPR is an unacceptable result of a process that should be ev idence-based, but has clearly gon e o ff course and lost its links to a substantial body of evidence.

Specific Comments:

1. Handling of uncertainty: On reading the doc um ent, I was troubled by the m a nner in which uncertainty was handled and emphasized. The obvious truism , that uncertainty is greater at the lower end of the dose-respons e relationship, received excessive em phasis, without adequate interpretation. The docum ent failed to adequately ca ll attention to how the points on the dose-response curve at which effects have been observed with certainty
has becom e increasingly lower, and guideline values have followed.

2. W ith regard to the handling of susceptibil ity, the ANPR addr essed som e of the groups
that m a y be at risk. Meriting greater em pha sis are those persons, prim arily inner-city children, who are at risk for highe r levels of exposure in genera l. There is potential that additional exposure fro m airborne lead will m ove them into a range of much greater risk.

B-44

### D r . Joe l Sc hw ar tz

Review of ANPRM for Lead

General Comments:

I am concerned that there are con tin uing choice s m a de, each for understandable reaso n s, all of which have the effect of biasing dow nward th e es tim ated health effects of lowering the
standard s, a nd which in net, cons titu te a large do wnward bias . For exam ple:

1. The effects of decreased renal function are dif f icult to qu a n tif y, but th ey are not zero. W hy not
either a crude attem p t to bound them , or a fu ller discussion when reporting the estim ated
benefits.

2. The effect of air lead on food lead is ignore d, despite evidence that it is an important source. The old CD had som e es tim ates, based on a peri od of higher air lead. The expected value of uncertainty is not zero. Why not a sensitivity an alysis assuming 40% of food lead is from air deposition?

3. Past air is treated as part of background, not pa rt of air. Again, a downward bias. A nd there are

m easures to control this source. I understand there are techn i cal lim itatio ns, but again

, a sensitivity analysis, which, for example, attribut es 15% of indoor dust to “past air”, and m a kes

som e assumptions about turnover rates, would av oid the im pr ession that there is a desire to
understate effects.

4. There m a y not be time to quantify the blood pre ssure benefits, but it should be noted that when that has been done in the past, e.g. the RIA for l ead in gasoline and the R I A for the water lead rule, the m a gnitude of th e benef its w a s of the sa m e order as the m a gnitude of the co gnitiv e benefits in children. Thus this decision alone like ly cuts the estim ated he alth ben e f its in half

. This needs to be discussed, with reference to the previous RIAs.

5. A back of the envelope estim a te of the effect s of lead exposure on criminal behavior, using
estim ates of the econom ic costs of crim e, suggest that again a potentially large benefit is being ignored.

I agree with the comm ents of Paul M u shak th at th is docum ent summarizes the risk assessm ent that OAQPS did, summ a r izes the risk assessm en t, but then ignores the recommendations of OAQPS, buries th em , and blith ely as ks f o r comments on a r a n g e of standa rds f r om zero to infinity. This is really no t accep table. The Cl ean Air Act requ ires th e adm i nistrator to set standards for a pollutant that “m ay reasonably be anticipated to endanger public health”, using criteria that “accurately reflect the latest scien tific knowledge us eful in in dicating the kind and
extent of all identifiable eff ects on public health and welfare wh ich m a y be expected from the presence of a pollutant in am bient air..”. Th e range of possibilities proposed for comments ignores the comm ents of CASAC on what those effects are at wh at levels, ignores the Staff

B-45Paper summary of those effects at dif f

erent standa rd levels, and ignores the risk assessm e nt. It

seem s, in fa ct, to ignore science. Are we now doing faith-based risk assessm e nt?

While the Clean Air Act requires special attent ion to susceptible popul ations, and the ANPRM
notes th at th ere is eviden ce of increas e d suscep tib ility in Bla c k s and perso n s with cer ta in ALAD varian ts, th ere is no p l ace in the ANPRM where this is spec if ically addr es sed in th e ris k

assessm ent or proposal for comm ent s

.

The ANPRM notes th at CASAC reviewed the s c ien ce and sa id tha t it wa s clear that air pollution by lead s till had public h ealth impacts, slide s by the Staff Paper and Risk Assessm ent docum ents which quantitate adverse effects on children’s IQ, and asks for comments on whether it would be appropriate to determ ine that ai r lead no longer has any public hea lth impa ct. “W e take not of the views of CASAC summa rized above ... W e recognize, however that there m a y be diffe r ing views on interpreting or weighing the ava ilable inform ation. “If CASAC is just another interested party
to subm it comments, what are we doing at this m eeting ? This is prec ise l y the issu e tha t has already been addressed by the statutory reviewer of science for EPA air standards, addressed by OAQPS in its Risk Assessm e nt and Staff Pape r docum ents, and again reviewed by CASAC. Either CASAC is the co mmittee tha t reviews the “differing views” or it is not. If this change in status has happened for CASAC, then I believ e that we need to inform the Congressional
Comm ittee’s that authorized CASAC in the clea n air a c t th at this has o c c u rred, so tha t they c a n determ ine whether this was their leg i sla tive inte nt.

HAPs are focused on m a jor stationary sources, and are in adequate to con t rol em issions from a variety of sm aller sources which becom e rele vant when we stop focusing on sm elters.

Specific Comments P19. States that 5 is the level at which there are significant eff ects reported, arguing that levels below that m a y not need protection. But this is a distor tion o f the literatu r e. Restric t ing analyses only to Blood Lead levels below 7, Lanphear has reported a significant association, which m a kes it highly unlikely that levels be low 5 have no effect. Indeed, the bulk of the literature indicates that the slope of the blood lead -IQ dose response curve increases as we get to lower blood lead levels, rather than decreasing to zero. If NHANES 2003-04 and has reported the m e dian, then the 95 th percentile m u st “exist”, contrary to the note on this page. Given a set of data, it m u st have a 95 th percentile, and the data clearly
exist if the m e dian has been published. CDC m a y not have published it, but that does not prevent EPA from asking them for the num ber.

P26. footnote 13. Duh! Of course uptake of lead in solutio n is greater than uptake of lead from food, som e of which m a y be non-soluble. However, this page seems to ignore the role that ai r lead plays in lead in food. Content of lead in red wine in France dropped considerably when le ad was banned as a gasoline additive, because of lower deposition on the skins of th e grapes. Lead conten t o f white wine, where the s k ins are quickly removed, had always been lower. Hence th e dicho t o m y between dietary lead and air lead being proposed is flawed. P33. Should note that there have been several pu blications since the cl ose of the CD which continue to report significant a ssociations of lead < 10 μg/dL and IQ, and continue to report

B-46steeper slopes at lower levels (e.g. T e llez-Rojo 2006, Lanphear 2007). It should also note that if a threshold existed, one would expect slopes to d e creas e as we lim ited the sam p le to subjects with lower and lower blood lead.

P47 should note a recent publication (Jain et al 2 007, EHP) which provides further support for the association of lead exposure with ischem ic heart disease, not just blood pressure. P 57. Again, an assump tion is m a de about the shape of the dose response that, based on the data,

appears un likely. If there were a th reshold be lo w which the dose-respon se becam e zero, then in repeated analyses that excluded blood lead concen trations above certain levels, one w ould expect the slope to decrease. This is not observed, rather the opposite is observed—a steeper slope at low levels. It is one thing to assum e that as we go to levels outside of the realm of the Lanphear study the slope stops increasing. It is another to assum e directi on of change in slope suddenly reverses, and the slope plumm e ts to zero. I agree that when we have no data, we need to m a ke an

assum p tion—but this one seem s m a them atically implausible. Further, there is other
circum stantial evidence that sugge sts it is not likely. Analyses of bone lead concentrations from inhabitants of the Southwest desert in the US from circa 1100 show m u c h lower bone lead
concentrations than in m odern Am ericans. Thes e bone lead concentrations are consistent with blood lead concentrations well below 0.1 μg/dL. Hence the range of blood lead we are talking about for this extrapolation is still about an order of m a gnitude higher than background
concentrations.

p.59 The argum e nt is m a de that the slope below 7.5 from Lanphear is unreliable because a)it

com e s predom inantly from one study; and b) it includes only 103 childre n. This argum ent is undercut by the subsequent publica tion of Tellez-Rojo (Pediatrics, 2006) of an analysis of a cohort of 294 children, whose blood lead concentrations never ex ceeded 10 μg/dL. This study reported a significant association in 294 children in two birth cohorts (not in the Lanphear pooled analysis) in Mexico City whose blood lead concentration never exceeded 10 μg/dL. The slope of the association between 24 m onth blood lead and 24 m onth MDI, when restricted to blood lead concentrations never exceeding 5 μg/dL was - 1.7 points/μg/dL, and highl y significant (p=0.01). When 90 children whose blood lead concentration s had exceed ed 10 μg/dL but otherwise m e t all inclusion criteria were analyzed, a sm aller slope was found at the higher dose. Hence, a significant associati on is found in another larg e cohort of children who never exceeded 10 μg/dL, it is sign if ic ant when res t ricted to children w ho never exceeded 5 μg/dL, and this study also
confirm s the nonlinear shape of the dose-response reported by Lanphear. This study should be cited in the ANPRM, and its support for the Lanphear study should re sult in a m odification of the

argum ent on p59 that support for the Lanphear analysis is “dissipated”, whic h incidentally elicits
an im age of a bedraggled Bruce, slumped over a bar. I attach a PDF of the study for convenience.

P 59. The discussion of dose response m a kes much of the fact that the loglinear function has undergone more extensive sensitivit y analysis than any other, and uses this to justify the loglinear function with lin e a rization at the low dose . However, this argum ent seem s logically inconsistent. First it argues that th e m o st convincing evidence is for a nonlinea r re lation with the slope of the dose-response curv e constantly increasing as one goes to low e r blood lead levels. Then it argues that the slope m u st be linear below the bottom of the blood lead levels observed in the study. But if all the evidence says we have a nonlinear relation, what is the justification for

B-47suddenly linearizing it? What that is saying is “everytim e we te st for a linear association, the evidence is against us, so let’s insist on it wh ere there is not enough ev idence to show we are once again wrong”. Anything is possible, bu t is this really the m o st likely?

Addendum to Comments on EP A’s ANPR for the Lead NAAQS

Dr. Joel Schw art z

Decem ber 14, 2007

The ANPRM has m a ny pages devoted to elucidati ng an alternative to the peer review ed risk

assessm ent, using instead the approach of 1978. In 1978, the evidence on the effects of lead on cognitive function was lim ited to a few studies sh owing lower cognitive func tion in children with “high” lead levels. Reasonably, EPA sent th e am bient s t anda r d with a goa l of lim iting the

num b er of children with “high” blood lead leve ls. Necessarily, such an approach recognizes no benefits to lowering blood lead levels within the “not high” category, o rwithin th e “ h igh” catego r y.

We know much m o re about the dose-response between lead and IQ now than we knew in 1978. The CASAC has reviewed the CD and the Staff Pa per and expressed itself on that is sue. W h ile there is always uncertainty in th e dose-response relationship, it is cl ear that it is continuous, not a step function, and that it persis ts to concentrations well below 5 μg/dL. Therefore, the proposed approach is a step ba ck ward and in consistent w ith th e scien ce. Mer e ly s ubstitu ting a level of 5μg/dL or 2 μg/dL for the earlier level does not rem e dy this defect, and ig nores the su bstantial
health benefits from lowering am bient concentr ations that has been docum ented by the peer reviewed risk assessm ent, m o st of which does no t involve children m oving from one category to another.

B-48

### Dr. Frank Speiz er

Pre-m eeting Comm ents on ANPR fo r Lead dated Decem ber 5, 2007

Subm itted b y Frank E. Speize r, MD 12/11 /07

General Comment: Although the id ea of replacing the Staff paper with this ANPR was only approxim a tely accomp lis hed as we transition fro m the “old s t yle” to th is new approach because of the court ordered Staff paper, and because of what we have here I for one have to congratu l ate the court for its fore-wisdom for insisting on a S t aff paper. The for m at of this ANPR is

extrem ely disappointing. In sum it simply restates what has com e before in the form of a staff paper, and whether CASAC agreed or did not ag ree with wh at was pr eviously produced, and what CASAC has recomm ended and then goes on to solicit further comm e n t, presum ably from CASAC again and the public. If we did not have a Staff paper it is not clear that the A N PR would have sufficient scientific input to m a ke any statem ent that resu lted in a position that cou l d be criticized one way or another. I would have ex pected the ANPR to come to som e conclusion rather than restating th e case, and by presenting the argum ent as it has simply leaves open to the
Adm i nistrator the option for doing a nything he wants, without scientif ic justif ication. Separate
f r om this pr ocess we will need to rev i sit wha t th e role of CASAC will be in the f u ture as well as what will b i nd the Adm i nistr a to r in u s ing scientif ic data with a m a rgin of saf e ty to m a ke a NAAQS. I as others on the comm ittee have alre ady suggested recomm e nd that we send not only a response to this ANPR but a sepa rate letter, addressed not only to the Adm i nistrator, but also SAB and potentially the Congressi on al overs ight comm ittees of our concerns with th e execution of the chang e s in th e standard setting process and the degree to which th e process ap pears not to be w o rking.

Paraphras e of areas in which EPA is solic iting c o mm ents

Prim ary Standard, Section III, C— Adequacy of the Current Standard.

1. Question of delisting. Pp 114, 131. The whole ques tion of delisting was pr eviously considered by CASAC and unanimously on tw o occasions (docum ented in the app e ndices to th e staff paper in which we responded to the Adm i nistrator) rejected. To raise it again can only be to solicit potentially biased responses from individuals a nd groups with potential and real conflict of
interest. Furtherm ore CASAC consi d ered whether the o t her Federal agencies were s u fficient to provide ad equate pro t ection. W e rejected that an d unless co mpelling arg u m e nt can b e brought forward in som e open forum I would recomm end we rejec t it again. This all rais es a p o tential issue for future NAAQS procedures, when the ANPR is supposed to replace the Staff paper. It is not clear that since the public ha d the opportunity already to have i nput into the process that lead to the CASAC summaries withou t r e peating what has already been sa id by CASAC isn’t th e Adm i nistrator essentially ste pping backwards and redoing w h at has already been done either with or without a Staff paper? Is the Adm i nistrator aware of othe r data that has not already been considered ? If so should n ’t th at be p a rt of the A N PR? W h at will be the procedure for vetting
the addition a l inf o rm ation that com e s into the a d m i nistr a tor ’ s of f i ce ? W ill it m e et the Feder a l

B-49Guideline of a Federal Advisory Committee if it is not vetted though CASAC? These are serious procedural issues that th e current offered ap proach of the ANPR by spe c ifically soliciting additional input at this stag e of the process creates.

2. Understanding the decline ratio for air-to-blood ratio. Pp120. I believe the data reported in 1986 and the summ ary s uggested in the CASAC pane l letter clearly indi cted what the ratio
implied. EPA seem s to be asking for new or add ition a l data to help them understand f u rther what we have written. Again, I think we need to refer them back to our previous comments.

Elem ents of the Standard

1. Indicator. P p135, 136. The exercise perform e d by Cavender and Schm idt dated as Mem o 11/26/07, suggest that there is generally a high correlation between TSP and PM10; it is
the cas e that there are s i gnificant d i s c repancies. At this po int in tim e I think this m eans that we have to continue to go with the con cept of all particles contribute to the risk. More research is obviously needed to sort this out. Further side by side studi es that take into account potential confounders and risk m odifiers m a y increase our knowledge as to
factors influ e ncing th e d e ltas seen between TSP and PM10; however, in that research it will also be im portant to look as cou r se a nd fine fractions as well. For no w I would

recomm end staying with the TSP system but could be persuaded otherwise.

2. Averaging tim e and For m pp143. CASAC has previously indicated a preference for a monthly average becaus e of the evid ence that blood Pb concentrations related to shorter
tim e scales and therefore this would be m o re protective than th e current qu arterly s cale. This was the recomm endation that w a s rejected b y the Adm i nistrato r in th e previous round of lead standard setting. In maki ng the recommendation again, C A SAC indicated that a secon d highest m onthly would be accep ta ble. W e now have some predictiv e data as indicated in Appendix tabl e 5.A. The table is quite in f o rmative in pred icting what

m i ght be seen and there clearly are regiona l differences in term s of potential for nonattainm e nt of new standards below 0.5. Select ing from that table it would appear for the total country were TSP Pb are m easured that an acceptable level of attainment for levels of exposure below 0.50 m i ght be in the range of 75-85%. To obtain su ch levels one must

move to som e where around 0.20 with any of th e averaging tim es of m a x quarterly, m a x monthly or 2 nd m a x m o nthly.

3. Level pp148. The entire argum ent suggesting because CDC uses 10μg/dl as a m onitoring level is simp ly wrong. The CDC level is an action level not a risk level. The data presented and fully discussed in both the CD and the Staff paper clearly demonstrates
important health effects at or below the 5μg/ dl and to even rais e this issue and ask for
comments is to m i slead the public.

B-50

### Dr. Ian von Lindern

COMM ENTS: TH E US EPA LEAD NAAQS ADVANCE NOTICE OF PROPOSED RULEMAKING (ANPR)

CASAC Panel Mem b er: Ian von Lindern, P.E.,Ph.D.

Decem ber 24, 2007

General Co mments

The Staff Pa per and the ANPR bot h include synthesis analyses of the NAAQS process to this point. As a result, it is important that the flow of inform ation, the assump tions and underlying strategies of the analyses, and the interpretati ons forwarded to the Adm i nistrator and the public be objective, transparent and cons istent. In that regard, there ar e candid discussions m i ssing from
these docum ents. There is concern th at the m e ssa ge carried fo rward to the Adm i nistrator does
not inform policy m a kers, or the public, of th e co nsequences of the Agency’s failu re to adequately regulate lead in air over the last fifteen years.

The regulato r y exercise that the EPA and CASAC are cu rren t ly engaged in evaluates th e costs and benefits of the various alte rnative scenarios in addressing c ontemporary lead exposures. This is clearly a d i fficult and challeng i ng task, largely due to lack of da ta regarding sources, transport

m echanis m s , and exposures throughout the nation. Th is lack of pertinent data can be traced to EPA’s decision to not update the NAAQS in 199 1, followed by suspension of m onitoring and
collection of characterization data.

In hindsight, EPA would have been well-advised to have lowered the NAAQS to a protective level consistent with observed am bient concentrations. In that case the m o nitoring program s would, likely, have not been aba ndoned. Failure to recognize this shortcom ing could result in repeating that m i stake in 2008 and elim inati ng the NAAQS, or adopting a NAAQS that simp ly
certifies current conditions.

The base of inform ation for the 2008 decision- making process was developed in the A Q CD. Those data and findings were forwarded to the R i sk Assessm ent docum ent, where analyses were perform e d to evaluate the potenti al risk to hum an health and welfare acro ss the nation

. Those results and findings were then interprete d and evaluated and St aff conclusions and

recomm endations were captured in the OAQPS St aff Paper. CASAC has followed, evaluated and provided input throughout this process and sta ff has been attentive to and responsive to
CASAC’s comm ents and suggestions. Staff di d an excellent job under the circum stances presented, and the Staff Paper recomm endations ar e reasonab l e and app r o p riate. Staff has also done a good job of summ arizing and presen ting CASAC’s views, conclusions and

recomm endations. Based on the outcom e of these docum ents, the recomm endations m a de by CASAC in past letters to the Adm i nistra tor shou ld stand as presented and that the S t aff Paper is adequate for use in assessing the NAAQS.

B-51However, those sam e conclusions do not exte nd to the ANPR. This docum ent see m s to be a

m eatless version of the Staff Paper, with no real conclusions or recomm e nda tions. No standard is proposed, n o position is taken on whether the s t andard shou ld be retain ed, there is vague m e ntion of, perhaps, deleting the standard, noting that lead compounds are included in HAPs, and no tentative Agency position is pr ovided. It seem s to be a solicitation for input on whether the Agency should agree or disagree with its own St aff and Scientific Advisors. The Agency should either agree or disagree with its staff and advisors, tell the public why, espouse a proposed course of action, and then solicit co mm ent on that position.

This is critically im portant with the lead NAAQS because the agency failed in 1990 to act on Staff and CASAC recommendations and that decision, unfortuna tely, had unintended adverse effects for the Nation’s health, and for the NAAQ S process. The current analyses could be
inte rpre ted to indica te th e num erous child ren hav e suf f

e red cognitiv e dec r em ents and the Agency
has little idea of the exte nt of deleterious exposures in m o st of the country.

Perhaps the most im portant function of the ANPR is to convey the status of air lead regulation to the public and underscore the policy the Agency is using to protect the health and welfare. This
docum ent fa ils to convey the poor state of knowledge regarding lead in air, the Agency’s role in allowing the knowledge base to deteriorate, the uncertainties resulting from that lack of knowledge, the likelihood that there is insufficient inform ation avai lable to consider deleting the NAAQS, and that large m a rgins of s a fety m a y be appropriate to assure p r otectiven es s in the developm ent of the revision.

The Agency has failed in the last fifteen years in one of its prim ary m i ssi ons to characterize the extent and severity of this prio rity pollutant’s exposures in the U.S. The deleterious effects of lead have always been underestim ated and now , from a health perspective, there m a y be significant dam a ge ongoing to susceptible popula tions. Consequently, the Agency must now reassess the significan ce of lead expo sures wit hout adequate data and greater uncertainty. Twenty years ago lead w a s am ong the best characte rized priority pollutants in term s of exposure and response relationships. As a result, the curr ent NAAQS was adopted with an atypically low

m a rgin of sa fety incorporated in the standard. Su ch a low m a rgin canno t be justif ied by the state of knowledge today.

This lack of data was f i rs t noted in th e in itial AQCD reviews by CASAC. Al m o st no useful

em issions or am bient air data were av ailab l e in th e peer-rev i ewed literatu re in 2005. CASAC urged EPA to use the Agency’s own resources an d the trade and professi o n al lite ratu re to

augm ent the knowledge base. The Staff did find som e useful inform ation and included this in the AQCD. However, there certainly w a s not sufficient data to conduc t a “national” risk assessm ent and Staff opted to develop pilot risk assessm ents f o r three sou r ce- type s itu ations. At th e risk

assessm ent stage, CASAC was again critical of this approach, urgi ng th at a “national” perspective risk evaluation be conducted. Staff m a de an adm i rable effort to accommodate this request in the urban analyses presente d in the fin a l Risk Assessm ent.

Despite the success of this effort, this risk assessm e nt should be recognized as largely a m odeling exercise utilizing num erous assum p tions, ofte n based on decades old data and empirical relationships derived from envir onmental regim e s that no longer ex is t in the U.S. This approach

B-52was necessary and had to be undertaken because the data do not exist to address this problem more appropriately. W ith regard to these shor tcom ings, the discussions do not sufficiently convey the lack of inform ation and unknowns associ ated with the knowledge base of lead in the air, as do cu m e nted in the AQCD.

Nevertheless, these analyses show that there is substantial indication of significant deleterious health effects (IQ decrem ents greater than 1 point) ongoing in, presum ab ly, m a ny areas of the country. These were effects that were suspected in 1990 and it was recom m e nded that a m a rgin of safety be incorporated into an NAAQS strategy to protect against this possibility. That was not
imple m ented. The default m a rgin of safety i nherent in the 1978 Prim ary NAAQS, wa s clearly inadequate. This lead s to a potential interpre tation– that, despite phenom enal lead exposure
declines in other m e dia, som e children were like ly harm ed in the in ter i m , and little data were collected to support conducting a “national” risk assessm ent when the Agency was forced in Court to reconsider the NAAQS.

The status today as summ arized, but not expl icitly m a de clear, in thes e do cum e nts is:

The 1978 Standard is clearly non-pr otective. A one to two order of m a gnitude reduction should be considered requisite to an e ffective health pr otective strategy.

The em issions and am bient air database is insuffi cient to characterize th e extent of potentially deleterious exposures across the U.S. Large urban areas are largely unchar acterized with respect to both area and point sources. There was not ev en sufficient data to characterize a sin g le secondary source in the country for this risk asse ssm ent. Hypothetical data and com b inations of
data from different sites and tim e periods had to be synthesized for the secondary source risk analyses.

The prim ary source analysis relies on an area that has been de-populat ed and rem e diated, but continues to show substantial risk. The m a xi m u m (or worst case) situation developed in the prim ary sm e lter application seem s to be about 50 % of the current NAAQS. This result seem s to derive from a com b ination of the ratio between the quarterly and annual average, and the current geographic disposition of populatio n relative to the sm elter in Mi ssouri. The ultim ate result is that potentially worst case exposures and estim a ted IQ decr em ent are possibly underestim ated by a factor of, perhaps, 1.5 to 2 tim es. Were th e 1.5 k m sub-area repopulated to previous d ecade densities, a substantial p o rtion of the ch ildhood p opulation would exhib it unacceptable risk levels, in the current NAAQS and cu rrent conditions scenarios.

As a result, exposures are likely underestim a ted, due to lack of m onitoring and coverage which
the Risk Ass e ssm ent and Staff Paper adm it for the urban cases, but seem less articulated in the ANPR. Neverthe less, th e pilo t stud ies as pre s ented indicate both urban and point source
communitie s are a t r i sk of substantia l harm

.

A critical issue that has been seem ingly ignor ed throughout this proce ss is the potential nonrepresentative nature of the database th at is being used as it m i ght apply for future applications.
All em issions and m o st of the am bient data ar e from the 2002-2005 era at best. This w a s an era of relatively low lead producti on and use in the U.S. The em is si ons picture and particularly, the

B-53spatial characterizations and peak-to-m ean ratios, used in the roll-up a nd roll-down calculations were based on an industry in a m i nim a l production and use mode.

There are su ggestiv e data that i ndicating the possibility that th is trend m a y reverse and that potential increases in point s ource emissions be considered. Ba se m e tal prices have exploded since 2005, first in copp er and zinc and, in the last year, by silver and lead . Recent m e tals exchange prices are app e nded below

. Productio n has increased, m i ning an d m illing op erations are being rehabilitated, and substa ntial legislative lobbying f o r cons iderations in several forum s supporting revival of the industry in the U.S. are underway; much of it for national security reasons. Significant dam a ge to som e of the nation’ s infrastructure is occurring due to base-m etal shortages and copper thievery. The energy crisis in petroleum is leading to even m o re dem a nd
f

o r these m e tals.

The country’s m i ning and m e tal-refining and fabric ation industries need to know wha t the rules will be, wha t leve l of controls will b e required, a nd where EPA believes there a r e ong oing and significant ambient air lead ri sk. The current standard and state of knowledge are both inadequate to this task.

Reliance on HAPs see m s questionable at this time. The docum ents only note that HAPs is applicable. No presentation is provided regarding the eff ectiveness of a technology based standard being protective in the case of this ubiquitous contam inant. The EPA has not evaluated, and for the most part does not know, the extent of deleterious exposures, where current sources
are lo cated, how these impact local airshed s , the sour ces that need to be c ontrolled, nor the level of control required. Had EPA revised the NAAQS to t hose levels considered to be of concern in the 1990’s and m onitored accord ingly, analyses of potential HAPs applicability cou l d be
undertak en. Unfortunately that database is prob ably lagging th e imposition of a new standard and appropriate monitoring by 3 to 5 years.

Few if any of these issues are discussed in the A N PR.

B-54

## Silver ( source L o nd on Metal s Exc h ange 12/4/0 7 

## )

Copper $US/tonne 

## ( source L o ndon Metal s Exch ange 12/4/07 

## )

B-55

## Zinc $US/tonne 

## ( source L o n d on Met a l s E x change 12 /4

/07 

## )

Lead $US/tonne 

## ( sourc e London Metals Exch ange 12/4/07 

## )

Post-me eting responses to Pb ANPR – Areas in w h ich EPA solicits co mment

The EPA invites general, specific, and/or t echnical comm ents on all issues discussed in this ANPR, includ ing iss u es related to the Agen cy’s review of the prim ary and secondary Pb NAAQS (sections III an d IV below) and associated m onitoring considera tions (sec tio n V below). EPA also invites comm e n ts on all inf o rm ation, fi ndings, and recomm endations presented in this notice (section VI below) . [pp. 23-24, section II.D.]

B-56Specifically , EPA solicits comments on ...

Primary Standard – Approach for Current Review {III.C.2 - p. 112}

... on the ap propriate weight to b e placed on the results from these {quantitative exposure/risk} assessm ents in ev aluating the adequ acy of the current prim ary standard and in considering alternative standards.

These risk assessments are appropr iate and should be given subs tantial weighting as these are the best that can be accomplished un der the ci rcumstances. Despite the success of this effo rt, this risk assessment should be recognized as lar g ely a mod e ling exer cis e utilizing n u merous assumptions, often based on decades old data a n d empirica l rela tions hips derived from
environmen tal reg imes that no longer exist in the U.S. This approach was necessary and had to be undertaken because the data do not exis t to address th is problem more appropriately. With regard to these sho r tcomings, the discu ssio n s do not sufficiently co nvey the la ck of informa tion and unknowns associa t ed with th e knowledge base of lead in the air, as documented in the AQCD.

... on a number of aspects of the design of the as s e ssm ents and inte rpre tation of the as sessm ent results, including in particular:

(1) the appropriateness of rolling up am bient Pb concentratio ns to sim u late just m eetin g the current s t andard for areas in which curren t co ncentration s are well below the level of
the current s t andard ;

The emiss i o n s picture a n d particula r ly, the spa t ial characterizations and peak-to-mean ratios, used in the roll-up and roll-down c a lculations were based on an industry in a minimal production-mode. There is suggest ive evid e nce that production of base metals and use of lead in consumer products may incr eas e in the for e seeable futu re. As EPA has indicated that it may enterta i n retain ing the current standard, ta ke no action as occurred in 1991, or develop a new standard between the current levels and th e current N AAQS, analyzing the po tentia l impacts under the current standard seems requisite.

Moreover, s h ould the Agency delete the N AAQS, and develo p a HAPs/technology-ba s ed approach and rely on other media controls to reduce risk, emissions and ambient concentrations; this would likely in crease e xposures in areas where new or expanding industrie s lo cate. As suc h , considera tion of th e impacts o f

in creased ambient conce n trations should be in cluded in th e decision-making process.

(2) the use of a proportional m e thod to roll-up and roll-down Pb concentrations to sim u late just

m eeting the curren t and alternative s t andards ;

The methodology should be consistent with the above, but acknowledge the inherent uncertainties, and should bias the analyses to w a rd protectiveness with an appropriate margin of safety. It should also be explicitly noted that the risk assessments are based on current

B-57source, receptor and population configurations . These do not emulate worst-case scenarios that would be used in compliance evaluations for NAAQS p o llutants. Should new sources be developed, the roll-up a n alyses pres ented in the risk assessments lik ely u n der-estima te exposures for the determining allowable emission rates un der a NAAQS scenario. Additionally there is no discussion in any of the documents relating to h o w potential impac ts would be addressed in a HAPs-multi-media strategy.

(3) the categorization and apportionm e nt of poli c y-re levant exposure pathways and policy-relevant background, partic ularly with regard to exposur es related to historically deposited Pb from leaded gaso line and from Pb paint; and

Lead is, and will contin ue to be , a multimed i a multi-sourc e ubiq uitous contamina n t. Multip le effects must be considered in any attainment strategy. Staff has done as good an analysis as can be provided, given the scarcity of data. Shoul d the Agency find tha t these sour ces in whole produce unacceptab l e risk levels, th en a coordinate d stra tegy to reduce exposures should be developed. Control of b o th recent a n d past lead will be r e quisite. Presu m ably, the e ffort required fo r the latter w ill d i minish over-time, a s the older s o urces are r e moved or s t abilized. Control of current sources will be an ongoing obligation.

(4) the weight to be given to risk estim ates derived using various concentration-response
functions.

The model form recommended by CASAC should be given the most weight as it provides a margin of safety appropriate to the state of knowledge. The results fr om the other functions should help frame the margin of safety inco rpor ated into the develop ment of the co ntrol strateg y . Please see the CASAC’s conclusions.

... on the approach of considering exposures and risks resulting from the ingestion of historically

em itted Pb that m a y now be present in indoor d u st and outd oor soil (e.g. , that associated with past use of Pb in gasoline or Pb paint) impact ed by am bient air Pb as being policy-relevant for the purpose of setting a NAAQS.

Consideration of these exposures is requisite to establishing a prot ective health strategy. Remediatio n of past so urces may b e an effectiv e element in an eventual compliance strateg y

. As a result, failure to co nsider thes e sources or relying on a technology-based standard only addressing current sou r ces would no t be efficient or effective.

Primary Standard

– Adequacy of the Current Standard {III.C.3 - pp. 114, 120, 131, 132}... and supporting inform ation on the issue of whether it would be appropriate for EPA to determ ine
that em issions of Pb no longer contribute to air pollution that m a y reasonably be anticipated to endanger public health.

Because the Agency has little knowledge of the ex tent of exposures curr ently in the U.S., EPA could only make this d e ter minatio n if it requir ed that all le ad emis sion s be reduced to zero.

B-58... and supporting inform ation on the extent to whic h reductions in the am bient air Pb standard would benefit public health.

The risk assessment developed indicates that cur r ent lead lev e ls in par tic ular areas likely contribute to an IQ decrement in children livi n g in these ar eas. The extent of continuing exposures in urban areas and the possibility th at lead emissions may in crease in the future indicate tha t this effect ma y manifest in other communities

. Lowering or preventing these

exposures a n d consequent neuro-cognitive effect s would be beneficial. The difficult question is how benefic i al in r e la tion to o t her risk s and expenditures. Please see the CASAC’s conclusions.

... on data or studies that m a y help infor m our understanding of this important param e ter {the air-to-blood relationship}

.

Several studies have add ressed th is factor and Staff has done a good job of identifyin g and comparing these results. It seems clear that th e r a tios repo rted all have site-specific and studyspecific con s iderations related to a host of fac t o rs common to the ubiquitous lead ex posures. The approach used in 1978, clearly underestimated this ratio for air qu ality regimes that followed an d has been inappropriate for decades, CASAC has advised u s ing 1.5 and addressing the uncertainty through applyi ng an appropriate margin of safety.

... on whether the b r oad range of curr ent m u ltimedia Fede ral and State P b contro l pr ogram s, summarized above in section II.C, are sufficient to provide appropriate pu blic health protection in lieu of a Pb NAAQS.

Several non

- air progra m s imp lemented by var i ou s entities have resulted in major r e ductions in lead exposures from non-air sou r ces, and de creases in r e -entra ined or fugitive s o urce emiss i ons. As a result the baseline lead le vel (f ro m non-air sources) has declined dramatically, as noted. CASAC estimated this red u ction as decr easing typ i cal mean blood lead levels fro m 12 μg/dl to 1-1.4 μg/dl. Exposures and blood lea d levels in some areas, however, remain higher as residual lead continue s to circula t e in the environ m ent. Signif icantly les s reduction, however, has been due to lead in air since the 1 990s. Most of the reductions in lead emissions were achieved by curtailment of ind u stry associated with th e economics of mineral industry and consumer goods that utilize lead. No an alyses have been presented in any of the documents regarding th e possibility of increased lead output and emissions.

... on delisting, revocation, and the adequacy of the current standard and the rationale upon which such views are b a sed.

There is overwhelming evidence o f

the adverse effects o f

lead at blood low-levels no ted for young children in the U.S. today. Lead is an ub iquitous contaminant present in several media involved in air-re lated transport an d transf or mation proces ses. There is an overwhelming absence of emissions and ambien t exposure data available to assess how many U.S. children at at-risk today. The EPA should not consider d e leting the NAAQS simply because the Agency has neglected to monitor.

B-59Primary Standard – Elements o f the Standard– Indicato r {III.C.4.a - pp. 135, 136}

... on previous Agency conclusions that the health evidence indicates tha t Pb in all p a r tic le size fractions, not just respirable P b, contributes to Pb in blood and to associated health effects.

The Agency should continue to assess and moni tor all siz e f r

actions thr o ugh direct or surrogate methods.

... and inform ation that would help infor m such analyses {of Pb particle size relationships} and the Agency’s views on the indicator for the prim ary Pb NAAQS.

Please see the CASAC’s conclusio n s.

Primary Standard - Elements of the Standard– Averaging Time and Form {III.C.4.b - pp. 143}

... on a range of options, including the recomm enda tions in the Staff Paper that include changing the averaging tim e to m o nthly, with a for m of ma xim u m or second m a xi mum , as well as

reta ining the quarte r ly av eraging tim e.

Please see the CASAC’s conclusio n s.

... on the options of changing the form to apply to a th ree-y e ar period as well as retaining a single-year period.

Please see the CASAC’s conclusio n s.

... on these ranges of averaging tim es and form s as well as v i ews and rela ted ra tiona le s that

m i ght support alternative options.

Please see the CASAC’s conclusio n s.

Primary Standard - Elements o f the Standard –Level {III.C.4.c-p p. 143, 148, 149, 150, 160, 161}

... on a wide range of possible options ... range f r om lowering the stand a rd, to the le vels

recomm ended by CASAC and the OAQ PS Staff paper or lower, as well as on other alternative levels, up to and including the current level, and the rationale upon which such views are based.

Lead should be retained as a criteria air pollu tant; (2 ) the lo wering of th e Lead NAAQS substantia lly below the current valu e is fully

- ju stified; and (3) a new in dicator for lead should be develop ed. Please see the CASAC conclusio n s.

... on the appropriateness of using a m ean or individual target blood Pb value of 10 μ g/dL as the foundation for deriving a level fo r the prim ary Pb standard.

B-60Totally inap propriate, p l ease see the CASAC’s conclusions.

... on m ean target blood Pb levels as well as other factors that would be important in applying the 1978 fram e w ork {using the current evid e nce}

.

The new standard should recognize the benefits of lowering blood lead levels a c ross the entire population, as well as preventing threshold conc entrations for the most-exposed ind i viduals. Please see the CASAC’s conclusio n s.

... on the definition and appropriate values f o r th is param e ter {the nonair (background) contribution to total blood Pb}

The NAAQS compliance strategy sh ould consider all sources of lead, coordinate with other federal, S t ate and local programs effecting redu ctions in other media and include past-air impacts and exposure reduction stra tegies directly in the NA QQS.

... and supporting inform ation rega rding the air-to-blood ratio and differences in the available
estim ates.

Please see the CASAC’s conclusio n s.

... on all of these factors {important to applica tion of 1978 framework}

... on the 1978 standard setting framework and on a lternate approaches and the factors that are relevant to those approaches.

Please see the CASAC’s conclusio n s.

... on levels of IQ loss considered to be si gnificant from a public health perspective.

Please see the CASAC’s conclusio n s.

... on the magnitude of IQ loss associated with exposures to am bient Pb by the pathways catego r ized as “recent air” in the risk assessm ent describ e d in this notice that are considered to be significant from a public health perspective.

Please see the CASAC’s conclusio n s.

... on the approach of adopting a public health polic y goal of lim iting policy-relevant air

exposure su ch that the increm ental blood Pb le v e l (and the associated res u lting IQ los s ) are below a specified level (e.g., to a m a gnitude of 0.5 or 1 μ g/dL, or other alternative values).

Please see the CASAC’s conclusio n s.

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### Dr. Ba rbara Zi elinska

THE US E P A LE AD NAAQS A DVANCE NOTICE O F PROPOSED RULE MAKING (ANPR)

Comments on Section V: Considerations fo r Ambient Monitoring

.

Barbara Zielinska

My general comment regarding the Pb ANPR is that if this d o cum e nt is designa ted to repla ce the Staff Paper in the future, I would expect it to be more conclusive and not only lim ited to a

restatem ent of the Agency’s Staff Paper findi ngs and CASAC recomm endations. Specifically, one would expect som e sort of justifiable recom m e ndations as to th e ind i cato r , lev e l, statistica l
for m , and averaging tim e of the standard and not only an inv i tation f o r a ll inte rested pa rties to
subm it their recomm endations. Af te r all, this do cum e nt was for m ulated after several years of gathering and synthesizing new sc ie ntif ic inf o rm ation on this s ubject and at th is stage the Agency should be able to for m ulate som e conclu sions regarding the range of the Pb standard. Saying tha t all po licy op tions a r e s till on the ta ble, from delisting Pb as a NAAQS, ke eping the present level of 1.5 μg/ m 3 or going down to 0.02 μg/m 3 , is like starting th e whole pro cess all over again.

My specific comments are lim ited to Section V, Considerations for Am bi ent Monitoring, as requested by Dr. Rogene Henderson. For this Se ction, the Agency invites comm ents regarding (a) samp ling and analysis m e thod; (b) network de sign; (c) sampling schedule; (d) data handling; and (e) m onitoring for secondary standard.

Regarding (a), the CASAC Pb Pane l had strongly enc ouraged the Agency in its previous letter to
the Adm i nistrator (Henderson, 3/27/07) to consid er revising the indicator for Pb sa m p ling from TSP to low volum e PM 10

. The current ANPR and associated support docum ents (m e m os by Cavender and Schm idt 11/26/07, and Ca m a lier and Ri ce, 11/29/07), reviewed the collocated PbTSP and Pb-PM 10 data and evaluated the precision and bias of the Pb-TSP m onitors. Although the high-volum e TSP methods have an average pr ecision of 11.7 % with a standard deviation of 18.6 %, it is evident from Figure 1 of Ca m a lier a nd Rice m e mos, that at the relevant am bient concentrations below 1 μg/m 3 this precision is much worse ( and this is after exclusion of 21% of

m easure m ents which were below MDL of 0.01 μg /m 3). The m e mo comp aring Pb-TS P and PbPM 10 data also shows that the relation between these two m eas urem ent m e thods is m u c h worse at lower concentrations (below 0.03 μg/m 3 ). Both, the average samp ling bias (based on the flow audits) and the bias for lab analyses were low (i n the range of 1%), so they do not contribute signif i can tly to the ove ra ll pr ecis i on of Pb-TSP monitors. T h ese pieces of infor m ation taken together indicate som e problem s with TSP m onitors . The variability of TSP sam p ler cut size, the higher m i nimum detection lim it (MDL) associated with TSP-Pb samp ling, and the relatively poor precision at lower Pb concentr ations all contribute to variability in the TSP-Pb indicator. In my opinion, PM 10 sa mp lers are preferred over the m u ch less reliable, old technology, TSP

samp lers. PM 10 sam p lers’ inlet is much better characterized , they are us ed in m a ny sam p ling locations and they are utilized for m a ny other m easurem ents, includ ing a s u ite of elem ents, in
addition to P b. The TSP monitors are used for lead only and they have been discontinued in

B-62m a ny sa m p l i ng locations. I do not recomm end r e taining hi-volum e Pb-TSP m onitors, neither investing in the developm ent of lo w-volum e, sequential Pb-TSP sa m p lers.

The m e mo “ S umm a ry of m e thod detection lim its ” by Rice, indicates that the current F R M analytical method (based on atom ic absorption) has the highest MDL. Since this MDL was
estim ated for high-volum e TSP sa mplers, if the low-volum e samp lers are to be used in the future, the analytical MDL would be even higher (per m 3 ). For these re asons, I wou l d ra ther

recomm end more sensitive and widely used an alytical m e thods, such as X R F or ICPMS. Clearly, ICPMS has a superior sensitivity of 0.00001 μg/m 3 ( f or high volum e samp le s). However, XRF (which is less expensive) m a y be suf f i cient f o r the lowest alte rnative NAAQS –
based on m y experience, the MDL for the equi valent high-volum e sa mp le would be 0.005 μg/m 3

Regarding (b), I favor the option nu mber 4: to u tilize the cu rrent PM 10 network. I’m not particularly concerned about finding an accep tab l e reg i onal o rsite-specific correlation of Pb-TSP
and Pb- PM 10 , since I do believe that Pb-TSP ar e much less accurate than Pb- PM 10 and I don’t think that the Pb-TSP method can serve as a “g olden standard”, especi ally if the Pb NAAQS will be tightened consid erably. S i nc e PM 10 m onitors m a y not be curren tly located near the large
Pb e m ission sources, the additional m onitors m a y be utilized at thes e specif ic sites. Also, since Pb levels and particle size range s are expected to be higher n e ar m a jor Pb em ission sources, PbTSP m onitors can be used, in addition to Pb-PM 10 to estab lis h the equiv a lency f a cto rf o r these specific s ites. There are only a few such m a jo r Pb em ission sources in the U.S. anywa y.

Regarding (c), samp ling schedule, if the m ont hly averaging period is se le cted, th e sa mpling frequency should be increased from 1-in-6 to at least 1-in-3 samp ling schedule. This would yield sufficient amount of samples per averaging peri od with 75% comp leteness. However, I’m not feeling very strongly about m ont hly averaging period. I think qua rterly averaging period could be accep table as well, es pecially a t sites th at cons isten tly f a ll below the s t andard.

Regarding (d), data handling, I assum e that that the third bullet should sp ecify that 50% of the expected number of sa mples is needed for a m ont h to be considered comp lete, if daily samp ling schedule is adopted. Otherwise, for 1-in-3 samp ling schedule, 75% should be required.

Regarding (e), m onitoring for the se condary NAAQS, I think that the Pb-PM 2. 5 data from the IMPROVE network should be utilized to track cha nges in a m bient Pb c oncentr ation s in rur a l an d

rem o te areas. Since it is very li kely that in these rem o te locations near ly a ll ( i f not all) Pb is present in the PM size range below 10 μm , PM 10 monitors can be used to develop the relationship between Pb- PM 10 and Pb- PM 2. 5 . Likewise, the data from the National Water Quality Ass e ssm ent (NAW QA) and Geochem i cal Landsc a p e proje c t sh ould be used to tr ack the concentrations of Pb in wate r bodies and soil, respectively.

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