is irrelevant, and therefore immaterial, with regard to EPA's final
tolerance revocation. The Petitioners have not responded to EPA's
explanation in the final rule of the reasons that the information and
methodology on which they relied to estimate a 4% PCT was flawed. As
discussed in the final rule, EPA had assumed that the data on which
they were relying was sales data, and so the resubmission of the
information sent in after the close of the comment period only confirms
that the Agency's analysis was correct; it does not rebut EPA's
substantive concern that such information is insufficient to support
the conclusions the Petitioners assert. In essence, the Petitioners
ignored EPA's extensive analysis of this issue in the final rule and
simply refiled their comments on the proposal as if EPA's determination
in the final rule did not exist. The statute, however, requires that
objections be filed on the final rule not the proposal. By ignoring
EPA's final rule on this issue, Petitioners have failed to lodge a
relevant objection. When an objector does not challenge EPA's
conclusions in the final rule, but merely reiterates comments made on
the proposed rule, without submitting some evidence that calls EPA
final rule conclusions into question, the objector has not raised a
live controversy as to an issue material to the final rule (See 73 FR
42698-42699 (July 23, 2008) (denying several NRDC hearing requests
because the objections were based on EPA's preliminary DDVP risk
assessment, rather than the revised risk assessment published with the
final order); 53 FR 53176, 53191 (December 30, 1988) (where FDA
responds to a comment in the final rule, repetition of the comment in
objections does not present a live controversy unless the objector
proffers some evidence calling FDA's conclusion into question)).
    An additional flaw in this objection is that the proffered evidence
is untimely and insufficient. Neither the proposed registration
amendments nor the evidence submitted as part of this objection,
including the modeling in Exhibit 15, was provided to the Agency during
the comment period. The modeling in Exhibit 15 was available, because
it was summarized in Petitioners' comments; however the underlying
modeling was withheld. Equally, there is no evident reason that the
sales data could not have been submitted as part of the Petitioners'
comments. Petitioners relied on this data to perform analyses completed
in 2006-2007, for purposes of the January 2008 SAP review of the draft
carbofuran NOIC, so the information was available long before their
comments needed to be filed. Accordingly, as discussed in Unit VI.D,
this information is not appropriately considered as a basis for
justifying a hearing on its final rule. Moreover, as explained below,
because no evidence was submitted in support of the newly proposed use
tracking system, reliance on that proposal to support a low PCT
constitutes nothing more than an allegation. This is not an adequate
basis on which to grant a hearing (40 CFR 178.32(b)(2)). Finally, to
the extent this objection relies on Petitioners' recently proposed risk
mitigation measures, as discussed in Units VI.C and D, objections and
hearing requests based on these new risk mitigation measures are not
appropriately considered at this stage of the administrative process,
and are denied as immaterial (40 CFR 178.32(b)(3)).
    iii. Denial of objection. While the Agency typically uses PCT in
developing estimates of pesticide residues in food, this is entirely
different than developing estimates of the percent of a watershed that
is treated for purposes of estimating drinking water exposures. Food is
generally randomly distributed for sale across the nation without
regard to where it is grown. This tends to even out any PCT variations
that may arise on local levels. By contrast, the source of water
consumption (and consequently exposure) is localized, either in a
private well or a community water system. The PCT in any watershed will
therefore directly impact the residues to which people living in that
watershed will be exposed.
    For this reason, among others, for drinking water exposure
estimation, the Agency assumes that 100% of the cropped area (or 100%
PCT) is treated with the pesticide. EPA also makes this assumption due
to the large uncertainties in the actual PCT on a watershed-by-
watershed basis. EPA included an extensive discussion of the
uncertainties in PCT and how they impact drinking water exposure
assessment in its proposed rule (73 FR 44834) and in a background
document provided to the SAP considering the draft carbofuran NOIC
(Ref. 45). Because usage is often not evenly distributed across the
landscape, due to differences in factors like pest pressure, local
consultant recommendations and weather, it may be much higher in some
areas. Further, temporal uncertainties can result in changes in use
that might be driven by weather, changes in insect resistance over
time, and changes in agronomic practices. To date, methods that account
for this uncertainty, given the nature of the available data, have not
been developed. Consequently, EPA cannot accurately estimate a
drinking-water watershed scale PCT that, when used in a quantitative
risk assessment on a national or regional basis, standing alone,
provides the necessary level of certainty to allow the Agency to
confidently conclude that exposures will meet the FFDCA section 408
safety standard.
    In most cases, EPA agrees that it is unlikely that 100% of the crop
will be treated with a single pesticide in most watersheds,
particularly in larger watersheds. However, for small watersheds, it is
reasonable to assume that an extremely high percentage of the crops in
the watershed may be treated.
    Moreover, EPA has an obligation to evaluate all legally permitted
use practices under the label, and to ensure that all such use meets
the requisite statutory standards, not simply to base its decisions on
the practices the majority might typically use. The September 2008
proposed label, submitted during the comment period, imposes no
restriction on the application of carbofuran related to whether a
particular percent of the watershed has been treated. Thus, even with
the restrictions on FMC's September 2008 labels, it remains legally
permissible for 100% of the watershed to be treated with carbofuran.
    Nor is EPA aware of an enforceable mechanism to ensure that farmers
applying pesticide to their individual fields will have the ability to
indendently determine whether a particular percentage of the watershed
has been treated. There are significant practical difficulties inherent
in implementing such label directions, as

they force individual growers to have continual knowledge of the
variances of the behavior of other farmers across the entire watershed.
While for small watersheds that involve only one or two farms it might
be feasible for neighbors to independently coordinate applications with
respect to adjacent fields, for larger watersheds or for smaller
watersheds with multiple farms, the practical difficulties increase
significantly. And as explained below in Unit VI.F.2.D, significant
questions remain regarding the efficacy of Petitioners' proposed use
tracking system.
    However, in the final rule, EPA conducted a sensitivity analysis to
explore the impact of the PCT assumption on dietary risk using an
assumed 10% PCT, a figure proposed previously by FMC (74 FR 23065-
23066). The results of that analysis demonstrated that even at these
low percentages, which may significantly underestimate exposures,
particularly in small watersheds, carbofuran exposures from drinking
water contribute significantly to children's dietary risks. EPA
conducted a similar sensitivity analysis for the final rule, discussed
below in Unit VI.F.3, which demonstrates that even assuming that a low
percentage of a watershed is treated, exposures will still be unsafe
for infants.
    Since EPA's 2006 determination that carbofuran does not meet the
safety standard, FMC has submitted three assessments that relied in
part on what they refer to as ``county-level usage data'' (Refs. 29,
74, and 89). Based on the information provided with the objections, the
original source of the ``county-level usage data'' is sales data,
apparently collected at the distributor level. The Petitioners claim to
have augmented these sales data in an unspecified manner, by
incorporating information from the distributors, which was used to
allocate carbofuran usage at the county level. In their comments on the
proposed rule, the Petitioners provided maps representing county level
and watershed-scale use estimates, but did not provide the actual usage
estimates in any clearly understandable format.
    The Petitioners did submit these sales data as part of their
objections, but have provided only a limited description of how these
data were collected and no description of how they were actually
analyzed or validated; what was characterized as ``careful and proven
techniques to capture this data'' were not described. The method used
to attribute carbofuran sales to counties was not described. Nor have
they explained what is meant by negative usage estimates.
    The Agency agrees that county-level use data would be useful in
generating reasonable estimates of PCT that might be appropriately used
in drinking water assessments. However, no usage data have been
provided. Rather, the Petitioners only provided county-level use
estimates for Illinois, although they have not submitted the analyses
that presumably are the basis for the estimates. County-level estimates
to support other risk assessments have not been submitted by the
Petitioners. Further, the Petitioners have provided limited
characterization of the source data, noting that these data were
derived from FMC billings and ``EDI data'', but they did not provide
either the billings or the EDI data, nor explain how they were
collected.
    There are two major problems in equating sales information with use
information: (1) Mapping the point and time of sale to the point and
time of use and (2) allocating the amount sold across the crops on
which it can be used. The submission did not explain how either of
these two problems was resolved.
    The first problem is highlighted by the fact that for some county/
crop/year combinations in the submitted tables, estimated usage is
negative. Use of a pesticide clearly cannot be negative, but sales at a
particular point and time can be negative because buyers can return
unused product. The fact that some usage estimates are negative
suggests that buyers are returning carbofuran product purchased in an
earlier time period or from another location. But if farmers are
returning carbofuran purchased in a previous time period, any
assessment must also account for the possibility that they also could
use stocks purchased previously. Thus, use in a given year may be
greater than sales in that year. Similarly, if farmers are returning
carbofuran purchased in another location, it must be recognized that
they could be using carbofuran purchased in another location. Thus, use
in any given county or watershed could be greater than sales in that
locality. That is, regardless of whether the issue is use over space,
time, or both, the results are that usage will be underestimated in
some localities. Further, zeroing out the negative values will not
result in appropriate estimates; the negative usage estimates merely
make the problem manifest. Even total sales at a point in time may
underestimate actual use.
    The second problem arises with the allocation of product sales
across the crops on which it can be used. The data provided as part of
the objections were aggregated for all crops, including crops on which
use is no longer allowed, such as cotton or alfala; the data were not
collected based on the individual crops. No explanation is provided to
indicate how the Petitioners divided the quantity sold between the
amount used on cotton, on alfalfa, and on all other crops. Since part
of the purpose of the Petitioners' assessment is presumably to show
that eliminating the use on the cancelled crops, such as alfalfa, will
sufficiently reduce any risks, it is critical to know how they
determined the amount used on alfalfa as opposed to other crops, and it
is difficult to imagine how this could be done with any accuracy. For
example, one could assume that the chemical is used on equal proportion
of all crops, but there is no basis for such an assumption. It might
not matter if all EPA were interested in was the total amount used in
an area, but this is not useful for purposes of assessing the risk on a
smaller scale, such as in the present case.
    The method the Petitioners used to generate use estimates from the
sales data does not account for the uncertainties described above nor
for the potential for use to be locally concentrated due to pest
pressures. The method that is summarily described as having been used
to allocate county-level usage estimates to watersheds appears to be
similar to a method that has been used by others to calculate ``best-
estimate'' county-level PCT (Ref. 73) to map nationwide pesticide
usage. However, these methods are not appropriate for calculating PCTs
for surface drinking water sources or watersheds that drain to
community water systems, because they do not adequately account for the
uncertainty in the data at the appropriate spatial scale. This
methodology produces an estimate that is a measure of central tendency
and, as such, roughly half the estimated values will underestimate the
PCT. Furthermore, because pesticide use varies from year to year, and
can in some cases be patchy, with high levels of use in small areas and
little use in most areas, the underestimates of PCT can be substantial
in small watersheds. As previously noted, methods for calculating PCT
that account for these uncertainties have not been developed.
Accordingly, EPA denies this objection.
    b. Objection/hearing request subissue: Results of FMC modeling. The
Petitioners claim that the prior surface water assessments submitted to
the Agency demonstrated that carbofuran concentrations in surface water
were not expected to exceed 1.1 ppb. They claim

that these studies provide further confirmation of the results of the
new modeling conducted to support their objections, which also
concluded that concentrations would be less than 1.1 ppb. In support of
this objection, the Petitioners reference the previously submitted
studies, along with the modeling provided in Exhibit 15. The modeling
in Exhibit 15 appears to be the modeling that was originally summarized
in their comments, but that the Petitioners withheld. The modeling was
also supplemented to account for the newly proposed registration
amendments submitted as part of the objections.
    i. Background. In their comments, the Petitioners alleged that the
results of their modeling showed that concentrations of carbofuran in
surface water would not exceed 1.1 ppb. The comments referenced two
surface water assessments that they had submitted to the Agency prior
to the proposed tolerance revocation: a surface water assessment based
on an Indiana Community Water System (CWS) (Refs. 89 and 90) and an
assessment based on the Watershed Regressions for Pesticides (WARP)
model. They also summarized additional surface water modeling that had
been conducted to support their comments on the proposed rule, a
Nationwide Community Water System Assessment (Ref. 57), but did not
submit the actual modeling, or identify or describe in detail the model
on which they relied.
    In the final rule, EPA explained the flaws in all of the
Petitioners' assessments that caused the Agency to reject the studies'
conclusions. For the two assessments that had actually been submitted
to the Agency, EPA was able to definitively explain the flaws. With
respect to the Nationwide CWS modeling that was summarized in their
comments, EPA evaluated the modeling based on the information it was
able to glean from the description provided in the comment discussion.
    ii. Denial of hearing request. A hearing is denied on this subissue
because EPA has concluded that Petitioners' objection on this issue is
irrelevant, and therefore immaterial, with regard to EPA's final
tolerance revocation regulation (40 CFR 178.32(b)(3)). In the final
rule, and in other rulemaking documents, EPA provided a detailed
explanation of the bases for its conclusions that the previously
submitted assessments were invalid (74 FR 23062-23064 (May 15, 2009)).
Petitioners have not challenged EPA's explanation, nor explained how
the resubmission of the same studies addressed the substantive issues
EPA raised. Because Petitioners ignored EPA's extensive analysis of
this issue in the final rule, they have essentially refiled their
comments on the proposal as if EPA's determination in the final rule
did not exist. The statute, however, requires that objections be filed
on the final rule, not on the proposal (21 U.S.C. 346a(g)(2)). By
ignoring the EPA's final rule on this subissue, Petitioners have failed
to lodge a relevant objection. Petitioners' resubmission of the exact
same information does nothing to call EPA's conclusion into question,
which is what is required to maintain their claim at this stage of the
proceeding. When an objector does not challenge EPA conclusions in the
final rule, but merely reiterates comments made on the proposed rule
without submitting some evidence that calls EPA final rule conclusions
into question, the objector has not raised a live controversy as to an
issue material to the final rule. (See 73 FR 42700-42701 (July 23,
2008) (hearing request denied where NRDC failed to challenge EPA's
conclusion that challenged study is consistent with several other
studies, but merely reiterated assertions from its original petition
that the study is not representative); 53 FR 53176, 53191 (December 30,
1988) (where FDA responds to a comment in the final rule, repetition of
the comment in objections does not present a live controversy unless
the objector proffers some evidence calling FDA's conclusion into
question)).
    With respect to the modeling submitted in Exhibit 15, this evidence
is untimely. The modeling submitted in Exhibit 15 appears to be a
fuller description of Petitioners' National CWS Assessment, which was
described but not provided as part of their comments on the proposed
rule. The modeling also has been revised to account for the newly
proposed risk mitigation measures. However, even with the greater
detail provided, the information contained in Exhibit 15 still fails to
address many of the deficiencies EPA identified in the final rule. For
example, although some further detail has been provided of how the
Petitioners modeled the vegetated buffer strip, the complete
information EPA would need to assess the modeling was not provided; the
material provided is insufficient to understand how the simulations
were performed or how the simulations were parameterized. Nor have the
Petitioners submitted the inputs used in modeling estimated
concentration from spray drift. As discussed in Unit VI.D, because the
modeling in Exhibit 15 was not provided during the comment period, and
to the extent that the detailed information EPA identified as lacking
in the final rule has still not been provided, the evidence submitted
in Exhibit 15 is not appropriately considered as a basis for justifying
a hearing on its final rule. And in the absence of this evidence, this
objection consists of mere allegations and general denials, which are
inadequate to justify a hearing (40 CFR 178.32(b)(2)).
    Further, to the extent that this objection relies on the ``no
application buffers,'' or the proposed use tracking system newly
submitted as part of their objections to support the models' assumption
of a low PCT, the hearing request is denied as irrelevant, and
therefore immaterial, to EPA's determination in the May 15, 2009 final
rule, for the reasons discussed in Unit VI.C. Petitioners are actually
not objecting to the conclusions in EPA's final rule; rather, they are
suggesting that EPA might reach a different result in a different
factual scenario. Objections, however, must be directed ``with
particularity [at] the provisions of the regulation or order deemed
objectionable'' (21 U.S.C. 346a(g)(2). And, as explained below, because
no evidence was submitted in support of the newly proposed use tracking
system, reliance on that proposal to support a low PCT constitutes
nothing more than an allegation. This is not an adequate basis on which
to grant a hearing (40 CFR 178.32(b)(2)).
    iii. Denial of objection. To the extent this objection relies on
Petitioners' newly submitted registration amendments, the objection is
denied as immaterial. EPA also denies the remaining objections because,
based on its review of the submitted modeling, EPA has concluded all of
the modeling has substantial flaws that render the model results
invalid. EPA has previously reviewed these assessments, and provided a
detailed explanation of the reasons for the Agency's conclusions, most
recently, in the final rule and the associated response to comments (74
FR 23060-23064, Ref. 84). EPA's reasoning is summarized briefly below.

Indiana CWS Assessment

    EPA has previously reviewed the Indiana surface water assessment,
and has provided comments on that submission (Ref. 45), many of which
were reiterated at length in the final rule and response to comments
documents (74 FR 23062-23064, Ref. 84). The Petitioners originally
submitted this study to demonstrate that ``EPA's standard index
reservoir scenario

overestimates surface water concentrations compared with expected
concentrations in actual Indiana CWS where carbofuran is used.'' The
Index Reservoir is designed to be used as a screen, and as such,
represents watersheds more vulnerable than most of those that support a
drinking water facility. It is thus protective of most drinking water
on a national basis. That, however, does not mean that EPA believes
this scenario overestimates concentrations for all drinking water
reservoirs. EPA agrees that it is an appropriate refinement to simulate
local and regional watersheds, and has in fact done so (Refs. 44, 46,
47, 48, and 84). However, for the reasons discussed below, EPA does not
believe that the Petitioners' assessment demonstrates that carbofuran
concentrations will not exceed 1.1 ppb in Indiana surface water sources
of drinking water. Even accepting the Indiana surface water assessment
at face value, the estimated 1-in-10-year peak concentrations at some
facilities were as high as 6.88 [micro]g/L, and these concentrations
substantially exceed the 1.1 ppb concentration the Petitioners now
claim represent reasonable estimates.
    The study also fails to support the Petitioners' other conclusions.
The study was originally intended to demonstrate two points: (1) That
the vulnerability of the Indiana CWS ``brackets'' the Index Reservoir,
and (2) that the concentrations they estimated for these locations are
significantly less than EPA estimates. Regarding the vulnerability of
the CWS, the assessment describes their approach for modifying the
parameters of the Index Reservoir scenario to represent 15 reservoir-
based watersheds in Indiana cropped in corn. The study indicates the
Petitioners have included data that, based on EPA's review of these
submissions, are not available at the appropriate scale to determine
all site-specific parameters. The Petitioners modified some of the
parameters based on available data to represent more localized
conditions that are more or less vulnerable than for the Index
Reservoir. From the description, the Petitioners' approach is similar
to the methods that EPA uses to develop new scenarios, in that soil and
weather data are varied in order to represent different locations.
However, for other parameters, EPA believes the modifications are
inconsistent with fundamental assumptions upon which the modeling is
based. In previous submissions to the Agency, FMC has described that
they have made modifications to scenarios to reflect local conditions
of each CWS in Indiana by modifying the soil and weather data and
altering the ratio of watershed drainage area to the reservoir capacity
(Ref. 89). EPA agrees that soil and weather data can be modified to
reflect conditions at local watersheds. However, EPA disagrees that
altering the ratio of watershed drainage area to the reservoir capacity
(i.e., the DA/NC) is a reasonable modification.
    The DA/NC parameter is associated with increased concentrations in
drinking water reservoirs to a certain point. The Petitioners adjusted
their EDWCs for each drinking water facility by a factor representing
the ratio of the DA/NC for each reservoir divided by the DA/NC for the
Index Reservoir (which is 12). EPA does not believe this is appropriate
for two reasons. First, the relationship between concentrations and the
DA/NC is not strictly linear. Small DA/NCs imply a small watershed
combined with a large reservoir. As the DA/NC increases, the relative
watershed size increases, and thus the runoff volume going into the
reservoir also increases. This is also means the reservoir's ability to
dilute the runoff decreases; the result is that concentrations increase
with an increase in the DA/NC. However, at some point, the runoff
volume exceeds the reservoir capacity, and rather than increasing the
pesticide concentration, the excess runoff flows out of the reservoir,
carrying the pesticide with it. Thus, because pesticide concentrations
are not linearly related to the DA/NC, it is not appropriate to
multiply the model output by a linear DA/NC adjustment factor.
Secondly, the PRZM model, which is used to simulate the watershed for
the Index Reservoir, is a field-scale model. As the watershed size (and
the DA/NC) increases, assumptions upon which PRZM relies (namely:
uniformity of soils, equal and simultaneous movement of runoff to the
reservoir, and uniform weather across the watershed) no longer hold and
the model becomes less valid for simulating the runoff processes. The
geometry of the Index Reservoir was chosen partly to avoid these two
limitations (Ref. 43).
    The study authors also calculated their own PCA values \19\ for
this assessment. EPA uses the maximum PCA calculated for any HUC8 (8-
digit hydrologic unit code) watershed in exposure estimates. HUC8s are
cataloging units for a watershed developed by the USGS and are used as
surrogates for drinking water watersheds. The process by which PCAs
were developed and how they are used by the Agency has been vetted with
the FIFRA SAP (Refs. 30 and 31). The Agency has developed PCAs for four
major crops--corn, soybeans, wheat, and cotton--and uses a default PCA
based on all agricultural land for characterizing other crops. The
Agency has also calculated regional default PCAs for use in
characterizing regional differences in drinking water exposure. EPA
limited further development of PCAs for additional crops in response to
the FIFRA SAP peer review, which concluded that the data were not
available at the appropriate scale to do so. The Petitioners'
assessment estimated PCAs for specific watersheds in Indiana, but did
not provide sufficient detail in their descriptions of how they
calculated those PCAs to enable EPA to assess their validity.
---------------------------------------------------------------------------

    \19\ The PCA is the fraction of the drinking water watershed
that is used to grow a particular crop.
---------------------------------------------------------------------------

    Regarding the statement that the concentrations estimated for the
study locations in Indiana are significantly less than EPA estimates,
EPA has determined that the Petitioners included an adjustment factor
to account for the percent of a crop that is treated with carbofuran.
As previously discussed, EPA does not believe that it is appropriate to
base its aggregate risk estimates on PCT within watersheds. This is
because data and/or methods are not available that would allow EPA to
develop PCT at the watershed scale with the necessary level of
confidence to allow EPA to make a safety finding. The PCT factors that
the Petitioners applied would generate significantly lower
concentrations than those estimated by EPA.

WARP Assessment

    EPA has reviewed the WARP assessment previously and has provided
comments on the submission (Refs. 45 and 86). The WARP model has not
been fully evaluated for quantitative use in exposure estimation by the
Agency, although it has been preliminarily reviewed by the SAP (Ref.
32). EPA used WARP to select monitoring sites for the herbicide
atrazine, based on predicted vulnerability of watersheds to atrazine
runoff within the corn/sorghum growing regions. EPA presented its
approach to the FIFRA SAP in December 2007. The SAP report concluded
that ``WARP appears to be a logical approach to identify the areas of
high vulnerability to atrazine exposure,'' endorsing EPA's use of this
tool only for atrazine, and for the limited purpose of designing a
monitoring program. The SAP noted that the most important explanatory
variable with WARP was use intensity, which underscores the

importance of having the most accurate data for this parameter.
    WARP is a regression model developed by the USGS to estimate
concentrations of the pesticide atrazine in rivers and streams. As a
regression model, it is based on monitoring data from 112 USGS NAWQA
monitoring locations. WARP does not directly estimate daily
concentrations, but predicts the percent of the time in a randomly
selected year that concentrations of the pesticide are less than a
specified value, with a specified level of confidence. USGS attempted
to develop an approach to estimate annual time series for other
pesticides, and concluded that ``further data collection and model
development may be necessary to determine whether the model should be
used for areas for which fewer historical data are available * * *
Because of the relative simplicity of the time-series model and because
of the inherent noise and unpredictability of pesticide concentrations,
many limitations of the model need to be considered before the model
can be used to assess long-term pesticide exposure risks'' (Ref. 92).
    The Petitioners had previously relied on their WARP assessment to
support the conclusion that the ``maximum 1-in-10-day estimated
concentrations of carbofuran at the 90th percentile level in Illinois,
Indiana, Iowa, and Nebraska * * * will be less than or equal to 0.3687
ppb.'' This is erroneous. WARP does not provide direct estimates of
return frequency, i.e., 1-in-10 days, but rather percentiles of the
expected distribution of measurements. This may be similar but not
identical to the return frequency expressed as a percentile, depending
on the number of measurements used to support the regression. EPA
lacked the information necessary to determine whether the contractor
calibrated the model correctly. However, taking the conclusion at face
value, the value the Petitioners predicted using WARP, 0.3687 ppb,
appears to represent the maximum of the estimated values of the annual
90th percentile among all the sites evaluated. Such a site would be
expected to have higher concentrations than 0.3687 ppb about 37 days a
year (10% of the year). Generally, the 90% prediction intervals tend to
be about plus or minus an order of magnitude. Thus, roughly 5% of such
sites could have about 37 days a year greater than about 3.7 ppb, or
over 3-fold higher than the 1.1.ppb concentrations the Petitioners now
claim will be the maximum concentrations in surface water.
    The Agency also disagrees that the differences between the
Petitioners' and EPA estimates are only due to Petitioners' use of
county-level use estimates. Most importantly, the Petitioners relied on
estimates of 1-in-10-day concentrations, rather than the 1-in-10-year
peak concentrations estimates used routinely by EPA. 1-in-10-day
concentrations are not the measurement endpoint EPA uses for human
health risk assessment and are not appropriate for estimating drinking
water exposure. The Agency uses 1-in-10-year peak concentrations for
screening level assessments, and the full time series (typically 30
years) of daily concentration values for refined assessments. EPA's
reliance on the 1-in-10-year peak concentration has been reviewed and
approved by the FIFRA SAP (Ref. 30).
    A concentration that occurs 1-in-10 days occurs 350 times as often
as a 1-in-10-year event. Using this value instead of the one EPA used
would result in significantly lower estimates of pesticide water
concentration and human exposure. For example, EPA's estimate of the 1-
in-10-year peak concentration from the simulation of corn in Kansas
with a 300 ft buffer was 31.8 ppb. By contrast, EPA's estimate of the
1-in-10-day concentration from the same simulation was 4.5. Use of the
1-in-10 day concentration to assess dietary risk would be inconsistent
with the SAP's advice and EPA's typical practice, as well as with EPA's
statutory requirement to protect human health.
    EPA disagrees with the Petitioners' claim that ``the extreme nature
of a 1-in-10-year event would result in dilution effects that cancel
out any increased loading.'' The Index Reservoir scenario has been
validated against monitoring collected at the site it was designed to
represent, Shipman City Lake in Illinois (Ref. 43). This assessment
showed that the 1-in-10-year event EPA modeled was similar in magnitude
to the peak value of the pesticide concentrations shown in 5 years of
monitoring data collected at that site. The 1-in-10-year peak
concentration calculated for that pesticide (not carbofuran), using the
Index Reservoir was 33 ppb, while the peak value from 5 years of
monitoring was 34 ppb.
    EPA cannot determine the validity of the use intensities assumed
for the Petitioners' assessment. The source of county level use data
appears to have been sales data at the distributor level, similar to
the data provided in the Petitioners' November 7, 2008 submission.
However, as previously explained, the method chosen to estimate county
level use estimates from the sales data was not provided. The county
level estimates used in the assessment for 2002 to 2004 for Illinois
were provided in a table. These estimates for each county were averaged
over the 3 years for input to the model. A summary description of how
watershed-scale use estimated from county level use data was provided,
but because the sales data for the individual crops and the method that
was used to generate county level estimates were not available, the
validity of this assessment cannot be evaluated.

Nationwide CWS Assessment

    EPA has previously reviewed the Petitioners' ``Nationwide CWS
Assessment'' and provided a response to the submission as part of the
final rule and Response to comments (Ref. 45). As a preliminary matter,
this assessment only included use intensity for reservoir-based
systems, and excluded use intensity for all stream- or river-based
systems from their assessment. Therefore, this assessment provides no
evidence to demonstrate that carbofuran can be safely used in stream or
river-based community water systems.
    Similar to the Indiana CWS study discussed above, this study relied
on county-level usage estimates to estimate use intensity. The National
CWS Assessment concluded that a use intensity below 2.1 lbs a.i/mi\2\
would assure that surface water concentrations will be below the level
of concern.
    To evaluate the study, it is therefore important to understand how
the use intensities were derived. The Petitioners' methods have been
poorly described, but EPA has been able to piece together a general
sense of the methods from the various reports provided to EPA. To
summarize, the Petitioners relied on sales data to generate the use
intensity estimates, but the method used to generate the county-level
use estimates from the sales data is not described. The actual county
level use estimates used in the use intensity calculations were not
provided. There is a limited description indicating only that the
county level use estimates were apportioned to different crops, but the
method used to do this was not provided. The Petitioners appear to have
used an objective method to group the county-level use estimates into 5
classes, but the method is only briefly described. Thus, because EPA
cannot determine how use intensity was estimated, the Agency cannot
determine if the conclusions made in the National CWS Assessment are
justified by the underlying data.

    In the absence of this information, EPA is unable to substantiate
the study conclusion that 75% of the permissible use areas have a
carbofuran use intensity below 2.1 lbs a.i/mi\2\--even assuming that
reliance on only 75% of the use areas would be protective, and nothing
has been submitted to substantiate that conclusion. Use intensity maps
that were provided with the Petitioners' comments appear to indicate
that carbofuran use varies year by year, and it is not clear for which
year or years, the Petitioners are relying to support their claim that
use intensity will be below 2.1 lbs a.i/mi\2\. No further support for
this claim was provided with the Petitioners' objections, even though
EPA presented its conclusions in the final rule.
    As noted, the National CWS Assessment assumed that a use intensity
below 2.1 lbs a.i/mi\2\ would assure that surface water concentrations
will be below the level of concern. EPA agrees that using lower rates
of carbofuran will result in lower exposure. But EPA does not agree
that it has been demonstrated that a use intensity below 2.1 lbs a.i./
mi\2\ will assure that surface water concentrations will be below the
applicable level of concern. The National CWS Assessment does not
justify such a finding, nor has any other assessment that has been
submitted to date. The Agency modeled use rates for carbofuran on corn
based on the label proposed in September 2008, which are the rates at
which farmers are legally allowed to apply carbofuran, and the results
clearly demonstrate that estimated exposures will substantially exceed
safe levels. The results of EPA's assessments are described in more
detail in Unit V.E. of this order, the final rule and in Reference 111.
    EPA is equally unable to confirm the study's claim that the no-
application buffers on the September 2008 labels will adequately
mitigate the risks ``in areas with historical use intensities greater
than 2.1 lbs a.i./sq. mi.'' On the September 2008 labels, FMC included
buffers of 300 feet on water bodies in Kansas, and 66 feet around water
bodies in other places, but EPA cannot evaluate how these buffers
relate to areas where carbofuran use intensities exceeded a specific
value, for all of the reasons stated above. EPA did, however, model the
effects from the buffers proposed on the September 2008 labels and
found that these buffers reduce exposure by 5.1% (33.5 to 31.8 ppb) for
corn in Kansas with a 300-foot spray drift buffer and 4.7% (29.9 to
28.5 ppb) for corn in Texas with a 66-foot spray drift buffer. However,
even with the buffers, EPA's analyses clearly demonstrate that
estimated exposures will substantially exceed safe levels. These
results are described in more detail in Unit V.E. of this order, the
final rule, and Reference 84, Appendix I. For all of these reasons, the
objection is denied.
    c. Objection/hearing request subissue: Challenges to EPA use of
NAWQA monitoring data. The Petitioners object to EPA's discussion in
the final rule of the extremely high concentrations detected in Zollner
Creek in Oregon. They argue that reliance on these concentrations to
confirm the results of EPA's modeling is not supportable because
Zollner Creek is a small isolated creek, not a drinking water source,
and that because of its size, is not representative of potential
drinking water anywhere else. They also argue that the majority of the
concentrations in the NAWQA data, including those detected at Zollner
Creek, are extremely low--below the 1.1 ppb they claim is supported by
their modeling. They also contend that the higher observed
concentrations in the NAWQA monitoring data are the result of use
patterns that are no longer permitted, and that allowed a much higher
use rate than is currently permitted.
    i. Background. In the proposed rule, EPA described the available
monitoring data that characterized carbofuran concentrations in surface
water. EPA described that the highest concentrations of carbofuran are
reported from a sampling station on Zollner Creek, which EPA
acknowledged ``is not directly used as a drinking water source'' (73 FR
44883). USGS monitoring at Zollner Creek from 1993 to 2006 detected
carbofuran annually in 40-100% of the samples. EPA stated that although
the majority of the concentrations detected were in the sub-part per
billion range, concentrations have exceeded 1 ppb in 8 of the 14 years
of sampling (Id.). The maximum measured concentration was 32.2 ppb,
observed in the spring of 2002. EPA compared its modeling results to
the concentrations seen in all of the USGS monitoring, Safe Drinking
Water Act (SDWA) monitoring, and to the results of the available field
scale studies. EPA concluded that the concentrations estimated in its
modeling were consistent with the results of all of the available
monitoring and studies (73 FR 44883-44884).
    In their comments on the proposed rule, the Petitioners alleged
that comparisons between EPA's modeling concentrations and Zollner
Creek detections were inappropriate because they were based on ``older
data [that] are not reflective of future carbofuran use areas and/or
intensities'' (Ref. 18 at 55). In support, they claimed that
``carbofuran was once used at several nurseries and strawberry farms in
the Zollner Creek watershed at estimated application rates of up to 15
lbs. a.i./acre (5 times higher than the maximum rate on the current
label, and 15 times higher than the most common use rates)'' (Id at
56).
    In the final rule, EPA explained that it had not relied solely on
Zollner Creek concentrations to validate its modeling. EPA again
described the results of all available modeling, which included the
detections at Zollner Creek, but also included results from all other
NAWQA sites, SDWA post-treatment monitoring, and the results of field
studies. Based on all of these data, EPA concluded that the results of
the revised modeling conducted for the final rule was consistent with
the available monitoring data.
    ii. Denial of hearing request. This subissue does not meet the
standard for a hearing. The objections regarding Zollner Creek are not
material. EPA did not rely in on the concentrations detected at Zollner
Creek to provide significant support its assessment.
    In the final rule, EPA was clear that it considered the levels seen
at Zollner Creek to be a rare circumstance:

    While available monitoring from other portions of the country
suggests that the circumstances giving rise to high concentrations
of carbofuran may be rare, overall, the national monitoring data
indicate that EPA cannot dismiss the possibility of detectable
carbofuran concentrations in some surface waters under specific use
and environmental conditions.

(74 FR 23081). The final rule was clear that EPA placed greater
reliance on the concentrations detected in Safe Drinking Water Act
(SDWA) post-treatment monitoring, showing concentrations ranging
between 4 and 7 ppb (74 FR 23079-23080). EPA also discussed the results
of the UK tile drain studies as supplemental confirmation of its
modeling (74 FR 23082).
    Petitioners' contentions regarding the NAWQA monitoring also fail
to present a genuinely-disputed issue of material fact. In both the
proposed and final rules, EPA acknowledged the large percentage of non-
detections and low concentration levels in the majority of the NAWQA
monitoring data, and repeatedly explained the reasons that these data
cannot serve as lower or upper bounds (73 FR 44882-44883; 74 FR 23081).
Petitioners do not dispute those conclusions, or submit evidence to
rebut them. When an objector does not challenge EPA conclusions in the
final rule, but merely reiterates

comments made on the proposed rule, without submitting some evidence
that calls EPA final rule conclusions into question, the objector has
not raised a live controversy as to an issue material to the final
rule. (See 73 FR 42700-42701 (denying hearing request where NRDC failed
to object to the basis EPA asserted in its petition denial for
rejecting their original challenge). Finally, no evidence has been
submitted to support the contention that all of the higher
concentrations exclusively result from uses or higher use rates that
are no longer permitted. Hearings will not be granted on mere
allegations (40 CFR 178.32(b)(2)).
    iii. Denial of objection. Data compiled in 2002 by EPA's Office of
Water show that carbofuran was detected in treated drinking water at a
few locations. Based on samples collected from 12,531 ground water and
1,394 surface water source drinking water supplies in 16 states,
carbofuran was found at no public drinking water supply systems at
concentrations exceeding 40 ppb (the MCL). Carbofuran was found at one
public ground water system at a concentration of greater than 7 ppb and
in two ground water systems and one surface water public water system
at concentrations greater than 4 ppb (measurements below this limit
were not reported). Sampling is costly and is conducted typically four
times a year or less at any single drinking water facility. The overall
likelihood of collecting samples that capture peak exposure events is,
therefore, low. For chemicals with acute risks of concern, such as
carbofuran, higher concentrations and resulting risk is primarily
associated with these peak events, which are not likely to be captured
in monitoring unless the sampling rate is very high.
    Unlike drinking water derived from private ground water wells,
drinking water from public water supplies (surface water or ground
water source) will generally be treated before it is distributed to
consumers. An evaluation of laboratory and field monitoring data
indicate that carbofuran may be effectively removed (60-100%) from
drinking water by lime softening and activated carbon; other treatment
processes are less effective in removing carbofuran (Ref. 81). The
detections between 4 and 7 ppb, reported above, represent
concentrations in samples collected post-treatment. As such, these
levels are of particular concern to the Agency. An infant who consumes
a single 8-ounce serving of water with a concentration of 4 ppb, as
detected in the monitoring, would receive approximately 130% of the
aPAD from water consumption alone.
    To further characterize carbofuran concentrations in surface water
(e.g., streams or rivers) that may drain into drinking water
reservoirs, EPA analyzed the extensive source of national water
monitoring data for pesticides, the USGS NAWQA program. The NAWQA
program focuses on ambient water rather than on drinking water sources,
is not specifically targeted to the high use area of any specific
pesticide, and is sampled at a frequency (generally weekly or bi-weekly
during the use season) insufficient to provide reliable estimates of
peak pesticide concentrations in surface water. For example,
significant fractions of the data may not be relevant to assessing
exposure from carbofuran use, as there may be no use in the basin above
the monitoring site. Unless ancillary usage data are available to
determine the amount and timing of the pesticide applied, it is
difficult to determine whether non-detections of carbofuran were due to
a low tendency to move to water or from a lack of use in the basin. The
program, rather, provides a good understanding on a national level of
the occurrence of pesticides in flowing water bodies that can be useful
for screening assessments of potential drinking water sources.
    The national monitoring data indicate that EPA cannot dismiss the
possibility of detectable carbofuran concentrations in some surface
waters under specific use and environmental conditions. Even given the
limited utility of the available monitoring data, there have been
relatively recent measured concentrations of carbofuran in surface
water systems at levels above 4 ppb and levels of approximately 1 to 10
ppb measured in streams representative of those in watersheds that
support drinking water systems (Ref. 81). Based on this analysis, and
since monitoring programs have not been sampling at a frequency
sufficient to detect daily-peak concentrations that are needed to
assess carbofuran's acute risk, the available monitoring data, in and
of themselves, are not sufficient to establish that the risks posed by
carbofuran in surface drinking water are below thresholds of concern.
Nor can the non-detections in the monitoring data be reasonably used to
establish a lower bound of potential carbofuran risk through this route
of exposure. Nevertheless, these results are consistent with the
results of EPA's surface water modeling (Refs. 12, 47, 67). For all of
these reasons, the Petitioners objection is denied.
    d. Objection/hearing request subissue: New label restrictions and
revised terms of registration. As discussed in Units VI.C and D, FMC
submitted a request to amend its existing registration to incorporate a
requirement intended to ensure that no more than 2% of any watershed
will be treated with carbofuran. Petitioners allege that these new use
restrictions will ensure that drinking water concentrations will not
exceed 1.1 ppb. In support, the objection presents a June 30, 2009
letter describing the restrictions, along with proposed revisions to
the carbofuran labels.
    i. Background. On June 30, FMC requested that EPA amend its
registration to incorporate a requirement that, within five days of
applying the product, all applicators report to FMC the following
information: the location that the product will be used; crop, use
rate, application method, acreage, and quantity applied. Based on this
information, FMC would track the percentage in each watershed.
``Whenever it appears that carbofuran has been applied to 1.75% of any
watershed,'' the registrant would report that information immediately
to EPA, ``cease further sales in any county that overlaps with such a
watershed for that use season, and shall attempt to recall all unused
carbofuran within such counties by offering to repurchase such unused
product'' (Exhibit 3). In addition, FMC requested that its registration
be amended to require that ``based on watershed boundaries, FMC * * *
prior to each uses season, allocate to its distributors in a manner
which will attempt to ensure that no distributor receives more for
carbofuran for sale than can be accommodated by the 2% watershed area
cap in any watershed supplied by that distributor.''
    ii. Denial of hearing request. EPA denies this hearing request on
two grounds. First, discussed in VI.C, Petitioners' objections and
hearing requests are denied as irrelevant, and therefore immaterial, to
EPA's determination in the May 15, 2009 final rule that the carbofuran
tolerances were unsafe and could not be sustained under FFDCA section
408. Petitioners are actually not objecting to the conclusions in EPA's
final rule; rather, they are suggesting that EPA might reach a
different result in a different factual scenario. Objections, however,
must be directed ``with particularity [at] the provisions of the
regulation or order deemed objectionable'' (21 U.S.C. 346a(g)(2)).
Further, as discussed in Unit VI.D, this objection is untimely, because
it was not raised in comments. Neither this specific proposal, nor any
other proposal regarding a potential tracking system, was presented to
EPA by the close of the September 29, 2008 comment period. EPA
therefore

considers this issue waived, and will not consider this as an
appropriate basis for justifying a hearing on its final rule.
    However, there is a further equally material defect in this hearing
request. The Petitioners have submitted no evidence to support their
allegation that these proposed requirements would be effective in
ensuring that carbofuran would be applied to no more than 2% of any
watershed. The only submission was the description provided in the June
30 letter (Exhibit 3), and repeated above. However, this vague
description leaves several critical questions unanswered. For example,
the critical component of this proposal is a post-use reporting scheme,
with a five-day delay between use and reporting. Even assuming that one
accepts that reporting an address would allow for complete
identification of the location within an individual watershed--a point
on which no evidence has been submitted--no evidence, or even an
explanation, has been provided to demonstrate how this after-the-fact
reporting requirement will prevent application to greater percentages
of the watershed. For smaller watersheds, as discussed in the final
rule, application to only one or two farms may be sufficient to
substantially exceed 2% of the watershed. In such cases, since
applicators are only required to report within five days after
application, it is likely that FMC would not be informed until after
the 2% cap had been exceeded. Further, there will inevitably be some
delay between FMC's attempt to repurchase the product and the reports
suggesting (or confirming) that the cap either has been or will shortly
be exceeded. Given the inevitable delay, it is not unlikely that
further application would occur before FMC could even attempt to
repurchase the product. No details whatsoever have been provided
regarding the timing or mechanism by which this would occur. Further,
this program operates in the absence of any enforceable use
restriction, and no description of the means by which this would be
enforced is provided. Although the company would ``attempt to recall
the product'' or make it less available by ``attempting'' to direct
sales to particular distributorships, in the absence of some mechanism
to prevent sales or use, such as a permitting process, there is no real
assurance that these voluntary measures would be effective (Exhibit 3).
This is further complicated by the extremely low percentages
contemplated by this proposal.
    Additionally, this scheme rests on a variety of assumptions that no
evidence has been submitted to substantiate. For example, the proposal
to restrict sales to distributors in particular watersheds rests on an
assumption that farmers always purchase products from a distributor
within their watershed. It also assumes that growers and distributors
will accept FMC's offer to repurchase unused stock of the products,
rather than seeking to stockpile the product for use in the next
growing season.
    In the absence of any evidence to demonstrate the efficacy of these
proposed restrictions, any objection based on these proposed amendments
constitute no more than mere allegations or denials. Hearings will not
be granted on such a basis (40 CFR 178.32(b)(2)).
    iii. Denial of objection. For the reasons discussed above, even if
it were appropriate to consider the proposed registration amendments,
EPA is unable to conclude that those amendments would ensure that
concentrations of carbofuran in drinking water derived from surface
water will not exceed 1.1 ppb. Accordingly, the objection is denied.
    e. Objection/hearing request subissue: Consistency with NMC surface
water estimates. Petitioners object to EPA's surface water exposure
estimates on the ground that they are inconsistent with the estimates
EPA developed for purposes of the NMC CRA. Petitioners further claim
that their revised surface water assessment is consistent with the EPA
estimates in the NMC cumulative risk assessment. The evidence proffered
for this objection consists of the modeling in Exhibit 15.
    i. Background. In comments on the proposed rule, the Petitioners
complained that as part of the NMC CRA, EPA relied on actual ``county-
or multi-county level pesticide use information, based on agricultural
chemical use surveys'' to develop its estimates of potential exposure,
rather than assuming 100% PCT.'' In the final rule, EPA provided a
lengthy and detailed explanation of the reasons that its approach to
assessing individual chemicals and its approach to assessing the
cumulative risks of multiple chemicals differed (74 FR 23067-23068 (May
15, 2009)).
    ii. Denial of hearing request. To the extent Petitioners base this
objection on the concerns raised in their comments, EPA denies the
hearing request on this subissue because there is no disputed factual
matter for resolution at a hearing. There is no dispute that EPA
assumed 100% PCT for carbofuran in its surface water modeling, nor that
EPA developed lower estimates in the NMC CRA, that accounted for the
percent of the crop that was likely to be treated with each individual
NMC chemical in order to more accurately account for the likelihood of
pesticide co-occurrence at a single drinking water facility. Thus, the
only question is whether EPA's basis for adopting a different approach
between the assessment of a single chemical's aggregate exposure and
the assessment of the cumulative exposures from several chemicals is
reasonable. This question requires the application of a legal standard
to undisputed facts. Hearings are not appropriate on questions of law
or policy (40 CFR 178.32(b)(1)); (73 FR 42706-42707 (July 23, 2008)).
FDA has repeatedly confirmed that the application of a legal standard
to undisputed facts is a question of law for which a hearing is not
required. (See, e.g., 68 FR 46403, 46406 n.18, 46408, 46409 (August 5,
2003) (whether facts in the record show there is a reasonable certainty
of no harm is a question of law; whether a particular effect is a
``harm'' is a question of law)).
    In addition, Petitioners have not challenged the substance of EPA's
response to their comments or submitted evidence that calls the
substance of EPA's conclusions into question (40 CFR 178.32(b)(3)).
Consequently, the Petitioners' objection on this issue is irrelevant,
and therefore immaterial, with regard to EPA's final tolerance
revocation regulation because Petitioners ignored EPA's extensive
analysis of this issue in the final rule and essentially resubmitted
their comments on the proposal as if EPA's determination in the final
rule did not exist. The statute, however, requires that objections be
filed on the final rule, not on the proposal (21 U.S.C. 346a(g)(2)). By
ignoring the EPA's final rule on this subissue, Petitioners have failed
to lodge a relevant objection. Both EPA and FDA precedent make clear
that when the agency substantively responds to comments on the
proposal, the commenter may only keep that issue alive in its
objections by addressing the agency's substantive response. See 73 FR
42698-42699 (When an objector does not challenge EPA conclusions in the
section 408(d)(4)(iii) order but rather challenges some prior
conclusion that was superseded by the section 408(d)(4)(iii) order, the
objector has not raised a live controversy as to an issue material to
the section 408(d)(4)(iii) order; 53 FR 53176, 53191 (December 30,
1988) (where FDA responds to a comment in the final rule, repetition of
the comment in objections does not present a live controversy unless
the objector proffers some evidence calling FDA's conclusion into
question)).

    To the extent this objection is simply an allegation that the
results of the modeling are consistent with the surface water estimates
in EPA's NMC risk assessment, the hearing request also suffers from a
fatal flaw. The modeling is based on the assumption the recently
proposed label restrictions are effective, and that the PCT will be 2%.
Because the objection and hearing request are inextricably intertwined
with the Petitioners' newly submitted proposed FIFRA registration
amendments, the objection and hearing request are denied as irrelevant,
as discussed in Unit VI.C. Further, as discussed, no evidence was
submitted to support the assumption that the newly submitted use
tracking proposal will be effective. The only evidence submitted in
this regard is the results of the modeling in Exhibit 15, which as
previously discussed is untimely, and therfore provides an
inappropriate basis for a hearing. This evidence, therefore, on
multiple grounds is insufficient to support a reasonable possibility
that the issue will be resolved in the Petitioners' favor. No hearing
is warranted under such circumstances (40 CFR 178.32(b)(2)).
    iii. Denial of objection. While it is true that in the NMC
assessment EPA used PCT numbers to estimate the cumulative exposure
from the contamination of such pesticides in surface water, this was
done in order to more accurately account for the likelihood of
pesticide co-occurrence at a single drinking water facility. But this
does not mean that use of PCT is appropriate in conducting an
assessment of aggregate exposure from carbofuran residues in surface
water. This difference in approach between the assessment of a single
chemical's aggregate exposure, and the assessment of the cumulative
exposures from several chemicals, stems from the differences in the
purpose and scope of the two assessments. These differences inevitably
require the application of different methodologies.
    In evaluating the acute risks associated with a single chemical's
contamination of drinking water, EPA must consider all of the
variations permitted under the label. Drinking water exposures are
driven by uniquely local factors; not only is the source of drinking
water local (i.e., a person drinks water from his or her local water
system, not from a combination of water systems from across the United
States), but the likelihood and degree of contamination of any
particular, local drinking water source, whether it is a reservoir or
well, varies widely based on local conditions (e.g, from local pest
pressures, weather). Given this local variability, EPA must evaluate
how all of the practices permitted under the label will affect drinking
water exposures, because all are legally allowed, and farmers may
choose any of them based on their particular individual local
conditions. This means that even if growers, on a national or regional
basis, do not frequently use a particular practice, EPA must still
evaluate whether aggregate exposures from that practice would be safe
because the practice is legally permissible and may be used due to
local conditions. Thus, for example, even if most growers tend to apply
the chemical only to a portion of the field, or typically only apply
one-half of the maximum application rate, EPA must determine whether
use by all or some growers on the entire field or at the maximum rate
in a local watershed would result in unsafe drinking water
concentrations.
    By contrast, it is not feasible to conduct the identical analysis
for a cumulative assessment of related chemicals. Since the potential
combinations of variations in pesticide use practices for the group of
pesticides to be assessed are essentially infinite, even with computer
modeling it would be impossible to model or evaluate all of the
combinations allowed under the labels. EPA therefore needed to narrow
its evaluation of the possible combinations to those deemed ``likely''
to occur. In contrast to the single chemical assessment, a cumulative
assessment is intended to develop a snapshot in time of what is likely
occurring at the moment. Moreover, the purpose of a cumulative
assessment is to identify major sources of risk that could potentially
accrue due to the concurrent use of several pesticides that act through
a common mechanism of toxicity. Thus, EPA is primarily interested in
the subset of circumstances in which residues from such pesticides
occur concurrently (or co-occur).
    In addition, one of the important attributes of a cumulative risk
assessment is that its scope and complexity can potentially lead to
inflated estimates of risk due to compounding conservatisms, which
would reduce the interpretability and ultimately the utility of the
assessments. Because many data sets need to be combined, reducing the
impact and likelihood of compounding conservative assumptions and over-
estimation bias becomes very important in constructing a reasonable
cumulative risk assessment.
    When little or no information is available to inform potential
sources of exposure, such as a reasonable or maximum watershed scale
PCT, it is both scientifically and legally reasonable for a single
chemical assessment to incorporate conservative assumptions to reflect
reasonable worst-case exposure estimates. But in a cumulative risk
assessment, the incorporation of such conservative assumptions would
imply multiple simultaneous reasonable worst-case exposure estimates
for each individual chemical. This is so unlikely that the results
would no longer represent even a reasonable worst-case estimate of the
likely risks. Consequently, some of the conservative assumptions
appropriately used in the single chemical risk assessments are not
appropriate or reasonable for use in a cumulative risk assessment, and
vice versa.
    As a result, EPA chose in the NMC to work with those data that most
closely reflect ``representative'' exposures, and developed
``representative'' estimates of PCT in regional watersheds. However, to
be clear, the PCT values used in the NMC assessment do not represent
estimates of 50% of watersheds, or even the ``average'' watershed;
rather, they represent values that are expected to be as likely to be
accurate as not, based on a random selection of watersheds. A
comparable example is the statistic that the average American family
has approximately 2 children; this may or may not be true for any
individual family, but there is an equally good chance that it will be
accurate for any randomly selected family, as that it will not be
accurate. For the cumulative assessment, EPA is able accept this level
of uncertainty in these estimates, precisely because it has confidence
that aggregate exposures from the individual chemicals will be safe,
based on the level of conservatism in the single chemical assessments.
But given the statute's mandate to ensure a ``reasonable certainty of
no harm,'' EPA could not rely on the approach used under the cumulative
assessment in the absence of the more conservative single-chemical
assessment that evaluates the full range of exposures permitted by the
registration.
    Nevertheless, as discussed in the final rule, in response to FMC's
concerns EPA performed a sensitivity analysis of an exposure assessment
using a PCT in the watershed to determine the extent to which some
consideration of this factor could meaningfully affect the outcome of
the risk assessment. The results suggest that, even at levels below 10%
CT, exposures from drinking water derived from surface waters can
contribute significantly to the aggregate dietary risks, particularly
for infants and children. Accordingly, these assessments suggest that
use of a reasonably conservative PCT estimate,

even if one could be developed, would not meaningfully affect the
carbofuran risk assessment, as aggregate exposures would still exceed
100% of the aPAD.
    f. Objection/hearing request subissue: Natural surface water pH
conditions. The Petitioners contend that the low PCT levels guaranteed
by the recent proposed use tracking system, along with natural surface
water pH conditions in the areas where use is permitted under the
revised label will ensure potential exposures are de minimis. In
support they reference the analysis in Exhibit 16, which they claim
demonstrates that the NAWQA USGS data show that average surface water
pH is above 7.5 and that ``in most regions, moving 2 standard
deviations away from average (which would capture 95% of all observed
values) results in pHs that are still greater than 7.5.''
    i. Background. In the proposed rule, EPA explained that the
variation in pH across the landscape was a significant uncertainty in
EPA's analysis. The proposal stated, that ``while it is well
established that carbofuran will degrade at higher rates when the pH is
above 7, and lower rates when below pH 7, due to the high variation of
pH across the country for many of the scenarios, a neutral pH (pH 7)
default value was used to estimate water concentrations (73 FR 44883).
Petitioners raised no issue regarding surface water pH in their
comments.
    ii. Denial of hearing request. EPA denies this hearing request
because the objection, as well as the proffered evidence is untimely.
EPA clearly described the potential impact that pH could have on its
estimates, and noted that this was a significant uncertainty in its
assessment. None of the analyses in Exhibit 16 were provided as
comments on the proposed rule. Nor were any of the issues inherent in
this objection raised as comments on the proposal. Since the proposed
rule was clear that the issue was relevant, and the NAWQA data were
available, Petitioners could have conducted these analyses and raised
the issue as part of their comments. Consequently EPA has determined
that the evidence submitted in support of this objection is not
appropriately considered as a basis for justifying a hearing on its
final rule. And in the absence of this evidence, the objection consists
of mere allegations and general denials, which do not warrant a hearing
(40 CFR 178.32(b)(2)). Further, to the extent the objection and the
evidence in Exhibit 16 rely on use tracking system and risk mitigation
proposals submitted as part of their objections, this hearing request
is denied as irrelevant, and therefore immaterial, as discussed in Unit
VI.C. Petitioners are actually not objecting to the conclusions in
EPA's final rule; rather, they are suggesting that EPA might reach a
different result in a different factual scenario. Objections, however,
must be directed ``with particularity [at] the provisions of the
regulation or order deemed objectionable'' (21 U.S.C. 346a(g)(2)). In
addition, for the reasons discussed in Unit VI.D, any hearing request
premised on the new mitigation measures is considered untimely, and not
appropriately considered at this stage of the administrative process as
a basis for granting a hearing under the FFDCA.
    EPA is also denying the requested hearing on the grounds that the
evidence, even if established, is insufficient to justify the action
urged (40 CFR 178.32(b)(3)). The analyses presented in Exhibit 16, as
the Petitioners explicitly acknowledge, only capture 95% of the values;
five percent of exposures are not, per se, de minimis. Second, just as
with the groundwater pH analyses presented in Exhibit 14, no
information was provided to explain how the samples relate to the state
or other geographic area in which carbofuran would be used. This is
important because NAWQA samples were not evenly distributed across most
states, but tended to be concentrated in particular regions; in
statistical parlance, the samples were not collected randomly. In other
words, no evidence was provided that would allow the Agency to
determine the percentage of the carbofuran use area represented by the
95% of the samples the Petitioners' analysis addressed. Nor was any
information provided to document the significance of the remaining 5%
of the samples that were not captured by their analysis; for example,
although this may have only represented 5% of the samples, it is not
clear whether this 5% relates to only 5% of the areas where carbofuran
may be used, or whether it actually represents a far greater percentage
of the use area. Because this information, even if established, would
provide an insufficient basis on which EPA could reasonably conclude
that the drinking water exposures would be ``safe,'' this issue is not
determinative.
    iii. Denial of objection. For the reasons presented above, the
Petitioners' objection is denied. Further, there are several
significant defects with the analysis in Exhibit 16. First, the
analysis was based on statewide averages, which ignores the fact that
pH is not evenly distributed, but randomly clustered. Second NAWQA
contained no data for Kansas (KS), Oklahoma (OK), and South Dakota
(SD); Petitioners simply assert that the ``given the similarity between
these states and the other High Plains states, it is reasonable to
extend the observations from Colorado (CO), Nebraska (NE), and North
Dakota (ND)'' (Exhibit 16 at 4). Although the `High Plains' states all
have extensive areas of grassland, they also have extensive geographic
soil and climatic differences--e.g. the Black Hills and Badlands (SD),
Sand Hills (NE), Flint Hills, Cheyenne Bottoms and Quivira wetlands
(KS), Red Hills and Cross Timbers region (OK). These differences are
not surprising since the distance from the Canadian border in ND to OK
is over 1000 miles. Consequently it is not reasonable to extend
observations from CO, NE, and ND to KS, OK, and SD.
    g. Objection/hearing request subissue: Effect of existing drinking
water treatment systems. The Petitioners contend that a review of
drinking water treatment systems in areas under revised labels
indicates that the majority of the ``total population in affected
states obtain their drinking water from surface water sources subject
to lime softening or activated charcoal filters. They allege that ``60%
of the total population in affected states'' will have their water
treated by methods that will substantially reduce or entirely remove
carbofuran concentrations. For the remaining 40%, they claim that a
significant portion use ground water sources, which are already
protected by the Petitioners' other mitigation measures, and the
remainder are protected by the Petitioners' proposed use reporting
scheme. In support of this objection, Petitioners rely on the analysis
in Exhibit 17.
    i. Background. In the proposed rule, EPA explained that one of the
more significant uncertainties in EPA's analysis was that EPA failed to
account for the potential effect of treatment in removing carbofuran
from finished drinking water before it is delivered to the consumer
supply system. EPA explained that an evaluation of laboratory and field
monitoring data indicate that carbofuran may be effectively removed
(60-100%) from drinking water by lime softening and activated carbon;
other treatment processes are less effective in removing carbofuran
(Ref. 81). Although the Agency was aware of the mitigating effects of
specific treatment processes, the processes employed at public water
supply utilities across the country vary significantly both from
location to location and throughout the year, and therefore EPA was
unable to quantitatively incorporate this factor into its drinking
water exposure

estimates. For example, lime softening would likely reduce carbofuran
concentrations. That process is used in 3 to 21% of drinking water
treatment systems in the United States (Ref. 14). Activated carbon has
been shown to also reduce carbofuran concentrations, but is used in 1
to 15% of drinking water treatment facilities (Id.). Petitioners noted
this discussion in their comments, and relied on it to support their
argument that their drinking water exposure assessments were
conservative, because they did not account for the effect of treatment
(Ref. 18 at 46-55). However they submitted no comments raising any of
the issues or evidence presented in this objection.
    ii. Denial of hearing request. EPA denies this hearing request on
the grounds that both the objection and the proffered evidence are
untimely. EPA clearly described the potential impact that treatment
could have on its estimates. None of the analyses in Exhibit 17 were
provided as comments on the proposed rule. Nor were any of the issues
inherent in this objection raised as comments on the proposal. Since
the proposed rule clearly identified the issue, and the USGS data were
available, the Petitioners could have conducted these analyses, or at
least raised the issue, as part of their comments. Consequently, as
discussed in Unit VI.D, EPA has determined that the evidence submitted
in support of this objection is not appropriately considered as a basis
for justifying a hearing on its final rule. In the absence of this
evidence, the objection consists of mere allegations and general
denials, which do not warrant a hearing (40 CFR 178.32(b)(2)). Further,
to the extent the objection and the evidence in Exhibit 17 rely on the
new registration proposals submitted in June 2009 as part of their
objections, this evidence as well is deemed both immaterial and
untimely. As discussed in Units VI.C and D, the new risk mitigation
measures are not appropriately considered at this stage of the
administrative process, and no hearing is warranted on this basis.
    EPA is also denying this hearing request on the grounds the
Petitioners' evidentiary proffer is insufficient to justify the factual
issue urged (40 CFR 178.32(b)(2)). The analysis in Exhibit 17 is based
on the percentage of the total population across all states combined,
not the percentage of the local populations served by an individual
surface water source--or even the percentage within each state. Even
assuming that the 60% figure could legitimately be translated to a
state-by-state basis, their own analysis shows that some percentage of
the population in individual states will remain unprotected. In
Colorado, only 24% of the population obtains their drinking water from
groundwater, and in Illinois, only 33% of the population obtains their
drinking water from groundwater. Sixteen percent of Colorado's
population is not de minimis. Consequently, even if the analysis were
accurate, it would not provide a sufficient basis on which to conclude
that exposures from drinking water would be ``safe.''
    A further consideration in this regard is that drinking water
exposures are driven by uniquely local factors; not only is the source
of drinking water local (i.e., a person drinks water from his or her
local water system not from a combination of water systems from across
the United States), but the likelihood and degree of contamination of
any particular, local drinking water source, whether it is a reservoir
or well, varies widely based on local conditions (e.g., from local pest
pressures, weather). Examining a population across an entire state--let
alone across several states--is an entirely inappropriate basis on
which to conclude that drinking water exposures will be safe.
    The evidence submitted therefore does not support their contention
that 60% of the population in ``affected states'' obtain their drinking
water from public systems that use the treatment processes effective at
mitigating carbofuran residues. For example, Exhibit 17 shows that a
major Chicago surface water drinking water system, which serves a
population of 9,000,000, has neither lime softening processes nor
filters. Petitioners have submitted no evidence that this population is
protected. The fact that a small population remains unprotected is not
outweighed by the fact that a larger population in another community or
state is protected. Their own evidence also shows that only 26 of 141
of community water systems use lime softening/filters (Exhibit 17 at 4-
9), which supports the conclusion in the final rule that approximately
20% facilities have appropriate treatment. See 57 FR 33244 (7/27/92)
(Studies cited by NRDC do not provide a basis for the hearing because
they ``support the [FDA] conclusion in question.''); 57 FR 6667 (2/27/
1992) (``A hearing must be based on reliable evidence, not on mere
allegations or on information that is inaccurate and contradicted by
the record.''); 49 FR 6672 (2/22/84) (no hearing if claim based on
demonstrably false premise).
    iii. Denial of objection. For the reasons discussed above, this
objection is denied. A further consideration is that treatment does not
necessarily remove all residues. As previously noted, in both the
proposed and final rules EPA discussed the SDWA monitoring detections
between 4 and 7 ppb, which represent concentrations in samples
collected post-treatment. As such, these levels are of particular
concern to the Agency. An infant who consumes a single 8-ounce serving
of water with a concentration of 4 ppb, as detected in the monitoring,
would receive approximately 130% of the aPAD from water consumption
alone. An infant who consumes a single 8-ounce serving of water with
the higher detected concentration of 7 ppb, as detected in the
monitoring, would receive approximately 220% of the aPAD from water
consumption alone.

G. Objections to EPA's Dietary Risk Assessment

    Petitioners raise two related objections to the way in which EPA
evaluated the aggregate dietary exposures to carbofuran residues. First
they raise several technical challenges to the way in which EPA
calculated the two recovery half-lives that were used in the risk
assessment supporting the final rule to account for the potential for
individuals to recover from the effect of ingesting carbofuran residues
between exposures. Second, they object to the fact that in the final
rule EPA included both aggregate exposure estimates that did not
account for the potential for individuals to recover from the effects
between exposures as well as estimates that did account for such
recovery. In support the Petitioners cite to Exhibits 9 and 10. Exhibit
9 is a memorandum prepared by Robert Sielken and Ciriaco Valdez-Flores.
Exhibit 10 is a published literature study by Elsa Reiner that presents
data on the rates of spontaneous reactivation of phosphorylated and
carbamylated cholinesterases.
    1. Objection/hearing request subissue: Inclusion of exposure
estimates that do not incorporate recovery in final rule. The
Petitioners object to the fact that the final rule presented aggregated
exposure estimates that did not incorporate the anticipated recovery
from carbofuran's effects between exposures, in addition to those that
did account for recovery. They claim that recovery time should be
included in EPA's ``primary'' risk assessment.
    i. Background. As discussed in Unit V, EPA's standard acute dietary
exposure assessment calculates total dietary exposure over a 24-hour
period; that is consumption over 24 hours is summed and no account is
taken of the

fact that eating and drinking occasions may spread out exposures over a
day. This total daily exposure generally provides reasonable estimates
of the risks from acute dietary exposures, given the nature of most
chemical endpoints. Due to the rapid recovery associated with some
chemical toxicity (e.g., AChE inhibition), 24-hour exposure periods may
or may not be appropriate. To the extent that a day's eating or
drinking occasions leading to high total daily exposure might be found
close together in time, or to occur from a single eating event, minimal
AChE recovery would occur between eating occasions (i.e., exposure
events). In that case, the ``24-hour sum'' approach, which sums eating
events over a 24-hour period, would provide reasonable estimates of
risk from food and drinking water. Conversely, to the extent that
eating occasions leading to high total daily exposures are widely
separated in time (within 1 day) such that substantial AChE recovery
occurs between eating occasions, then the estimated risks under any 24-
hour sum approach may be overstated. In that case, a more sophisticated
approach--one that accounts for intra-day eating and drinking patterns
and the recovery of AChE between exposure events--may be more
appropriate. This approach is referred to as the ``Eating Occasions
Analysis'' and it takes into account the fact that the toxicological
effect of a first dose may be reduced or tempered prior to a second (or
subsequent) dose.
    In the proposed rule, EPA conducted an Eating Occasion analysis
based on two half-lives: 150 minutes and 300 minutes (73 FR 44887 (July
31, 2008)). These half-lives were not specific to carbofuran, but were
calculations derived for the NMC Cumulative Risk Assessment. EPA
concluded that incorporating these analyses into the risk assessment
had little impact on the risk estimates from exposures from food alone,
but that risk estimates from combined exposures from food and water
were reduced by approximately 2-3X (Id). However, because many of EPA's
risk concerns stemmed from a single exposure (e.g., one meal) and
because, even when recovery was accounted for, aggregate exposures far
exceeded safe levels, EPA concluded that ``risks to carbofuran is
indeed not substantively overestimated using * * * the 24-hour
approach'' (Id).
    In their comments, Petitioners complained that EPA had failed to
incorporate recovery into their risk assessment. They further argued
that EPA should calculate the per capita 99.9th percentile based on all
person minutes rather than all person-days. In addition, they submitted
an aggregate dietary risk assessment they had conducted using a 150-
minute half-life input. They submitted no explanation for using only
the 150-minute half-life rather than also including estimates based on
the 300-minute half-life that EPA has used for the proposed rule.
    In the final rule EPA explained that it had conducted a revised
Eating Occasion analysis to evaluate the impact of carbofuran's rapid
reversibility on its risk estimates (74 FR 23086 (May 15, 2009)). EPA
concluded that incorporating Eating Occasion Analysis and the 186-
minute or 426-minute recovery half-lives for carbofuran did not
significantly change the risk estimates for food exposures alone (74 FR
23086 (May 15, 2009)). EPA concluded that risk estimates based on
combined food and drinking water exposures are reduced considerably--by
a factor of two or more in some cases, but nonetheless still
substantially exceed EPA's level of concern for infants and children.
EPA also explained that the Agency remains concerned about the risks
from single eating or drinking events. Finally, EPA noted that the
Eating Occasion Analyses underestimate exposures to the extent that
they do not take into account carry-over effects from previous days,
and because drinking water concentrations are randomly picked from the
entire 30-year distribution (Id at 23087).
    ii. Denial of hearing request. EPA is denying this hearing request
on two grounds. First, the objection fails to present a disputed issue
of material fact. The record is clear that EPA did incorporate recovery
into its analysis; indeed, one of Petitioners' objections relates to
the manner in which EPA incorporated recovery into its risk assessment
(Obj at 30-33). Rather, their only challenge is that the final rule
should have only presented risk estimates that accounted for recovery.
The sole issue is whether it was reasonable for EPA to have also
communicated aggregate risks that did not account for recovery, when
(1) EPA's estimates showed that accounting for recovery demonstrated
that EPA's standard 24-hour estimates were not substantially
overstated; (2) EPA's approach to accounting for recovery
underestimates some risks; and (3) EPA's risk assessments concluded
that infants received unsafe exposures from a single meal (eating
occasion). This is a policy issue, and hearings are not appropriate on
such (40 CFR 178.32(b)(1)).
    Second, the fact that EPA relied on 24-hour aggregate exposures in
addition to analyses that accounted for recovery is not material. As
documented in the final rule, EPA would still have concluded that
revocation of all tolerances were warranted on the grounds that, even
accounting for recovery, aggregate exposures are not ``safe.'' Even
though accounting for recovery resulted in a 2-3X reduction in exposure
estimates, many of EPA's estimates for aggregate exposures ranged
between 2700% aPAD and 9400% aPAD for infants. Accounting for recovery
does not, therefore, demonstrate that aggregate exposures will be safe
for infants. Of greater significance in this regard is EPA's finding
that infants are at risk from a single exposure. Recovery is only
relevant, by definition, where the risk is derived from multiple
exposures over time.
    iii. Denial of objection. The reason for not simply adopting the
assessment incorporating recovery time was that the Agency has concerns
that other aspects of its exposure model tends to understate exposure.
If the assessment using recovery time had suggested that carbofuran
risks may be acceptable, EPA would have had to further examine how
exposure was assessed. However, because both the assessment based on
24-hour exposure and the one incorporating recovery time showed
carbofuran exposures to be well over the safe level, EPA concluded that
its exposure assessment was reasonable. As explained in the final rule,
incorporating Eating Occasion Analysis and the 186-minute or 426-minute
recovery half-lives for carbofuran resulted in a reduction in the risk
estimates for which food and drinking water are jointly considered
(i.e., Food + Drinking Water) by a factor of two or more in some cases.
But even though the risk estimates from aggregate exposure are reduced,
they nonetheless still substantially exceed EPA's level of concern for
infants and children. Using drinking water derived from the surface
water from the Idaho potato surface water scenario, which estimated one
of the lowest exposure distributions, aggregate exposures at the 99.9th
percentile ranged from 328% of the aPAD under the scenario for which
infants rapidly metabolize carbofuran (e.g., 186-minute half-life), to
a high of 473% of the aPAD under the scenario for which infants
metabolize carbofuran more slowly (e.g., scenarios in which a 426-
minute half life is assumed). Either way, the tolerances are unsafe.
    Moreover, even accounting for the estimated decreased risk from
accounting for carbofuran's rapid reversibility, for which recovery
between exposures is irrelevant. The Agency remains concerned about the

risks from single eating or drinking events, as illustrated in the
following example, based on an actual food consumption diary from the
CSFII survey. A 4-month old male non-nursing infant weighing 10 kg is
reported to have consumed a total of 1,070 milliters (ml) of indirect
water over eight different occasions during the day. The first eating
occasion occurred at 6:30 a.m., when this 4 month old consumed 8 fluid
ounces of formula prepared from powder. The FCID food recipes indicate
that this particular food item consists of approximately 87.7% water,
and therefore, 8 ounces of formula contains approximately 214 ml (or
grams) of indirect water; with the powder (various nutrients, dairy,
soy, oils, etc.) accounting for the remaining 12.3%. This infant also
reportedly consumed a full 8-ounce bottle of formula at 12 p.m., 4
p.m., and 8 p.m. that day. The food diary also indicates that the
infant consumed about 1 tablespoon of water (14.8 ml) added to prepare
rice cereal at 10 a.m., about 2 ounces of water (59.3 ml) added to pear
juice at 11 a.m., another \1/2\ tsp of water (2.5 ml) to prepare more
rice cereal at 8:30 p.m.; and finally, he consumed another 4 ounces of
formula (107 ml) at 9:30 p.m.
    The infant's total daily water intake (1,070 ml, or approximately
107 ml/kg/day) is not overly conservative, and represents substantially
less than the 90th percentile value from CSFII on a ml water/kg
bodyweight (ml/kg/bw) basis. As noted, carbofuran has been detected in
finished water at concentrations of 4 ppb. For this 10 kg body weight
infant, an 8-ounce bottle of formula prepared from water containing
carbofuran at 4 ppb leads to drinking water exposures of 0.0856
micrograms of active ingredient/kilogram of bodyweight ([mu]g ai/kg
bw), or 114% of the aPAD from that bottle alone. Based on the total
daily water intake of 1,070 ml/day (no reversibility), total daily
exposures from water at 4 ppb concentration would amount to 0.4158
[mu]g ai/kg bw, or 555% of the aPAD; this is the amount that would be
used for this person-day in the Total Daily Approach.
    Peak inhibition occurs following each occasion on which the infant
consumed 8 fluid ounces of formula (6 a.m., 12 p.m., 4 p.m. and 8
p.m.); however, the maximum persisting dose occurs following the 9:30
p.m. eating occasion, based on a 186-minute half-life parameter. This
produces a maximum persisting dose of 0.1457 [mu]g ai/kg bw, or about
30% of the total daily exposure of 0.4158 [mu]g ai/kg bw derived above,
or expressed as a fraction of the level of concern, the maximum
persisting dose amounts to about 194% of the aPAD (or 30% of 554%).
Note that with drinking water concentration at 4 ppb, an infant
consuming one 8 oz bottle of formula--prepared from powder and tap
water containing carbofuran at 4 ppb will obtain exposures of
approximately 114% of aPAD. Since many infants consume the equivalent
of this amount on a single eating occasion, accounting for
reversibility over multiple occasions is not essential to ascertain
that infants quite likely have obtained drinking water exposures to
carbofuran exceeding the level of concern based on drinking water
concentrations found in public drinking water supplies.
    The approach discussed above is used to evaluate the extent to
which the Agency's 24-hour approach to dietary risk assessment
overestimates risk from carbofuran exposure. The results of both
approaches indicate that the risk from carbofuran is indeed not
substantively overestimated using the current exposure models and the
24-hour approach.
    In this regard, it is important to note EPA's Eating Occasion
Analyses underestimate exposures to the extent that they do not take
into account carry-over effects from previous days, and because
drinking water concentrations are randomly picked from the entire 30-
year distribution. As discussed previously, DEEM-FCID is a single day
dietary exposure model, and the DEEM-based Eating Occasion Analysis
accounts for reversibility within each simulated person-day. All of the
empirical data regarding time and amounts consumed (and corresponding
exposures based on the corresponding residues) from the CSFII survey
are used, along with the half-life to assess an equivalent persisting
dose that produced the peak inhibition expected over the course of that
day. This is a reasonable assumption for food alone; since the time
between exposure events across 2 days is relatively high (compared to
the half-life)--most children (>9 months) tend to sleep through the
night--and the time between dinner and breakfast the following morning
is long enough it is reasonable to ``ignore'' persisting effects from
the previous day. A single day exposure model will underestimate the
persisting effects from drinking water exposures (formula) among
infants, and newborns in particular (<3 months), since newborns tend to
wake up every 2 to 4 hours to feed. Any carry over effects may be
important, especially if exposures from the previous day are relatively
high, since the time between the last feeding (formula) of the day and
the first feeding of the subsequent day is short. A single day model
also does not account for the effect of seasonal variations in drinking
water concentrations, which will make this effect more pronounced
during the high use season (i.e., the time of year when drinking water
concentrations are high). Based on these analyses, the Agency concludes
that the current exposure assessment methods used in the carbofuran
dietary assessment provide realistic and high confidence estimates of
risk to carbofuran exposure through food and water.
    In summary, there are several factors that may cause EPA's
exposure/risk model to either understate or overstate exposure/risk. It
is unreasonable to present risks only incorporating factors that tend
to reduce exposure/risk estimates (e.g., recovery time), as Petitioners
suggest. EPA's approach of evaluating the impact that these factors may
have on the risk assessment is an appropriate method of taking all
relevant factors into account. Petitioners' objection to EPA's policy
decision to present acute risks in terms of 24-hours of exposure is
therefore denied because EPA's policy approach here is reasonable.
    2. Objection/hearing request subissue: Technical challenges to
EPA's calculated half-lives. Petitioners contend that EPA's calculation
of carbofuran half-lives of 186 minutes and 426 minutes were flawed,
and that the data instead support the use of a 150-minute half-life.
Petitioners identify three specific challenges: (1) Because one of the
time course studies showed that the time-to-peak effect was one hour,
EPA's assumption that the time-to-peak effect in each study was 15
minutes is incorrect; (2) EPA included the control rats in its
modeling, which distorts the estimated recovery half-life because it
incorporates AChE from animals that were not dosed and did not need to
recover; (3) Biochemically, the recovery half-lives of all NMC
chemicals should be the same, which supports the use of a 150-minute
half-life. In support of these claims, Petitioners offered a summary of
written testimony from Drs. Sielken and Valdez-Flores (Exhibit 9) and a
published study (Exhibit 10).
    i. Background. In the proposed rule, EPA relied on half-lives of
150 minutes and 300 minutes (73 FR 44887). These values were calculated
for the NMC cumulative risk assessment and so were intended to
encompass the half-lives for all of the NMC pesticides.
    In the final rule, EPA calculated half-lives specific to carbofuran
to ensure that its analyses accurately reflected carbofuran's risk.
Using the two FMC

time course studies in rat pups EPA calculated half-lives for recovery
of 186 and 426 minutes (Id). The two values were derived from two
different studies using rat pups of the same age (Refs. 24, 25); the
two values provide an indication that half-lives to recovery can vary
among juvenile rats. By extension, children are expected to vary in
their ability to recover from AChE inhibition where longer recoveries
would be associated with a potentially higher ``persisting dose.''
    ii. Denial of hearing request. The issue of the appropriate half-
lives for carbofuran is not material. Petitioners have proffered no
evidence to show that reliance on a 150-minute half-life rather than a
186-minute half-life would make a significant difference to their
estimates. By contrast, in the risk assessment supporting the final
rule, EPA's estimates show that the use of a 150-minute or 186-minute
half-life makes little or no difference. For example, EPA's estimated
exposures from food alone for children 1-2 were 43% of the aPAD,
assuming a 186-minute half-life, and 41% of the aPAD, assuming a 150-
minute half-life. Similarly, for infants, the estimates ranged from 31%
aPAD, assuming a 186-minute half-life, and 30% of the aPAD, assuming a
150-minute half-life. For all other age groups, the estimated exposures
were identical, whether one assumed a 150-minute or 186-minute half-
life.
    In any event, Petitioners' objection would have ultimately no
effect on the Agency's conclusion that the carbofuran tolerances are
not ``safe.'' Given EPA's assessments showing that a single exposure
can result in excessive risks to infants--a conclusion that Petitioners
have not challenged--the extent of recovery between subsequent
exposures is irrelevant. This conclusion alone provides an adequate
basis to revoke the carbofuran tolerances. Accordingly, because the
action would be the same even if the factual issue were resolved in the
manner sought, this request does not meet the standard for granting a
hearing (40 CFR 178.32(b)(3)).
    There is yet a further consideration affecting the materiality of
this objection. EPA's recalculation of half-lives in the final rule
would ordinarily mean that Petitioners could appropriately challenge
EPA's methodology for deriving the revised half-lives for the first
time in their objections. This is because the Petitioners would have
had no prior opportunity to challenge the manner in which these
estimates were developed, as EPA had not previously relied on
carbofuran-specific estimates. However in this case, the Petitioners
never commented on the 300-minute estimate EPA used in the proposal,
nor raised any issue to challenge the reliance on a longer half-life to
account for the variation in children's sensitivity. For the reasons
discussed in Unit VI.D, they have therefore waived any objection to use
of a 300-minute half-life. Accordingly, the question of whether the
Petitioners' half-life of 150-minutes or EPA's estimated half-life of
186-minutes is immaterial, since the lower amount of recovery
associated with the longer 300-minute half-life would be expected to
have a far greater impact than the use of a 186-minute half-life.
    EPA is also denying the hearing request because the evidentiary
proffer in support of this objection is inadequate. Petitioners have
not provided the underlying analyses conducted in support of their
calculated half-lives. The remainder of Exhibit 9 consists of
contentions that EPA's analyses were mistaken. In the absence of the
analyses that support their claim that the data support a half-life of
150 minutes, Petitioners' evidentiary proffer consists of no more than
mere allegations and denials. Hearings will not be granted on this
basis (40 CFR 178.32(b)(2)) (See 73 FR 42706 (July 23, 2008) (``NRDC
does no more than state `[w]e are aware of no statistical test' which
would support EPA's use of the Gledhill data. As EPA's regulations make
clear, a mere `denial' of an EPA position is not sufficient to satisfy
the standard for granting a hearing'') (citations omitted); 53 FR
53176, 53199 (December 30, 1998) (``Rather than presenting evidence
[the objector] asserts that FDA did not adequately justify its
conclusions. Such an assertion will not justify a hearing.'').
    The published paper in Exhibit 10 does not cure this defect. The
paper was submitted to support the claim that the Petitioners' 150-
minute half-life is consistent with the ``available literature on the
AChE recovery'' (Obj at 32). This evidence is immaterial. The Reiner
paper relates to the reactivation of the AChE enzyme; however the
relevant issue is not the reactivation of the cholinesterase enzyme,
but the level of chemical in that target tissue, which this study does
not address. Moreover, this study concludes that ``[I]t follows from
the data in Tables 1 and 2 that the rate of spontaneous reactivation
cannot be predicted, but must be separately determined for each
compound and each enzyme source (Exhibit 10 at 1). The paper did not
include data specifically on carbofuran, and it is therefore difficult
to see how this could be argued to support the Petitioners' half-life
of 150-minutes.
    iii. Denial of objection subissue. All of Petitioners' claims are
incorrect.
    Appropriate time to peak effect. The Petitioners claim that the
time to peak effect in the study with MRID 47143704 (Ref. 2) should
have been 1 hour instead of the 15 minutes EPA calculated. Petitioners
chose this value simply by choosing the data point with the highest
level of inhibition. But this approach is flawed in a number of
regards: First as a practical matter, using the same criteria on which
the Petitioners rely, the time to peak effect in MRID 46688913 (Ref. 3)
is 15 minutes. Petitioners have presented no basis for excluding those
results.
    More significantly, the Petitioners' approach fails to account for
the variability of the estimated AChE activity at each time point. As a
point of background, the level of the highest inhibition is not
something that can be observed, in the way that motor activity is
observed. To determine inhibition, samples are taken and measured--the
samples may or may not capture the highest point of inhibition; the
technician has not external indicia that will determine the moment of
the ``peak.'' Determining peak inhibition is estimated based on the
available measurements. But because measurements are generally
variable--the animals differ and the sampling itself is not identical,
as people cannot perfectly replicate their actions time after time--in
order to accurately capture the peak levels, the variability needs to
be accounted for. When, as here, the individual values are quite
variable, then for a half-life as long as carbofuran's, the sampling
variability will make the study means bounce up and down around a trend
line representing the true recovery rate. Figure 2 illustrates the
sampling variability of the measured AChE activity and its relationship
to EPA's modeling estimates for PND11 pups. In brief, this plots
observed versus predicted for all the data. Each little point is an
individual animal, while the time-group mean is the larger version of
the same plotting symbol. The vertical lines are the 95 percent
confidence intervals for each mean, the vertical lines. The diagonal
line in each figure is the identity line--i.e., the line all the data
would fall on if there were no variability and the model were perfect.
Normally, one would expect some random scatter about the identity line.
In such a case, simply visually picking the time with the lowest mean,
which is what the Petitioners have done, will

not be a very reliable way to estimate the time to peak effect.
[GRAPHIC] [TIFF OMITTED] TR18NO09.001

    Inclusion of data from control animals. It is standard scientific
practice to include concurrent control animals (i.e., animals that are
not dosed with the test substance) as part of any experimental design.
The purpose of controls is to determine the effects of the inevitable,
unexpected, and uncontrolled variations in experimental practice, such
as the biological variation between individual living animals. EPA's
model simply used control levels to establish a baseline against which
to evaluate the recovery of the treated animals. For example, as
discussed above, measurements of AChE activities may change, and that
concurrent controls are set up so that the same non-dose-related
factors that affect treated animals will also affect control animals.
Thus, EPA measured activity and computed inhibition based on measures
of activity in treated animals and concurrent control animals. Thus, if
the control animals showed that measured levels of AChE typically
varied by 5 percent, if the dosed animal showed inhibition levels of 20
percent, EPA would consider that only 15 percent of the inhibition
would be related to the chemical exposure. EPA did not estimate a half-
life of recovery for the control animals and incorporate that into the
estimated half-lives, which seems to be the Petitioners' allegation.
    Biochemically, the recovery half-lives of all NMC chemicals should
be the same. Although the Petitioners' claim that the recovery rate of
AChE inhibited by carbamate compounds is dictated by the commonly-
shared NMC carbamyl group is theoretically plausible, in reality, it is
not supported by the data on the NMC compounds. EPA had originally
hoped, based on the same mechanistic argument Petitioners make, that
half-lives would be the same across all NMCs, thus greatly simplifying
the cumulative risk assessment. It turned out, though, in the NMC data
sets analyzed for the NMC cumulative risk assessment, that estimated
recovery half-lives changed (generally, they got longer) as dose
increased, which is counter to the results that would be predicted from
the Petitioners' simple mechanistic argument (Ref. 81). Ultimately,
this is due to the fact that the relevant question is not the abstract
reactivation of the cholinesterase enzyme, but the level of chemical in
the living animal's target tissue, which is a function both of the
pharmacokinetics of the NMC (i.e., the rate at which the chemical is
absorbed, distributed among tissues, and eliminated) in the animal and
the rate of hydrolysis of the leaving group off the AChE molecule.
These parameters vary at least somewhat for the different carbamates,
accounting for the differences in half-lives between the NMC
pesticides.

H. Objection to EPA's Decision Not To Rely on Carbofuran Human Study

    Petitioners object to EPA's reliance on a default 10X interspecies
factor, which accounts for the uncertainties inherent in extrapolating
from animal data to the anticipated effects in humans. They argue, for
several reasons, that EPA should have instead used a 3X interspecies
factor. All of their arguments, however, depend on EPA consideration of
an oral carbofuran dosing study conducted in humans. EPA did not rely
on the cited human study because it found, taking into account the
advice of the HSRB, that the study was scientifically invalid. EPA's
Human Research rule prohibits EPA from considering scientifically
invalid human studies (40 CFR 26.1701). In their objections,
Petitioners argue that the HSRB's, and presumably EPA's, evaluation of
the scientific validity of the human study was flawed because (1) the
human study was not considered in light of the animal data on
carbofuran; (2) insufficient weight was given prior independent reports
on the value of the Arnold study which reached the opposite conclusion
from the HSRB; (3) the ``technical'' concerns raised by the HSRB are
addressed by ``the data within the study'' and that these ``technical''
deficiencies do not render the Arnold study unreliable.
    1. Background. There are three intentional dosing human studies
conducted with carbofuran that were conducted by J.D. Arnold in 1976,
1977, and 1978. One study was an oral ingestion toxicity study and two
studies were intended to evaluate toxicity from dermal exposure (Refs.
7, 8, 9). The oral study conducted with carbofuran was carried out in
nine healthy male

volunteers using an ascending dose schedule and single doses of 0.05,
0.1 and 0.25 mg/kg (Ref. 7). The two dermal toxicity studies were found
to have significant ethical deficiencies and the EPA's Human Studies
Review Board recommended against their use. The Petitioners do not
challenge the decision to disregard these studies.
    As previously noted, EPA did not rely upon any of the existing
intentional dosing human toxicity study deriving an acceptable level of
exposure for carbofuran. Instead, EPA relied on data conducted with
rats, and applied the default 10 x interspecies factor to account for
the potential uncertainty in extrapolating from animal data. EPA's
decision not to rely on the Arnold studies was made pursuant to its
Human Research rule. As explained in Unit III.B, that rule establishes
different ethical standards for the review of completed human studies
depending on whether they were initiated before or after the effective
date of the rule on April 7, 2006. For an intentional human exposure
study such as the Arnold studies, that was initiated prior to April 7,
2006, EPA is barred, subject to a very limited exception, from relying
on it if there is clear and convincing evidence that the conduct of the
research was fundamentally unethical or significantly deficient with
respect to the ethical standards prevailing at the time the research
was conducted (40 CFR 26.1704, 26.1706). Further, the rule limits the
human research that can be relied upon by EPA to ``scientifically valid
and relevant data'' (40 CFR 26.1701). Finally, because the Arnold study
was conducted with the purpose of identifying or measuring a toxic
effect, EPA is required by the rule to submit its determination
regarding these issues to an independent expert advisory body known as
the Human Studies Review Board (``HSRB'') for review. These procedures
were followed with regard to the Arnold study.
    The HSRB reviewed the Arnold oral and dermal carbofuran human
studies at its May, 2006 meeting (Refs. 7, 8, 9). The Board found
numerous technical deficiencies regarding the conduct of the oral study
and that overall, the weaknesses of the studies far outweigh the
strengths. These deficiencies included: (1) There was no justification
or rationale for the selection of doses used in any of the three
studies. (2) The sample size was very small (typically two subjects per
dose or condition) with few or no controls (no more than two control
subjects in any study). Such a design prevented evaluation of
statistical significance for any parameter measured in the studies. (3)
The values obtained for RBC and plasma cholinesterase levels were
highly variable. Factors that contributed to this variability included
the small sample size, the inclusion of only a single baseline sample
collected immediately prior to dosing used to compare all post-dosing
samples, the small number of control subjects, and an uncommon method
for analytical determination of cholinesterase activities. The
contribution of potential laboratory error cannot be ruled out. (4)
Plasma cholinesterase levels were highly variable in all studies so as
to preclude any useful interpretation. In general, plasma
cholinesterase levels were not consistent with changes in RBC
cholinesterase activities. (5) One subject who presented with abnormal
vestibular mechanisms in the pre-dose evaluation was used in the oral
study and showed serious symptoms after treatment. (6) Subjects were
allowed to smoke during the study period.
    In response to a specific request from the Agency, the Board
provided additional analysis concerning the potential for the data in
human subjects for carbofuran to be applied to: (1) The calculation of
a benchmark dose (BMD10) and identification of the
BMD10L (lower confidence limit); (2) the identification of a
NOAEL or LOAEL for effects or (3) the comparison to other species for
possible adjustments to uncertainty factor for the cumulative
assessment. The HSRB provided the following additional perspective
relative to the Agency's question:

    The utility of the human studies with carbofuran was limited by
the very small sample size used in all of the studies. The Agency
proposed to use the RBC cholinesterase data for determination of the
BMDL10. However, under conditions where the group size
was only two, it would be imperative to have highly accurate, valid,
reliable and consistent measures of RBC cholinesterase activity in
both control and carbofuran-treated subjects. This rigor was simply
not achieved in the human studies. Rather, RBC cholinesterase
activities were compared to a single baseline value, were highly
variable across subjects, including controls, and did not show any
consistency with plasma cholinesterase levels. As such, although EPA
scientists calculated a BMDL10 from the time course of
changes in RBC cholinesterase values in the nine subjects evaluated
in the oral study, the HSRB concluded that the accuracy and
reliability of this calculation was limited by the technical
shortcomings noted for the study. Therefore, the HSRB reiterated its
recommendation that the BMDL10 calculated by the Agency
from the human data should not be used.
    In a similar manner, the small sample size, compounded by the
lack of consistent changes in cholinesterase activities in all
studies, the inappropriate methods used for dermal application of
the compound in the dermal studies and the inclusion of at least one
subject who presented with abnormal vestibular function in a pre-
dose assessment limited the general utility of the data.
Collectively, the weaknesses in the conduct and outcomes of the
carbofuran human studies cast doubt on the utility of the data for
identifying a NOAEL or LOAEL or for comparing across species in
consideration of the interspecies uncertainty factor for the
cumulative risk assessment. Thus the majority of HSRB members agreed
the human oral data should not be used to identify a NOAEL or LOAEL,
and there was unanimous agreement that the human dermal data should
also not be used for these evaluations.

    The HSRB concluded that while these studies were informative, due
to the numerous technical issues regarding the conduct of the oral
study, overall, the weaknesses of the studies far outweigh the
strengths. Describing the studies as ``poor science,'' the HSRB
recommended against the use of the oral study conducted with carbofuran
in human subjects for the single chemical assessment or in informing
the interspecies uncertainty factor for the cumulative assessment.
    In their comments opposing EPA's proposal to revoke carbofuran
tolerances, Petitioners essentially raised the same arguments they
present in their objections.
    In responding to Petitioners' comments, EPA explained that it
agreed with the HSRB's conclusions that the studies were scientifically
flawed, and that, therefore, under the Human Research rule, EPA was
barred from considering them (Ref. 85 at 9).
    2. Denial of hearing request. The critical issue here is EPA's
determination under the Human Research rule that the Arnold study was
scientifically invalid. All of Petitioners' arguments concerning the
choice of the interspecies safety factor rely on EPA's consideration of
the Arnold study. As noted above, Petitioners make three arguments as
to why EPA erred in its determination. For the reasons discussed below,
none of those arguments satisfy the regulatory standard for granting a
hearing. Further, as explained in Unit VI.H.3., Petitioners' objections
to EPA's determination have no merit. Thus, there is no need to
consider Petitioners' more general arguments about EPA's decision to
use a 10X interspecies factor in assessing carbofuran's risk.
    Petitioners' first argument as to why EPA erred in its
determination that the Arnold study was scientifically invalid is that
EPA failed to consider the animal data on carbofuran in assessing the
scientific quality of the Arnold study. This claim is not material and
thus not

appropriate for a hearing (40 CFR 178.32(b)(3)). Under the Human
Research Rule, the relevant question is whether the Arnold study is
scientifically valid, not whether consideration of the Arnold study in
conjunction with the animal data could justify a lower interspecies
factor. EPA, and the HSRB, found the Arnold study to be flawed at its
core--due primarily to its small sample size and the high variability
in measurement of AChE inhibition--and no amount of data from other
studies in animals can cure these defects in the Arnold study. Thus,
Petitioners' claim here is irrelevant and immaterial to EPA's decision.
Ultimately, Petitioners' objection is a challenge to the policy
established in the Human Research rule that EPA will not routinely
consider all human data. They contend that ``[s]ince [human] data exist
for carbofuran, they should have been used to select the interspecies
uncertainty factor.'' However, this policy question is not open for
debate under the terms of the Human Research rule. And more
importantly, such a question does not provide a basis for a hearing (40
CFR 178.32(b)(1)).
    Second, Petitioners argue that insufficient weight was given the
prior independent reports on the Arnold study. However, the weight EPA
should give under the Human Research rule to pre-rule independent
reviews as opposed to the conclusions of the HSRB--the body established
by the rule for the purpose of aiding EPA's implementation of it--is a
legal/policy question and not a factual one. Hearings will not be
granted on legal/policy issues (40 CFR 178.32(b)(1)).
    Finally, Petitioners' claims that EPA and the HSRB identified
merely ``technical'' deficiencies in the Arnold study and that these
deficiencies are ``address[ed]'' by ``data within the study itself''
and, therefore, do not render the study ``unreliable'' are no more than
mere allegations and thus provide an insufficient basis for the
granting of a hearing (40 CFR 178.32(b)(2)). Petitioners have proffered
no evidence regarding the ``technical'' nature of the deficiencies in
the Arnold study or how the deficiencies in sample size or variability
are addressed within the study. Moreover, the record is clear that the
deficiencies in the study are fundamental in nature and a hearing will
not be granted on bald objections that are contradicted by the record
(73 FR 42696 (July 23, 2008) (hearing denied when objection was
contradicted by record and no evidence proffered in support)).
    3. Denial of objection. Petitioners have offered no response to
EPA's explanation for accepting the HSRB's reasoning as to the
weaknesses of the studies that rendered them scientifically invalid.
Specifically, Petitioners do not address the HSRB's conclusion, adopted
by EPA, that ``the weaknesses in the conduct and outcomes of the
carbofuran human studies cast doubt on the utility of the data for * *
* comparing across species in consideration of the interspecies
uncertainty factor.'' Nor do Petitioners offer any reason as to why the
HSRB's conclusion is not ``justifiable'' in light of the individual
peer review reports from Drs. Brimijoin, Chambers, and Pope. Actually,
there are several very good reasons for EPA to place primary weight on
the HSRB's report compared to the three individual reports from Drs.
Brimijoin, Chambers, and Pope prepared in 1997. First, the prior
reports were not produced under the rubric of the Human Research rule,
which has a different scope of inquiry than a traditional peer review.
Second, Drs. Brimijoin, Chambers, and Pope made their recommendation
regarding use of the Arnold study for a RfD in the context of a very
different overall database for carbofuran. A significant number of new
toxicity studies have been submitted since 1997. Third, Drs. Brimijoin,
Chambers, and Pope all noted the severe deficiencies in the Arnold
study but proposed that they be dealt with through the use of
additional safety factors. Given these considerations it was reasonable
for EPA to place primary reliance on the HSRB's report.
    The bulk of Petitioners' argument concerning EPA's determination on
the scientific validity of the Arnold study is devoted to suggesting
that the HSRB's review of the Arnold study was somehow ``inadequate''
because two members of the HSRB (Drs. Brimijoin and Chambers) were
recused from the review due to their prior participation in a prior
independent peer review. Petitioners also assert that the HSRB was
hampered because EPA ``never informed the HSRB that it could call upon
these experts for questioning or information regarding their prior peer
review of the human studies, nor was it informed of--or provided with--
those prior reviews.''
    These claims are wholly without merit. As laid out in a letter
responding to FMC's complaint regarding the recusal of Drs. Brimijoin
and Chambers from the HSRB review of the carbofuran human studies, the
recusal was entirely appropriate, and consistent with EPA's policies
and regulations. The facts outlined in that letter also demonstrate
that the HSRB's review was in no way restricted or hampered by the
limited recusal of the two Board members.
    First, the HSRB was fully apprised of the earlier peer review
reports. EPA relied on the reports because EPA's position before the
HSRB was that the Arnold study should be found to meet the standard of
the Human Research rule and would be useful in establishing points of
departure for the carbofuran's single chemical assessment and in
informing the interspecies uncertainty factor for the NMC CRA. It was
clearly in EPA's interest that the HSRB be made aware of the earlier
reports. In fact, the background materials provided to the Board
included the peer review reports by Drs. Brimijoin, Chambers, and Pope,
and the Agency's Weight-of-the-Evidence presentation to the HSRB which
noted the contributions of these reviewers. Further, both the peer
review reports and EPA's Weight-of-Evidence presentations were included
in the public docket for the HSRB review. To the extent that the HSRB
was still somehow unaware of the prior reports, FMC clearly referenced
them in both its written and oral comments to the Board.
    Second, EPA's determination on the recusal of Drs. Brimijoin and
Chambers was clearly consistent with Agency policy and well with EPA's
discretion. The EPA's Peer Review Handbook (3rd Edition) (Ref. 80)
provides guidance about peer review processes of the Agency. Of
particular relevance is the Handbook's guidance regarding independent
peer reviewers. While the Handbook notes that there is no prohibition
against using the same peer reviewer more than once on the same
product, it nevertheless advises that ``it is preferable to use
different people each time to provide a broader perspective (Ref. 80 at
13). Further the Handbook advises that the review of experts who ``have
participated substantially in the development of a product * * * may
not qualify as unbiased, independent peer review * * *'' (Id.).
Therefore, EPA concluded that, under the circumstances, a question
could be raised regarding the impartiality of Drs. Brimijoin and
Chambers from the particular matter under review by the HSRB. Further
support on this point can be found in the regulations at 5 CFR
2635.502(a)(2), and in the preamble to the original regulation (56 FR
33778 (July 23, 1991)).
    In light of these considerations, EPA addressed the appearance
issue regarding Drs. Brimijoin and Chambers by determining whether
authorization by the Agency designee should be invoked (see, 5 CFR
2635.502(d)). Three factors were particularly relevant to the
determination of Drs. Brimijoin and Chambers (see, 5 CFR
2635.502(d)(4), (5), and (6)): the sensitivity of the

matter, the difficulty of reassigning the matter to another employee,
and adjustments that may be made in the employee's duties that would