impacts. Considering the cost-effectiveness (for all pollutants) of the
beyond-the-floor control measures, which averaged $27,000 per ton for
large units and $940 million per ton for small units, EPA determined
that the beyond-the-floor measures were not reasonable and, therefore,
MACT for new units is based on the MACT floor level of control for all
of the subcategories.
2. Existing Units
    The Court raised three specific concerns regarding EPA's approach
for existing units in concluding that EPA had not adequately explained
why the combination of regulatory and uncontrolled (i.e., combustion-
controlled) data provided a ``reasonable

estimate'' of HMIWI performance. First, the Court ruled that EPA did
not discuss the possibility that HMIWI might be substantially
overachieving the regulatory limits, which would result in those limits
having little value in estimating the top 12 percent of HMIWI
performance (167 F.3d at 663). Second, the Court found that EPA gave no
reason for believing that HMIWI that were not subject to regulatory
limits did not employ any emission controls. Without this, the Court
concluded it was unable to assess the rationality in using
``uncontrolled'' (i.e., combustion-controlled) data for the units that
were not subject to regulatory requirements (167 F.3d at 664). Third,
the Court held that even if the regulatory data was a good proxy for
the better controlled units and there were shortfalls in reaching the
necessary 12 percent, EPA did not explain why it was reasonable to use
the highest of its test run data to make up the gap. Id.
    With regard to the Court's first concern, additional Court rulings
issued after EPA's 2007 proposed response to the remand and public
comments regarding the 2007 proposal gave us reason to revisit our MACT
floor methodology, including the use of State regulations and State-
issued permits as a surrogate for estimated actual emission limitations
achieved. A comparison between the regulatory limits and emissions test
data in the 1997 record indicate that in some instances the emissions
data was higher than or about the same as the regulatory limit, but in
most instances the regulatory limit was higher than the emissions data.
Thus, we are no longer confident that the regulatory limits in the 1997
record provided a reasonable estimate of emission limitations for HMIWI
operating at that time. Use of those particular regulatory limits as
surrogates for actual emissions levels achieved also would not account
for factors other than control technology that we have since learned in
fact affect HMIWI performance. These uncertainties are two of the
reasons that this action's proposed remand response is not based on
information in the 1997 record but, rather, on data for the 57
currently operating HMIWI. This is not to say that as a general matter
it is inappropriate to use regulatory limits as a means to estimate the
emissions limitations achieved by best performing sources. In some
cases, it may be that such regulatory limits can be shown to reflect
the emissions performance achieved by both add-on controls and other
measures that affect such performance. In the case of HMIWI, however,
the regulatory data used in support of the 1997 rule was not adequate
for this, and cannot be used to support a MACT floor determination that
comports with the requirements of the CAA as interpreted by the Court.
    The Court's second concern was that EPA had not made a finding that
HMIWI that were not subject to regulatory requirements did not use
emissions controls of any kind. The Court viewed such a finding as a
necessary prerequisite to using uncontrolled (i.e., combustion-
controlled) data for units not subject to regulatory requirements. EPA
continues to view the 1997 record as showing that most HMIWI were not
at that time equipped with add-on air pollution control. Therefore, the
use of uncontrolled emission estimates for units for which where there
was no indication air pollution control technology was in place and
applicable regulatory limits allowed higher levels of emissions than
our combustion-controlled emissions values reflected, was warranted for
purposes of identifying emissions levels achieved by combustion-control
alone. However, it did not necessarily reflect emissions levels as
influenced by measures other than the use (or lack of use) of add-on
control technology, such as waste segregation. EPA's decision to use
data for the 57 currently operating HMIWI to re-propose a response to
the Court remand fully addresses the Court's concern, in that the data
reflect all measures, add-on control technology or otherwise, that
affect the emissions levels achieved by the best performing sources.
For each HMIWI, we have detailed information regarding control
technologies used, as well as actual emissions data resulting from the
use of those technologies and any other measures.
    The Court's third concern regarded our use of the highest of the
test run data to reflect uncontrolled (i.e., combustion-controlled)
emissions in cases where regulatory data did not comprise the necessary
12 percent of best performing sources. As described below, the
methodology that supports this action does not continue that approach.
    a. Development of the MACT Floors and Proposed Emission Limits for
Existing Units. When establishing the MACT floors for existing units,
section 129(a)(2) of the CAA requires that EPA determine the average
emissions limitation achieved by the ``best performing 12 percent of
units'' in a source category. Thus, EPA must determine some measure of
the average emissions limitation achieved by the best performing 12
percent of HMIWI within each subcategory for each pollutant to be
regulated. The MACT floor for existing units is based on the level of
``emissions control'' that is attained by any emission reduction
strategies used by the best performing 12 percent of HMIWI. As is the
case with new HMIWI, the use of actual emissions levels in the MACT
floor determinations supporting the proposed emission limits for
existing HMIWI accounts for all emission reduction strategies (i.e.,
add-on controls or other emission reducing measures) used by individual
HMIWI.
    We are retaining the large, medium, small, and small rural
subcategories from the 1997 rulemaking. As previously explained, we
continue to consider these subcategories to be ``classes'' of similar
units in that all units within each ``class'' have been subject to the
same regulatory requirements in the 1997 HMIWI standards. Thus, we
believe it is appropriate to determine MACT floors and proposed
emission limits using data for HMIWI within each ``class'' and to then
apply those revised emission limits to those same HMIWI within each
``class.''
    Within each subcategory and for each pollutant, EPA determined the
best performing 12 percent of HMIWI based on an examination of average
emissions levels for each HMIWI. (Note that section 129 of the CAA does
not include the section 112 text regarding the MACT floor for existing
sources being based on the best performing 5 sources where there are
fewer than 30 sources in the category or subcategory.) In determining
how many HMIWI comprise the best performing 12 percent, we rounded up
the number of sources to the next whole number. This ensures that the
CAA section 129 requirement to consider the best performing 12 percent
of sources is met, as not rounding up would result in a number of
sources that would be less than 12 percent. Further, rounding of a
sample size is a common sampling technique (Cochran, William G.
Sampling Techniques. Third Edition. John Wiley & Sons, 1977. page 76
and pages 72-87).
    Table 8 of this preamble presents the total number of HMIWI in each
subcategory and the number of HMIWI that comprise the best performing
12 percent of units (i.e., the MACT floor pool) for each subcategory.

 Table 8--Number of HMIWI That Are in Each Subcategory and That Comprise
                             the MACT Floors
------------------------------------------------------------------------
                                                             Number of
                Unit size                  Total number    HMIWI in MACT
                                             of HMIWI       floor pool
------------------------------------------------------------------------
Large...................................              36               5
Medium..................................              17               3
Small...................................               2               1
Small Rural.............................               2               1
------------------------------------------------------------------------

    The next step in the MACT analysis for existing HMIWI was to
determine the average emission limitation achieved by the best-
performing 12 percent of existing sources. Our general approach to
identifying the average emission limitation has been to use a measure
of central tendency, such as the arithmetic mean or the median. First,
unit average emissions for each pollutant within each subcategory were
ranked from lowest to highest. Then, a MACT floor emissions level for
each pollutant was identified based on the arithmetic mean of the
emissions values for the best performing 12 percent of HMIWI within
each subcategory. MACT floors for each pollutant within each
subcategory, with the exceptions of NOX and SO2
for small HMIWI, were based on this approach. As previously explained,
we do not have any NOX or SO2 emissions data for
the two small HMIWI because they have not tested for NOX or
SO2 and are not required to do so by the 1997 HMIWI
standards. Both small units use wet scrubbers, as do the best
performing 12 percent of medium HMIWI (3 units) with respect to
NOX and SO2. In both of these instances, the
NOX and SO2 emission limits being proposed for
existing medium HMIWI also are being proposed for existing small units,
since they employ the same emissions control technology, and we do not
have information suggesting that the small units are employing other
measures that would further affect their emissions performance. A
summary of the various add-on control technologies used, in addition to
any other emission reduction measures, by the best performing 12
percent HMIWI on a pollutant-specific basis for existing large and
medium HMIWI is presented in Table 9 of this preamble.

 Table 9--Summary of Add-On Control Technologies for Best Performing 12
                    Percent of Large and Medium HMIWI
------------------------------------------------------------------------
            Pollutant                 Large HMIWI        Medium HMIWI
------------------------------------------------------------------------
HCl.............................  wet scrubber......  wet scrubber
CO..............................  wet scrubber; dry   dry scrubber; wet
                                   scrubber; fabric    scrubber
                                   filter.
Pb..............................  carbon adsorber/    dry scrubber
                                   wet scrubber; dry
                                   scrubber.
Cd..............................  carbon adsorber/    dry scrubber
                                   wet scrubber; dry
                                   scrubber.
Hg..............................  fabric filter; wet  wet scrubber
                                   scrubber; carbon
                                   adsorber/wet
                                   scrubber; dry
                                   scrubber.
PM..............................  dry scrubber; dry   dry scrubber; wet
                                   scrubber/wet        scrubber
                                   scrubber; fabric
                                   filter.
CDD/CDF.........................  dry scrubber;       wet scrubber
                                   carbon adsorber/
                                   wet scrubber; wet
                                   scrubber.
NOX.............................  carbon adsorber/    wet scrubber
                                   wet scrubber; wet
                                   scrubber; dry
                                   scrubber.
SO2.............................  dry scrubber; wet   wet scrubber
                                   scrubber.
------------------------------------------------------------------------

    Table 10 of this preamble presents the same information for
existing small HMIWI and for existing small HMIWI meeting the rural
criteria.

 Table 10--Summary of Add-On Control Technologies for Best Performing 12
                 Percent of Small and Small Rural HMIWI
------------------------------------------------------------------------
            Pollutant                 Small HMIWI      Small Rural HMIWI
------------------------------------------------------------------------
HCl.............................  wet scrubber......  combustion control
CO..............................  wet scrubber......  combustion control
Pb..............................  wet scrubber......  combustion control
Cd..............................  wet scrubber......  combustion control
Hg..............................  wet scrubber......  combustion control
PM..............................  wet scrubber......  combustion control
CDD/CDF.........................  wet scrubber......  combustion control
NOX.............................  wet scrubber......  combustion control
SO2.............................  wet scrubber......  combustion control
------------------------------------------------------------------------

    We then used emissions data for those best performing 12 percent
HMIWI to determine emission limits to be proposed, with an accounting
for variability. As previously explained in this preamble with respect
to development of emission limits for new HMIWI, EPA must exercise its
judgment, based on an evaluation of the relevant factors and available
data, to determine the level of emissions control that can be
customarily achieved by the best performing HMIWI under variable
conditions. To account for pollutant-specific variability at the best
performing HMIWI, we used emissions data for each test run conducted by
the best performing 12 percent of HMIWI within each subcategory. The
amount of pollutant-specific test data for the best performing 12
percent HMIWI within each subcategory varies from 33 data points to 60
data points for large units; 9 data points to 70 data points for medium
units; 3 data points to 12 data points for small units (excluding
NOX and SO2 for which there is no data for small
units); and 3 data points to 4 data points for small rural units.
Similar to the analyses for new HMIWI, we determined use of the 99.9
percent UCL to be an appropriate method of estimating variability. The
UCL represents the statistical likelihood that a value, in this case an
emission value from the average source in the best performing 12
percent of sources, will fall at or below the UCL value. The 99.9
percent UCL is appropriate for use in this analysis because sources
must meet the standards at all times, and the limited amount of test
data introduces a degree of uncertainty. To calculate the emission
limit, including variability, we used the equation: 99.9 percent UCL =
mean + 3.09 * standard deviation. The mean and standard deviation are
based on the test runs for the best performing 12 percent HMIWI for
each pollutant. Accounting for variability using the 99.9 percent UCL
means: ``For each pollutant, the performance of the average HMIWI
within the best performing 12 percent HMIWI is estimated to meet (i.e.,
not exceed) the emission limit 99.9 percent of the time.'' As described
for new HMIWI, the emission values adjusted for variability are
presented with two significant figures. After determining the MACT
floor-based emission limits for each pollutant, EPA examined additional
measures that could be taken to further reduce emissions. Table 11 of
this preamble presents a summary of the emissions reductions and costs
associated with the beyond-the-floor options for each subcategory.

             Table 11--Summary of Beyond-the-Floor Emissions Reductions and Costs for Existing HMIWI
----------------------------------------------------------------------------------------------------------------
                                                                                Small rural
                                                    Large HMIWI    Medium HMIWI     Small HMIWI        HMIWI
                    Pollutant                       reductions,     reductions,     Reductions,     reductions,
                                                      lb/yr a         lb/yr a         lb/yr a         lb/yr a
----------------------------------------------------------------------------------------------------------------
HCl.............................................           8,000             110               0             570
CO..............................................           1,900             160              57               0
Pb..............................................              47            0.23             3.4            0.32
Cd..............................................              11               0               0            0.18
Hg..............................................              39             0.8            0.12               0
PM..............................................           5,400           1,100             180               0
Total CDD/CDF...................................             1.9           0.032           0.033            0.21
TEQ.............................................           0.027               0               0          0.0047
NOX.............................................         280,000          30,000           3,400             190
SO2.............................................           6,700           1,000             140              58
Total...........................................         300,000          32,000           3,800             820
BTF Cost........................................     $14,000,000      $1,200,000        $500,000        $390,000
----------------------------------------------------------------------------------------------------------------
a Sums of individual numbers may not equal totals due to internal rounding. CDD/CDF and TEQ emissions in grams
  per year.

    As discussed in section IV.A.2.b of this preamble, EPA determined
that these additional beyond-the-floor measures are not reasonable
based on the high costs that would be incurred and the minimal
additional emissions reductions that could be achieved. Therefore, all
of the emission limits proposed in this action for existing HMIWI are
based on the MACT floor level of control.
    A summary of the pollutant-specific average emissions associated
with the best performing 12 percent HMIWI, the emission values adjusted
for variability, and the emission limits being proposed for existing
HMIWI are presented in Table 12 of this preamble.

Table 12--Summary of Average Emission Values, Emission Values With Variability, and Emission Limits for Existing
                                                      HMIWI
----------------------------------------------------------------------------------------------------------------
                                                                     Average      Emission value     Proposed
              Pollutant  (units)                  Unit size\1\      emission           with       emission limit
                                                                    value\2\      variability\2\        \2\
----------------------------------------------------------------------------------------------------------------
HCl (ppmv)....................................                L         0.47             2.38             2.4
                                                             M          0.60             2.50             2.5
                                                             S          1.03             4.47             4.5
                                                            SR        135              432              440
CO (ppmv).....................................                L         1.03             3.88             3.9
                                                             M          0.95             2.96             3.0
                                                             S          2.27             8.18             8.2
                                                            SR          5.4             11.9             12
Pb (mg/dscm)..................................                L         0.0032           0.0130           0.013
                                                             M          0.0041           0.0163           0.017
                                                             S          0.073            0.174            0.18
                                                            SR          0.226            0.346            0.35
Cd (mg/dscm)..................................                L         0.00077          0.00408          0.0041
                                                             M          0.00116          0.00701          0.0071
                                                             S          0.0026           0.0115           0.012
                                                            SR          0.0380           0.0671           0.068
Hg (mg/dscm)..................................                L         0.00210          0.00943          0.0095
                                                             M          0.00136          0.00782          0.0079
                                                             S          0.00292          0.00742          0.0075
                                                            SR          0.00158          0.00391          0.0040
PM (gr/dscf)..................................                L         0.00143          0.00559          0.0056
                                                             M          0.0036           0.0119           0.012
                                                             S          0.0076           0.0167           0.017
                                                            SR          0.0128           0.0294           0.030
CDD/CDF, total (ng/dscm)......................                L         0.37             1.54             1.6
                                                             M          0.158            0.621            0.63
                                                             S          2.89             8.28             8.3
                                                            SR         30              122              130
CDD/CDF, TEQ (ng/dscm)........................                L         0.0074           0.0282           0.029
                                                             M          0.00306          0.00970          0.0097
                                                             S          0.00453          0.00792          0.0080
                                                            SR          0.62             2.59             2.6
NOX (ppmv)....................................                L        73              135              140
                                                             M         63              193              200
                                                             S         63          \3\ 193          \3\ 200
                                                            SR         95              110              110
SO2 (ppmv)....................................                L         0.80             2.71             2.8
                                                             M          0.90             2.79             2.8
                                                             S          0.90         \3\ 2.8          \3\ 2.8

                                                            SR         22.6             42.7            43
----------------------------------------------------------------------------------------------------------------
\1\ L = Large; M = Medium; S = Small; SR = Small Rural.
\2\ All values are measured at 7 percent oxygen.
\3\ Emission value reflects data from best performing medium HMIWI.

    Table 13 of this preamble summarizes the emission limits
promulgated in 1997, the emission limits proposed in 2007 in response
to the Court's remand, and the emission limits being proposed in this
action in response to the Court's remand for existing HMIWI.

   Table 13--Summary of 1997 Promulgated Emission Limits, Emission Limits Proposed in 2007 in Response to the
        Remand, and Emission Limits Currently Being Proposed in Response to the Remand for Existing HMIWI
----------------------------------------------------------------------------------------------------------------
                                                                                Proposed
                                                                               Remand response        remand
        Pollutant  (units)            Unit size\1\   Promulgated limit \2\    limit proposed in   response limit
                                                                                2007 \2\              \2\
----------------------------------------------------------------------------------------------------------------
HC1 (ppmv)........................                L  100 or 93% reduction.  78 or 93% reduction.          2.4
                                                 M   100 or 93% reduction.  78 or 93% reduction.          2.5
                                                 S   100 or 93% reduction.  78 or 93% reduction.          4.5
                                                SR   3,100................  3,100...............        440
CO (ppmv).........................                L   40..................  40..................          3.9
                                                 M   40...................  40..................          3.0
                                                 S   40...................  40..................          8.2
                                                SR   40...................  40..................         12
Pb (mg/dscm)......................                L  1.2 or 70% reduction.  0.78 or 71%                   0.013
                                                                             reduction.
                                                 M   1.2 or 70% reduction.  0.78 or 71%                   0.017
                                                                             reduction.
                                                 S   1.2 or 70% reduction.  0.78 or 71%                   0.18
                                                                             reduction.
                                                SR   10...................  8.9.................          0.35
Cd (mg/dscm)......................                L  0.16 or 65% reduction  0.11 or 66%                   0.0041
                                                                             reduction.
                                                 M   0.16 or 65% reduction  0.11 or 66%                   0.0071
                                                                             reduction.
                                                 S   0.16 or 65% reduction  0.11 or 66%                   0.012
                                                                             reduction.
                                                SR   4....................  4...................          0.068
Hg (mg/dscm)......................                L  0.55 or 85% reduction  0.55 or 87%                   0.0095
                                                                             reduction.
                                                 M   0.55 or 85% reduction  0.55 or 87%                   0.0079
                                                                             reduction.
                                                 S   0.55 or 85% reduction  0.55 or 87%                   0.0075
                                                                             reduction.
                                                SR   7.5..................  6.6.................          0.0040
PM (gr/dscf)......................                L  0.015................  0.015...............          0.0056
                                                 M   0.03.................  0.030...............          0.012
                                                 S   0.05.................  0.050...............          0.017
                                                SR   0.086................  0.086...............          0.030
CDD/CDF, total (ng/dscm)..........                L  125..................  115.................          1.6
                                                 M   125..................  115.................          0.63
                                                 S   125..................  115.................          8.3
                                                SR   800..................  800.................        130
CDD/CDF, TEQ (ng/dscm)............                L  2.3..................  2.2.................          0.029
                                                 M   2.3..................  2.2.................          0.0097
                                                 S   2.3..................  2.2.................          0.0080
                                                SR   15...................  15..................          2.6
NOX (ppmv)........................                L  250..................  250.................        140
                                              M, S   250..................  250.................        200
                                                SR   250..................  250.................        110
SO2 (ppmv)........................                L, 55...................  55..................          2.8
                                                SR   55...................  55..................        43
----------------------------------------------------------------------------------------------------------------
\1\ L = Large; M = Medium; S = Small; SR = Small Rural.
\2\ All emission limits are measured at 7 percent oxygen.

    b. Consideration of Options More Stringent than the MACT Floor for
Existing HMIWI. As discussed earlier regarding new HMIWI, after
establishing the MACT floor emission level for each pollutant for
existing sources, EPA is required to look ``beyond-the-floor'' at
additional measures that could be taken to further reduce emissions.
The beyond-the-floor options for large and medium HMIWI included the
addition of wet scrubber or DIFF controls (for units not already
projected to be operating both types of controls based on the MACT
floor requirements); replacement of DIFF controls; increased activated
carbon, sodium bicarbonate, and/or caustic usage; combustion
improvements; and addition of SNCR. For some units, no beyond-the-floor
measures were identified because we

estimated that to achieve the MACT floor limits, those units would have
to use all available add-on controls and other control measures. The
beyond-the-floor options for small units included addition of DIFF
controls, increased activated carbon and/or caustic usage, combustion
improvements, and addition of SNCR. EPA analyzed the additional air
pollutant reductions, costs, and secondary impacts for the beyond-the-
floor options, and detailed information on the analyses are available
in a memorandum entitled ``Analysis of Beyond-the Floor Options'' that
is included in the docket. Considering the cost-effectiveness (for all
pollutants) of the beyond-the-floor control measures, which averaged
$167,000 per ton for large units, $118,000 per ton for medium units,
$325,000 for small units, and $1.3 million per ton for small rural
units, EPA determined that the beyond-the-floor measures were not
reasonable and, therefore, MACT is based on the floor level of control
for all of the subcategories.
3. Opacity Limits for New and Existing Units
    EPA also is proposing a revised opacity standard for new and
existing HMIWI as part of responding to the Court's remand. The 1997
standards require that opacity testing be conducted according to EPA
Test Method 9 of appendix A-4 of 40 CFR part 60. Method 9 specifies
that opacity shall be determined as an average of 24 consecutive
observations recorded at 15-second intervals (i.e., 6-minute block
average). Method 9 also specifies that opacity observations shall be
recorded to the nearest 5 percent at 15-second intervals. The opacity
data that we have is in terms of averages rather than single opacity
readings. Based on these averages alone, without any accounting for
variability, the MACT floor for new units, as well as existing units,
would be 0 percent. We then considered how to appropriately account for
variability given the differences in opacity testing versus testing for
the 9 regulated pollutants. We have continuous opacity monitoring
system (COMS) data for an HMIWI that is in the MACT floor pool for PM
for existing medium units. In that instance, we can determine the
single highest opacity reading. Because the level of opacity can be
impacted by the amount, type, and particle characteristics of PM in the
gas stream, as well as process operation, we believe that using the
highest opacity reading from one of the best performing HMIWI with
respect to PM is an appropriate method for determining the opacity
level that has been achieved under variable conditions. While opacity
may not be a reliable indicator of short-term mass emissions, opacity
can serve as an indicator of and provide qualitative information on the
operation and maintenance of particulate control equipment (Current
Knowledge of Particulate Matter (PM) Continuous Emission Monitoring,
EPA-454/R-00-039, September 2000). When PM emissions control devices
are operated and maintained in the same manner as during successful PM
emissions testing, our expectation is that PM emissions from those
sources meet the standards. Therefore, as a continuous check on proper
operation and maintenance of PM control devices, opacity can serve as
an appropriate surrogate for PM emissions. The single highest COMS
reading for the HMIWI that is in the MACT floor pool for PM is 1.1
percent. EPA commonly sets opacity standards based on whole numbers,
and rounding down would cause the unit upon which the standard is based
to have demonstrated performance at a level that would not meet the
standard. Thus, we rounded up and are proposing a MACT-floor based
opacity limit of 2 percent for both new and existing HMIWI.
4. Percent Reduction Limits for New and Existing Units
    The 1997 standards included percent reduction limits for HCl, Pb,
Cd, and Hg for new and existing HMIWI. For those pollutants, sources
have had the option of demonstrating compliance by meeting the emission
limits (expressed as emissions rates) or the percent reduction limits.
For the 1997 rule, the percent reduction limits were developed using
the pollutant concentrations at the inlet and outlet of a control
device and reflected only the efficiency of the control device in
reducing specific pollutants. Because, as previously explained in this
preamble, factors other than control technology affect pollutant
emissions from HMIWI, and because we did not take these factors into
account when we set the 1997 standards based on percent reduction, we
now believe it is inappropriate to provide in this rule percent
reduction limits based only on control technology performance.
Moreover, not many HMIWI determined the efficiency of their control
devices, and none of the HMIWI used the percent reduction limits to
demonstrate compliance with the 1997 rule. None of the HMIWI
demonstrated compliance with the Pb, Cd, or Hg percent reduction limits
or even conducted the testing necessary to determine the efficiency of
their control devices. No medium or small HMIWI demonstrated compliance
with the HCl percent reduction limits or conducted control device inlet
and outlet testing. Eight large HMIWI tested for HCl at their control
device inlets and outlets, but all of those units were in compliance
with the HCl emission limit and, therefore, didn't need to rely on
their control technology efficiency calculations to show that,
alternatively, they were in compliance with the HCl percent reduction
limit. None of these eight large HMIWI are among the best performing 12
percent of large units for HCl (i.e., HCl emissions based only on
control technology outlet testing). Therefore, this action does not
propose revised percent reduction limits, and proposes to eliminate the
continued use of the 1997 percent reduction limits after the compliance
date of the proposed revised emission limits.

B. Rationale for the Proposed CAA Section 129(a)(5) 5-Year Review
Response

    Earlier in today's notice, we explained that section 129(a)(5)
provides the Agency with broad discretion to revise MACT standards for
incinerators.
    As we explained, we do not interpret section 129(a)(5) as requiring
that EPA in each round of review re-calculate MACT floors, and we
regard the D.C. Circuit's recent ruling in NRDC and LEAN v. EPA, in
which the Court held that the similar review requirement in section
112(d)(6) does not require a MACT floor re-calculation, as supporting
our view. Nevertheless, given the unique facts of this rulemaking, in
which due to issues with respect to the 1997 rulemaking record we have
had to re-calculate MACT floors based on more recent data in response
to the remand at a point in time following the statutory deadline for
conducting the section 129(a)(5) review, it may appear that we are
performing the ``MACT-on-MACT'' review that we believe is not
statutorily required by section 129(a)(5). We stress that our proposed
revised standards are the result of what we now think is necessary to
satisfy our initial duties under section 129(a)(2) to have set MACT
limits for HMIWI, in response to the Court's remand. Our action today
does not reflect an independent MACT floor reassessment performed only
under section 129(a)(5). However, since today's proposed revised
standards do reflect the emissions levels currently achieved in
practice by the best performing HMIWI, and we have no other information
that would cause us to reach different conclusions were a section
129(a)(5) review to be conducted in isolation, we believe that this

rulemaking responding to the Court's remand, based on the most current
HMIWI emissions information, will necessarily discharge our instant
duty under section 129(a)(5) to review and revise the current
standards.
    In performing future 5-year reviews of the HMIWI standards, we do
not intend to recalculate new MACT floors, but will instead propose to
revise the emission limits to reflect the actual performance of the
emission reduction techniques that formed the basis of MACT, consistent
with our interpretation as presented earlier in today's notice. We
believe this approach reflects the most reasonable interpretation of
the review requirement of CAA section 129(a)(5), and is consistent with
how we have interpreted the similar review requirement of CAA section
112(d)(6) regarding MACT standards promulgated under section 112.
    We believe that this action's proposed remand response fulfills our
obligations regarding the first 5-year review of the HMIWI standards
because the revised MACT floor determinations and emission limits
associated with the remand response are based on performance data for
the 57 currently operating HMIWI that are subject to the 1997 standards
and account for all non-technology factors that affect HMIWI
performance. The proposed remand response also addresses whether new
technologies and processes and improvements in practices have been
demonstrated at HMIWI subject to the 1997 standards. Table 14 of this
preamble provides a comparison between the emission limits promulgated
in 1997, the emission limits proposed in 2007 in response to the 5-year
review requirement, and the emission limits being proposed in this
action in response to the Court's remand for new HMIWI.

  Table 14--Summary of 1997 Promulgated Emission Limits, Emission Limits Proposed in 2007 in Response to the 5-
  Year Review Requirement, and Emission Limits Currently Being Proposed in Response to the Remand for New HMIWI
----------------------------------------------------------------------------------------------------------------
                                                                                Proposed
                                      Unit size                             5-Year review limit       remand
         Pollutant  (units)              \1\      Promulgated limit \2\    proposed in 2007 \2\   response limit
                                                                                \2\
----------------------------------------------------------------------------------------------------------------
HCl (ppmv)..........................          L  15 or 99% reduction....  15 or 99% reduction...         0.75
                                             M   15 or 99% reduction....  15 or 99% reduction...         1.8
                                             S   15 or 99% reduction....  15 or 99% reduction...         4.5
CO (ppmv)...........................          L  40.....................  25....................         2.9
                                             M   40.....................  25....................         1.9
                                             S   40.....................  25....................         8.2
Pb (mg/dscm)........................          L  0.07 or 98% reduction..  0.060 or 99% reduction         0.00047
                                             M   0.07 or 98% reduction..  0.060 or 99% reduction         0.016
                                             S   1.2 or 70% reduction...  0.64 or 71% reduction.         0.18
Cd (mg/dscm)........................          L  0.04 or 90% reduction..  0.0050 or 99%                  0.00012
                                                                           reduction.
                                             M   0.04 or 90% reduction..  0.0050 or 99%                  0.0071
                                                                           reduction.
                                             S   0.16 or 65% reduction..  0.060 or 74% reduction         0.012
Hg (mg/dscm)........................          L  0.55 or 85% reduction..  0.19 or 96% reduction.         0.00093
                                             M   0.55 or 85% reduction..  0.19 or 96% reduction.         0.0020
                                             S   0.55 or 85% reduction..  0.33 or 96% reduction.         0.0075
PM (gr/dscf)........................          L  0.015..................  0.0090................         0.0048
                                             M   0.015..................  0.0090................         0.0099
                                             S   0.03...................  0.018.................         0.017
CDD/CDF, total (ng/dscm)............          L  25.....................  16....................         0.60
                                             M   25.....................  16....................         0.35
                                             S   125....................  111...................         8.3
CDD/CDF, TEQ (ng/dscm)..............          L  0.6....................  0.21..................         0.014
                                             M   0.6....................  0.21..................         0.0097
                                             S   2.3....................  2.0...................         0.0080
NOX (ppmv)..........................          L  250....................  212...................       110
                                          M, S   250....................  212...................        38
SO2 (ppmv)..........................          L  55.....................  21....................         1.9
                                             M   55.....................  21....................         0.78
                                             S   55.....................  28....................         0.78
----------------------------------------------------------------------------------------------------------------
\1\ L = Large; M = Medium; S = Small.
\2\ All emission limits are measured at 7 percent oxygen.

    With two exceptions, the emission limits for new HMIWI being
proposed in this action are more stringent than the 5-year review
emission limits proposed in 2007. The Cd and PM emission limits for new
medium units being proposed in this action are higher than the 5-year
review limits proposed in 2007 (0.0050 mg/dscm versus 0.0081 mg/dscm
for Cd; and 0.0090 gr/dscf versus 0.0099 gr/dscf for PM). As explained
with respect to PM emissions in Table 7 of this preamble, there are
several potential causes for these differences in emission limits.
There are three fewer medium HMIWI now and we have more emissions data
to consider.
    Table 15 of this preamble provides a comparison between the
emission limits promulgated in 1997, the emission limits proposed in
2007 in response to the 5-year review requirement, and the emission
limits being proposed in this action in response to the Court's remand
for existing HMIWI.

  Table 15--Summary of 1997 Promulgated Emission Limits, Emission Limits Proposed in 2007 in Response to the 5-
  Year Review Requirement, and Emission Limits Currently Being Proposed in Response to the Remand for Existing
                                                      HMIWI
----------------------------------------------------------------------------------------------------------------
                                                                                Proposed
                                         Unit                               5-Year review limit       remand
         Pollutant  (units)            size\1\    Promulgated limit \2\    proposed in 2007 \2\   response limit
                                                                                \2\
----------------------------------------------------------------------------------------------------------------
HCl (ppmv)..........................          L  100 or 93% reduction...  51 or 94% reduction...         2.4
                                             M   100 or 93% reduction...  51 or 94% reduction...         2.5
                                             S   100 or 93% reduction...  51 or 94% reduction...         4.5
                                            SR   3,100..................  398...................       440
CO (ppmv)...........................          L  40.....................  25....................         3.9
                                             M   40.....................  25....................         3.0
                                             S   40.....................  25....................         8.2
                                            SR   40.....................  25....................        12
Pb (mg/dscm)........................          L  1.2 or 70% reduction...  0.64 or 71% reduction.         0.013
                                             M   1.2 or 70% reduction...  0.64 or 71% reduction.         0.017
                                             S   1.2 or 70% reduction...  0.64 or 71% reduction.         0.18
                                            SR   10.....................  0.60..................         0.35
Cd (mg/dscm)........................          L  0.16 or 65% reduction..  0.060 or 74% reduction         0.0041
                                             M   0.16 or 65% reduction..  0.060 or 74% reduction         0.0071
                                             S   0.16 or 65% reduction..  0.060 or 74% reduction         0.012
                                            SR   4......................  0.050.................         0.068
Hg (mg/dscm)........................          L  0.55 or 85% reduction..  0.33 or 96% reduction.         0.0095
                                             M   0.55 or 85% reduction..  0.33 or 96% reduction.         0.0079
                                             S   0.55 or 85% reduction..  0.33 or 96% reduction.         0.0075
                                            SR   7.5....................  0.25..................         0.0040
PM (gr/dscf)........................          L  0.015..................  0.015.................         0.0056
                                             M   0.03...................  0.030.................         0.012
                                             S   0.05...................  0.030.................         0.017
                                            SR   0.086..................  0.030.................         0.030
CDD/CDF, total (ng/dscm)............          L  125....................  115...................         1.6
                                             M   125....................  115...................         0.63
                                             S   125....................  115...................         8.3
                                            SR   800....................  800...................       130
CDD/CDF, TEQ (ng/dscm)..............          L  2.3....................  2.0...................         0.029
                                             M   2.3....................  2.0...................         0.0097
                                             S   2.3....................  2.0...................         0.0080
                                            SR   15.....................  15....................         2.6
NOX (ppmv)..........................          L  250....................  212...................       140
                                          M, S   250....................  212...................       200
                                            SR   250....................  212...................       110
SO2 (ppmv)..........................          L, 55.....................  28....................         2.8
                                            SR   55.....................  28....................       43
----------------------------------------------------------------------------------------------------------------
\1\ L = Large; M = Medium; S = Small; SR = Small Rural.
\2\ All emission limits are measured at 7 percent oxygen.

    With four exceptions, the emission limits for existing HMIWI being
proposed in this action are more stringent than the 5-year review
emission limits proposed in 2007. The HCl, Cd, and SO2
emission limits for existing small rural units being proposed in this
action are higher than the 5-year review limits proposed in 2007 (398
ppm versus 440 ppm for HCl; 0.050 mg/dscm versus 0.068 mg/dscm for Cd;
and 28 ppm versus 43 ppm for SO2). The PM emission limit
being proposed for small rural HMIWI is the same as the 5-year review
emission limit proposed in 2007. These differences in emission limits
are likely due to the fact that there are now four fewer small rural
HMIWI (leaving only two rural units).

C. Rationale for Other Proposed Amendments

1. Performance Testing and Monitoring Requirements
    We are proposing some adjustments to the performance testing and
monitoring requirements that were promulgated in 1997. For existing
large, medium, and small HMIWI (i.e., all currently operating large,
medium, and small HMIWI), we are proposing retaining the current
requirements of the rule and adding the following requirements:
     Demonstration of initial compliance with the revised
NOX and SO2 emission limits;
     Annual inspections of scrubbers, fabric filters, and other
air pollution control devices that may be used to meet the emission
limits; and
     One-time testing of the ash handling operations at the
time of the next compliance test using EPA Method 22 of appendix A-7 of
40 CFR part 60.
    For existing small rural HMIWI, who have been subject to fewer
performance testing and monitoring requirements, we are proposing
retaining the current requirements of the rule and adding the following
requirements:
     Demonstration of initial compliance with the revised
NOX, SO2, HCl, Cd, and Pb emission limits;
     Annual compliance testing for PM, CO, and HCl;
     Annual inspections of scrubbers, fabric filters, and other
air pollution control devices that may be used to meet the emission
limits; and

     One-time testing of the ash handling operations at the
time of the next compliance test using EPA Method 22 of appendix A-7 of
40 CFR part 60.
    Currently, existing HMIWI are not required to conduct initial
emissions testing for NOX or SO2. Existing small
rural HMIWI are not currently required to conduct initial compliance
testing for HCl, Pb, Cd, NOX, or SO2, and are
also not required to conduct annual compliance testing for any of the
nine regulated pollutants. In addition, existing HMIWI are not
currently required to conduct any testing of the ash handling. These
proposed requirements were selected to provide additional assurance
that sources continue to operate at the levels established during their
initial performance test. The proposed amendments would allow sources
to use the results of previous emissions tests to demonstrate
compliance with the revised emission limits as long as the sources
certify that the previous test results are representative of current
operations. Those sources whose previous emissions tests do not
demonstrate compliance with one or more of the revised emission limits
would be required to conduct another emissions test for those
pollutants (note that most sources are already required to test for
HCl, CO, and PM on an annual basis).
    Additional requirements also are proposed for new HMIWI. For new
sources, we are proposing retaining the current requirements and adding
the following requirements:
     Demonstration of initial compliance with the revised
NOX and SO2 emission limits;
     Annual inspections of scrubbers, fabric filters, and other
air pollution control devices that may be used to meet the emission
limits;
     Use of CO CEMS;
     Use of bag leak detection systems for fabric-filter
controlled units; and
     Annual testing of the ash handling operations using EPA
Method 22 of appendix A-7 of 40 CFR part 60.
    For existing sources, we also are proposing to allow for the
optional use of bag leak detection systems. We also are clarifying that
the rule allows for the following optional CEMS use: CO CEMS for
existing sources; and PM CEMS, HCl CEMS, multi-metals CEMS, Hg CEMS,
integrated sorbent trap Hg monitoring, and integrated sorbent trap
dioxin monitoring for existing and new sources. The optional use of HCl
CEMS, multi-metals CEMS, integrated sorbent trap Hg monitoring, and
integrated sorbent trap dioxin monitoring will be available on the date
a final performance specification for these monitoring systems is
published in the Federal Register or the date of approval of a site-
specific monitoring plan. The proposed monitoring provisions are
discussed below.
    a. Monitoring Provisions for SNCR. The proposed amendments would
require monitoring of secondary chamber temperature and reagent (e.g.,
ammonia or urea) injection rate for HMIWI that install SNCR as a method
of reducing NOX emissions. All HMIWI are currently required
to monitor secondary chamber temperature.
    b. Bag Leak Detection Systems. The proposed amendments would
provide, as an alternative PM monitoring technique for existing
sources, and a requirement for new sources, the use of bag leak
detection systems on HMIWI controlled with fabric filters. Bag leak
detection systems have been applied successfully at many industrial
sources. EPA is proposing to remove the opacity testing requirements
for HMIWI that use bag leak detection systems.
    c. CO CEMS. The proposed amendments would require the use of CO
CEMS for new sources, and allow the use of CO CEMS on existing sources.
Owners and operators that use CO CEMS would be able to discontinue
their annual CO compliance test as well as their monitoring of the
secondary chamber temperature, unless the source uses SNCR technology.
The continuous monitoring of CO emissions is an effective way of
ensuring that the combustion unit is operating properly. The proposed
amendments incorporate the use of performance specification (PS)-4B
(Specifications and Test Procedures for Carbon Monoxide and Oxygen
Continuous Monitoring Systems in Stationary Sources) of appendix B of
40 CFR part 60.
    The proposed CO emission limits are based on data from infrequent
(normally annual) stack tests and compliance would be demonstrated by
stack tests. The change to use of CO CEMS for measurement and
enforcement of the same emission limits must be carefully considered in
relation to an appropriate averaging period for data reduction. In past
EPA rulemakings for incineration units, EPA has selected averaging
times between 4 hours and 24 hours. Because sufficient CO CEMS data are
unavailable for HMIWI, EPA concluded that the use of a 24-hour block
average was appropriate to address potential changes in CO emissions
that cannot be accounted for with short term stack test data. The 24-
hour block average would be calculated following procedures in EPA
Method 19 of appendix A-7 of 40 CFR part 60. Facilities electing to use
CO CEMS as an optional method would be required to notify EPA 1 month
before starting use of CO CEMS and 1 month before stopping use of the
CO CEMS. In addition, EPA specifically requests comment on whether
continuous monitoring of CO emissions should be required for all
existing HMIWI.
    d. PM CEMS. The proposed amendments would allow the use of PM CEMS
as an alternative testing and monitoring method. Owners or operators
who choose to rely on PM CEMS would be able to discontinue their annual
PM compliance test. In addition, because units that demonstrate
compliance with the PM emission limits with a PM CEMS would clearly be
meeting the opacity standard, compliance demonstration with PM CEMS
would be considered a substitute for opacity testing. Owners and
operators that use PM CEMS also would be able to discontinue their
monitoring of minimum wet scrubber pressure drop, horsepower, or
amperage. The proposed amendments incorporate the use of PS-11
(Specifications and Test Procedures for Particulate Matter Continuous
Emission Monitoring Systems at Stationary Sources) of appendix B of 40
CFR part 60 for PM CEMS, and PS-11 QA Procedure 2 to ensure that PM
CEMS are installed and operated properly and produce good quality
monitoring data.
    The proposed PM emission limits are based on data from infrequent
(normally annual) stack tests and compliance would be demonstrated by
stack tests. The use of PM CEMS for measurement and enforcement of the
same emission limits must be carefully considered in relation to an
appropriate averaging period for data reduction. Because PM CEMS data
are unavailable for HMIWI, EPA concluded that the use of a 24-hour
block average was appropriate to address potential changes in PM
emissions that cannot be accounted for with short term stack test data.
The 24-hour block average would be calculated following procedures in
EPA Method 19 of appendix A-7 of 40 CFR part 60. An owner or operator
of an HMIWI unit who wishes to use PM CEMS would be required to notify
EPA 1 month before starting use of PM CEMS and 1 month before stopping
use of the PM CEMS.
    e. Other CEMS and Monitoring Systems. EPA also is proposing the
optional use of HCl CEMS, multi-metals CEMS, Hg CEMS, integrated
sorbent trap Hg monitoring, and integrated sorbent trap dioxin
monitoring as alternatives to the existing methods for demonstrating
compliance with the HCl, metals (Pb, Cd, and Hg), and CDD/CDF

emissions limits. Because CEMS data for HMIWI are unavailable for HCl
and metals, EPA concluded that the use of a 24-hour block average was
appropriate to address potential changes in emissions of HCl and metals
that cannot be accounted for with short term stack test data. EPA has
concluded that the use of 24-hour block averages would be appropriate
to address emissions variability, and EPA has included the use of 24-
hour block averages in the proposed rule. The 24-hour block averages
would be calculated following procedures in EPA Method 19 of appendix A
of 40 CFR part 60. Although final performance specifications are not
yet available for HCl CEMS and multi-metals CEMS, EPA is considering
development of performance specifications. The proposed rule specifies
that these options will be available to a facility on the date a final
performance specification is published in the Federal Register or the
date of approval of a site-specific monitoring plan.
    The use of HCl CEMS would allow the discontinuation of HCl sorbent
flow rate monitoring, scrubber liquor pH monitoring, and the annual
testing requirements for HCl. EPA has proposed PS-13 (Specifications
and Test Procedures for Hydrochloric Acid Continuous Monitoring Systems
in Stationary Sources) of appendix B of 40 CFR part 60 and believes
that performance specification can serve as the basis for a performance
specification for HCl CEMS use at HMIWI. In addition to the procedures
used in proposed PS-13 for initial accuracy determination using the
relative accuracy test, a comparison against a reference method, EPA is
taking comment on an alternate initial accuracy determination
procedure, similar to the one in section 11 of PS-15 (Performance
Specification for Extractive FTIR Continuous Emissions Monitor Systems
in Stationary Sources) of appendix B of 40 CFR part 60 using the
dynamic or analyte spiking procedure.
    EPA believes multi-metals CEMS can be used in many applications,
including HMIWI. EPA has monitored side-by-side evaluations of multi-
metals CEMS with EPA Method 29 of appendix A-8 of 40 CFR part 60 at
industrial waste incinerators and found good correlation. EPA also
approved the use of multi-metals CEMS as an alternative monitoring
method at a hazardous waste combustor. EPA believes it is possible to
adapt proposed PS-10 (Specifications and Test Procedures for Multi-
metals Continuous Monitoring Systems in Stationary Sources) of appendix
B of 40 CFR part 60 or other EPA performance specifications to allow
the use of multi-metals CEMS at HMIWI. In addition to the procedures
used in proposed PS-10 for initial accuracy determination using the
relative accuracy test, a comparison against a reference method, EPA is
taking comment on an alternate initial accuracy determination
procedure, similar to the one in section 11 of PS-15 using the dynamic
or analyte spiking procedure.
    Relative to the use of Hg CEMS and integrated sorbent trap Hg
monitoring, EPA believes that the specifications and procedures
described in the May 18, 2005 Federal Register notice that promulgated
standards of performance for new and existing electric utility steam
generating units (70 FR 28606) could provide the technical basis for
site-specific monitoring plans. The options of using Hg CEMS or an
integrated sorbent trap Hg monitoring system would take effect on the
date a final performance specification is published in the Federal
Register or the date of approval of a site-specific monitoring plan. An
owner or operator of an HMIWI unit who wishes to use Hg CEMS would be
required to notify EPA 1 month before starting use of Hg CEMS and 1
month before stopping use of the Hg CEMS. The use of multi-metals CEMS
or Hg CEMS would allow the discontinuation of wet scrubber outlet flue
gas temperature monitoring. Mercury sorbent flow rate monitoring could
not be eliminated in favor of a multi-metals CEMS or Hg CEMS because it
also is an indicator of CDD/CDF control. Additionally, there is no
annual metals test that could be eliminated.
    The integrated sorbent trap monitoring of Hg would entail use of a
continuous automated sampling system with analysis of the samples at
set intervals using any suitable determinative technique that can meet
appropriate criteria. The option to use a continuous automated sampling
system would take effect on the date a final performance specification
is published in the Federal Register or the date of approval of a site-
specific monitoring plan. Integrated sorbent trap monitoring of Hg
would allow the discontinuation of wet scrubber outlet flue gas
temperature monitoring. Mercury sorbent flow rate monitoring could not
be eliminated in favor of integrated sorbent trap monitoring of Hg
because it also is an indicator of CDD/CDF control. Additionally, there
is no annual Hg test that could be eliminated.
    The integrated sorbent trap monitoring of dioxin would entail use
of a continuous automated sampling system and analysis of the sample
according to EPA Reference Method 23 of appendix A-7 of 40 CFR part 60.
The option to use a continuous automated sampling system would take
effect on the date a final performance specification is published in
the Federal Register or the date of approval of a site-specific
monitoring plan. Integrated sorbent trap monitoring of dioxin would
allow the discontinuation of fabric filter inlet temperature
monitoring. Dioxin/furan sorbent flow rate monitoring could not be
eliminated in favor of integrated sorbent trap monitoring of dioxin
because it also is an indicator of Hg control. Additionally, there is
no annual CDD/CDF test that could be eliminated. If integrated sorbent
trap monitoring of dioxin as well as multi-metals CEMS, Hg CEMS, or
integrated sorbent trap Hg monitoring are used, Hg sorbent flow rate
monitoring and CDD/CDF sorbent flow rate monitoring (in both cases
activated carbon is the sorbent) could be eliminated. EPA requests
comment on other parameter monitoring requirements that could be
eliminated upon use of any or all of the optional CEMS discussed above.
Table 16 of this preamble presents a summary of the HMIWI operating
parameters, the pollutants influenced by each parameter, and
alternative monitoring options for each parameter.

    Table 16--Summary of HMIWI Operating Parameters, Pollutants Influenced by Each Parameter, and Alternative
                                      Monitoring Options for Each Parameter
----------------------------------------------------------------------------------------------------------------
                                   Pollutants influenced by operating parameter  (by control
 Operating parameter/ monitoring                         device type)                             Alternative
           requirement           ------------------------------------------------------------     monitoring
                                     Dry scrubber        Wet scrubber       Combined system         options
----------------------------------------------------------------------------------------------------------------
Maximum charge rate.............  All...............  All...............  All...............  None.

Minimum secondary chamber         PM, CO, CDD/CDF...  PM, CO, CDD/CDF...  PM, CO, CDD/CDF...  CO CEMS.\1,2\
 temperature.
Maximum fabric filter inlet       CDD/CDF...........  ..................  CDD/CDF...........  Integrated sorbent
 temperature.                                                                                trap dioxin
                                                                                monitoring system
                                                                                (ISTDMS).
Minimum CDD/CDF sorbent flow      CDD/CDF...........  ..................  CDD/CDF...........  ISTDMS and multi-
 rate.                                                                                metals CEMS, Hg
                                                                                CEMS or
                                                                                integrated
                                                                                sorbent trap
                                                                                mercury
                                                                                monitoring system
                                                                                (ISTMMS).
Minimum Hg sorbent flow rate....  Hg................  ..................  Hg................  ..................
Minimum HCl sorbent flow rate...  HCl...............  ..................  HCl...............  HCl CEMS.
Minimum scrubber pressure drop/   ..................  PM................  PM................  PM CEMS.
 horsepower amperage.
Minimum scrubber liquor flow      ..................  HCl, PM, Cd, Pb,    HCl, PM, Cd, Pb,    HCl CEMS, PM CEMS,
 rate.                                                 Hg, CDD/CDF.        Hg, CDD/CDF.        multi-metals
                                                                                CEMS, ISTDMS, and
                                                                                ISTMMS.
Minimum scrubber liquor pH......  ..................  HCl...............  HCl...............  HCl CEMS.
Maximum flue gas temperature      ..................  Hg................  ..................  Hg CEMS, ISTMMS,
 (wet scrubber outlet).                                                                        or multi-metals
                                                                                CEMS.
Do not use bypass stack (except   All...............  All...............  All...............  None.
 during startup, shutdown, and
 malfunction).
Air pollution control device      All...............  All...............  All...............  None.
 inspections.
----------------------------------------------------------------------------------------------------------------
\1\ Optional method for existing sources; required for new sources.
\2\ Monitoring secondary chamber temperature could not be eliminated if the source uses SNCR technology.

    Table 17 of this preamble presents a summary of the HMIWI test
methods and approved alternative compliance methods.

                    Table 17--Summary of HMIWI Test Methods and Approved Alternative Methods
----------------------------------------------------------------------------------------------------------------
                                                                  Approved alternative
         Pollutant/parameter              Test method(s) \1\           method(s)                 Comments
----------------------------------------------------------------------------------------------------------------
PM...................................  Method 5, Method 29....  PM CEMS................  PM CEMS are optional
                                                                                for all sources in
                                                                                lieu of annual PM
                                                                                test.
CO...................................  Method 10..............  CO CEMS................  CO CEMS are optional
                                                                                for existing sources
                                                                                in lieu of annual CO
                                                                                test; CO CEMS are
                                                                                required for new
                                                                                sources.
HCl..................................  Method 26 or Method 26A  HCl CEMS...............  HCl CEMS are optional
                                                                                for all sources in
                                                                                lieu of annual HCl
                                                                                test.
Cd...................................  Method 29..............  Multi-metals CEMS......
Pb...................................  Method 29..............  Multi-metals CEMS......
Hg...................................  Method 29..............  ASTM D6784-02, multi-
                                                                 metals CEMS, Hg CEMS,
                                                                 or integrated sorbent
                                                                 trap mercury
                                                                 monitoring system.
CDD/CDF..............................  Method 23..............  Integrated sorbent trap
                                                                 dioxin monitoring
                                                                 system.
Opacity..............................  Method 22..............  Bag leak detection       Bag leak detection
                                                                 system or PM CEMS.       systems are optional
                                                                                for existing sources;
                                                                                and are required for
                                                                                new sources in lieu of
                                                                                annual opacity test.
Flue and exhaust gas analysis........  Method 3, 3A, or 3B....  ASME PTC 19-10-1981
                                                                 Part 10.
Opacity from ash handling............  Method 22..............  None...................
----------------------------------------------------------------------------------------------------------------
\1\ EPA Reference Methods in appendix A of 40 CFR part 60.

V. Impacts of the Proposed Action for Existing Units

    Over the last 3 years, about 25 percent (19 of 76 units) of the
existing HMIWI have ceased operation. This trend is not surprising, and
supports EPA's analysis, which shows that even in the absence of
increased regulatory requirements, less expensive alternative waste
disposal options are available for almost all facilities that operate
HMIWI. Therefore, EPA expects this trend of unit closures to continue
even in the absence of the proposed regulatory changes. The additional
costs that would be imposed by this action are likely to accelerate the
trend towards alternative waste disposal options, and our analysis
suggests that sources are likely to respond to the proposed increased
regulatory requirements by choosing to shut down existing HMIWI and
utilizing alternative waste disposal options rather than incurring the
costs of continued operation and compliance.
    The EPA's objective is not to discourage continued use of HMIWI;
EPA's objective is to adopt EG for existing HMIWI that fulfill the
requirements of CAA section 129. In doing so, the primary outcome
associated with adoption of these EG may be an increase in the use of
alternative waste disposal and a decrease in the use of HMIWI.
Consequently, EPA's impact analyses of the proposed rule include
complete analyses of two potential scenarios. The first scenario, which
will be referred to as the ``MACT compliance'' option for the remainder
of this preamble, assumes that all units continue operation and take
the necessary steps to achieve compliance. The second scenario, which
will be referred to as the ``alternative disposal'' option for the
remainder of this preamble, assumes that all facilities choose to
discontinue operation of their HMIWI in favor of an alternative waste
disposal option. While several different disposal options, such as
sending waste to a municipal waste combustor or commercial HMIWI, may
be available to some facilities, EPA assessed the impacts of one
alternative waste disposal option. This option involves on-site
sterilization of the waste using an autoclave followed by landfilling
of the sterilized waste. EPA selected the autoclave/landfilling option
because it is widely available. The results of both options are
provided in the discussion of impacts. While the likely outcome of the
proposed rule revisions is somewhere in between the two options that
EPA selected for analysis (some units will comply with the standards
and some will discontinue operations), EPA's analyses provide a broad
picture of potential impacts.
    As explained in section IV.A.2 of this preamble, the proposed
emission limits for existing HMIWI are based on the average of the best
performing 12 percent of sources for each pollutant in each
subcategory. This proposed action would require varying degrees of
improvements in performance by almost all HMIWI. Depending on the
current configuration of each unit and air pollution controls, the
improvements could be achieved either through the addition of add-on
air pollution control devices (APCD), improvement of existing add-on
APCD, increase in sorbent usage rates, and various combustion
improvements. More specifically, the improvements anticipated include:
most wet scrubber-controlled units adding a fabric filter-based system
for improved control of PM and metals; most units with fabric filter-
based systems adding a packed bed wet scrubber for improved control of
HCl; adding activated carbon injection or increasing activated carbon
usage rate for improved Hg and dioxin control; upgrading fabric filter
performance for improved control of PM and metals; increasing lime use
for improved control of HCl and, in a few instances, SO2;
and combustion improvements primarily associated with decreasing CO and
CDD/CDF emissions. We also project that a few units may require add-on
controls (SNCR) to meet the proposed NOX emission levels.
Facilities may resubmit their most recent compliance test data for each
pollutant if the data show that their HMIWI meets the proposed emission
limits. In these instances, facilities must certify that the test
results are representative of current operations. Those facilities
would then not be required to test for those pollutants to prove
initial compliance with the revised emission limits.

A. What are the primary air impacts?

    EPA estimates that reductions of approximately 468,000 pounds per
year (lb/yr) of the regulated pollutants would be achieved if all
existing HMIWI improved performance to meet the proposed emissions
limits. If all HMIWI selected an alternative disposal method,
reductions of approximately 1.52 million lb/yr would be achieved. Table
18 shows the estimated reductions by pollutant for the two scenarios.

     Table 18--Projected Emission Reductions for MACT Compliance and
             Alternative Disposal Options for Existing HMIWI
------------------------------------------------------------------------
                                                           Reductions
                                         Reductions     achieved through
              Pollutant               achieved through     alternative
                                        meeting MACT     disposal  (lb/
                                           (lb/yr)             yr)
------------------------------------------------------------------------
HCl.................................           184,000           198,000
CO..................................             6,860            20,200
Pb..................................               361               420
Cd..................................                22              35.1
Hg..................................               637               682
PM..................................            27,300            89,900
CDD/CDF.............................            0.0907            0.0985
NOX.................................           148,000         1,080,000
SO2.................................           100,000           126,000
                                     -----------------------------------
Total...............................           468,000         1,520,000
------------------------------------------------------------------------

B. What are the water and solid waste impacts?

    EPA estimates that, based on the MACT compliance option,
approximately 4,420 tpy of additional solid waste and 187,000 gallons
per year of additional wastewater would be generated as a result of
operating additional controls or using increased amounts of various
sorbents.
    EPA estimates that, based on the alternative disposal option,
approximately 15,100 tpy of additional solid waste would be sent to
landfills. This option would result in no additional waste water
impacts.

C. What are the energy impacts?

    EPA estimates that approximately 29,100 megawatt-hours per year of
additional electricity would be required to support the increased
control requirements associated with the MACT compliance option.
    For the alternative disposal option, EPA estimates that
approximately 12,400 megawatt-hours per year of additional electricity
would be required to operate the autoclaves.

D. What are the secondary air impacts?

    Secondary air impacts associated with the MACT compliance option
are direct impacts that result from the increase in natural gas and/or
electricity use that we estimate may be required to enable facilities
to achieve the proposed emission limits. We estimate that the
adjustments could result in emissions of 941 lb/yr of PM; 8,870 lb/yr
of CO; 9,290 lb/yr of NOX; and 1,880 lb/yr of SO2
from the increased electricity and natural gas usage.
    For the alternative disposal option, EPA estimates secondary air
impacts of 692 lb/yr of PM; 5,040 lb/yr of CO; 2,550

lb/yr of NOX; and 4,980 lb/yr of SO2 from the
additional electricity that would be required to operate the
autoclaves. In addition, EPA estimates that landfilling would result in
an additional 626 tpy of methane and 0.03 lb/yr of mercury emissions.

E. What are the cost and economic impacts?

    EPA estimates that for the MACT compliance option, the national
total costs for the 57 existing HMIWI to comply with this proposed
action would be approximately $21.1 million in each of the first 3
years of compliance. This estimate includes the costs that would be
incurred based on the anticipated performance improvements (i.e., costs
of new APCD and improvements in performance of existing APCD), and the
additional monitoring (i.e., annual control device inspections),
testing (i.e., initial EPA Method 22 of appendix A-7 test and initial
compliance testing), and recordkeeping and reporting costs that would
be incurred by all 57 HMIWI as a result of this proposed action.
Approximately 96 percent of the estimated total cost in the first year
is for emissions control, and the remaining 4 percent is for
monitoring, testing, recordkeeping and reporting.
    EPA estimates that for the alternative disposal option, the
national total costs for the 57 existing HMIWI to dispose of their
solid waste by autoclaving and landfilling would be approximately $10.6
million per year. This estimate includes the costs that would be
incurred based on the purchase and operation of autoclaves and the
projected landfill tipping fees that would be incurred based on the
volume of waste to be landfilled.
    Currently, there are 57 existing HMIWI at 51 facilities. They may
be divided into two broad categories: (1) Captive HMIWI, which are co-
owned and co-located with generating facilities and provide on-site
incineration services for waste generated by the hospital, research
facility, university, or pharmaceutical operations; and (2) commercial
HMIWI, which provide commercial incineration services for waste
generated off-site by firms unrelated to the firm that owns the HMIWI.
EPA analyzed the impacts on captive HMIWI and commercial HMIWI using
different methods. Of the 57 HMIWI, 14 are commercial and 43 are
captive.
    Owners of captive HMIWI may choose to incur the costs of complying
with the proposed revised HMIWI standards or close the HMIWI and switch
to another disposal technology like autoclaving and landfilling or have
their waste handled by a commercial disposal service. EPA's estimate of
autoclaving and landfilling costs indicate that even without additional
regulatory costs, the costs of autoclaving and landfilling may be lower
than the costs of incinerating. However, even if all owners of captive
HMIWI choose to continue to operate with the additional regulatory
cost, the cost-to-sales ratios for firms owning captive HMIWI are low.
This reflects the relatively small share of overall costs that are
associated with hospital/medical/infectious waste management at these
firms. Of the 35 firms owning captive HMIWI, 22 have costs of
compliance that are less than 0.1 percent of firm sales. Of the 13 with
costs exceeding 0.1 percent of sales, only one, a hospital, has costs
exceeding 1 percent of sales, and their cost-to-sales ratio is 1.01
percent. Therefore, EPA expects no significant impact on the prices and
quantities of the underlying services of the owners of the captive
HMIWI, whether the costs are passed on or absorbed.
    Impacts on commercial HMIWI are analyzed using the simplifying
assumption that they operate as regional monopolists (in general, only
one HMIWI is considered as a treatment option by generators located
nearby). The approach to modeling the impact for commercial HMIWI seems
very appropriate for all of the facilities except for one. The other
commercial HMIWI facilities have costs of compliance that are no more
than 6.1 percent of revenues. That one facility has a ratio of 28.5
percent. Even with monopoly pricing power and the highest estimated
waste throughput, it is not clear whether the company will be able to
acquire the capital and pass on such a large price increase. Additional
information and modeling would be required to project the outcome for
this facility with confidence. For more details regarding EPA's
analysis of the economic impacts, see the docket entry entitled
``Economic Impacts of Revised MACT Standards for Hospital/Medical/
Infectious Waste Incinerators.''

VI. Impacts of the Proposed Action for New Units

    Information provided to EPA indicates that negative growth has been
the trend for HMIWI for the past several years. While existing units
continue to shut down, since promulgation of the HMIWI NSPS in 1997,
four new units have been constructed and one unit has been
reconstructed. This information indicates that in the absence of
further regulation, new HMIWI may be built. However, based on the
stringency of revisions being proposed for the NSPS, sources would
likely respond to the proposed rule by choosing not to construct new
HMIWI and would utilize alternative waste disposal options rather than
incur the costs of compliance.
    Considering this information, EPA does not anticipate any new
HMIWI, and therefore, no impacts of the proposed NSPS for new units.
For purposes of demonstrating that emissions reductions would result
from the NSPS in the unlikely event that a new unit is constructed, EPA
estimated emissions reductions and other impacts expected for each of
the three HMIWI model plants.

A. What are the primary air impacts?

    EPA estimated emissions reductions for each of the model plants to
demonstrate that the NSPS would, if a new unit were built, reduce
emissions compared to an HMIWI meeting the current NSPS. Table 19 of
this preamble presents the emissions reductions for the HMIWI model
plants. The three model plants (with capacities of 100 lb/hr, 400 lb/
hr, and 4,000 lb/hr) represent typical HMIWI. For pollutants where a
``zero'' value is shown, the model plant performance estimate meets the
proposed new source limit, which is not surprising since the models are
based on the performance of the newest sources, which are among the
best performers in the industry.

                              Table 19--Emissions Reductions on a Model Plant Basis
----------------------------------------------------------------------------------------------------------------
                                                                  Emission reduction for HMIWI model plants (lb/
                                                                                yr)
                            Pollutant                            -----------------------------------------------
                                                                     100 lb/hr       400 lb/hr      4,000 lb/hr
                                                                     capacity        capacity        capacity
----------------------------------------------------------------------------------------------------------------
HCl.............................................................               0             262           2,340
CO..............................................................            30.5            5.15             124

Pb..............................................................               0               0            3.82
Cd..............................................................               0               0           0.296
Hg..............................................................               0           0.245            2.51
PM..............................................................               0               0           2,360
Dioxins/furans, TEQ.............................................               0       6.15x10-6               0
NOX.............................................................             863           3,120               0
SO2.............................................................              49              72               0
    Total.......................................................             942           3,460           4,840
----------------------------------------------------------------------------------------------------------------

B. What are the water and solid waste impacts?

    While EPA believes it is unlikely that any new HMIWI will be
constructed, we estimated the following water or solid waste impacts
associated with the proposed NSPS for three different HMIWI model
sizes: for large units, we estimate 7,120 gallons per year of
additional wastewater and 51 tpy of additional solid waste; for medium
units, we estimate 877 gallons per year of additional wastewater and
5.7 tpy of additional solid waste; and, for small units, we estimate 30
gallons per year of additional wastewater and no additional solid
waste.

C. What are the energy impacts?

    While EPA believes it is unlikely that any new HMIWI will be
constructed, we estimated the following energy impacts associated with
the proposed NSPS for three different HMIWI model sizes: For large
units, we estimate that 3,980 megawatt-hours per year of additional
electricity would be required to support the increased control
requirements; for medium units, we estimate 448 megawatt-hours per
year; and, for small units, we estimate 107 megawatt-hours per year.

D. What are the secondary air impacts?

    Secondary air impacts for new HMIWI are direct impacts that would
result from the increase in natural gas and/or electricity use that we
estimate may be required to enable facilities to achieve the proposed
emission limits. While EPA believes it is unlikely that any new HMIWI
will be constructed, we estimated the secondary air impacts associated
with the proposed NSPS for three different HMIWI model sizes. For large
units, we estimate that the adjustments could result in emissions of 40
lb/yr of PM; 1,180 lb/yr of CO; 1,320 lb/yr of NOX; and 120
lb/yr of SO2. For medium units, we estimate that the
adjustments could result in emissions of 4.5 lb/yr of PM; 132 lb/yr of
CO; 149 lb/yr of NOX; and 14 lb/yr of SO2. For
small units, we estimate that the adjustments could result in emissions
of 1.2 lb/yr of PM; 32 lb/yr of CO; 35 lb/yr of NOX; and 4.2
lb/yr of SO2.
    For the alternative disposal option, EPA estimated secondary air
impacts from the additional electricity that would be required to
operate autoclaves in lieu of each size of HMIWI. For large units, we
estimate secondary emissions of 66 lb/yr of PM; 478 lb/yr of CO; 241
lb/yr of NOX; and 471 lb/yr of SO2. For medium
units, we estimate secondary emissions of 5.0 lb/yr of PM; 36 lb/yr of
CO; 18 lb/yr of NOX; and 36 lb/yr of SO2. For
small units, we estimate secondary emissions of 1.2 lb/yr of PM; 9.1
lb/yr of CO; 4.6 lb/yr of NOX; and 9.0 lb/yr of
SO2. In addition, EPA estimates that an additional 59 tpy of
methane and 0.003 lb/yr of mercury emissions would result from
landfilling waste that would have been processed in a large HMIWI, 3.3
tpy of methane and 0.0002 lb/yr of mercury emissions would result from
landfilling waste that would have been processed in a medium HMIWI, and
0.5 tpy of methane and 0.00003 lb/yr of mercury emissions would result
from landfilling waste that would have been processed in a small HMIWI.

E. What are the cost and economic impacts?

    While EPA projects that three new HMIWI would be constructed in the
absence of the proposed revisions, we believe that, in response to the
proposed revisions, sources may decide against constructing new HMIWI.
Nevertheless, we estimated the following costs associated with
installation and operation of air pollution controls needed to meet the
proposed NSPS: For new large units, $476,000 per year; for new medium
units, $195,000 per year; and, for new small units, $120,000 per year.
    EPA's analysis of impacts of the proposed revisions to the HMIWI
standards on potential new HMIWI sources compares the with-regulation
estimated prices that would be charged by new large, medium, and small
HMIWI to the range of with-regulation prices estimated to be charged by
existing commercial HMIWI in various regional markets. This comparison
indicates that new large and medium commercial HMIWI may be viable, but
new small commercial HMIWI probably would not be viable. On the other
hand, generators of hospital/medical/infectious waste could have
reasons to purchase and install a new small HMIWI. Comparison of
autoclave treatment coupled with off-site landfill disposal shows that,
for new facilities as for existing ones, autoclave/landfill treatment
and disposal is generally less costly than incineration. Thus, the
motivation to improve waste segregation to minimize the waste that must
be incinerated is likely to continue.

VII. Relationship of the Proposed Action to Section 112(c)(6) of the
CAA

    Section 112(c)(6) of the CAA requires EPA to identify categories of
sources of seven specified pollutants to assure that sources accounting
for not less than 90 percent of the aggregate emissions of each such
pollutant are subject to standards under CAA section 112(d)(2) or
112(d)(4). EPA has identified HMIWI as a source category that emits
five of the seven CAA section 112(c)(6) pollutants: polycyclic organic
matter (POM), dioxins, furans, Hg, and polychlorinated biphenyls
(PCBs). (The POM emitted by HMIWI is composed of 16 polyaromatic
hydrocarbons (PAH) and extractable organic matter (EOM).) In the
Federal Register notice Source Category Listing for Section 112(d)(2)
Rulemaking Pursuant to Section 112(c)(6) Requirements, 63 FR 17838,
17849, Table 2 (1998), EPA identified medical waste incinerators (now
referred to as HMIWI) as a source category ``subject to regulation''
for purposes of CAA section 112(c)(6) with

respect to the CAA section 112(c)(6) pollutants that HMIWI emit. HMIWI
are solid waste incineration units currently regulated under CAA
section 129. For purposes of CAA section 112(c)(6), EPA has determined
that standards promulgated under CAA section 129 are substantively
equivalent to those promulgated under CAA section 112(d). (See Id. at
17845; see also 62 FR 33625, 33632 (1997).) As discussed in more detail
below, the CAA section 129 standards effectively control emissions of
the five identified CAA section 112(c)(6) pollutants. Further, since
CAA section 129(h)(2) precludes EPA from regulating these substantial
sources of the five identified CAA section 112(c)(6) pollutants under
CAA section 112(d), EPA cannot further regulate these emissions under
that CAA section. As a result, EPA considers emissions of these five
pollutants from HMIWI ``subject to standards'' for purposes of CAA
section 112(c)(6).
    As required by the statute, the CAA section 129 HMIWI standards
include numeric emission limitations for the nine pollutants specified
in section 129(a)(4). The combination of waste segregation, good
combustion practices, and add-on air pollution control equipment (dry
sorbent injection fabric filters, wet scrubbers, or combined fabric
filter and wet scrubber systems) effectively reduces emissions of the
pollutants for which emission limits are required under CAA section
129: Hg, CDD/CDF, Cd, Pb, PM, SO2, HCl, CO, and
NOX. Thus, the NSPS and EG specifically require reduction in
emissions of three of the CAA section 112(c)(6) pollutants: dioxins,
furans, and Hg. As explained below, the air pollution controls
necessary to comply with the requirements of the HMIWI NSPS and EG also
effectively reduce emissions of the following CAA section 112(c)(6)
pollutants that are emitted from HMIWI: POM and PCBs. Although the CAA
section 129 HMIWI standards do not have separate, specific emissions
standards for PCBs and POM, emissions of these two CAA section
112(c)(6) pollutants are effectively controlled by the same control
measures used to comply with the numerical emissions limits for the
pollutants enumerated in section 129(a)(4). Specifically, as byproducts
of combustion, the formation of PCBs and POM is effectively reduced by
the combustion and post-combustion practices required to comply with
the CAA section 129 standards. Any PCBs and POM that do form during
combustion are further controlled by the various post-combustion HMIWI
controls. The add-on PM control systems (either fabric filter or wet
scrubber) and activated carbon injection in the fabric filter-based
systems further reduce emissions of these organic pollutants, and also
reduce Hg emissions, as is evidenced by HMIWI performance data.
Specifically, the post-MACT compliance tests at currently operating
HMIWI that were also operational at the time of promulgation of the
1997 standards show that, for those units, the 1997 HMIWI MACT
regulations reduced Hg emissions by about 60 percent and CDD/CDF
emissions by about 80 percent from pre-MACT levels. (Note that these
reductions do not reflect unit shutdowns, units for which exemptions
were granted, or new units.) Moreover, similar controls have been
demonstrated to effectively reduce emissions of POM and PCBs from
another incineration source category (municipal solid waste
combustors). It is, therefore, reasonable to conclude that POM and PCB
emissions are substantially controlled at all 57 HMIWI. Thus, while the
proposed rule does not identify specific limits for POM and PCB,
emissions of those pollutants are, for the reasons noted above,
nonetheless ``subject to regulation'' for purposes of section 112(c)(6)
of the CAA.

VIII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735; October 4, 1993), this
action is a ``significant regulatory action'' because it is likely to
raise novel legal or policy issues arising out of legal mandates, the
President's priorities, or the principles set forth in the Executive
Order. Accordingly, EPA submitted this action to the Office of
Management and Budget (OMB) for review under Executive Order 12866, and
any changes made in response to OMB recommendations have been
documented in the docket for this action.

B. Paperwork Reduction Act

    The information collection requirements in this rule have been
submitted for approval to the OMB under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq. The Information Collection Request (ICR) documents
prepared by EPA have been assigned EPA ICR number 2335.01 for subpart
Ce, 40 CFR part 60, and 1730.07 for subpart Ec, 40 CFR part 60.
    The requirements in this proposed action result in industry
recordkeeping and reporting burden associated with review of the
amendments for all HMIWI, EPA Method 22 of appendix A-7 testing for all
HMIWI, and inspections of scrubbers, fabric filters, and other air
pollution control devices that may be used to meet the emission limits
for all HMIWI. Stack testing and development of new parameter limits
would be necessary for HMIWI that need to make performance improvements
in order to meet the proposed emission limits and for HMIWI that, prior
to this proposed action, have not been required to demonstrate
compliance with certain pollutants. Any new HMIWI would also be
required to continuously monitor CO emissions. New HMIWI equipped with
fabric filters would also be required to purchase bag leak detectors.
    The annual average burden associated with the EG over the first 3
years following promulgation of this proposed action is estimated to be
44,275 hours at a total annual labor cost of $1,873,286. The total
annualized capital/startup costs and operation and maintenance (O&M)
costs associated with the monitoring requirements, EPA Method 22 of
appendix A-7 testing, storage of data and reports, and photocopying and
postage over the 3-year period of the ICR are estimated at $1,457,506
and $687,398 per year, respectively. (The annual inspection costs are
included under the recordkeeping and reporting labor costs.) The annual
average burden associated with the NSPS over the first 3 years
following promulgation of this proposed action is estimated to be 2,705
hours at a total annual labor cost of $102,553. The total annualized
capital/startup costs are estimated at $137,058, with total operation
and maintenance costs of $116,190 per year. Burden is defined at 5 CFR
1320.3(b)
    An Agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it currently displays
a valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy
of the provided burden estimates, and any suggested methods for
minimizing respondent burden, EPA has established a public docket for
this action, which includes these ICR documents, under Docket ID No.
EPA-HQ-OAR-2006-0534. Submit any comments related to the ICR documents
for this proposed action to EPA and OMB. See ADDRESSES section at the
beginning of this action for where to submit comments to EPA. Send
comments to OMB at the Office of Information and Regulatory Affairs,
Office of Management and Budget, 725 17th Street, NW., Washington, DC
20503, Attention: Desk Office for EPA.

Since OMB is required to make a decision concerning the ICR between 30
and 60 days after December 1, 2008, a comment to OMB is best assured of
having its full effect if OMB receives it by December 31, 2008. The
final rule will respond to any OMB or public comments on the
information collection requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedures Act or any other statute unless the Agency certifies that
the proposed action will not have a significant economic impact on a
substantial number of small entities. Small entities include small
businesses, small government organizations, and small government
jurisdictions.
    For purposes of assessing the impacts of this proposed action on
small entities, small entity is defined as follows: (1) A small
business as defined by the Small Business Administration's (SBA)
regulations at 13 CFR 121.201; (2) a small governmental jurisdiction
that is a government of a city, county, town, school district or
special district with a population of less than 50,000; or (3) a small
organization that is any not-for-profit enterprise that is
independently owned and operated and is not dominant in its field.
    After considering the economic impacts of this proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. The one
small entity directly regulated by this proposed action is a small
governmental jurisdiction that owns two HMIWI. We have determined that
this one small entity may experience an impact of approximately $1.56
million per year to comply with the proposed rule, resulting in a cost-
to-sales ratio of approximately 6.1 percent. The one small entity is a
commercial facility owned by a county in Texas. Because there are only
nine other commercial facilities and the closest are in Tennessee and
Kansas, the entity is a regional monopolist and is able to raise the
price by more than the per unit cost increase. We expect there to be a
reduction in the amount of its services demanded due to the price
change. Because of closures of captive HMIWI there may also be an
increase in the demand for its services that may reduce the decrease in
revenues associated with the price increase.
    Three other entities are defined as borderline small: Their parent
company sales or employment in 2007 are above the SBA size-cutoff for
small entities in their NAICS codes, but are near enough to the size
cut-off that variations in sales or employment over time might move
them below the small business criterion. One of them is the facility
with a cost-to-sale a ratio of 28.5 percent. Additional information and
modeling would be required to project the outcome for this facility
with confidence.
    Although the proposed rule will not have a significant economic
impact on a substantial number of small entities, EPA nonetheless has
tried to reduce the impact of this rule on small entities. For each
subcategory of HMIWI, we are proposing emission limits that are based
on the MACT floor level of control, which is the minimum level of
stringency that can be considered in establishing MACT standards.
Although under the CAA and the case law EPA can set standards no less
stringent than the MACT floor and, therefore, we were unable to reduce
the impact of the emission limits on the small entity that would be
regulated by the proposed rule, EPA worked to minimize the costs of
testing and monitoring requirements to the extent possible under the
statute. We continue to be interested in the potential impacts of this
proposed action on small entities and welcome comments on issues
related to such impacts.

D. Unfunded Mandates Reform Act

    This action contains no Federal mandates under the provisions of
Title II of the Unfunded Mandates Reform Act (UMRA), 2 U.S.C. 1531-1538
for State, local, or tribal governments or the private sector. This
proposed action imposes no enforceable duty on any State, local or
tribal governments or the private sector.
    Therefore, this proposed action is not subject to the requirements
of sections 202 or 205 of the UMRA.
    This proposed action is also not subject to the requirements of
section 203 of UMRA because it contains no regulatory requirements that
might significantly or uniquely affect small governments. There are 2
HMIWI owned by one small governmental jurisdiction that would be
regulated by this proposed action. For each subcategory of HMIWI, we
are proposing emission limits that are based on the MACT floor level of
control, which is the minimum level of stringency that can be
considered in establishing MACT standards. EPA can set standards no
less stringent than the MACT floor and, under this proposed action, all
HMIWI would be subject to emission limits based on the MACT floors.
Thus, the regulatory requirements being proposed would not be
considered as significantly or uniquely affecting the small entity that
would be impacted by the proposed rule because it would be subject to
standards based on the same minimum levels of stringency as all other
HMIWI.

E. Executive Order 13132: Federalism

    Executive Order 13132 (64 FR 43255; August 10, 1999), requires EPA
to develop an accountable process to ensure ``meaningful and timely
input by State and local officials in the development of regulatory
policies that have federalism implications.'' ``Policies that have
federalism implications'' are defined in the Executive Order to include
regulations that have ``substantial direct effects on the States, on
the relationship between the national government and the States, or on
the distribution of power and responsibilities among the various levels
of government.''
    This proposed rule does not have federalism implications. It will
not have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in Executive Order 13132. This proposed action will not
impose substantial direct compliance costs on State or local
governments, and will not preempt State law. Thus, Executive Order
13132 does not apply to this rule.
    In the spirit of Executive Order 13132, and consistent with EPA
policy to promote communications between EPA and State and local
governments, EPA specifically solicits comment on this proposed rule
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications, as specified in
Executive Order 13175, (65 FR 67249; November 9, 2000). EPA is not
aware of any HMIWI owned or operated by Indian tribal governments.
Thus, Executive Order 13175 does not apply to this action.
    EPA specifically solicits additional comment on this proposed
action from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks

    EPA interprets Executive Order 13045 (62 FR 19885; April 23, 1997)
as applying to those regulatory actions that

concern health or safety risks, such that the analysis required under
section 5-501 of the Order has the potential to influence the
regulation. This proposed action is not subject to Executive Order
13045 because it is based solely on technology performance.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution or Use

    This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355; May 22, 2001) because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy. EPA estimates that the requirements in
this proposed action would cause most HMIWI to modify existing air
pollution control devices (e.g., increase the horsepower of their wet
scrubbers) or install and operate new control devices, resulting in
approximately 29,100 megawatt-hours per year of additional electricity
being used.
    Given the negligible change in energy consumption resulting from
this proposed action, EPA does not expect any significant price
increase for any energy type. The cost of energy distribution should
not be affected by this proposed action at all since the action would
not affect energy distribution facilities. We also expect that any
impacts on the import of foreign energy supplies, or any other adverse
outcomes that may occur with regards to energy supplies would not be
significant. We, therefore, conclude that if there were to be any
adverse energy effects associated with this proposed action, they would
be minimal.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law No. 104-113 (15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards (VCS) in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by VCS bodies. NTTAA directs EPA to provide Congress, through
OMB, explanations when the Agency decides not to use available and
applicable VCS.
    This proposed rulemaking involves technical standards. EPA has
decided to use two VCS in this proposed rule. One VCS, ASME PTC 19.10-
1981, ``Flue and Exhaust Gas Analyses,'' is cited in this proposed rule
for its manual method of measuring the content of the exhaust gas as an
acceptable alternative to EPA Method 3B of appendix A-2. This standard
is available from the American Society of Mechanical Engineers (ASME),
P.O. Box 2900, Fairfield, NJ 07007-2900; or Global Engineering
Documents, Sales Department, 15 Inverness Way East, Englewood, CO
80112.
    Another VCS, ASTM D6784-02, ``Standard Test Method for Elemental,
Oxidized, Particle-Bound and Total Mercury Gas Generated from Coal-
Fired Stationary Sources (Ontario Hydro Method),'' is cited in this
proposed rule as an acceptable alternative to EPA Method 29 of appendix
A-8 (portion for mercury only) for measuring mercury. This standard is
available from the American Society for Testing and Materials (ASTM),
100 Barr Harbor Drive, Post Office Box C700, West Conshohocken, PA
19428-2959; or ProQuest, 300 North Zeeb Road, Ann Arbor, MI 48106.
    While the Agency has identified 16 VCS as being potentially
applicable to this proposed rule, we have decided not to use these VCS
in this rulemaking. The use of these VCS would be impractical because
they do not meet the objectives of the standards cited in this rule.
See the docket for this proposed rule for the reasons for these
determinations.
    Under 40 CFR 60.13(i) of the NSPS General Provisions, a source may
apply to EPA for permission to use alternative test methods or
alternative monitoring requirements in place of any required testing
methods, performance specifications, or procedures in the final rule
and any amendments.
    EPA welcomes comments on this aspect of the proposed rulemaking and
specifically invites the public to identify potentially-applicable
voluntary consensus standards and to explain why such standards should
be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629) (February 16, 1994) establishes
federal executive policy on environmental justice. Its main provision
directs federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
    EPA has determined that this proposed rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it increases the
level of environmental protection for all affected populations without
having any disproportionately high and adverse human health or
environmental effects on any population, including any minority or low-
income populations. This action would establish national standards that
would result in reductions in emissions of HCl, CO, Cd, Pb, Hg, PM,
CDD/CDF, NOX and SO2 from all HMIWI and thus
decrease the amount of such emissions to which all affected populations
are exposed.

List of Subjects in 40 CFR Part 60

    Environmental protection, Administrative practice and procedure,
Air pollution control, Intergovernmental relations, Reporting and
recordkeeping requirements.

    Dated: November 14, 2008.
Stephen L. Johnson,
Administrator.

    For the reasons stated in the preamble, title 40, chapter I, part
60 of the Code of Federal Regulations is proposed to be amended as
follows:

PART 60--[AMENDED]

    1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401, et seq.

Subpart Ce--[Amended]

    2. Section 60.32e is amended by revising paragraph (a) and adding
paragraph (j) to read as follows:

Sec.  60.32e  Designated facilities.

    (a) Except as provided in paragraphs (b) through (h) of this
section, the designated facility to which the guidelines apply is each
individual HMIWI:
    (1) For which construction was commenced on or before June 20,
1996, or for which modification was commenced on or before March 16,
1998.
    (2) For which construction was commenced on or before December 1,
2008, or for which modification is commenced on or before [DATE 6
MONTHS AFTER PUBLICATION OF THE FINAL RULE IN THE Federal Register].
* * * * *
    (j) The requirements of this subpart as promulgated on September
15, 1997,

shall apply to the designated facilities defined in paragraph (a)(1) of
this section until the applicable compliance date of the requirements
of this subpart, as amended on [DATE OF PUBLICATION OF THE FINAL RULE
IN THE Federal Register]. Upon the compliance date of the requirements
of this subpart, designated facilities as defined in paragraph (a)(1)
of this section are no longer subject to the requirements of this
subpart, as promulgated on September 15, 1997, but are subject to the
requirements of this subpart, as amended on [DATE OF PUBLICATION OF THE
FINAL RULE IN THE Federal Register].
    3. Section 60.33e is revised to read as follows:

Sec.  60.33e  Emission guidelines.

    (a) For approval, a State plan shall include the requirements for
emission limits at least as protective as the following requirements,
as applicable:
    (1) For a designated facility as defined in Sec.  60.32e(a)(1), the
requirements listed in Table 1 of this subpart, except as provided in
paragraph (b) of this section.
    (2) For a designated facility as defined in Sec.  60.32e(a)(2), the
requirements listed in Table 1A of this subpart, except as provided in
paragraph (b) of this section.
    (b) For approval, a State plan shall include the requirements for
emission limits for any small HMIWI constructed on or before June 20,
1996, which is located more than 50 miles from the boundary of the
nearest Standard Metropolitan Statistical Area (defined in Sec.
60.31e) and which burns less than 2,000 pounds per week of hospital
waste and medical/infectious waste that are at least as protective as
the requirements in paragraphs (b)(1) and (b)(2) of this section, as
applicable. The 2,000 lb/week limitation does not apply during
performance tests.
    (1) For a designated facility as defined in Sec.  60.32e(a)(1), the
requirements listed in Table 2 of this subpart.
    (2) For a designated facility as defined in Sec.  60.32e(a)(2), the
requirements listed in Table 2A of this subpart.
    (c) For approval, a State plan shall include the requirements for
stack opacity at least as protective as the following, as applicable:
    (1) For a designated facility as defined in Sec.  60.32e(a)(1), the
requirements in Sec.  60.52c(b)(1) of subpart Ec of this part.
    (2) For a designated facility as defined in Sec.  60.32e(a)(2), the
requirements in Sec.  60.52c(b)(2) of subpart Ec of this part.
    4. Section 60.36e is amended as follows:
    a. By revising paragraph (a) introductory text;
    b. By revising paragraph (b);
    c. By adding paragraph (c); and
    d. By adding paragraph (d).

Sec.  60.36e  Inspection guidelines.

    (a) For approval, a State plan shall require each small HMIWI
subject to the emission limits under Sec.  60.33e(b) and each HMIWI
subject to the emission limits under Sec.  60.33e(a)(2) to undergo an
initial equipment inspection that is at least as protective as the
following within 1 year following approval of the State plan:
* * * * *
    (b) For approval, a State plan shall require each small HMIWI
subject to the emission limits under Sec.  60.33e(b) and each HMIWI
subject to the emission limits under Sec.  60.33e(a)(2) to undergo an
equipment inspection annually (no more than 12 months following the
previous annual equipment inspection), as outlined in paragraph (a) of
this section.
    (c) For approval, a State plan shall require each small HMIWI
subject to the emission limits under Sec.  60.33e(b)(2) and each HMIWI
subject to the emission limits under Sec.  60.33e(a)(2) to undergo an
initial air pollution control device inspection, as applicable, that is
at least as protective as the following within 1 year following
approval of the State plan:
    (1) At a minimum, an inspection shall include the following:
    (i) Inspect air pollution control device(s) for proper operation,
if applicable;
    (ii) Ensure proper calibration of thermocouples, sorbent feed
systems, and any other monitoring equipment; and
    (iii) Generally observe that the equipment is maintained in good
operating condition.
    (2) Within 10 operating days following an air pollution control
device inspection, all necessary repairs shall be completed unless the
owner or operator obtains written approval from the State agency
establishing a date whereby all necessary repairs of the designated
facility shall be completed.
    (d) For approval, a State plan shall require each small HMIWI
subject to the emission limits under Sec.  60.33e(b)(2) and each HMIWI
subject to the emission limits under Sec.  60.33e(a)(2) to undergo an
air pollution control device inspection, as applicable, annually (no
more than 12 months following the previous annual air pollution control
device inspection), as outlined in paragraph (c) of this section.
    5. Section 60.37e is amended as follows:
    a. By revising paragraph (a);
    b. By revising paragraphs (b) introductory text and (b)(1);
    c. By redesignating paragraphs (c) and (d) as paragraphs (d) and
(e);
    d. By redesignating paragraphs (b)(2) through (b)(5) as paragraphs
(c)(1) through (c)(4);
    e. By adding a new paragraph (b)(2);
    f. By adding paragraph (c) introductory text;
    g. By revising newly redesignated paragraphs (c)(3) and (c)(4);
    h. By revising newly redesignated paragraph (d);
    i. By revising newly redesignated paragraph (e) introductory text;
    j. By revising newly redesignated paragraph (e)(3); and
    k. By adding paragraph (f).

Sec.  60.37e  Compliance, performance testing, and monitoring
guidelines.

    (a) Except as provided in paragraph (b) of this section, for
approval, a State plan shall include the requirements for compliance
and performance testing listed in Sec.  60.56c of subpart Ec of this
part, with the following exclusions:
    (1) For a designated facility as defined in Sec.  60.32e(a)(1)
subject to the emission limits in Sec.  60.33e(a)(1), excluding the
test methods listed in Sec.  60.56c(b)(7) and (8), the fugitive
emissions testing requirements under Sec.  60.56c(b)(14) and (c)(3),
the CO CEMS requirements under Sec.  60.56c(c)(4), and the compliance
requirements for monitoring listed in Sec.  60.56c(c)(5)(ii) through
(v), (c)(6), (c)(7), (e)(6) through (10), (f)(7) through (10), (g)(6)
through (10), and (h).
    (2) For a designated facility as defined in Sec.  60.32e(a)(2)
subject to the emission limits in Sec.  60.33e(a)(2), excluding the
annual fugitive emissions testing requirements under Sec.
60.56c(c)(3), the CO CEMS requirements under Sec.  60.56c(c)(4), and
the compliance requirements for monitoring listed in Sec.
60.56c(c)(5)(ii) through (v), (c)(6), (c)(7), (e)(6) through (10),
(f)(7) through (10), and (g)(6) through (10). Sources subject to the
emission limits under Sec.  60.33e(a)(2) may, however, elect to use CO
CEMS as specified under Sec.  60.56c(c)(4) or bag leak detection
systems as specified under Sec.  60.57c(h).
    (b) Except as provided in paragraphs (b)(1) and (b)(2) of this
section, for approval, a State plan shall require each small HMIWI
subject to the emission limits under Sec.  60.33e(b) to meet the
performance testing requirements listed in Sec.  60.56c of subpart Ec
of this part. The 2,000 lb/week limitation under Sec.  60.33e(b) does
not apply during performance tests.

    (1) For a designated facility as defined in Sec.  60.32e(a)(1)
subject to the emission limits under Sec.  60.33e(b)(1), excluding the
test methods listed in Sec.  60.56c(b)(7), (8), (12), (13) (Pb and Cd),
and (14), the annual PM, CO, and HCl emissions testing requirements
under Sec.  60.56c(c)(2), the annual fugitive emissions testing
requirements under Sec.  60.56c(c)(3), the CO CEMS requirements under
Sec.  60.56c(c)(4), and the compliance requirements for monitoring
listed in Sec.  60.56c(c)(5) through (7), and (d) through (k).
    (2) For a designated facility as defined in Sec.  60.32e(a)(2)
subject to the emission limits under Sec.  60.33e(b)(2), excluding the
annual fugitive emissions testing requirements under Sec.
60.56c(c)(3), the CO CEMS requirements under Sec.  60.56c(c)(4), and