which would destroy the captured THC. It may be necessary to add a
polishing baghouse thereby increasing costs 10 to 15 times that of using
ACI alone.

Dioxins/Furans may be increased when using ACI to control THC for cement
plants that burn hazardous waste.

Several commenters (2844 and 2845) noted that EPA has proposed using ACI
to provide simultaneous control for both mercury and THC. Although a
standard powdered activated carbon may control both mercury and THC
(greater than 90 percent removal), there is no data to support the
removal of THC when a halogenated carbon was used to control high
elemental mercury concentrations.

Commenters 2864 and 2889 expressed concerns about operating problems
caused by a HCl wet scrubber ahead of a RTO. Commenter 2864 provided an
example of their experience with RTO with wet scrubbers at two wet
kilns. Although 89 percent THC removal was reported initially, the
system was plagued with problems and equipment failure. After six years
of repairs and upgrades, the system worked in the 2008 ozone season and
the plant was shut down permanently later that year. Commenter 2889
stated that EPA has not considered the costs due to kiln outages caused
by the unreliability of wet scrubbers and RTO required by the proposed
amendments. Both wet scrubbers and RTO in the cement industry and other
industries have been subject to frequent maintenance problems. Existing
kilns installing wet scrubbers in series with a RTO will compound the
reliability issue. Problems affecting either one of the control systems
will require the kiln to shut down. The cost for the lost production
should be included in these cost impact analyses.

Commenters 2844 and 2889 stated that EPA’s claimed activated carbon
injection system THC control efficiency of 75 to 80 percent is not
adequately supported and does not take into account the low control
efficiency for light hydrocarbons. As a consequence of the
unrealistically highly assumed ACI removal efficiency for THC, EPA has
underestimated the number of RTO that will be needed to achieve the
standard for existing kilns. The cost, environmental, energy, and
economic impacts of the proposed amendments described in Section VI of
the Preamble are inaccurate due to the probable need for numerous RTO.

Commenter 2844 stated that RTO are not expected to provide for
continuous compliance with the limit. Vendors have not been willing to
guarantee levels below the proposed standards of 6 and 7 ppm. The one
commercial application of an RTO on a kiln cannot meet the standard, and
a number of units have such high THCs that RTO may not be able to lower
the emissions sufficiently to get close to the proposed limit. Where the
concentrations of THC in kiln stacks is low, but still over the
standard, the emissions reductions that an RTO can provide are small.

Commenters 2841, 2844, 2845, and 2889 stated that the requirement of
regenerative thermal oxidizers (RTO’s) for control of THC will result
in an increase of CO2 emissions, along with a host of other emission
impacts due to increased fuel and energy consumption.

One commenter (2845) stated the following regarding the use of RTO’s
for THC control:

RTO will increase cost, energy use, and greenhouse gas emissions.

RTO have performance limitations. Based on available data, RTO have a
performance limit of 10 ppm THC which restricts the emission control
capabilities. Therefore, the THC emission standards should be no less
than 10 ppm.

RTO are not cost-effective due to high maintenance costs (especially in
harsh weather). Maintenance includes component replacements and periodic
cleaning and washing.

Numerous cement plants lack access or have limited access to the natural
gas need to operate RTO.

RTO use will increase green house gas emissions with higher NOx
emissions due to the use of natural gas or propane used for firing. The
commenter included data concerning the increase greenhouse gas emissions
with their comment.

Commenter 2900 provided stack test data for THC emissions. The data
demonstrates that the plant may have three or more times the new EPA
limit in emissions and may be unable to meet compliance.

Response: Hazardous waste burning cement kilns are not subject to the
subpart LLL standards. The proposed level of control for THC is exceeded
in practice by the only cement plant in the U.S. equipped with an ACI
system. With regards to the comment regarding dioxins/furans emissions
potentially increasing as a result of these rule requirements, hazardous
waste burning cement kilns are not subject to subpart LLL standards. For
those comments related to control device performance and the secondary
impacts of increased CO2 and GHG emissions from oxidizers, those impacts
were considered in our analysis and were based on the best information
available to us. If a given facility wants to avoid such secondary
impacts, the organic HAP limit is a viable compliance option for them.

Comment: One commenter (2928) stated that RTO are technically feasible
and cost effective options that can be used to meet the proposed
standards. TXI operates the largest cement kiln in the state of Texas in
Midlothian with an RTO acting as an effective afterburner for VOC, THC
and CO emissions. It is 80-90 percent effective in removing these
contaminants from the plume. As has already been noted, SCR technology
also significantly reduces VOCs/THCs from the exhaust.

Response: EPA does not anticipate that widespread use of RTOs will be
needed to comply with the THC standard. See Regulatory Impact Analysis:
Amendments to the NESHAP and NSPS for the Portland Cement Manufacturing
Industry, Final Report, August 2010.

Baseline THC emissions

Comment: One commenter (2845) stated that when evaluating the emissions
database for each kiln EPA used, the standardized format is problematic
from multiple standpoints. Here are several related examples:

In reviewing data for those facilities for which EPA had actual data,
there appears to be the following types of issues:

Projected emission rates were extrapolated from a particular time period
of production (2002 production extrapolated to 2005) that does not
necessarily reflect the actual emissions for a particular kiln

Kiln emission allocations for facilities with multiple kilns are not
consistent, with the following examples:

Main stack emission rates where 3 kilns feed a common stack are applied
to each of the three kilns individually for some pollutants; thereby
overestimating individual kiln emissions.

Emission rates are apportioned improperly between the multiple kilns.

Deriving factors to extrapolate HAP emissions from those facilities
where EPA has data to the remainder of the kilns, does not have a sound
justification as a basis for such detailed cost calculations. For the
THC factor, removing facilities with high levels of THC is not
warranted. With many facilities not having THC data, and THC emissions
being based on geographic location, other cases of higher THC emissions
is a realistic outcome. EPA’s factor of 21 ppm was compared to the
average of industry’s corresponding database. Removing only the
highest THC emission kiln (which is now closed), the average THC
emission rate was calculated to be 28.1 ppm.

The use of dry versus actual flow rates appears to be used
inconsistently.

The assumption that most plants burn coal is not accurate and will
affect flow rates, and therefore emissions.

The data includes some HWC (waste burning kilns) and kilns currently
shut down. The inclusion of this type of data skews the database.

Factors established by kiln type may not be as relevant as factoring by
geographic area, as the newly regulated HAPs generally are variable due
to the limestone and/or silica source quarried on-site.

Response: The database for this rulemaking has been updated to account
for the kilns active in 2009 that are subject to this rule. Hazardous
waste kilns are included in the database for the ISIS Cement Model but
are not subject to this rule. THC emissions for each kiln subject to
this rule were calculated using emission factors developed from the data
EPA received thru the Information Collection Request (ICR). For kilns
where we did not have specific emissions information, we developed an
average emissions factor. We removed the highest emitting kiln because
we believe it represents an outlier. We know of no other facility that
has emission even close to the highest THC emitting kiln. We recognize
that using an average emissions factor may overestimate or underestimate
costs. However, we know of no more accurate way to estimates emissions
and costs.

 2.6.6	Other

THC emissions due to burning waste vs due to limestone

Comment: One commenter (2928) supported the proposed emission standard
for THC. The commenter noted that cement industry will argue that the
entireties of their THC and CO emissions are from the cooking of the
limestone that contains these chemicals naturally. EPA should be
skeptical of this claim without proof when so many cement plants are
burning wastes, including tires, asphalt shingles and oil filter fluff
that contribute directly to these kinds of emissions. Industry must
distinguish between those THC emissions legitimately caused by raw
materials and those cause by the burning of waste fuels.

Response: EPA acknowledges the commenter’s support and notes that the
expansion of the database for THC more accurately reflects performance
than the more limited information at proposal.

2.7	HCl Standards

Comment: One commenter (2898) recommended that EPA adopt the proposed
MACT floor for HCl.

Response: EPA acknowledges the support of this commenter, although the
proposed standard did not properly account for variability in the
analytic detection method due to its quantitation limit.

2.7.1	Legal Issues

Health based vs MACT emission standards

Comment: Many commenters expressed their preference for EPA’s previous
health-based approach to setting limits for HCl.

Commenter 2830 requested that EPA clearly articulate why it did not
reaffirm its position in the original proposed NESHAP where it found
that an HCl standard is not necessary given the low HCl emissions from
cement kilns and risk assessment findings from a national survey of the
industry showing a lack of risk to health or the environment from any
cement facility. There is no compelling environmental or public health
reason for EPA to change course at this time, and relying on §112(d)(4)
would be consistent with Congressional intent to not impose burdensome
HAPs regulations where no risk to public health or the environment
exists.

Commenters 2841, 2844, 2859, and 2890 stated that in previous MACT
rulemakings, the Agency determined that HCl’s nature as a threshold
pollutant and the clearly demonstrated lack of risk posed by HCl
emissions at the property boundaries of cement manufacturing facilities
precluded the need to set such a standard. EPA’s reversal of this
approach in this latest proposed rulemaking runs completely counter to
its approach in other rulemakings.

Commenters 2844, 2845, 2859, 2864, 2874, 2901, 2915, and 2916 stated
that to the extent that EPA believes it needs to address HCl in this
rulemaking, the standard should continue to be health-based.

Commenter 2845 proposes that sources be allowed to set a site-specific
limit, ensuring that a national standard of a hazard index of 1.0 is not
exceeded, thereby demonstrating an ample margin of safety. This approach
was adopted in EPA’s hazardous waste combustor MACT rule and the
industrial boiler MACT rule (for HCl). There is no compelling
environmental or public health reason for EPA to change course at this
time, and relying on §112(d)(4) would be consistent with Congressional
intent to not impose burdensome HAPs regulations where no risk to public
health or the environment exists.

Commenters 2845, 2874, and 2901 stated that EPA should reaffirm the
position it took in the December 2006 Portland Cement NESHAP rule that
in accordance with §112(d)(4) that it is not necessary to set a MACT
standard for HCl. In two MACT rulemakings for other industry sectors,
EPA has decided that an HCl standard was not warranted where EPA
determined that even the individuals with the greatest exposure to HCl
emissions from neighboring facilities would be safe with an ample margin
of safety. EPA now proposes to reverse course because controls installed
to reduce HCl emissions would supposedly result in emissions reductions
of sulfur dioxide and other non-HAP pollutants. MACT standards, however,
may only address HAPs. The commenter states that it is inconsistent with
CAA §112(d) and arbitrary for EPA to depart from precedents in the 2006
and other earlier MACT rulemakings to set an HCl standard for the
purpose of reducing criteria and other non-HAP pollutants.

If EPA does decide to set a standard, commenters 2845, 2874, and 2901
stated that EPA should follow the approach it adopted in its hazardous
waste combustor MACT rule (for total chlorine) and the industrial boiler
MACT rule (for HCl), where EPA established health-based compliance
alternatives. In those rulemakings, EPA set a national standard such
that for someone living at the fence line of the facility, the hazard
index could not exceed 1.0 (thus providing an ample margin of safety).
The facility then would be able to set a site-specific limit, ensuring
that the hazard index did not exceed 1.0.

Commenters 2845, 2874, and 2901 noted that EPA’s 23 ppm by volume
(ppmv) suggested not-to-exceed limit is an order of magnitude less
stringent than the proposed 2.0 ppmv existing source standard for HCl.
Thus, if EPA adopts the standard in the Proposal, it will be setting a
standard that is an order of magnitude more stringent than the level
(using extremely conservative assumptions) necessary to protect human
health. Commenters 2844 and 2901 suggested that if EPA decides that an
HCl limit is needed, the Agency should set a limit based on protection
of health at 23 ppmv.

Commenter 2901 stated that although some might argue that HCl is not a
threshold pollutant because it has not been shown to be
non-carcinogenic, Congress stated that ammonia was a HAP with a
well-established threshold for which EPA could set a risk-based
standard. A comparison of the Integrated Risk Information System (IRIS)
information relating to carcinogenicity for ammonia and HCl shows that
the two chemicals have the same notation relating to carcinogenicity,
not undergone a complete evaluation and determination under U.S. EPA’s
IRIS program for evidence of human carcinogenic potential.

Commenters 2845 and 2846 stated that the proposal solicits comment on
whether EPA should promulgate a health-based standard for HCl under
§112(d)(4) that would be in the form of a not-to-exceed standard, based
on risk analysis of 68 facilities using a screening level dispersion
model (AERSCREEN). EPA states that such a not-to-exceed standard would
be set at a level of 23 ppmv.

Commenter 2845 disagreed that EPA must issue a standard.

Commenter 2846 agreed that a health-based approach will allow facilities
alternative compliance options so that capital and operating costs are
not incurred solely on controls for control’s sake, for example, where
there is no HCl health risk and where investing in a control technology
brings minimal or no co-benefit.

Commenter 2901 stated that EPA’s analysis for this proposed rule shows
that 23 ppmv emitted from any plant would result in an annual average
ground concentration of more than 20 µg/m3. Because the RfC for HCl is
20 µg/m3 an emission standard of 23 ppmv would be protective for any
facility. The commenter stated that a 2 ppmv technology-based standard
is unnecessary when EPA has already concluded that 23 ppmv is protective
with an ample margin of safety, and why Congress gave EPA the
flexibility to use a risk-based alternative. As Congress noted in the
legislative history, §112(d)(4) was enacted to avoid expenditures by
regulated entities which do not have public health or environmental
benefit.

Response: Most of these issues are responded to in the preamble in
section IV.A.1.d.iv. Given the enormous environmental benefits projected
from a MACT standard for HCl, EPA rejects the characterization that a
MACT standard would be ‘control for control’s sake’.

Comment: Several commenters (2816, 2898 and 2911) agreed with EPA’s
decision to not propose a health-based standard. The commenters agreed
that a health-based standard should not replace a MACT standard for HCl.
The CAA allows the EPA to consider the health threshold for a HAP in
setting emission standards, if one has been established. 42 U.S.C.
§7412(d)(4). The commenter noted that the use of the term has been is
retrospective, and shows that Congress intended that EPA may only use
the authority when an accepted threshold is already in existence.
Further, Congress specified the kind of proof that EPA needed in order
to invoke subsection 112(d)(4): direct evidence of no effects. The
Senate report on the 1990 CAA stated that the provision allows EPA to
use the no observable effects level (NOEL). Thus, unless there is clear
evidence of an existing threshold for the pollutants in question, EPA
may not rely on subsection 112(d)(4) at all. The Agency may not
speculate from inconclusive science; rather, it must be sure that there
are no effects from exposure at the level chosen for the emission
standard.

Commenter 2898 stated that the 2006 rule that EPA relies on for a
possible alternative health-based standard has been challenged in court
and is being held in abeyance pending the results of EPA’s
reconsideration of the rule, carried out in the present rulemaking (74
FR 21139-40, 21154). Thus, the 2006 rule cannot be said to have
established a health threshold.

According to commenter 2911, HCl is not the only acid gas that cement
plants emit. Among the other acid gases that cement plants emit are at
least two listed hazardous air pollutants, hydrogen fluoride and
hydrogen cyanide. EPA has a clear statutory duty to set emission
standards for each HAP that a source emits and, even if EPA could set
§112(d)(4) standards for HCl, the agency does not and cannot claim that
there is an established threshold either for hydrogen fluoride or for
hydrogen cyanide. Further, because EPA must set standards for the latter
pollutants under §112(d)(2) and (3), a §112(d)(4) standard for HCl
could not possibly serve as a surrogate for either of them. To satisfy
the CAA, EPA must set individual standards for both hydrogen fluoride
and hydrogen cyanide or must use a valid surrogate standard for them.

Response: EPA thanks the commenters for their support on our decision to
not set health based standard for HCl. Regarding the suggestion that EPA
set limits for HG and HCN, EPA notes that a factor in not setting a
health-based standard was that setting a MACT standard for HCl not only
controlled HCl but also co-controlled other HAP (such as HF, Chlorine
(Cl2), and hydrogen cyanide (HCN)) and criteria pollutants yielding very
substantial environmental benefits. EPA agrees that HF and HCN emissions
from cement manufacturing should be reduced when possible and believes
that the final rule helps to accomplish that end.

Claiming benefits from SO2 reduction not permissible

Comment: Several commenters (2841, 2844, 2846, and 2916) stated that
MACT standards may only address HAP pollutants, but EPA is trying to
control sulfur dioxide and other non-HAP pollutants through application
of control technology used to reduce HCl.

Commenter 2846 stated that basing MACT limits on such considerations is
not permissible and limiting compliance flexibility by excluding other
options is not good policy. Section 112(d)(2) provides an express list
of factors that EPA may consider in setting MACT standards – including
the cost of achieving such emission reduction, and any non-air quality
health and environmental impacts and energy requirements. This list does
not allow consideration of non-HAP air quality benefits, such as the
co-benefits of reducing PM2.5 emissions.

One commenter (2898) stated that Congress intended EPA to consider
benefits such as a reduction in emissions of SO2 and other acid gases,
along with condensable PM, ammonia, and semivolatile compounds when
setting a MACT floor, and EPA has appropriately considered these
co-benefits in deciding not to set health-based standards for HCl.

Response: Although MACT standards may directly regulate only HAPs and
not criteria pollutants, Congress did recognize, in the legislative
history to section 112(d)(4), that MACT standards would have the
collateral benefit of controlling criteria pollutants as well and viewed
this as an important benefit of the air toxics program.. See S. Rep. No.
101-228, 101st Cong. 1st sess. at 172. EPA consequently does not accept
the argument that it cannot consider reductions of criteria pollutants,
for example in determining whether to take or not take certain
discretionary actions, such as whether to adopt a risk-based standard
under section 112 (d)(4) or to adopt standards for HAP metals that truly
reflect MACT by amending the PM standard. There appears to be no valid
reason that, where EPA has discretion in what type of standard to adopt,
EPA must ignore controls which further the health and environmental
outcomes at which section 112 (d) of the Act is fundamentally aimed
because such controls not only reduce HAP emissions but emissions of
other air pollutants as well. Thus, commenter 2844’s invocation of the
decision factors enumerated in section 112 (d)(2) seems off point, since
the issue being addressed is not whether to regulate non-HAP (EPA is
not), whether to consider other air quality benefits in setting section
112 (d)(2) standards (EPA is not), but rather whether to make the
discretionary choice to regulate certain HAP based on the MACT approach
and whether EPA must put blinders on and ignore collateral environmental
benefits when choosing whether or not to exercise that discretion. EPA
knows of no principle in law or common sense that precludes it from
doing so.

 With regard to the comments specifically addressing SO2, EPA is
regulating SO2 emissions for new sources and modified sources under the
NSPS rulemaking. EPA is not regulating SO2 in the NESHAP, although EPA
recognizes that any other SO2 emission reduction obtained from existing
sources is a co-benefit resulting from the control technology selected
to comply with either the mercury and/or HCl NESHAP limits. EPA
recognizes the multi pollutant interactions and co-benefits of this
rulemaking and how a well planned integrated control strategy can
maximize the environmental results while optimizing the cost invested by
a facility to comply with such regulation.

SO2 as surrogate

Comment: Several commenters (2898 and 2911) agreed with EPA’s decision
not to propose using SO2 as a surrogate for HCl. HCl is not present in
SO2, and control of SO2 is not the only means by which cement kilns
achieve reductions in HCl. To the contrary some kilns achieve HCl
reductions through the use of raw materials and fuels that contain less
chlorine.

Response: We agree with the comments and are not using SO2 as a
surrogate for HCl.

2.7.2	Adequacy of Floor Determinations (Existing and New)

Adequacy of data

Comment: One commenter (2144) agreed with EPA’s HCl emission limit of
2 ppmvd for existing sources or a more stringent standard if the
statistical methodology biased the results on the high side. The
commenter agrees with the 0.1 ppmvd for new kilns unless the statistical
methodology justifies and the law allows a greater limit not to exceed 2
ppmvd. The commenter has not yet determined whether it agrees with the
method by which existing and new kiln emission standards were set.

Commenter 2898 agreed with the EPA proposal to base the MACT floor for
HCl for existing sources at the average of the lowest emitting 12
percent of the kilns for which it has data and at the emission rate of
the single lowest emitting source for new sources is consistent with the
CAA’s requirements.

Response: The final standards for HCl are 3 ppmvd on a dry basis at 7
percent oxygen, for both new and existing sources. A detailed discussion
of the MACT floor determination for HCl is included in the preamble
(section IV.A.1.e).

Comment: Many commenters stated that EPA’s MACT floor analysis for HCl
was inadequate or that EPA lacked adequate data.

Several commenters (2830, 2836, 2845, and 2859) stated that EPA should
reaffirm its position in the 2006 NESHAP where it found that a HCl
standard is not necessary given the low HCl emissions from cement kilns
and risk assessment findings from a national survey of the industry
showing a lack of risk to health or the environment from any cement
facility. The commenters further stated that EPA’s HCl emissions data
is not sufficient to establish a defensible MACT standard. The majority
of emissions data used by EPA is from area sources of HAPs and/or
suffers from data quality issues, such as data recorded below the
quantification limits of the test method or by using improper test
methods. After reviewing the data, the commenters believe EPA has
emission data from only one source that would be a defensible data
point. EPA should not base a nationwide existing NESHAP standard on data
from one facility. Clearly, no variability considerations are afforded
as a result of using one data point.

Commenter 2841 stated that EPA gave limited notice to the industry to
respond and provide additional data, is inappropriate when considering
the development of any standard.

Commenters 2845, 2846, 2863, and 2889 stated that EPA should not use HCl
emission data below the current Method 321 practical quantification
limit. The commenters stated that it is unnecessary to set a floor or
standard for HCl, but if EPA decides to do so it should exclude all test
data below the practical quantification limit and exclude from the pool
of MACT floor sources any kiln with test data below that limit. Given
that the data were gathered when Method 321 identified a practical
quantification limit in the range from 1000 to 5000 parts per billion
for specific path length and test conditions, EPA should not use any
data below that range. If EPA believes it may be appropriate to revise
Method 321, it should conduct a formal review process for the Method,
and make available to the public any relevant supporting information.
But if EPA does amend Method 321, it should not apply the changes
retroactively.

Commenters 2836, 2844, 2845, 2859, 2863, and 2889 stated that the
existing source floor is improperly based on inadequate data. Commenters
2845 and 2863 stated that there are not enough data upon which to
establish an existing source MACT floor. One-third of the sources in
EPA’s database – 9 of the 27 sources listed in Table 5 of the
preamble – are true area sources. Commenters noted that test data for
so many of the 27 kilns are invalid that when true area sources and
sources with invalid data are excluded, only one kiln remains (i.e.,
only Kiln 20 in the table is a major source for which there are valid
HCl test data). Additional concerns presented by the commenters were:

EPA established the proposed HCl MACT floor for existing sources based
upon Method 321 test data from what it describes as the top 12 percent
of kilns for which it had such data. There were only 8 of 27 kilns in
EPA Table 5 of the preamble with Method 321 data and EPA examined the
top four kilns without respect to test method. The lowest emitters,
Kilns 1 and 2 used data from California Air Resources Board (CARB) 421,
which is specifically disallowed.

Only one of the kiln sets from which EPA calculated the floor is a major
source. EPA must change the kilns from which it sets that existing
source floor. The proposal notes that it is appropriate to limit the
floor database to major sources. This is correct because area sources
are not in the same category or subcategory as the major sources for
which EPA is setting the floor and issuing standards. CAA §112(d)(3).

EPA should use data from 5 kilns, rather than 4, to establish the floor.
Where there are 30 or more sources in a category, but fewer than 30 with
data, CAA §112(d)(3) should be read to require the use of 5 sources to
establish the floor.

Much of the HCl data are based on invalid tests. EPA must exclude
results from HCl testing conducted with methods other than Method 321 or
ASTM D6348. Some methods were incorrectly applied. The commenter
provided an appendix with tables detailing the commenter’s concerns
about test data. The commenter recommended that EPA exclude 19 kilns
from its database due to invalid tests.

Response: In response to comments we received on the HCl MACT floor
analysis, EPA revised its analysis. We have removed those natural area
sources from the floor analysis and because many of the source tests
were not actually EPA Method 321 tests and others lacked important
quality assurance information, we used our authority under section 114
to collect additional data. We used this new data set to calculate a
MACT floor. See the preamble to the final rule for a discussion of the
revised analysis.

Comment: Several commenters (2830, 2844, and 2845) stated that EPA has
provided no support for its assumption that the stack testing data used
to establish the HCl MACT floors can be correlated to continuous
emissions monitoring data to demonstrate compliance. The commenter
states that EPA has provided no analysis to demonstrate that the
variability of data provided by the proposed emission monitoring methods
would be equivalent to the variability of the stack tests. Under the
Proposal, the HCl MACT floor was set based on the averaging of stack
test data. However, compliance emission measurements will need to be
made based on continuous measurements. The D.C. Circuit disfavors
standards that impose a method for demonstrating compliance that differs
significantly from the method used to arrive at the standard. This is
precisely the case here.

Response: As stated in the preamble to the final rule, EPA has
significantly increased the level of the standard to account for any
uncertainty associated with the analytic method detection level, and is
also expressing the standard as a 30-day limit. Since the level of the
standard is higher than the stack measurements, and is averaged over 30
days (which normally would result in a lower level due to the multiple
observations which dampen variability), EPA does not believe there is
any legitimate issue that use of a CEM to measure the standard makes the
standard more stringent than the underlying data would support. At the
same time, EPA believes that its approach is a legitimate way to gauge
best performers’ performance given the uncertainty associated with the
analytic method detection limit..

Subcategorization

Comment: One commenter (2863) suggested that EPA should subcategorize to
reflect arid sources. EPA cannot reasonably set a standard based on a
control technology type that cannot be employed in a large portion of
the western United States. EPA considered wet scrubbers as a basis for
meeting the HCl standard and no consideration was given for alternative
types of control. However, wet scrubbers are not a viable control
technology in vast parts of the western United States where water is not
available for use in a scrubber. The commenter stated that given the
unavailability of water, EPA should create a subcategory for arid areas
for those plants that cannot use wet scrubbers. Failure to do so would
break from well established precedent and arbitrarily impact plants in
one part of the country.

Response: As noted in the preamble, we are not mandating wet scrubber
control technology in this rule. Other control techniques are available
(hydrated finely ground lime, spray dryers, fuel and additive switching)
that we believe would allow a cement kiln to meet the HCl emission
limits in areas where sufficient water for a wet scrubber is not
available. Although we have no cost data available for these alternative
control techniques (some of which would be site-specific), we anticipate
that these control techniques would be no more expensive that a wet
scrubber.

CISWI

Comment: One commenter (2889) stated that the MACT floor for HCl should
be re-evaluated after the data anticipated in response to the EPA §114
Letter CISWI request, to be submitted by October 2009 is evaluated.

Response: EPA performed a separate date gathering for HCl emission data
as part of this rulemaking and used these data to recalculate the MACT
floor.

2.7.4	Compliance Assurance

Support proposed monitoring method

Comment: One commenter (2144) stated that EPA should require HCl-CEMS
for compliance.

Response: EPA acknowledges the commenter’s support

Comment: Commenter 2832 supports EPA’s proposal to reject EPA
Reference Method 26/26A stack testing data. Method 26/26A does not
accurately measure HCl.

Response: EPA acknowledges the commenter’s support

Compliance Based on Performance Testing

Commenter 2845 stated that EPA should require that compliance with HCl
limits should be measured by periodic stack tests. Because the HCl
floors were developed from HCl stack test data, the standard for HCl
should be based on periodic stack testing. EPA must evaluate valid data
from Method 321/ASTM D6348 stack tests instead of the data contained in
Table 5 of the proposal. Using CEMS to measure compliance effectively
makes the standard more stringent than what has been achieved by the
best-performing sources. If CEMS compliance demonstration is retained,
then the limit for CEMS compliance must be raised to reflect the added
variability that will be measured by the CEMS. While continuous
measurement will capture variability of emissions 24 hours per day, 7
days per week over the full range of process and control system
operating conditions over the life of the plant and its associated
quarry, the stack test is merely a snapshot in time. By definition, a
stack test contains no parameter related to variability other than that
obtained during the three hours of testing. In addition to the inherent
variability of HCl emissions, a CEMS standard must also consider the
inaccuracy of the CEMS as determined (and allowed) relative to the
required stack test methods, the uncertainty of calibration
standards/materials, and other factors affecting the sampling,
transport, and analysis of HCl which is a highly reactive compound.

Response: See response in preamble, as well as the response above to
commenter 2844.

Monitoring requirements for scrubbers

Comment: One commenter (2911) disagreed with EPA’s proposed
requirement to test sources with limestone scrubbers no more than every
five years. The commenter stated that monitoring must be sufficient to
assure continuous compliance with emission standards and to enable
sources to certify accurately whether their compliance with emission
standards is continuous or intermittent and to report any deviation from
those standards. Because both chlorine inputs and the performance of the
scrubber may change significantly over five years, testing just once
every five years cannot possibly provide the required assurance.

Response: Given the efficiency of wet scrubbers in removing HCl, we
believe that parameter monitoring is generally sufficient to demonstrate
compliance combined with periodic testing. However, we agree that a 5
year period between tests may be too long for the reason noted by the
commenter and have changed the testing frequency to 30 months. .

Issues with use of CEMS for HCl compliance monitoring

Comment: Many commenters cited difficulties in the use of CEMS to
determine compliance with the HCl emission limits.

Commenters 2622 and 2889 stated that there will be difficulties
conducting a RATA on HCl CEMS operating at HCl concentrations below 2
ppmvd. Commenter 2622 stated that because that proposal calls for RATA
on HCl monitors when the emission limits are low, EPA will need to set a
low emissions criteria for passing a RATA. The commenter expressed
concern that 20 percent of the reference method or 10 percent of the
emission limit will be too restrictive.

Commenter 2844 stated that that given the level of the standard, a CEMS
will require FTIR and the commenter is not aware of such CEMS available
for purchase. The commenter recommends that compliance be based on
periodic stack tests.

Commenters 2844 and 2846 stated that the new source HCl limit is below
the published Method 321 detection limit and it is not appropriate to
adopt a limit that is inconsistent with the existing standardized test
method.

Commenters 2845, 2846, 2858, and 2859 stated that HCl CEMS cannot be
used to demonstrate compliance at the levels proposed by EPA in this
rule. Although HCl CEMS are installed in some hazardous waste
incinerators, the concentrations being monitored at the incinerators are
much higher than the HCl detection limit based concentration standard
proposed by EPA for cement plants. In addition, calibration gases are
not commercially available at the concentration levels proposed by EPA
in this rule. Commenter 2845 expects a very high learning curve
associated with operating and maintaining these technically challenging
devices. This industry has little experience with their use and, since
HCl CEMS are not widely used in other industries, very little outside
assistance can be provided through industry workgroups. As with mercury
CEMS, EPA should resolve the reliability and performance issues with HCl
CEMS before imposing substantial risks and costs on the portland cement
industry. Although SO2 control is not the primary purpose of installing
a wet scrubber under the proposed rule, the scrubber would be designed
as if SO2 removal were the purpose.

Commenter 2855 stated that FTIR based HCl CEMS cannot function at cement
plants at the concentration levels proposed in the Rule. HCl CEMS are
installed at some hazardous waste incinerators, but generally are
process instruments relied on to provide measurements of HCl levels from
the incineration process and are not FTIR based. The use of an
FTIR-based CEMS for monitoring compliance at a cement plant at such low
levels of HCl introduces a number of problems and concerns for the
cement industry:

Calibration gases are not commercially available at the concentration
levels proposed by EPA in this rule. The lowest concentrations of HCl
calibration gases commercially available are between 5 and 10 ppm, with
an accuracy of ±10% (0.5 ppm to 1 ppm). These calibration gases are 25
to 5 times greater than the proposed HCl standard for existing plants.

There is no independent anchor for HCl calibration gas certification and
the lowest concentration range available is over twice the proposed
standard with a +/- 10% accuracy, numerous uncertainties are introduced
to any data that are collected for the purposes of demonstrating
compliance.

The industry expects a very high learning curve associated with
operating and maintaining these devices. The industry has little
experience with their use and manufacturers have not sold many
monitoring systems into the cement industry.

Commenter 2855 stated that the current state of the technology for FTIR
CEMS for HCl is such that providing precise accurate measurements below
2 ppm HCl will be a challenge and has not routinely been demonstrated in
full-scale industrial applications.

Commenter 2855 stated that a moratorium of 18 months is needed for any
HCl monitoring requirements that may prevail for new and refurbished
kilns having to meet the requirements of the standard on startup or
promulgation.

Response: Several comments relate to the low level of the proposed HCl
standards. We believe that these comments have merit and explain in the
preamble that we are adopting a standard of 3 ppmv to accommodate
issues relating to uncertainties of reliably measuring below that value.
We have also modified the RATA emissions criteria to allow measurements
up to 20 percent of the limit, as we have done in other relatively low
emissions concentrations situations.

Regarding concerns about the use of FTIR, a number of vendors sell FTIR
instruments, and they will work with their customers to adapt the
instruments to the needs of particular facilities. In addition,
calibration gases are readily available at 5 ppm and even down to 2.9
ppm. Method 205 may be used for further gas dilution (yielding high
quality standards) down to the levels needed. We have also talked to
vendors who state they can measure HCl down to 2 ppm. (Email from
Jeffrey Lacoss to Rima Howell RE: Quick Question: PS-15.  March 5, 2010.
 As forwarded to Robin Segall on March 5, 2010.  Document in Docket).

Commenters also raise concerns about the learning curve associated with
HCl CEMS. We note that sources have 3 years to comply with the standard,
which will be sufficient time to implement a working CEMS.

Comment: One commenter (2855) provided comments related to detection
limit issues:

EPA erred when they focused on detection limits in setting the proposed
standard and mandated use of an FTIR based CEMS.

Accuracy is unknown at the detection level; therefore accuracy at the
proposed compliance level cannot be demonstrated.

EPA focused on the detection limits associated with Method 321 area
source tests contained in the docket for HCl in establishing the
proposed HCl standard. EPA must not establish standards based on the HCl
detection level of Method 321, nor should they establish standards for
any compounds at their corresponding method detection levels.

The commenter noted that there is a difference between the detection
limit and practical quantification limit. There is also a difference
between test methods and continuous monitoring systems, although EPA has
proposed a continuous monitoring requirement and cited test Method 321.

The commenter requested that EPA provide information regarding the
differences between current detection levels and those established more
than 15 years ago.

Detection limits are only useful to determine if the measurement is
possible. Accuracy at the detection limit and values below is unknown.
Therefore, proposing a standard at the analytical noise level will
result in the inability to make accurate determinations of compliance.

Commenter 2855 stated that the current stated lower practical
quantification limit for Method 321 still holds true. EPA has proposed
to make changes to Method 321 without providing the information relevant
to this change. It is the belief of the commenter and its member
companies that the Practical Quantitation Limit (PQL) of Method 321 is
between 1 ppm and 5 ppmv wet depending on how well the analytical system
is optimized for HCl. These values are well within the guidance of 5-10
times the analytical detection limit, and any claims to the contrary
must be proven through laboratory demonstrations and placed in the
docket to this rulemaking.

Commenter 2855 stated that EPA had requested comment on which way to set
the emission detection limit and to handle emissions information below
the detection limit for use in this rule. The commenter stated in
response that it is inappropriate to set any standard at a level where
accuracy is unknown and thus demonstration of compliance is not defined.
Further, EPA should not make changes to a promulgated test method (see
changes to Method 321 in the Proposal at 21,192) without first providing
information in the docket for public review and comment.

Commenter 2855 stated that EPA should focus on measurement system
capability and the availability of quality calibration materials in
their standard setting. The commenter provided results of an analysis of
analyte spike data showing sampling and analytical system biases when
non-detect values were reported. The commenter stated that a
concentration based standard cannot be based on values such as detection
limit that do not represent the difficult nature HCl measurement. The
standard cannot be set at a level below the demonstrated system bias and
should account for uncertainties in the calibration materials and the
measurement system ability.

Response: We have provided additional information in the docket on
detection limits (list) and have reviewed test data below detections
limits. Sources can optimize their system to measure HCl and thus
satisfy the PQL of Method 321. However, given that the final standard is
3 ppmv (for both existing and new sources), we believe that these
concerns are addressed since the standard provides an adequate margin
above the method detection limit to account for uncertainties of
measurements near the detection limit.

Procedure 15

Comment: One commenter (2855) stated that PS-15 for FTIR Based CEMS is
not appropriate for an HCl CEMS for portland cement applications. EPA
requested comments on whether a CEMS can meet the requirements of PS-15
to measure HCl emissions. The commenter stated that EPA should develop a
PS for HCl CEMS that does not mandate a specific technology, but is
directly applicable to measurement of HCl. Additional problems stated by
the commenter concerning PS-15 are:

PS-15 is outdated and does not reflect how CEMS function.

PS-15 requires that an FTIR based CEM be used. It is unclear why an FTIR
must be used when other technology is also available (i.e., GFCIR and
TDL).

Performance Specification-15 requires that a spectroscopist or operator
be present on a nearly continuous basis to meet the performance
criteria.

Performance Specification-15 is not specific for HCl and many of the
technical requirements contained therein cannot be met for the 0.1 ppm
to 2 ppm HCl concentration levels proposed by EPA.

Performance Specification-15 contains no requirements for: a)
determining calibration error or drift; b) setting instrument span
range; or, c) determining relative accuracy such as those contained in
the Lilly documents.

There are no NIST traceable HCl calibration gases as suggested by PS-15
at any concentration level.

There are no HCl calibration gases that can meet the 2% accuracy
certification requirement contained in Section 9.1.1, particularly at
the 0.1 ppm to 2 ppm concentration levels.

The highest quality HCl calibration standard available today is at a
concentration level of 5-10 ppm with a vendor certification of ±10%.
The certification of the gas is by an FTIR calibrated with HCl gas
standards prepared by the manufacturer. The certification has no
independent anchor to NIST or other certifying organization.

The requirements of PS-15 for data storage (one interferogram per hour,
all absorbance spectra, all sample spectra, all background spectra, all
CTS spectra, etc...) and spectral audits cannot be met with any
available FTIR Based CEM systems.

PS-15 requires modification of the FTIR CEM analytical program when
analytical results are not within ± 5 percent of the certified audit
concentration for each analyte. FTIR CEMS programs are largely
proprietary and cannot be modified by CEM operators at cement plants.
Furthermore, FTIR CEMS cannot simply load outside software for analyses
of audit spectra. This process must be tested with manufacturers of FTIR
CEMS at the concentration levels proposed in this rule.

Requirements included in PS-15 assume the presence of a full time FTIR
CEMS operator, which is impractical.

Commenter 2915 disagreed with EPA’s proposed standards for the use of
HCl CEMS:

There is a lack of appropriate EPA performance specifications or quality
assurance procedures for HCl CEMS;

There are serious technical feasibility issues with implementation of
the available technology; and

The proposed standards are at or below the CEMS practical quantification
limit and/or the minimum detection limit of the analyzer.

Response: PS-15 is an FTIR CEMS procedure, but it does not specify any
instrument. Any commercially available FTIR instrument may be used as
long as the performance specifications and quality assurance
requirements of PS-15 are met. We recognize, however, that there are
also non-FTIR technologies available to monitor HCl. We are planning to
develop an HCl monitoring performance specification to address these
additional technologies over the next year or so in advance of the
compliance date of this rule; however, in the interim, owner/operators
always have the option to petition the Administrator for an alternative
testing approach for HCl under §63.7 (f).

The commenter is concerned that a spectroscopist or FTIR operator will
need to be present on a nearly continuous basis at a monitoring
installation. PS-15 has initial certification requirements that may
require the assistance of a spectroscopist, as do most monitoring
performance specifications, but we do disagree that PS-15 will require a
full time operator. This issue has never been brought to our attention
by users of this PS-15.

Regarding the comment that there are no NIST traceable HCl calibration
gases, at least one specialty gas vendor (Air Liquide) sells high
quality “Protocol” gases for HCl which are NIST traceable. These
gases are currently available in concentrations ranging from 2.9 ppm to
5000 ppm. For levels below this range, Method 205 (40 CFR Part 51,
Appendix M) is available for operators to use prepare dilution gases in
lower concentrations from the higher level cylinder gases.

As the cost of computer data storage continues to decrease, we do not
expect the data storage requirements of PS-15 to be particularly
burdensome. We do not have and are not planning to develop spectral
audits for FTIR. Should we decide to develop them in the future, we will
have to address the issue of proprietary software systems at that time.

Comment: Commenter 2855 stated that specific data storage requirements
and data submission requirements that are subject to outside party
interpretation should not be contained in any PS for a continuous
monitoring system. For example, PS-15 requires that the data be
submitted to EPA, and that EPA would interpret these data, and also
provide audit spectra. The commenter stated that they were unaware that
EPA had a spectroscopic branch that is developing these spectral audit
materials, or that they are prepared to handle such data submissions in
the future. If EPA is developing such materials, they should be provided
in the docket so that the cement industry can evaluate how such a
process could be handled.

Response: As stated in the prior response, EPA has no plans to develop
audit samples or audit spectra for the FTIR. If no audit materials are
available, then an audit is not required. We believe the PS-15
requirements for spiking and other quality assurance requirements are
sufficient in the collection of quality data. The data storage
requirements are necessary due to the unique properties of FTIR. In
particular, for the data analysis and review, the interferograms are
critical in identifying and quantifying the target pollutants, and the
pollutant results are not transparent to the data reviewer unless the
raw data are available to allow reproduction of the results.

Comment: Commenter 2855 stated that EPA should develop an HCl monitoring
PS or work with ASTM in such an effort should the HCl monitoring
requirements prevail in this rule. The PS should employ analyte spiking
as a means to both certify and validate the system rather than
comparisons with Method 321 for Relative Accuracy testing. The commenter
recommended documents EPA OTM 22 and EPA OTM 23 submitted by Eli Lilly
prescribing the use of HCl CEMS at hazardous waste incinerators as a
starting point for a new HCl monitoring performance specification.

Commenter 2915 stated that they do not believe that an HCl CEMS could
meet PS-15, and EPA should develop appropriate, achievable performance
specifications that are applicable to all the available technology and
not dictate a monitoring technology such as FTIR. Once those are
established, EPA should collect data with those technologies to
determine whether they are appropriate for determining compliance with
the proposed limit. If a technology meeting appropriate performance
specifications is not capable of detecting or quantifying emissions at
the level of the standard, the technology is not appropriate for use as
a compliance method for that standard. The commenters provided a list of
difficulties in using PS-15 for continuously monitoring HCl.

Response: Facilities that desire to use monitoring technologies other
than FTIR may utilize the General Provision to request approval to use
an alternative method by providing the alternative specifications and
QA/QC measures they would use. We agree there may be benefits to an ASTM
process as well, and will work with them to evaluate such methods.

Comment: Commenter 2855 stated that EPA has specified use of Appendix F,
Procedure 1 along with PS-15. Appendix F, Procedure 1 was written for
SO2, NOx and diluent CEMS (O2, and CO2). It is not directly
transferrable to an FTIR CEMS monitoring HCl at extremely low
concentration levels. Appropriate on-going quality assurance procedures
are needed.

Response: We have revised the QA procedures to accept values up to 20
percent of the emission limit.

Comment: Commenter 2855 stated that the initial compliance demonstration
procedures for HCl emissions from kilns or kilns/in-line raw mills
appear contradictory and should be revised to be consistent with the
proposed emission standards and 30-day rolling average. Section
63.1349(b)(6)(ii) is inconsistent specifying a performance test duration
of 24-hours, and requiring calculations of the daily average HCl
concentrations from the hourly averages during the performance test.
This is inconsistent with the language in the preamble and in
§63.1343(a).

Response: The 24-hour period is consistent with the RATA, which is used
to demonstrate that the CEMS is operating properly. In this case,
operation while the raw mill is on, is the only requirement and the
final rule has been revised to reflect this condition. Initial
compliance is determined by the first 30 days of data.

Comment: One commenter (2855) stated that the initial performance
demonstration should be based on a properly calibrated and compliant
CEMS (if such a system becomes available that is capable of accurate
measurements at the level of the HCl emissions) and the initial
performance test result must be based on the calculated average HCl
concentration for 30 kiln operating days. A definition for kiln
operating day must be established and must reflect a specified number of
hours of kiln or raw material dryer operation at normal production
conditions. Days with fewer operating hours than a kiln operating day
should not be included in the 30 day average. There should be no
specification for separate tests for mill-on and mill-off for in-line
raw mills.

Response: We agree that a definition of “kiln operating day” is
needed and have added one to the final rule. We also agree that a raw
mill off test is not required.

Comment: One commenter (2855) stated that the initial compliance
demonstration procedures for HCl emitted from sources not controlled by
a wet scrubber specifies a performance test duration and conditions that
are not appropriate. Furthermore, 40 C.F.R. §63.1349(b)(6)(ii)(2008)
states that initial compliance shall be demonstrated by conducting
separate performance tests for in-line kiln/raw mills with the mill
operating and with the raw mill off. This would require the facility to
run in a mill-off condition for 24 hours, which is not possible. There
should be no specification for separate initial compliance tests for
mill-on and mill-off for in-line raw mills.

Response: We agree that a raw mill off test is not required and have
changed the final rule to reflect this.

Comment: One commenter (2901) stated that EPA did not follow the
Agency’s own protocols in proposing to change the practical lower
quantification range of Method 321.

Response: We believe we have adequately followed protocol in proposing
changes the M321 through this notice and comment rulemaking process.

Monovents

Comment: One commenter (2888) proposed that monovent facilities stack
test for HCI, using EPA approved methods, on the same 30-month frequency
as required for Dioxin/Furan testing under the current Portland Cement
Maximum Achievable Control Technology (PC MACT).

Response: Sources equipped with scrubbers are required to test every 5
years. Such sources would have to construct a stack for testing.
However, where sources use CEMS, we believe the current monitoring
methodology is appropriate. Sources may request alternative performance
testing requirements under the General Provisions to address site
specific circumstances.

Clarifications

Comment: One commenter (2845) stated that §63.1343(b)(6) and
§63.1343(c)(6) should be clarified to state that the HCl standard is
corrected to 7 percent oxygen based on a 30-day rolling average.

Response: We agree and have made the suggested clarifications.

Comment: One commenter (2845) stated that §63.1350(q)(2) should provide
specific requirements rather than reference to 40 CFR part 63, subpart
SS, which may change in a manner that could make it inappropriate for a
kiln system. The commenter provided detailed language to include in this
section.

Response: While there are merits to using cross references, in this case
we agree to add information specific to this rule to avoid the use of a
cross reference.

Coal mills

Comment: One commenter (2910) asked that EPA clarify in the proposed
revisions that in-line coal mills that vent directly to the atmosphere
be exempt from installing or operating an HCl CEMS. The commenter stated
that they knew of no basis for concluding that coal drying would
increase the HCL concentration in the in-line coal mill exhaust. The
commenter stated that monitoring the concentration of HCl in the main
stack would be an appropriate way to measure compliance with the HCl
standard.

Response: We agree and have clarified the final rule accordingly.

2.7.5	Impacts

SO2 scrubbers and HCl control

Comment: Several commenters (2845 and 2900) stated that the scrubbers
that would be used to control HCl are generally designed to control
sulfur dioxide, not HCl. Vendors of HCl scrubber systems indicated that
the system they would install would be designed for SO2, not HCl, if SO2
is present in the flue gas. The limited number of wet scrubbers in the
U.S. on cement plants are designed to remove SO2, and are not intended
to be used to comply with and HCl limit.

One commenter (2844) stated that there is little experience with
scrubbers designed to control both SO2 and HCl. The commenter stated
that based on limited short term HCl data, many kilns have preliminary
HCl levels that will require much greater control.

Several commenters (2845 and 2900) stated that there are no data to
support the conclusion that, under various conditions, a wet scrubber
designed to utilize lime will provide the required collection efficiency
to meet a 2 ppm emission standard. One commenter (2845) provided
information about vendors’ HCl scrubbers, stating that the systems
that can provide 99 percent control of HCl use NaOH as the scrubbing
media. These systems are installed for applications that have been
producing little if any SO2, and the inlet HCl concentrations are
substantially higher than would be typical in cement plants. Because of
product quality/specifications and economic concerns, NaOH would not be
a reasonable reagent for cement kilns. Lime is easily obtained by cement
plants, but NaOH would have to be purchased. Neither the portland cement
industry nor the Agency have any data to support the conclusion that a
wet scrubber designed to utilize lime will provide the required
collection efficiency to meet a 2-ppm emission standard when SO2 is
present in the flue gas and the inlet HCl concentration is very low.

Commenter 2889 disagreed with EPA’s estimates of wet scrubber
efficiencies of 99 to 99.9 percent. The commenter notes that at the
lower HCl concentrations found in cement kiln gas streams, it is
unlikely that a wet scrubber could achieve those efficiencies.

Response: We agree that the wet scrubbers currently on U.S. cement
plants are designed to remove SO2, rather than HCl. However, an EPA
review of HCl emissions from 21 plants indicated an average
concentration of 12 ppm, and a maximum concentration of 55 ppm.
Therefore, required HCl removal efficiencies to meet the 3 ppm emissions
standard are expected to be much lower than 99 percent for virtually all
kilns. A preliminary review of data gathered from a 2010 Information
Collection Request (ICR) for Electrical Generating Units indicates that
wet scrubbers utilizing lime will be able to provide the necessary
collection efficiency to meet the 3 ppm emissions standard. We also
think that test data from the secondary aluminum industry regarding the
HCl removal by lime-coated fabric filters (e.g., Docket A-92-61, Item
II-A-9) indicate that the 3 ppm emissions standard can be achieved by
alternatives to scrubbers.

Baseline HCl emissions

Comment: One commenter (2845) stated that for HCl, EPA assumed that all
kilns without recent test data would emit at the average rate observed
across those relatively few kilns for which test data were available.
While this may be true on average, this approach ignores the large
variability that undoubtedly exists across untested kilns in terms of
their actual HCl emissions rates. Some of the kilns to which EPA applies
the average HCl emissions rate will in fact have high emissions and will
need more intensive and costly HCl controls; EPA fails to accurately
represent total control needs across the entire industry by missing
these kilns that have emission rates well above the average.

Response: It is true that kilns may have emission rates above the
average, and, therefore, may require more costly controls. However,
there are also kilns that have emission rates below the average, and,
therefore, would require less costly controls. Data available to EPA
indicated that there were more kilns with HCl emissions lower than the
average rate utilized by EPA in cost calculations than there were kilns
with HCl emissions above the average rate. Therefore, we believe the
cost calculations are accurate, if not overestimating the total control
costs for the industry.

Achievability using wet scrubber

Comment: One commenter (2900) provided a summary of information about
one of their plant’s wet scrubbers. Information includes water and
power use, costs, and HCl stack emission data. Prior to the installation
of the scrubber, the plant conducted extensive tests in 2000 for
purposes of evaluating HCl emissions from the various stacks. The data
from 2000 demonstrates that the HCl emission rate as lb/hr was doubled
when the raw mill was shut down and indicates a scrubbing effect through
its operation. The data taken in 2006 using similar methods showed that
the plant experienced some reduction in HCl emission but not enough to
achieve the EPA limit at less than 2.3 ppmvd at 7 percent oxygen. A data
point was not found for the raw mill down condition. It is expected that
the results will be less with the operation of the scrubber than the
data point in 2000; but higher than the new EPA limit. Both the raw mill
running and down conditions will likely be noncompliant with the new
limit. The commenter noted that the scrubber at their plant was set at
5.5 to 6.5 for strictly SO2 control, and that the set point was well
below the 8 to 10 pH that the commenter stated is needed for HCl
control. As this scrubber is utilizing water, limestone, and some lime
concentration present in the stone, it can be surmised that the EPA’s
limit is difficult to achieve even with the best available scrubber
technology.

Response: We believe that a preliminary review of data gathered from a
2010 Information Collection Request (ICR) for Electrical Generating
Units indicates that wet scrubbers utilizing lime will provide the
necessary collection efficiency to meet the 3 ppm emissions standard.
Furthermore, because the HCl standard is established at a level higher
than all measured values (to account for the inability to reliably
measure any lower standard) and measured based on 30day averages, it
provides an ample compliance margin. The 30-day averaging period assures
that several operating cycles of raw mill on and off are included in
each average, thereby averaging them out over the 30-day period.

Water availability for scrubbers

Comment: Several commenters (2845 and 2941) stated that wet scrubbers
are highly water-intensive, and based on the locations of many of the
cement plants, obtaining additional water rights could be very
difficult, particularly for plants located in states where water rights
issues have been contentious. The commenter provided several estimates
of water use, including an estimate for a typical cement plant of 460
million gal/yr, and an estimate that a scrubber will require, on
average, 30 million gallons of water annually.

Response: As noted in the preamble, we are not mandating wet scrubber
control technology in this rule. Other control techniques are available
(hydrated finely ground lime, spray dryers, fuel and additive switching)
that we believe would allow a cement kiln to meet the HCl emission
limits in areas where sufficient water for a wet scrubber is not
available. Although we have no cost data available for these alternative
control techniques (some of which would be site-specific), we anticipate
that these control techniques would be no more expensive that a wet
scrubber.

Scrubber costs are underestimated

Comment: Several commenters (2830 and 2845) stated that EPA has
underestimated the cost of wet scrubbers to capture HCl, and there will
be problems if a facility uses both a wet scrubber and a RTO in series.
If the proposal for HCl is implemented, wet scrubbers will need to be
installed at many of the cement plants. Wet scrubbers are designed such
that the flue gas exiting the scrubber is saturated. As a result, the
exiting flue temperature will be 160°–180°F. Therefore, plants that
install these scrubbers will either need to reheat the flue gas to
prevent condensation in the stack and provide flue gas buoyancy, or it
will be necessary to line the stack with a material to withstand
continuous water condensation. In either case, this will be an added
cost to the plant. If natural gas were used to reheat the flue gas from
160° to 225°F, the theoretical plant generating 200,000 dry standard
cubic feet per minute (dscfm) would generate an additional 7,500 tons
CO2/year.

According to commenters 2830 and 2845, if an RTO is required because of
THC emissions, the exhaust exiting the wet scrubber enters the RTO fully
saturated with moisture, meaning that as it is heated, it passes through
the temperature range with the highest corrosion potential (above the
water dew point and below the acid dew point). Thus, very costly nickel
alloys must be used at certain areas within the RTO. Also, in designing
the RTO, if the heat exchanger is designed to achieve high thermal
efficiency (low gas consumption), then the RTO outlet temperature will
be below the acid dew point. As a result, all outlet ducting and the
stack must be resistant to acid condensation and high levels of
corrosion. If the outlet temperatures are raised above the critical acid
dew point temperature, then the RTO will consume very large quantities
of natural gas. Therefore, the choice forced upon the kiln by the
proposed rule is either high energy costs or high material (alloy)
costs.

Response: As noted in a previous response, we believe that the wet
scrubber costs are accurate, if not overestimated, for the reasons
cited. The wet scrubber and RTO costs were calculated based on actual
costs from the industry for those systems, and, therefore, should
already account for the factors mentioned by the commenter. Furthermore,
as noted in the preamble, the wet scrubber/RTO combination has already
been demonstrated in cement kiln applications.

Accounting for scrubber waste handling

Comment: Several commenters (2841, 2845, and 2889) stated that there
will be problems with the solids and liquid handling of wet scrubbers.
The commenter provided an overview of the wastes associated with wet
scrubber operation. The commenter’s concerns include:

Plants will need to dispose of some or potentially all of the sludge.
EPA has assumed that the solids would be recycled to the finishing mill,
but the chemistry of the sludge will be site specific and may not allow
recycling. Disposal of solid waste would require additional permits.

Dewatered solids from the scrubber have a moisture content of 25% to
35%. This material is difficult to handle in the finish mill and its
associated classifier. Furthermore, the solids from a wet scrubber are
not composed strictly of gypsum (calcium sulfate). The waste material
includes sodium and potassium salts. There will also be some calcium
sulfite. There are limits to the concentrations of these contaminants
that can be included in the cement product.

Because of recirculation of the slurry, the concentration of chlorine in
the slurry liquid can rise to high steady-state concentrations,
requiring wastewater treatment.

The costs for water treatment imposed by the proposed rule would be at
least $50,000 per year, not taking into account total dissolved solids
(TSS) or biochemical oxygen demand (BOD) costs.

Response: Our wastewater and solid waste impacts estimates for wet
scrubbers were determined based on information from industry and, as
such, should already account for the situations cited by the commenter.
As noted in the preamble, all of the facilities currently using wet
scrubber mix the gypsum created in the scrubber with clinker in the
finish mill and were assumed to also account for other waste materials
that accumulate during the normal operation of the facility. As noted in
the preamble, there are four facilities (five kilns) that currently use
wet scrubbers that report no water releases at any time, such as that
cited by the commenter. We requested comment in the Portland Cement
NESHAP proposal on the potential for water releases due to wet scrubber
system purges and any regulations that might apply. Though commenters
raised concerns of the possibility of water impacts, they did not
provide a rationale of why it would be expected, when it is not
occurring at the four facilities that currently use wet scrubbers, due
to their on-site reuse of water. If discharges did occur, there would be
a potential for water quality issues. But given these facts, we believe
our estimate of no water quality impacts resulting from production of
wastewater by wet scrubbers is reasonable.  The sludge that is generated
is used again in the process, so there is no cost of disposal associated
with sludge.

HCl emissions data, Table 5 of Preamble

Comment: One commenter (2863) stated that Table 5 in the preamble
outlines the available HCl data for the 27 kilns for which Method 321
data were available. Ash Grove’s Durkee plant is identified as source
#26 on that list with emissions of 34.68 ppm HCl. This is not correct.
The Durkee plant’s HCl emission rate is 3.2 ppm (7 percent
oxygen)—an order of magnitude lower than what is stated in Table 5.
Portland cement kilns are not significant sources of HCl.

Response: As noted in the preamble, the analysis for the HCl MACT floor
was revised to remove errors identified in comments on the proposal,
including this error.

Dry scrubbers

Comment: One commenter (2889) stated that there are problems associated
with spray dryer absorbers or lime injection-based dry scrubbers
recommended for arid regions. A review of recent boiler BACT analyses
summarized in the RBLC Clearinghouse indicates that the HCl removal
efficiencies are well below the 99 percent levels assumed by EPA.
Furthermore, both types of dry scrubbers generate significant quantities
of solid waste.

Response: EPA expects that the HCl removal efficiencies needed to comply
with the 3 ppm HCl emissions standard will be well below 99 percent for
virtually all kilns. Regarding the solid waste argument, as stated in
the preamble, the PM captured in the kiln fabric filter (cement kiln
dust) is essentially recaptured raw material, intermediate materials, or
product. Based on the available information, it appears that most
captured PM is typically recycled back to the kilns to the maximum
extent possible. Therefore, we estimate that any additional PM captured
will also be recycled to the kiln to the extent possible.

2.8	PM Standards

2.8.1	Legal Issues

MACT-on-MACT

Comment: Many commenters (2830, 2832, 2841, 2844, 2845, 2858, 2859,
2863, 2864, 2874, and 2914) stated that EPA lacks the authority to
promulgate new PM standard using the MACT floor approach because EPA
issued new and existing source NEHSAP for PM in 1999. Once the NESHAP is
established, the CAA §112(d)(6) requires any revision to the standard
to be accomplished using a technology review and not using the process
proposed by EPA in this rulemaking. The proposed EPA standard in this
rulemaking leads to a MACT-on-MACT approach which results in a floor
that is much more stringent than it would have been if EPA had used
emissions data from sources that had not already complied with the 1999
PM standards.

Response: This is factually incorrect. If EPA properly established MACT
for PM using the 1999 data base, the standard for existing and new
sources would be higher than the standard adopted in today’s rule, as
explained in the preamble to the final rule (although EPA considers its
current data base to be more representative, and so is using it to amend
the standard).

Comment: Due to the inappropriateness of EPA’s proposal and the fact
that the 2000 remand did not address PM at all, the commenters urge EPA
to maintain the 1999 PM standard. Commenter 2864 argued that EPA does
not have the authority under the CAA to completely recalculate PM MACT
floors for cement plants where the initial floors were upheld. Although,
EPA has the authority to revise the PM MACT standards for the industry,
EPA must do so in accordance with §112(f) or §112(d)(6) without
recalculating the floors. Because EPA has failed to conduct the analyses
necessary under those provisions, it has no authority to revise the PM
MACT standards for either existing or new cement plants.

Response: As stated in the preamble to the final rule, MACT-on-MACT is a
misnomer because the 1999 standard simply does not represent MACT. For
the reasons stated in the preamble, EPA does not see that it is barred
from amending that standard here to make a proper determination of MACT.

2.8.2	Adequacy of Floor Determinations (Existing and New)

Support for PM standards

Comment: Several commenters (2898 and 2911) supported EPA’s proposed
standards for PM and EPA’s proposed standards for area source cement
kilns under §112(d)(2)-(3).

Several commenters (2786 and 2898) stated that particulate metal
emissions from cement plants may pose health risks at very low levels
and therefore stringent emission controls are needed. Cement facilities
are sources of the non-volatile metal HAPs antimony, cadmium, lead,
selenium, chromium, arsenic, nickel and manganese.

Commenter 2928 supported the proposed emission standards for PM.

Response: EPA acknowledges the commenters’ support.

Comment: Two commenters (2845 and 2859) said that EPA has not
promulgated any regulations requiring PM CEMS at any source category due
to its inability to address fundamental technical and policy issues and
must resolve these issues through rulemaking before requiring PM CEMS at
any cement plants. Furthermore EPA has not performed a legitimate
technical analysis of emissions variability and compliance determination
uncertainty to allow the use of PM CEMS for determining continuous
compliance with a PM limit at cement plants.

Response: We reject the commenters’ assertions that PM CEMS have not
been required via rulemaking because of unresolved fundamental technical
or policy issues. Concerns about PM CEMS were identified and addressed
prior to the January 2004 publication of Performance Specification 11
and Quality Assurance Procedure 2 for PM CEMS (69 FR 1786, January 12,
2004). As mentioned in that rule’s preamble, “…we believe that the
PM CEMS field demonstrations completed to date encompass a range of
operating conditions and emission characteristics…” including those
exhibited by sources such as cement kilns.

Moreover, we disagree with the assertion that our analysis of PM
emissions variability is not legitimate, yielding an overly-stringent PM
emissions limit. The PM limit is based on our analysis of PM emissions
from test data, adjusted from an hourly to a 30-day averaging period and
further adjusted for variability. As mentioned in the preamble to the
Credible Evidence Rule (62 FR at 8314, February 24, 1997), we have
addressed and continue to address concerns about perceived “…limited
number and distribution of test runs and the inherent variability in
levels of emissions…” by a number of approaches, including changing
emissions averaging periods. Further, a statistically-based adjustment
to account for emissions variability, and which, in this case, increases
the numerical value of the standard (and its longer averaging period) by
fifty percent, does not make the standard more stringent.

Variability

Comment: Several commenters (2830, 2844, 2845, 2859, and 2864) stated
that because the data in the proposed NESHAP is based on a limited data
set (3-hour stack tests) that short term tests will not address the
variability issues. The commenter analyzed EPA’s released PM data and
found that EPA did not use all available PM data and according to the
commenters, EPA used an inappropriate statistical analysis (UPL instead
of upper tolerance level UTL). The commenter suggested that when an
appropriate statistical analysis using all of the EPA’s PM data is
used, the PM MACT standard should be 0.092 lbs/ton of kiln feed for
existing sources and 0.0625 lbs/ton of kiln feed for new sources.
Commenters 2845 and 2859 submitted PM data as part of their comments on
the proposed NSPS rules for portland cement.

Commenters 2845 and 2864 stated that the data set used to set the MACT
floor was too small. The commenter recalculated the PM floors using
additional data, and presented data showing the relationship between bag
life and PM emissions. The commenter stated that it is important that
EPA includes as part of the MACT floor the operational variability
experienced due to filter life and the baghouse itself that EPA needs to
include as part of the MACT floor. The commenters provided graphs
showing the effects of age on baghouse performance.

Response: In its comments, commenter 2859 stated that EPA ignored one of
two data points. They stated that EPA selected 0.0108 lb/ton clinker and
ignored a data point of 0.032 lb/ton clinker. The commenter
misunderstood how EPA calculated PM emissions for the Sugar Creek kiln;
EPA did not select one data point over another. The PM data for that
kiln was obtained from the Missouri Department of Natural Resources
(MDNR) and was used to calculate average emissions for that kiln. The
Sugar Creek kiln is one of the six MACT floor kilns used in the analysis
of the MACT floor for PM. The data for the Sugar Creek kiln used in the
MACT floor analysis is presented in the following table.

Lafarge Sugar Creek, PM Emissions: MDNR Data for 2002 and 2007

Roller Mill On

Run	Date	PM (lb/hr)	Kiln Clinker Production (tph)	PM Rate (lb/ton
clinker)

103*	8/7/2002	0.044	125.33	0.0004

105*	8/8/2002	0.587	119.37	0.0049

101*	10/30/2002	0.967	113.82	0.0085

111*	9/5/2007	2.52	127.00	0.0198

112*	9/5/2007	1.7	126.93	0.0134

113*	9/5/2007	1.09	126.93	0.0086

	AVG (mill on)	0.0093

Roller Mill Off

Run	Date	PM (lb/hr)	Kiln Clinker Production (tph)	PM Rate (lb/ton
clinker)

101*	8/6/2002	8.118	124.42	0.0652

104*	8/7/2002	1.823	120.27	0.0152

106*	8/9/2002	1.746	120.72	0.0145

101*	11/6/2007	5.22	119.12	0.0438

102*	11/6/2007	7.24	123.59	0.0586

103*	11/6/2007	4.84	118.32	0.0409

 	 	 	AVG (mill off)	0.0397

	WTD AVG (Mill on & off)	0.0108

In their comment, commenter 2859 provided PM test results for 2002 and
2007 as well as new PM run data for tests conducted in 2004, which EPA
did not have when it was the developing the MACT floor for PM. The
commenter’s PM data for 2002 and 2007 is essentially the same as the
data set we used with minor differences due to differences in kiln feed
rates. The individual run data submitted by commenter 2859 are presented
below.

Lafarge Sugar Creek, PM Emissions: Lafarge Data for 2002, 2004, 2007

Roller Mill On

Date	Filterable PM (lb/hr)	Kiln Production (tph)	PM rate

(lb/ton clinker)

8/7/02	0.04	127.87	0.0003

8/8/02	0.59	121.80	0.0048

10/30/02	0.97	116.18	0.0083

5/20/04	3.02	117.95	0.0256

5/20/04	2.51	125.77	0.0200

5/20/04	2.65	126.10	0.0210

5/20/04	2.27	121.14	0.0188

5/20/04	2.76	108.80	0.0253

5/20/04	2.69	108.80	0.0248

6/25/04	3.30	126.10	0.0262

6/25/04	3.52	126.10	0.0279

6/25/04	3.41	125.88	0.0271

7/14/04	3.79	125.99	0.0301

7/14/04	3.97	126.10	0.0315

7/14/04	3.52	126.10	0.0279

9/5/07	2.52	129.52	0.0195

9/5/07	1.70	129.41	0.0131

9/5/07	1.00	129.52	0.0077

AVG (mill on)	0.0200

	Roller Mill Off

Date	Filterable PM (lb/hr)	Kiln Production (tph)	PM rate

(lb/ton clinker)

8/6/02	8.12	126.98	0.0639

8/7/02	1.82	122.69	0.0149

8/8/02	1.75	123.13	0.0142

5/18/04	4.90	128.86	0.0381

5/18/04	3.79	126.54	0.0300

6/29/04	9.07	126.10	0.0719

7/15/04	8.02	126.10	0.0636

7/15/04	8.95	126.10	0.0710

8/12/04	12.57	129.52	0.0971

11/6/07	5.22	117.06	0.0446

11/6/07	7.24	111.22	0.0651

11/6/07	4.84	117.17	0.0413

AVG (mill off)	0.0513

WTD AVG (Mill on & off)	0.0216

Adding in the 2004 test runs increases the weighted average (assuming
the raw mill is on 95 percent of the time and off 5 percent of the time
per the MDNR) for the kiln from 0.0108 lb/ton clinker to 0.0216 lb/ton
clinker. The kiln is still among the top six performing kilns.

One commenter (2845) stated that they collected additional PM data and
combined the new data with the EPA data set to create a new MACT data
set consisting of a total of 319 runs/test data points for 47 kilns. The
commenter’s data included the number of runs/data points, the minimum
and maximum PM values, and the mean PM emissions in lb/ton clinker.
Based on average emissions for each kiln in the new data set, the
commenter identified a new list of the top 6 kilns with average PM
emissions for the 6 MACT floor kilns of 0.024 lb/ton clinker. Commenter
2864 concurred with the reanalysis of the MACT floor using the new MACT
data. EPA evaluated the new data and found shortcomings that led us to
not include the data in our analysis for the PM MACT floor. The
shortcomings identified include the following:

Individual run data from which the commenter calculated average emission
rates were not included preventing us from fully evaluating the
emissions data or the average emissions they presented.

When EPA selected the top performing kilns, it used the average PM
emissions for each kiln and ranked them from lowest to highest. In the
case of kilns with raw mills, EPA calculated the weighted averaged
emissions using test run data during raw mill on and raw mill off
periods. Because a raw mill operates 85-95 percent of the operating
time, the PM emissions during the raw mill on period will dominate the
weighted average. It appears that the commenter calculated a simple
arithmetic mean rather than a weighted average for kilns that have raw
mills. This was determined because for two kilns with raw mills that
only reported two values for each kiln, the commenter calculated the
simple arithmetic mean of the two values. Because PM emissions tend to
be lower when the raw mill is on and because the raw mill is typically
on 85-95 percent of a kiln’s operating time, calculating a simple
arithmetic mean as the commenter did, will likely overstate emissions.
Because individual test runs were not supplied, it was not possible to
recalculate the weighted averages for those kilns with raw mills. Among
the six MACT floor kilns identified by the commenter, four operate raw
mills.

No explanation was given for excluding the Lehigh, Union Bridge kiln
from its data set or for dropping it from the top 6 kilns used in
EPA’s analysis. The average emissions for Lehigh, Union Bridge would
put it in the top 6 in the commenter’s set of new MACT floor kilns.

The commenter’s data set for Lafarge kiln 2 at Whitehall consisted of
13 data points whereas we used 15 test runs.

Commenters 2845 and 2864 commented that EPA’s PM limits did not
account for declining fabric filter performance over time. Commenter
2864 provided graphical evidence for one of its kilns that it claimed
showed that PM emissions increased with aging bags. The graph indicates
low emissions during the initial performance test as well as several
years later after replacing all of the baghouse bags. Following
replacement, PM emissions increased after installationof new bags and
remained high even when the bags were again replaced. Contrary to the
commenter’s claim, performance declined even when new bags were
installed. Based on the information provided by the commenter, it
appears that there were factors other than aging bags that contributed
to declining PM performance. EPA has reviewed PM test data for several
kilns over time and have concluded that PM emissions can be highly
variable. This variability can even be evident in consecutive test runs
on some kilns. The first figure below shows the highly variable PM test
results from a single for nine test runs over a 3-day period. The second
figure plots the average test results for six different kilns over
varying number of years. From these data, there are no clear indications
that baghouse performance necessarily declines over time, rather it
indicates that performance is variable. Obviously it will be necessary
for cement plant owners and operators to operate and maintain their
baghouses in peak condition to comply with the new PM limits. But EPA
rejects the commenters’ arguments that baghouse performance
necessarily declines over time and that the PM limits should be less
stringent to account for this.

Condensable PM

Comment: Several commenters (2845 and 2874) stated that it would be
inappropriate to regulate condensable fraction of PM2.5 for the
following reasons:

Because there are known problems with the test method 202 which is used
to determine the emissions for PM2.5 and the little data EPA has is
based on questionable AP-42 factors which is based on several tests, EPA
used limited available data that were of very uncertain accuracy.

The EPA did not show that listed HAP can be found in the condensable
fraction and therefore cannot reasonable use condensable PM as a HAP
surrogate under the authority of CAA §112(d).

If HAP existed in condensable PM, they would be controlled by other
means which include PM control devices for filterable PM, mercury which
is already directly regulated, and organic HAP are regulated through the
THC surrogated. Therefore, there would be no need to include condensable
PM as part of the PM standards.

EPA would need to propose PM standards because the current proposed
standards are based only on filterable PM and not both filterable PM and
condensable fraction of PM.

Response: The PM limits address filterable PM, including PM2.5 and PM10,
but not condensable PM. We do not have information on emissions of
condensable PM from cement kilns sufficient to set emission limits and
the limited information we do have is highly uncertain. We also believe
that these emissions will be controlled to some degree via controls on
HCl in the NESHAP and SO2 in the NSPS. EPA has recently promulgated a
new test method for condensable PM (revised Method 202) which will allow
for more reliable assessments of condensable PM. We anticipate that data
more representative of condensable primary PM emissions will be
available at the time of the next review of the NSPS.

Combined stack gases

Comment: One commenter (2841) stated that the proposed standards are
based on a kiln stack or some estimated number based on the flow
apportioned from a kiln and clinker cooler. This does not address
situations, such as those where additional sources of particulate are
included into the same duct system leading to one stack. In order for
facilities to design more efficient manufacturing operations, other
configurations are likely and should be encouraged. In addition, using a
grain loading standard is easily measured and can be monitored more
effectively.

Another commenter (2845) stated that the MACT floor for combined stacks
(new or reconstructed kiln or in-line kiln/raw mill) should be
calculated based on all available data and should subcategorize PM
standards by different kiln types. The alternative PM standard should
provide for including other exhaust gas streams in the main stack such
as coal mills. Facilities should have the option of meeting a grain
loading based standard instead of the lbs PM/ton of clinker standard, if
that is retained by EPA. The rule should be worded such that it is clear
that for combined exhausts, the gas flow and PM testing only needs to be
measured at the stack when using the alternative PM limit. The rule
should be worded such that it is clear that PM testing will not need to
be conducted in mill-on/mill-off conditions.

Response: Regarding these two comments, facilities have the option to
petition the EPA Administrator for a site-specific emissions standard
for the situations described above (e.g., including additional sources
of particulate in the same duct system leading to one stack, meeting an
alternative grain loading based standard), as long as the facility can
demonstrate that the alternative standard will achieve an emissions
reduction equivalent to that obtained under the promulgated standard.

Clinker coolers

Comment: One commenter (2845) stated that §63.1345(a) standards for
clinker coolers should not be changed, remaining at 0.10 lb per ton of
feed (dry basis).

Response: We disagree with this comment for the reasons discussed in the
in the preamble regarding the PM limit for kilns. Therefore, we are
setting the same PM emissions limits and compliance requirements for
both clinker coolers and kilns.

Increased PM with use of wet scrubbers

Comment: One commenter (2889) stated that EPA has not adequately
considered the emissions of particulate matter from wet scrubbers due to
reentrainment of solids-containing droplets from mist eliminators.
Subcategorization is needed with respect to particulate matter emissions
from wet scrubber-controlled cement kilns. Based on similar units in the
lime industry, it is apparent that this will be a significant problem.
In fact, Subpart AAAAA includes a higher particulate matter allowance
for wet scrubber-controlled lime kilns than for fabric filter controlled
lime kilns. Without a similar form of subcategorization, there will be
an incentive not to install wet scrubbers and instead use a less
efficient dry scrubbing system.

Response: The commenter is confused about the structure of subpart
AAAAA. First, the separate higher PM limits in subpart AAAAA of part 63
are there to permit facilities with wet PM scrubbers installed before
2004 to continue using them but to require more effective PM control for
newer units. The rule recognizes that wet PM scrubbers are not as
effective as fabric filters for PM control. Secondly, wet scrubbers
designed and operated to provide that gaseous SO2 or HCl react with
caustic slurries are fundamentally different from wet scrubbers designed
to remove PM (e.g., Venturi scrubbers). Acid gas scrubbers are not
intended to be PM removers; any collection of PM in an acid gas scrubber
is incidental to the primary purpose and probably minimal. The commenter
is correct that a poorly operating mist eliminator downstream of an acid
gas scrubber may produce PM emissions that could affect overall PM
control. The source must provide effective mist elimination in order to
maintain compliance with not only the acid gas emissions limit but to
avoid increasing PM emissions.

Commenter 2900 provided data on particulate emissions before and after
installation of a wet scrubber. The data indicated particulate emissions
decreased. EPA expects installation of scrubbers after fabric filters
will result in slightly lower filterable particulate emissions than with
fabric filters alone. We do not think that Subpart AAAAA cited by the
commenter provides evidence that installing a scrubber downstream of a
particulate filter results in higher particulate levels than a fabric
filter alone.

2.8.4	Compliance Assurance

Performance of bag leak detection systems and other PM monitoring
systems

Comment: Several commenters (2845, 2859, and 2887) stated that in
proposing PM compliance assurance provisions, EPA did not, but should,
conduct a technical evaluation of the applicability, installation,
design, performance, certification, quality assurance and alarm level
setting procedures for all PM monitoring approaches and then re-propose
appropriate technical requirements for monitoring kilns, kilns/in-line
raw mills, and clinker coolers using bag leak detectors (BLDs),
Particulate Matter Detectors (PMD) and Continuous Opacity Monitors
options. According to the commenters, EPA does not recognize that many
BLD designs are inappropriate and inadequate for use under the varying
effluent matrix and conditions, especially at kilns/in-line raw mills
nor does EPA acknowledge that technically superior and far more
practical PM monitoring approaches have been developed for cement plants
that burn hazardous waste. The commenters stated that the proposed PM
monitoring provisions are inconsistent with the promulgated PM
monitoring requirements for cement plants that burn hazardous waste (40
CFR 63, Subpart EEE-2008), which includes provisions for the use of PMD
on both Electrostatic precipitators (ESP) and fabric filter controlled
cement. EPA appeared to be unaware that recent work at a cement plant
with membrane coated fabric filters has demonstrated that continuous
opacity monitoring system (COMS) can also meet the rigorous ASTM
D7392-07 requirements for certification as a PMD.

Response: At this point, we still find that BLD is an appropriate
technology for PM monitoring. We believe that sources will work with
system vendors to install and use appropriate systems for kiln-specific
conditions. We note that cement kilns that burn hazardous waste operate
under different conditions than ordinary kilns. However, we will
continue to review advances in PM monitoring technologies in general and
will be happy to consider source-specific requests for alternative
approaches. The rule already provides BLD as an alternative for PM CEMS.

Comment: Several commenters (2845 and 2859) stated that EPA has not
demonstrated acceptable performance of BLDs to monitor kiln, kiln/
in-line raw mills at cement plants and has not developed necessary
guidance for or technical requirements that will be necessary for a BLD
to meet the requirements in the proposed rule. EPA has provided no
guidance on appropriate alarm setting procedures, installation,
operation, and quality assurance procedures and corrective action
procedures and relevant validated procedures are not available from the
measurement system suppliers for installations on cement kilns and
kilns/inline raw mills. According to the commenter, in the selection of
BLD devices it is clear that the most widely used probe type BLDs (such
as triboelectric, or probe electrification, or charge transfer devices)
are unsuitable for use on kilns/in-line raw mills because the responses
of these devices are proportional to the square or to the cube of the
local gas velocity and are also affected by changes in effluent
temperature, moisture content, and resistivity of the dust. All of these
factors change when the raw mill operational status changes.

Several commenters (2845 and 2859) stated that because EPA did not
provide technical specifications, installation procedures, operation and
maintenance procedures, quality assurance procedures, or alarm setting
procedures or any relevant guidance for these issues for BLDs, the
burden is on the user to develop this information. If EPA cannot provide
technical requirements, criteria or guidance, then it certainly has no
basis to review the site-specific plans for approval. With no
established criteria or guidance, review by different regional offices
or states as delegated authorities will likely result in different
requirements and different interpretations, and confusion. The deadline
for submission of the site-specific BLD plan is not explicitly stated.
There is no time limit for EPA’s approval, no obligation for EPA to
render an opinion as to the acceptability of the plan, no instruction to
the user as to monitoring prior to receipt of approval, and no
indication of the consequences in the event the plan is not approved.
Until legitimate guidance and criteria are developed, the commenter
stated that it is sufficient that site-specific monitoring plans be
available for review. The commenters stated that, for the above reasons,
the requirement to submit the site-specific plans for approval should be
removed.

Several commenters (2845 and 2859) stated that EPA needs to provide
appropriate design and performance specifications so that manufacturers
can certify that their BLD meets applicable criteria in order that the
regulated user of such devices can rely on the manufacturer’s
certifications. Without an appropriate design and performance
specifications, there are no means available to the cement plant
operator to verify claims made by the BLD vendor or manufacturer
regarding detection capability. Plant operators cannot be responsible
for the design or performance of these systems and cannot be expected to
able to determine the technical validity of vendor claims, especially
where there are in effect no regulatory or technical requirements.

Response: While there is not a formal performance specification, there
is existing guidance on BLD. We have written a performance-based rule
for sources to use to tailor operation of the BDL to meet the needs at
each plant including variations in operation with the mill on vs. mill
off. The final rule clarifies that the resulting plans must be kept on
site. Submittal is not required. There are several types of BDL and, as
stated above, we believe that sources will work with system vendors to
install and use appropriate systems for kiln-specific conditions.
Sources have 3 years to comply with the final standards and should use
this time to ensure they are using a system that works well for their
application.

Comment: Several commenters (2845 and 2859) had the following comments
concerning BLD and alarms:

The proposed requirements for recording the BLD output and setting the
activating alarm are inconsistent with procedures actually used for
contemporary BLD.

EPA should remove the out-of-date requirement that the BLD should
activate an audible alarm and use more up-to-date guidance which applies
to settling alarm levels for the full range of BLD and fabric filter
configurations that are found at cement kilns that burn hazardous waste.
The proposal reflects bias to a particular manufacturer and particular
approach which is not applicable to all cement kilns. The commenter
provided several examples of what the commenter considered to be
out-of-date requirements.

The requirements to initiate procedures to determine the cause of every
alarm within one hour and alleviate the cause of the alarm within three
hours are problematic. EPA must revise its requirements to accommodate
real-world conditions that cannot be avoided and EPA must recognize
site-specific BLD monitoring plans will need to be revised as actual
experience is gained from the use of these devices at kilns and
kilns/in-line raw mills. The commenter provided examples to support
their position.

The time allowed for alleviating the cause of a BLD alarm is not
sufficient especially when a false alarm is due to malfunction of the
BLD or an in appropriate alarm setting procedure.

The requirement for audible alarms may be distracting and are
unnecessary. The type of alarm should be at the discretion of the plant
operator. The commenter stated that many control rooms are equipped with
visual alarms that the operator must acknowledge and respond to. These
alarms include situations with far greater safety and emergency priority
and consequences than BLDs alarms and are critical to operation of the
plant.

Response: We agree that an audible alarm is not required and have
changed the final rule to reflect this. We have also provided additional
time for the operator to determine the cause of the alarm (3 hours
instead of 1 hour) and up to 24 hours to alleviate the cause of the
alarm (up from 3 hours) to better reflect some of the complex situations
that operators may face.

PM detectors

Comment: Several commenters (2845 and 2859) had the following comments
concerning PMD:

Because PMD are a technically superior and more practical alternative to
BLDs, EPA should allow the use of PMD as an alternative to BLDs as is
allowed for cement plants that burn hazardous waste under 40 CFR 63
subpart EEE.

PMD should be allowed as an alternative to BLDs and/or ESP predictive
monitors and the PMD alarm set-point should be established during PM
source tests demonstrating compliance with the applicable PM standard.

PMD avoid the problems with attempting to set qualitative alarms based
on nearly instantaneous shifts in peak instrument responses, baseline
shifts, or rates of decay, as is the case with BLDs. PMD provide an
integrated average and warn the operator of the need for corrective
action, before an exceedance has occurred. According to the commenter,
EPA’s failure to allow the PMD under Subpart LLL causes redundant and
unnecessary monitoring for cement plants that are not subject to Subpart
EEE when not burning hazardous waste. For sources where the PM
concentration can be varied, a series of tests should be allowed to
determine the PMD output corresponding to the highest PM concentration
which is demonstrated to meet the applicable standard. For sources for
which the PM concentration cannot be varied (certain fabric filters)
alternative procedures to determine the PMD output corresponding to the
level of the emission limitation should be established. If future work
demonstrates that a representative PM spiking approach can be applied to
increase the PM level, the regulations should then be revised to allow
such an approach.

EPA should acknowledge that particulate matter detections systems (PMDS)
and/or BLDs meeting ASTM D7392-07 are acceptable for monitoring because
it was developed to fill the void in EPA requirements so that reliable
instruments could be used at cement plants that burn hazardous waste.
The practice provides a comprehensive set of design and performance
specifications for a broad range of monitoring technologies specifically
intended for monitoring of PM at cement plants. In addition to technical
requirements applicable to various cement plant configurations, the
Standard Practice includes detailed approaches for setting PMD and BLD
alarm set points that are more appropriate than those contained in EPA
guidance. It is also important to recognize that:

EPA was obligated to consider this ASTM standard under National
Technology Transfer Act, but apparently did not do so.

EPA Office of Air Quality Planning and Standards (OAQPS) and/or Office
of Solid Waste (OSW) representatives participated in the development of
the voluntary ASTM D7392-07 Standard Practice for use at cement kilns
that burn hazardous waste, offered comments during participation at
meetings and through correspondence on various drafts, and raised no
negative votes during balloting.

PMDS are superior to BLDs and are required by ASTM D 7392 to meet more
rigorous specifications, do not suffer from subjective and interpretive
alarm setting procedures, and should be allowed as an alternative.

PMDS can be used on kiln stacks with co-mingled emissions (e.g.,
kiln/in-line raw mill and coal mill emissions) where as separate BLDs
would be required for each baghouse.

PMDS are far more practical and far more cost effective than PM CEMS and
should be allowed as an alternative.

Teledyne Monitor Labs (the major American manufacturer of COMS used at
cement plants) has demonstrated that a contemporary LightHawk Model 560
transmissometer meeting ASTM D 6216-07 was able to meet the rigorous
ASTM D 7392-07 PMD requirements based on field tests at a cement kiln
burning hazardous waste equipped with high efficiency membrane coated
fabric filters.

Response: PMDs were not considered in the proposal. We will consider
requests to use PMDs on a case-by-case basis as an alternative to BLDs.
An owner or operator who wishes to use a PMD as an alternative
monitoring procedure must submit an application to the Administrator.

COMS

Comment: Several commenters (2845, 2859, and 2887) had the following
commenter concerning COMS:

COMS should be allowed as an alternative to PMDS and BLDS for both ESP
and fabric filter controlled sources as an option that can be selected
by the plant operator because they are a highly evolved, mature
technology that is well understood by both cement plant operators and
agency personnel. These devices are capable of detecting changes in PM
concentrations downstream of both ESP controlled sources and fabric
filter controlled sources and the need for inspection or corrective
action of the PM control device. The selection of the most appropriate
monitoring approach should be left to the plant operator and should
include the use of COMS, where applicable, as an option.

EPA’s attempt to dismiss COMS based simply on its opinion that they
lack sufficient accuracy at the proposed PM emission limit levels is
technically wrong and contrary to current work and other recently
promulgated regulations. EPA provides no technical support for its
dismissal of the accuracy of COMS and EPA appears to be completely
unaware of other developments that should have been considered.

EPA’s dismissal of COMS for units equipped with fabric filters is
based on an incorrect assertion about measurement accuracy in favor of
BLDs which are a purely qualitative measurement technique making
absolutely no claim to accuracy and relying on subjective, interpretive,
and un-documentable procedures to set alarm set points. EPA attempts to
dismiss the long established and well understood use of COMS which
include:

Highly evolved ASTM D 6216-07 design and performance specifications for
manufacturer certification. 40 CFR 60, Appendix B, PS-1 (2008) and the
initial field certification procedures;

Well known quality assurance procedures and external audit capabilities
using NIST traceable calibration materials to facilitate audits by users
and control agencies;

Daily zero and upscale calibration checks, lens cleaning requirements
and other operation, maintenance, data recording, record keeping and
reporting requirements contained in the general provisions of 40 CFR 60
and 63;

A technology that is well understood by plant operators, plant
technicians, control agencies, and instrument manufactures;

Existing COMS requirements included in virtually every state operating
permit for cement kilns, kilns/in-line raw mills and clinker coolers.

Response: We disagree with the commenter that the accuracy of a COMS
meeting the ASTM D6216-07 and Performance Specification 1 requirements
is at issue in this decision. A COMS so verified will reproduce opacity
measurements satisfactorily (e.g., within 0.2 percent opacity) for
levels of 3 percent and higher. The concern about monitoring the
operation of a fabric filter control device is the need to discern
between very small changes in opacity that are already at very low
levels that would indicate a leak that may indicate a compliance
problem. Such leaks will produce changes in opacity of less than 0.1
percent out of an average opacity of 0.5 to 1 percent. These are values
that would be comparable to the instrumental output noise in the data
from COMS making the data insensitive to the leaks. PM CEMS and bag leak
detectors are much more sensitive to these levels of change necessary to
confirm compliance.

Comment: Several commenters (2845 and 2859) stated that the proposal
does not remove the COMS requirement for kilns and kiln and/or inline
raw mills for sources that would use BLDs. More important, EPA cannot
remove COMS requirements that already exist in state operating permits
for cement plants because it is expected that States will not be willing
to reopen permits and other States would refuse based on previous and
continuing reliance on COMS and Method 9 as the primary performance
tools that are more proven than BLDs. The commenter argued that
redundant BLDs and COMS are not wanted and are not needed. Due to these
complexities and overlapping requirements, the plant operator should
have the final decision as to the selection of the most appropriate
monitoring option.

Response: We agree that this was an oversight in the proposed rule and
we have corrected it in the final rule.

PM CEMS

Comment: Two commenters (2845 and 2859) said that EPA has not
promulgated any regulations requiring PM CEMS at any source category due
to its inability to address fundamental technical and policy issues and
must resolve these issues through formal rulemaking before requiring PM
CEMS at any cement plants. Furthermore EPA has not performed a
legitimate technical analysis of emissions variability and compliance
determination uncertainty to allow the use of PM CEMS for determining
continuous compliance with a PM limit at cement plants.

The use of PM CEMS in Europe and other countries does not constitute a
valid basis for application of PM CEMS at cement plants in the United
States. Light scattering, light transmission, and extractive beta
attenuation instruments are all inferential measurement devices and a
correlation must be established to relate the device output to the
actual PM concentration, then the accuracy and bias of the reference
test and the uncertainty of the statistical correlation, as well as the
stability of the correlation must be considered. Under the German TUV
and the European monitoring standard (EN 14181) these uncertainties are
considered; emissions are not considered to exceed the allowable limit
until the lower bound of the confidence interval and/or tolerance
interval exceeds the emission limit; emission standards may contain
different averaging periods requiring different levels of conformance;
and when a problem is encountered, the emphasis is on resolving the
emission problem rather than direct enforcement and collection of
financial penalties. All of these considerations place the European
monitoring program in an entirely different regulatory context than the
proposed PM monitoring requirements.

Response: We reject the commenters’ assertions that PM CEMS have not
been required via rulemaking because of unresolved fundamental technical
or policy issues. Concerns about PM CEMS were identified and addressed
prior to the January 2004 publication of Performance Specification 11
and Quality Assurance Procedure 2 for PM CEMS (69 FR 1786, January 12,
2004). As mentioned in that rule’s preamble, “…we believe that the
PM CEMS field demonstrations completed to date encompass a range of
operating conditions and emission characteristics…” including those
exhibited by sources such as cement kilns. Moreover, we disagree with
the assertion that our analysis of PM emissions variability is not
legitimate, yielding an overly-stringent PM emissions limit. The PM
limit is based on our analysis of PM emissions from test data, adjusted
from an hourly to a 30-day averaging period and further adjusted for
variability. As mentioned in the preamble to the Credible Evidence Rule
(62 FR 8314, February 24, 1997), we have addressed and continue to
address concerns about perceived “…limited number and distribution
of test runs and the inherent variability in levels of emissions…”
by a number of approaches, including changing emissions averaging
periods.

Certainly, lengthening the averaging period beyond the duration
associated with conducting a performance test (typically three hours) to
30 days without changing the value of the emissions limit does not
increase stringency of an emissions limit. As mentioned in the
description of the Salo and Pederson memoranda, “…(t)he effect of
the change from a 3-hour averaging time to a 30-day averaging time is to
make the standard more lenient…” Further, a statistically-based
adjustment to account for emissions variability, and which, in this
case, increases the numerical value of the standard (and its longer
averaging period) by fifty percent, does not make the standard more
stringent.

Comment: Two commenters (2845 and 2859) had the following comments
concerning technical issues associated with application of PM CEMS.

EPA has not addressed nor resolved the primary technical issues limiting
the effective application of PM CEMS at cement plants including:

inability to generate a sufficiently wide range of PM concentrations to
establish an acceptable correlation (i.e., calibration),

accuracy and precision limitations of reference method at PM levels
necessary to generate valid correlation, and

subsequent changes in effluent matrix and/or PM (i.e., particle size
distribution, refractive index, particle density, etc.) that influence
the stability of the correlation and hence, the relationship between the
output of the inferential measurement device relative to actual PM
concentration.

Valid PM CEMS correlations cannot be established for PM CEMS at cement
plants due to limitations of process operation and control equipment in
conjunction with the proposed emission limitation.

The requirements in Appendix A, PS-11 for the PM CEMS correlation and in
Appendix F, Procedure 2 do not provide a sufficiently reliable means to
determine compliance with emission limitations.

Response: We have not identified problems cited by the commenters at
existing installations. PS-11 establishes the acceptable range for the
concentrations for the correlation. This range is site specific.

The acceptable accuracy and precision is specified in PS-11 by
statistical criteria. If the reference method accuracy and precision is
poor, a poor correlation would result and the statistical criteria
limits would not be met. PS-11 strongly suggests the use of paired
trains to insure that accuracy and precision is obtained.

Section 2.4 of PS-11 stresses the importance of planning for subsequent
changes in effluent matrix and/or PM that might influence the
correlation and describes the process required to enhance the
probability of obtaining a successful correlation and the selection of
the most appropriate CEMS for the installation.

We note that PS-11 has several features to address correlation issues
due to any limitations of process operation and control equipment. PS-11
provides for the addition of a zero point. For example, if control
equipment operations cannot be varied adequately to achieve higher PM
concentrations resulting in a cluster of data points at a very low
level, making it difficult to achieve PS-11 criteria, an artificial data
point may be selected at zero that allows the correlation curve to be
developed, meeting correlation criteria.

PS-11 provides the steps in obtaining a reliable successful correlation
with reference methods, thereby insuring compliance data that is
sufficient to determine compliance with PM emission limits. Procedure 2
describes the required audits to insure that subsequent measurements are
stable and within acceptable limits, thereby insuring reliable
compliance data.

Comment: Two commenters (2845 and 2859) had the following comments
concerning PS-11 and Procedure 2.The requirements at §63.1349 for PM
CEMS are incomplete and ambiguous and EPA has failed to specify
important QA frequencies and other information relevant to the
implementation of PM CEMS in accordance with PS-11 and Procedure 2. The
proposed Subpart LLL revisions fail to address critical elements
including the following sections of PS-11 and Procedure 2:

PS-11 3.20, species reference method as method defined in applicable
regulations (Method 5 with 250ºF filtration temperature) but this is
inadequate for low concentrations where Method 5I should be used, and is
inapplicable to sources with PM that condenses between the stack
temperature (mill on and mill off, if applicable) and 250ºF where
Method 17 should be used or ASTM D 6831.

PS-11, 6.2 You must ensure that the averaging time, the number of
measurements in an average, the minimum data availability, and the
averaging period for your CEMS conform to those specified in the
applicable regulation - but none are specified.

When using PS-11, 6.5 Your CEMS must sample the stack effluent such that
the averaging time, the number of measurements in an average, the
minimum sampling time, and the averaging procedure for reporting and
determining compliance conform to those specified in the applicable
regulation - but none are specified.

Procedure 2, 10.3 You must conduct an response correlation audit (RCA)
and an relative response audit (RRA) at the frequency specified in the
applicable regulation… but none are specified.

Procedure 2, 10.3, You must perform an RRA at the frequency specified in
the applicable regulation… but none is specified.

When using Procedure 2, 10.3(7) You must perform an RCA at the frequency
specified in the applicable regulation… but none is specified.

When using Procedure 2, 10.9 You must report the accuracy results for
your PM CEMS at the frequency specified in the applicable regulation…
but none is specified.

Response: We recognize that PS-11 does not specify a reference method;
we have revised the final rule to specify Method 5 or Method 5I (40 CFR
60, appendix A) as the reference method. Facilities with issues in
application of these reference methods, may petition the Administrator
for alternatives or modifications under §60.8(b) or §63.7(f). The
averaging times and data reduction specifications have been added to
§§60.63(c) and 63.1350(b) of the rule. There is no specific data
availability requirements, §§60.63(g) and 63.1348(b) require that
monitoring be conducted at all times the affected source is operating
except for periods of monitoring system malfunctions, repairs, or
quality assurance/quality control activities. The language of the final
rule has been revised to specify the frequency of the Relative Response
Audits (annually) and the Response Correlation Audits (every three
years), for specifics, see §§60.63(c) (2) and 63.1350(b)(2). Absolute
Correlation Audits are required by Procedure 2 on a quarterly basis.

Comment: Two commenters (2845 and 2859) said that the monitoring of PM
emission concentrations downstream of wet scrubbers is not possible at
cement plants due to the presence of water droplets and, during scrubber
upsets, gypsum slugs. Heated extractive systems (either Beta gage or
light scattering) are used at monitoring locations downstream of wet
scrubbers at electric utilities. However, none of these devices can
operate reliably in the presence of gypsum spray or very large
particles. During malfunctions, upsets of the PM APCD, or during period
of bypass, the wet scrubber will collect a large portion of the PM so
that monitoring upstream of the wet scrubber may overstate actual PM
emissions.

Response: We agree that PM CEMS would not work some of in these
situations. However, the types of wet scrubbers that would be used for
acid gas control are typically spray towers, which are not effective in
controlling PM. Therefore, in these situations the source could elect to
monitor for PM upstream of the wet scrubber without significantly
affecting the PM measurements during these malfunction situations. In
cases where this is not feasible, the source can apply for an
alternative monitoring on a source specific basis.

Format of PM limit

Comment: Two commenters (2845 and 2859) stated that in the current
rulemaking, EPA proposed an alternate PM MACT standard for sources that
combine kiln and cooler exhaust streams to a single stack. The commenter
agreed that an alternate PM MACT standard is required for sources that
combine exhaust streams. However, the commenter argued that EPA failed
to recognize all potential exhaust streams and has overly complicated
the formula to account for the various exhaust gases. These commenters
recommended that the PM standard should be based on units of pounds PM
per ton of dry feed. This eliminates the need for a typical feed:clinker
conversion factor and have also recommended that EPA revise the PM MACT
standards for existing and new sources to be more in line with the
values derived by Commenter 2845. Using the values of 0.092 lb/t of dry
feed and 0.062 lb/t of dry feed for existing and new sources,
respectively and EPA’s assumption of a standardized kiln flow rate of
54,000 dscf/t of feed, the applicable grain loading rate for each case
would be 0.012 gram per dry standard cubic feet (gr/dscf) for existing
sources and 0.008 gr/dscf for new sources. Lastly, it is not necessary
to measure the volumetric rate from each exhaust stream separately. If
two or more streams are combined into a single exhaust point, the
measurable volumetric flow rates will already be added. A simplified
formula can be found as part of the comments for Commenter 2859.

Response: As we noted at proposal, some kilns combine the clinker cooler
gas with the kiln exhaust and send the combined emissions to a single
control device. There are significant energy savings (and attendant
greenhouse gas emission reductions) associated with this practice, since
heat can be extracted from the clinker cooler exhaust. However, there
need to be different conversion factors from concentration to mass per
unit clinker in these cases to allow for the increased gas flow, which
result in a different PM emissions limit. We proposed adjustment factors
that would account for these differences and create a site specific PM
emission limit of this situation. See 74 FR 21155-56 and 2184. We
received no comments on these factors and are thus adopting them as
proposed, except that the factors have been changed to account for
changes n the underlying kiln and clinker cooler emissions limits.

A site-specific compliance method can be requested for situations where
additional sources of particulate are included in the same duct system
leading to one stack.

See the preamble discussion under format of the normalized standards in
the NESHAP and the NSPS, for more information on EPA’s decision
regarding format of the standard.

Comment: One commenter (2844) requested that sources be given the option
of compliance with an equivalent grain loading figure that would be in
the rule and the rule automatically approve the current methods for
converting feed to clinker. This should be done on a monthly rather than
daily basis. The commenter ask that there be an ongoing compliance
demonstration (between stack tests) alternative based on retaining the
use of COMS as the indicator of acceptable operating conditions.

Response: See the preamble discussion under format of the normalized
standards in the NESHAP and the NSPS, for more information on EPA’s
decision regarding format of the standard.

We are removing all opacity standards for kilns and clinker coolers
because these sources will be required to monitor compliance with the PM
emissions limits by more accurate means. Although some commenters
requested retention of opacity as a backup standard, and others as an
alternative, none of these comments offered any convincing information
or other justification for perpetuating a less reliable compliance
methodology.

Clarifications and corrections

Comment: Several commenters (2845 and 2859) stated that EPA has several
areas in their proposed regulatory language that must be revised. In
particular, EPA has language requiring opacity monitoring for kilns and
coolers that no longer have opacity standards. Also, EPA has mandated
performance testing where CEMS are required. Performance testing is
typically required for sources that must conduct stack testing
periodically to demonstrate that compliance is maintained. If CEMS are
mandated performance testing is not necessary when compliance is
demonstrated on a continuous basis.

One commenter (2845) stated that the current language for
§63.1343(b)(2) limits opacity from kilns to no greater than 20 percent
and in §63.1343(a)(2) limits opacity from clinker coolers to no greater
than 10 percent, but the preamble of the proposed rule states We are
proposing to remove all opacity standards for kilns and clinker coolers
because these sources will be required to monitor compliance with the PM
emissions limits by more accurate means. The commenter suggested that
EPA should remove the opacity limits from the rule text for sources
demonstrating compliance with a BLDS, PMDS or PM CEMS unless opacity
monitoring is used as an alternative to the proposed options for
monitoring PM emissions. EPA should provide an option for sources to
comply with an opacity limit of 10 percent for kilns and 5 percent for
clinker coolers using a COMS in lieu of the requirements for a BLD, PMD,
and/or PM CEMS.

One commenter (2845) stated that §63.1349(b)(1) should be updated to
account for clinker coolers that use PM CEMS. The commenter suggested
the following alternative language: §63.1349 (b)(1) .The owner or
operator of a clinker cooler subject to limitations on PM emissions that
is not equipped with a PM CEMS shall demonstrate initial compliance by
conducting a performance test as specified in paragraphs (b)(1)(i)
through (b)(1)(iii) of this section. The owner or operator shall
determine the opacity of PM emissions exhibited during the period of the
Method 5 (40 CFR 60, Appendix A–3) performance tests required by
paragraph (b)(1)(i) of this section as required in paragraphs (b)(1)(v)
through (vi) of this section, if the unit is not equipped with a BLDS,
PMDS or PM CEMS.

One commenter (2845) stated that the opacity limits in §63.1349(b)(1),
§63.1350(c), §63.1350(d) need to be removed from the rule text for
source demonstrating compliance with a BLDS, PMDS, or PM CEMS unless
opacity monitoring is used as an alternative to the proposed options for
monitoring PM emissions. Example language for each section is provided
by the commenter.

Response: We have corrected the rule to remove duplicative requirements
related to opacity monitoring for units that no longer have opacity
standards and performance testing requirements for sources that are
using CEMS. Regarding the comment that COMS be allowed as an
alternative, EPA’s experience is that facilities can significantly
exceed PM limits without exceeding opacity limits. In contrast, BLD
systems are much more sensitive to the point they are considered to be