1



## National Emission Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing Industry (Subpart LLL) and Standards of Performance

for Portland Cement Plants (Subpart K)

Response to Comments

Final Reconsideration May

2015

List of Commenters

EPA

- HQ

- OAR

- 2011

- 0817

- 0861 Portland Cement Association

EPA

- HQ

- OAR

- 2011

- 0817

- 0862 Seth L. Johnson, Attorney, Earthjustice

EPA

- HQ

- OAR

- 2011

- 0817

- 0863 Duplicate of EPA

- HQ

- OAR

- 2011

- 0817

- 0862

EPA

- HQ

- OAR

- 2011

- 0817

- 0864 Vivek Kapur, Arizona Department of Environmental Quality



## Subpart LLL Portland Cement Manufacturing

1. Reinstatement of the opacity standard

Commenter 0862 states that EPA should reinstate the opacity standard removed in the 2010
rule. The commenter explains that at the time, EPA was requiring bag leak detectors and CEMS and thought an opacity standard was “redundant.” 75 Fed. Reg. 54,970, 55,008/2 (Sept. 9, 2010), and in 2013, EPA eliminated the CEMS requirement and replaced it with the stack test and CPMS operating limit regime now in place.78 Fed. Reg. 10,006, 10,010/1‐2 (Feb. 12, 2013).

RESPONSE 

### : EPA did not solicit comment on this issue, and thus a response is not legally required. However, if a response is deemed necessary, EPA disagrees that the existing source opacity limit should be reinstated. In the final 2010 rule, we stated that we were removing all opacity standards for kilns and clinker coolers because these sources will be required to monitor compliance with the

PM emi ssions limits by more accurate means

. Even though the final 2013 rule requires CPMS rather than CEMS, CPMS are much more sensitive in detecting increases on PM emissions than opacity (see 75FR54989). Therefore the basic rationale in the 2010 rule (see 74F R21157) that an opacity standard is redundant, remains.2

SO 2 monitoring parameter issues (Comments 2 through 4):



### 2. Rationale for the SO 2 monitoring alternative.

Commenter 0862 believes that the new SO 2 monitoring alternative is not rationally explained , and that the explanation for why the scaling would maintain compliance with the HCl standard is lacking.

RESPONSE : We agree with the commenter that some additional rationale would be helpful.

The alternative monitoring proposed is not based on a surrogate relationship between SO 2 and HCl. It is based on the fact that acid gas controls effectively remove the more reactive HCl in preference to

SO 2 . Therefore, even if the SO 2 emission rate incr eases, we can be reasonably certain that the HCl
emissions level has not. The SO 2 parameter is simply an indicator that tells us that the SO2 control is working properly, which indicates that HCl continues to be controlled (see docket item EPA

- HQ

OAR2011

- 0817

- 0130 ). However, the available information on SO2 emissions indicates that they fluctuate over time. Without the scaling factor, facilities may be forced to continually retest HCl emissions unnecessarily due to these changes in SO2 emissions, even tho ugh, as previously noted, an increase in SO2 emission levels does not indicate a corresponding increase in HCl emissions levels. Even so, we recognize that there is some potential for a control system to lose its ability to control acid gases at all, so we have limited the scaling. We selected the 75% of SO 2 emissions standard level as a reasonable level that will allow facilities some flexibility to operate their controls and meet their SO 2 limits as their systems fluctuate normally, and place a reasona ble action level on HCl, rather than assume that HCl emissions are always controlled to the level of the HCL limit if a wet scrubber or dry injection control system is in place.

The commenter also stated that EPA has not explained why SO 2 controls will b e operating and also states that in the preamble, EPA indicates that scaling is an “alternative” that a source “may” use, but according to S 63.1349(b)(8)(vii), the source “must” set the SO 2 operating limit using scaling if HCl stack test averages are belo w 75% of the HCl limit.

RESPONSE : The EPA believes that facilities equipped with wet or dry scrubbers will be controlling for

SO 2 . Although SO 2 is not regulated under Subpart LLL, it is regulated under the New Source Performance Standard Subpart F for new sources who construct, reconstruct, or modify after June 16, 2008 (see 75FR55035). Also, many states require SO 2 control at Portland cement facilities to satisfy SO 2 or PM attainment requirements. Thus, we believe there will b e a subset of Portland cement facilities using SO 2 controls, and these sources would have the ability to utilize the SO 2 parameter to gauge HCl compliance.

Relative to the discrepancy of the use of the word “may” in the preamble, and the word “must” in

Se ction 63.1349(b)(8)(vii), the EPA agrees that there is a discrepancy and will correct this issue in the final rule under Section 63.1349(b)(8)(vii), and indicate that this is a compliance alternative, not a mandated mode of demonstrating compliance.

3. Pr oposal to allow use of a scaling factor for SO 2 CEMS operating limit for HCl compliance for units
with scrubbers.

Commenter 0861 agreed with the proposed approach to set the SO 2 operational limit to mirror the same approach used for the PM CPMS. In addit ion, the commenter stated that an error was found in the definition of “R” in Equation 18 found in 40 CFR 1349(b)(8), where the EPA lists “ppmv at 7% O2”. This phrase should read “ppmvd at 7% O2”.3

RESPONSE : The EPA agrees with this typographical error , and has made the correction in the final rule.

4. Utilizing SO 2 parameter monitoring for kilns without SO 2 controls

Commenter 0861 agrees with the alternative scaling approach for HCl compliance, for units equipped with wet scrubbers or sorbent injection, but requests that the same approach be allowed for HCl monitoring at all kilns.

RESPONSE: The EPA disagrees. The final rule do es not allow the SO 2 parameter approach for sources that demonstrate their HCl is 75% below the limit, but do not have a wet scrubber or sorbent injection system. As noted above, the basic premise that SO 2 monitoring provides an indication that HCL

emis sions are being maintained at the level shown during the compliance test is that there is some type
of SO 2 control in place, and the fact that SO 2 controls preferentially remove HCl. Without the scrubber device acting to remove the HCl from the gas flow, m onitoring SO 2 provides no assurance that the HCl is being maintained at the level it was at during the time of the compliance test. The scrubber is required for HCl removal; monitoring alone does nothing to remove HCl from the flue gas. Put even more
dir ectly, without a control device HCl emissions will not be controlled; SO 2 monitoring in the absence of
a control device does not alter this fundamental fact.

5. Issue with revision of Section 63.1354(b)(9)(iv)

Commenter 0862 stated that the proposed revi sion to Section 63.1354(b)(9)(iv), which removed the component of the regulation that required the results of the inspection to be reported, weakens the reporting requirement for no reason, since the results of the inspections matter to the public and shou ld still be reported regularly to the agency.

RESPONSE: The EPA disagrees with this comment. The proposed revision to 63.1354(b)(9)(iv) and the other revisions to Section 63.1354 are due to clarifications and further requirements needed for facilities

t o submit electronic summary reports semiannually to the Compliance and Emissions Data Reporting Interface (CEDRI). Inspection results for combustion system components must be kept on record and are available to the Administrator by request. These data ar e not compatible with the CEDRI electronic system, as it should be noted that provision 63.1354(b)(9)(iv) addresses inspections required under Section 63.1347(a)(3), which does not delineate what the component condition has to be, but rather requires that procedures be outlined for the inspection of the components to the combustion system. The procedures of how the inspection will be performed are the important parts of the operation and maintenance plan and must be approved by the Administrator. It shoul d be noted that any deviations that would occur from a failed inspection are required to be reported semiannually under Section 63.1354(b)(9)(vii); thus even though the outcome of the inspection is not reported, the deviation occurring from the failed insp ection is indeed reported. We believe this system is sufficient to demonstrate compliance. Again, this information must be kept on record, and if needed can still be requested at the discretion of the Administrator, but not in electronic form.

6. Defini tion of Rolling Average

Several commenters (0861 and 0862) stated that the proposed definition of rolling average was unclear, as the definition of rolling average proposed does not match the various forms of the standard found in
the rule.4

RESPONSE: The EPA agrees with the commenters that the rolling average proposed does not match the various forms of the standard found in the rule, and thus has revised the definition in the final rule. The
final definition is listed below:



### " Rolling average means t he weighted average of all data, meeting QA/QC requirements or otherwise normalized, collected during the applicable averaging period. The period of a rolling average stipulates the frequency of data averaging and reporting. To demonstrate compliance
with an operating parameter a thirty

- day rolling average period requires calculation of a new average value each operating day and shall include the average of all the hourly averages of the specific operating parameter. For demonstration of compliance with a n emissions limit based on pollutant concentration a thirty

- day rolling average is comprised of the average of all the hourly average concentrations over the previous thirty operating days. For demonstration of compliance with an emissions limit based on lbs

- pollutant per production unit the thirty

- day rolling average is calculated by summing the hourly mass emissions over the previous thirty operating days, then dividing that sum by the total production during the same period."

7. Restoring the previous limits which apply until September 9, 2015

Commenter 0861 stated that the previous limits that are in effect until September 9, 2015 should be added to the rule, instead of only a reference to the former federal register notice whic h contained the former limits, since it is not convenient for sources to locate and interpret former notices.

RESPONSE: The EPA agrees with this comment that it is more convenient for sources to refer to one eCFR, and has published the former limits i n the final rule.

8. Performance Test Frequency

Commenter 0861 stated that other NESHAP rules and the CISWI rule allow flexibility for an additional month around the due date for annual retesting. For example, instead of requiring annual testing within

1 2 months, the test can be in up to 13 months (see 40 CFR 63.10006(f)) for the comparable provisions in the Utility NESHAP rule and 40 CFR 60.2150 for the comparable provision under the CISWI rule). The commenter believes this is very important because it allows one to book the testing for the same time each year rather than constantly moving the date up each year to be sure the testing is done before the 12 month anniversary of the prior test. The commenter also believes that this helps one avoid having

a nnual shutdowns conflict with annual tests. The commenter thus requests that the annual testing for PM under 40 CFR 63.1349(c) and for mercury from alkali bypass and coal mills under 40 CFR 1350(k)(5)(i)
both be extended to 13 months.

RESPONSE: We ag ree with the commenter that moving the date up each year in order to meet the 12 month anniversary is not practical, and thus we are granting this request. We have revised this requirement in the final rule under 40 CFR 63.1349(c), which covers requiremen ts both for 30 month testing and 12 month testing.

9. The use of a temperature parameter during startup and shutdown

Commenter 0861 stated that the revised requirement for startup and shutdown (see 40 CFR5

63.1346(g)(3) lacked clarity and was impractical. The concern was that the temperature threshold should only apply to injection systems and not all air pollution control devices. Also the commenter stated that the language suggests that the temperature w ould be determined as the gas stream reaches the control device, which might be read to mean the temperature at an injection system rather than at the PM control device inlet, which is what the commenter believes is relevant and indicated in the next

sente nce. The commenter also believes that an averaging time is needed for the temperature at the inlet to the PM control device to avoid a temporary change in temperature over the threshold of 300 degrees which the commenter believes would result in non

- compl iance. The commenter also states that during shutdown, injection systems should not be operating. The commenter stated that when feed is pulled, flow to the particulate control device drops and any material injected may fall out and deposit, creating pro blems for restart. Instead the commenter believes the requirement should be to operate PM control devices only during shutdown. The commenter suggests revised wording to the proposed regulatory text to solve these issues.

RESPONSE: The EPA agrees with the commenter that the proposed regulatory text lacked clarity. Thus, the EPA has agreed to include the clarifications found in the commenter’s proposed suggestions and has incorporated these revisions into the final regulatory text. The EPA also has cla rified the text to include language that assures all HAP controls are being operated during startup and shutdown conditions. This language is included below:



### “(3) All dry sorbent and activated carbon systems that control hazardous air pollutants must be turned on and operating at the time the gas stream at the inlet to the baghouse or ESP reaches 300 degrees Fahrenheit (five minute average) during startup. Temperature of the gas stream is to be measured at the inlet of the baghouse or ESP every minute . Such injection systems can be turned off during shutdown. Particulate control and all remaining devices that control hazardous air pollutants should be operational during startup and shutdown.”

10. Quality assurance of mercury CEMS data above the span value

Commenter 0861 states that two of the three options for quality assurance of data above the span value are impractical and would result in unacceptable monitor availability. The commenter includes an explanation as to why two of the three options are not impractical and also includes an Attachment to the comment letter which the commenter states may be useful in understanding their comments (see
docket item EPA

- HQ

- OAR

- 2011

- 0817

- 0861, Attachment A). The commenter believes that the option provided in (2) (iii) should be retained without substantial changes from what is currently in the rule, since the commenter believes this is the only option that is consistent with the scientific principal of checking the high level performance during periods of h igh level emissions, and in the commenter’s view, the option which minimizes the time for Hg CEMS equilibration and recovery and minimizes corruption of low level data. Also the commenter states that this is the only option that does not require high level calibration checks daily or weekly if no periods of Hg emissions above the span level occur and that this is the best technical option.

Also the commenter states that the meanings of the proposed minor wording changes to (2)(iii) are ambiguous. The c omment believes that replacing “be of” with “target” to imply that there is some additional tolerance relative to the 50 to 150 percent range, that the word “expected” conflicts with “measured”, and also states that because (2)(iii) allows the above span c heck to be performed “within6

24 hours before or after” the above span period, the commenter interprets that “expected” is inserted to accommodate above span checks conducted prior to the above span period. Also the commenter
states that the word “measure d” should be deleted to avoid conflicting interpretation, and that basing the requirement of the “expected” value rather than the “measured” value is consistent with the new option (2)(ii). The commenter proposes edits to the proposed text for this issue , and also suggests edits to 2(iii) and a new paragraph is suggested.

The commenter further states they support 

### EPA’s proposal of the new option provided in (2)(ii) to perform a single high level “linearity” check weekly, as an alternative to (2)(iii), since this option is easy to initiate from the DAS or the CEMS controller as a scheduled sequence. The comment believes it could be coordinated to occur during planned raw mill maintenance periods and does not require comple x new DAS programming. However, the commenter states that it explicitly requires the operator to regularly expose the Hg CEMS to Hg concentrations greater than the expected highest one

- hour average, which the commenter believes will necessitate the greates t CEMS equilibration and recovery times. According to the commenter, when such a check is performed during mill on operation, the large concentration difference will result in the longest period of invalid data.

The commenter continues to comment on th e new option provided in (2)(ii) and believes it should be modified to allow the use of certified reference gases with concentrations less than “greater than your highest expected concentration” to provide additional flexibility and a more representative calibration check level. The commenter gives an example, that a target concentration of 75% of the highest hourly average measured concentration may be more representative for sources with few measurements at the very highest levels, and recommends that EPA add the underlined phrase below.

“Conduct a weekly “above span linearity” calibration challenge of the monitoring system using a reference gas with a certified value greater than your highest expected hourly concentration, or greater
than 75% of t he highest measured hourly concentration.”

The commenter states that in view of the two corrective action options provided under the new option in (2)(ii), the commenter supports the more restrictive ±10% acceptance criterion relative to the
acceptance criterion of ±20% in (2)(iii). The commenter includes the passage from the regulatory text,
which is:

“If the value measured by the Hg CEMS during the above span linearity challenge exceeds 10 percent of the certified value of the reference gas, the m onitoring system must be evaluated and repaired and a new “above span linearity” challenge met before returning the Hg CEMS to service, or data above span from the Hg CEMS must be quality assured using the procedure established in (k)(2)(iii).”

The com menter states that they interpret the last phrase to allow the Hg CEMS operator to directly apply the ±20% acceptance criterion of (2)(iii) to the above span linearity check which surpassed the 10% acceptance criterion of (2)(ii), and normalize any above s pan data according to Equation 22, if the 20% criterion is exceeded. No other corrective action would be required. Alternatively if the attempted above span linearity check was performed during mill on operations, the commenter believes that the Hg CEMS op erator could, within the time window for option provided by (2)(iii) (i.e., 24

- hours before or7

after above span condition), perform a new above span check according to the requirements of (2)(iii), and normalize the above span monitoring data according to Equation 22 if the 20% criterion is exceeded. The commenter believes that neither of these allowed approaches would result in any invalid data and neither of these approaches would affect the validity of data below the span value. The
commenter further st ates that If these interpretations are not clear enough in the rule, these particular action alternatives under (2)(ii) should be made explicit in the rule.

The commenter further states that an explicit exemption from the requirements in the general

pr ovisions 63.8(c)(6), PS12A and Appendix F, Procedure 5 to perform the normal daily upscale calibration checks (typically at 80

- 100% of the span value) should be provided (a) during periods when emission concentrations significantly exceed the span value, o r (b) during periods when Hg0 generator is operating at the elevated concentrations necessary for (2)(i)

- (iii) requirements, or (c) during periods when the generator is in the process of re

- equilibration to operate at the normal calibration levels, or (d) during rapidly changing effluent concentrations associated with changing mill operating status. The commenter includes their rationale for this statement by stating that performing low level calibration checks during these periods is not possible during ge nerator equilibration, and even when the generator is available, will not provide reliable results during elevated or rapidly changing Hg concentrations. The commenter believes that insisting that the calibration check be done will result in inappropriat e adjustments to the Hg CEMS, only to be undone by the following calibration check after stable conditions are achieved, and the commenter further states that such inappropriate adjustments detract from data quality, waste valuable technical effort, create frustration, and complicate recordkeeping and reporting. The commenter then includes suggested language to be inserted as a new paragraph in (k)(2)(iv).

The commenter adds that cement kiln operators that have chosen to install Hg CEMS should be given a time extension for implementing Hg monitoring in the event that NIST fails to accurately certify high level Vendor Prime Hg Calibration Gas Generators in sufficient time for vendors to certify their respective User Generators. The commenter asserts that the following facts have occurred:

“There have been some problems with Vendor Prime generators certifications by NIST requiring the candidate generators to be returned to NIST for recertification and causing delays of several months.

No Tekran hig h

- level 3310 Hg0 Generators have been certified by NIST as Vendor Prime Generators.

Thermo expected NIST certification of its high

- level 81iH Generator as a Vendor Prime in August of 2014 and received it in November. However, there appear to be signifi cant discrepancies between the setpoint values and the NIST certified concentrations. The generator is being returned to NIST for
reevaluation.

Some weeks will be required for generators installed at cement kilns to be shipped to the respective manufacturers, certified relative to the Vendor Prime generators, shipped back to the cement plant, and installed in the Hg CEMS.”

The commenter further states that cement kiln operators cannot be held responsible for delays beyond their control that occur at NIST or problems which prevent the Hg CEMS manufacturers from complying with the certification of user generators in accordance with the 2009 Interim Traceability Protocol.8

RESPONSE : The EPA thanks the commenter for their support of our modification to the span value.

The EPA agrees with the comment that wording changes to (2)(iii) and (l)(1)(ii)(C) were unclear and has

t aken steps to clarify that language in the rule. The use of the word “target” implies flexibility which was our intent. The word “expected” is meant to include above span calibrations that were done before hand, and we have clarified that in the rule tex t.

The EPA agrees with commenter’s interpretation of (2)(ii) in that we did intend to allow the Hg CEMS operator to note a CEMS whose linearity check surpassed the 10% level, to switch to a 20% criteria by referencing (2)(iii) and proceeding down that p ath. We intend that a CEMS that does meet the 10% level under (2)(ii) would continue to follow the (2)(ii) pathway. We will extend this to include (l)(1)(ii)(B) and (l)(1)(ii)(C) HCl monitoring language. We have clarified the language in the final version to reflect
this intent.

The EPA agrees that the user of the option for above span validation provided in (2)(ii) and (l)(1)(ii)(B) will result in instances of Hg concentrations greater than the expected one

- hour average and will result
in increased d ata availability concerns. This is the primary reason why this option is a weekly check and not a daily check. Where such checks result in unacceptable monitor availability for a facility they may wish to choose a different option for above span value val idation.

The EPA agrees with the addition of “...or greater than 75% of the highest measured hourly concentration.” to the procedure description in (2)(ii) and (l)(1)(ii)(B) and has modified the rule text to reflect this change.

Relative to the comment that adjusting monitors based on low level calibration checks done during milloff periods that might otherwise not require adjustments if conducted during mill

- on periods, should be exempted from the requirements in the general provisions 63.8(c)(6): we a gree with the commenter that this otherwise required adjustment is not needed and may create unnecessary corrective actions that are not generally helpful or serve to improve monitoring accuracy. We are modifying the rule language to reflect this change and provide the exception.

The EPA disagrees with the commenter’s’ suggestion of excluding such periods from a daily calibration check in that we find sound value in requiring a daily upscale calibration check and, where done during
mill

- off conditions we will modify the rule language to reflect that we expect to see a higher upscale value during these periods, but without monitor adjustment as may be required through the more
standard mill

- on lower

- level daily calibration. We are modifying the rule lan guage to reflect this change.

With respect to the issue of data substitution in (l)(1)(ii)(C), the EPA agrees with the reasons stated by the commenter and has removed the requirement for missing data substitution.

Regarding the issue of a delay in th e NIST primary standards, the EPA recognizes NIST traceability audit and calibration gases as one of the key components of compliance emissions monitoring, and so we recognize the concern industry is voicing over availability of high level calibration stan dards that are NIST traceable. The EPA is aware that NIST is currently recertifying their Primary Calibration Standards and has plans to move toward providing Primary Standards to Vendors such that Vendors can provide9

NIST traceable high

- level gas generat ors to facilities in time to meet compliance with the rule. Where timing is a concern with respect to the effective compliance date of this rule and availability of a NIST Traceable high

- level calibration gas generator and/or high level NIST traceable calibration gas cylinders, a facility may choose to apply for an alternative test method, under the provisions allowed in 63.7 (f), whereby they could operate their CEMS and report the values they measure based on their current calibration gas generator an d using the highest concentration gas available for the ‘above span’ calibrations, retaining all rule required monitoring records as well as a letter from their CEMS vendor stating that a high level calibration gas generator was unavailable during such tim e. Facilities must have obtained a NIST traceable form of high

- level calibration gas and certify their CEMS by the compliance date of the rule. Facilities who are concerned that this is not a workable approach for their monitoring needs may also choose to apply for an extension of one year for their Hg limit compliance demonstration under the General Provisions Section 63.6(i)(4(i)(A).

11. HCL CEMS requirements

Commenter 0861 has various concerns about the proposed revisions to the HCl CEMS requireme nts and has delineated each of these concerns in their comment letter and summarized here (see docket
EPAHQ

- OAR

- 2011

- 0817

- 0861). In addition, the commenter has included an Attachment A to the comment letter to provide background on the issues they have ra ised.

The commenter voiced strong support for EPA’s proposed change to the HCl CEMS span value to 10 ppm, but suggests that EPA reinsert deleted language that may provide flexibility and avoid complexity of above span calibrations for kilns systems without in

- line raw mills which have occasional periods of emissions exceeding 10 ppm. The commenter provides suggested revisions to what was proposed, in the following submittal:

“(l)(1)(i) You must use a m easurement span value for any HCl CEMS of 0

- 10 ppmvw, or higher value that represents the upper limit of HCl concentrations that occur during normal in

- line raw “mill on” operation.”

The commenter states that EPA has proposed to revise 40 CFR 63.1350(l) (1)(ii) to provide a new third option for dealing with above the span value HCl CEMS data. The (A) option is unchanged and the (C) option has minor word changes relative to the promulgated requirements. The (B) option is new. The
commenter believes that t hese options are almost identical to the same options as provided for Hg CEMS. The commenter believes that the option provided in (l)(1)(ii)(A) of setting a second span to encompass mill off HCl concentrations and performing all QA activities required by P S18 and Procedure 6 (except mill off RATA) is impractical and would potentially result in unacceptable monitor availability, and states that with the similar option for Hg CEMS, this doubles the amount of QA checks, doubles the amount of QA activities detr acting from monitor availability, and doubles chances to exceed a specification and render the HCl CEMS non

- certified and/or “out

- of

- control” further decreasing monitor availability. The commenter further states that achieving acceptable levels of HCl CEM S availability is expected to be challenging for cement kiln operators, especially those using extractive HCl CEMS which require very long periods of calibration gas injection to achieve stable responses and additional time to recover, especially after hig h level HCl gas injections. The commenter believes that doubling the QA activities is not a viable option.10

The commenter states that there is a typographical error in (l)(1)(ii)(A): “μg/m 3 ” should be replaced by “ppm” in the following sentence.

“ This second span may be rounded to a multiple of 5 μg/m 3 ppm of total HCl.”

The commenter also states that there are several text changes in the option provided in (l)(1)(ii)(C) needed to align the language with the very similar requirements in the para llel Hg CEMS option (2)(iii) to provide consistency and avoid unnecessary complex programming, and the commenter states that they have previously requested that EPA make these changes.

The commenter further states that the word “consecutive” needs to be added to the second sentence of (C) option in order to enable the complex programming for this option already developed for Hg to be used for HCl CEMS. Failing to make this change renders a successful automated approach unlikely, according to the commenter.

The commenter also states that the same flexibility for the above span target concentration target should be provided for HCl CEMS as for Hg CEMS by changing “100 percent” to “150 pe rcent” in the following sentence of Option C:

“The ‘above span’ reference gas must meet the requirements of the applicable performance specification and be of a concentration level between 50 and 100 150 percent of the highest hourly concentration measu red during the period of measurements above span, and must be introduced at the probe.”

The commenter believes that the same minor text changes proposed for §63.1350 (k)(2)(iii) should be made to (l)(1)(ii)(c) and included the suggested change:

“The ‘above span’ reference gas must meet the requirements of the applicable performance specification and target a concentration level between 50 and 100 percent of the highest expected hourly concentration measured during the period of measurements above spa n, and must be introduced at the probe.”

The commenter also states that the missing data substitution requirement in (l)(1)(ii)(C) should be removed because it is inconsistent with the procedures specified for the other two HCl options for quality assurance of “above span” HCl data. Furthermore, the commenter believes that the missing data substitution requirements are not included in any Part 60 or Part 63 regulations, and that the last sentence in this section (shown below) should be deleted:

“If the ‘above span’ calibration is conducted dur ing the period when measured emissions are above span and there is a failure to collect the required minimum number of data points in an hour due to the calibration duration, then you must determine the emissions average for that missed hour as the average of hourly averages for the hour preceding the missed hour and the hour following the missed hour.”11

The commenter believes that the option provided in (l)(1)(ii)(C) and (D) should be retained without substantial changes to achieve consistency with the Hg above span requirements. Also, the commenter states that on the proposed revision to 40 CFR 63.1350(l)(1)(ii), the option provided in (l)(1)(ii)(A) is impractical and would potentially result in unacceptable monitor availability. In addition, the

comm enter believes several text changes are needed in (l)(1)(ii)(C) to align the language with the very similar Hg CEMS option ((2)(iii)) to provide consistency. The commenter offers suggested language. Finally, the commenter has stated support for the new o ption provided in (l)(1)(ii)(B) to perform a single high level “linearity” check weekly, but offers modifications to the language to allow the use of certified reference gases with concentrations less than “greater than your highest expected concentration” to provide flexibility and a more representative calibration check level. The commenter includes a suggested addition to the regulatory language as underlined below:

“Conduct a weekly “above span linearity” calibration challenge of the monitoring syste m using a reference gas with a certified value greater than your highest expected hourly concentration, or greater than 75% of the highest measured hourly concentration.”

The commenter also states that in view of the two corrective action options provid ed in (l)(1)(ii)(B), the commenter supports the more restrictive ±10% acceptance criterion relative to the acceptance criterion of ±20% in (l)(1)(ii)(C). The commenter includes proposed language that states:

“If the value measured by the HCl CEMS durin g the above span linearity challenge exceeds 10 percent of the certified value of the reference gas, the monitoring system must be evaluated and repaired and a new “above span linearity” challenge met before returning the HCl CEMS to service, or data above span from the HCl CEMS must be quality assured using the procedure established in (I)(1)(C).”

The commenter states that they interpret the last phrase to allow the HCl CEMS operator to directly apply the ±20% acceptance criterion of (C) to the above s pan linearity check which surpassed the 10% acceptance criterion of (B), and normalize any above span data according to Equation 23, if the 20% criterion is exceeded. The commenter believes that no other corrective action would be required, and
alternativ ely if the attempted above span linearity check was performed during mill on operations, the HCl CEMS operator could wait until within the window for option provided by (C) (i.e., 24

- hours before or after above span condition) to perform a new above span c heck according to the requirements of (C), and normalize the above span monitoring data according to Equation 23 if the 20% criterion is exceeded. The commenter believes that neither of these allowed approaches would result in any invalid data, neither of these approaches would affect the validity of data below the span value, and further states that if need be, these particular action alternatives should be made explicit in the rule.

The commenter states that an explicit exemption from the requirements in the general provisions 63.8(c)(6), and the proposed PS18 and proposed Appendix F, Procedure 6 to perform the normal daily upscale calibration checks (typically at 80

- 100% of the span value) should be provided (a) during periods
when emission concentrat ions significantly exceed the span value, or (b) during rapidly changing effluent concentrations associated with changing mill operating status. The commenter further states that performing low level calibration checks during these periods will not provi de reliable results during elevated or rapidly changing HCl concentrations. Insisting that the calibration check be done will result in inappropriate adjustments to the HCl CEMS only to be undone by the following calibration check after12

stable conditions a re achieved. The commenter believes that such inappropriate adjustments detract from data quality, waste valuable technical effort, create frustration, and complicate recordkeeping and reporting.

The commenter offers suggested language as follows, be inserted as a new paragraph (l)(1)(ii)(E):

“(E) Routine daily upscale calibration checks required by Appendix F, Procedure 5 and 63.8(c)(6) that are performed at levels below the span value, are not required on days when above span
calibration checks are performed. Routine daily upscale calibration checks during periods when HCl concentrations exceed the span value or are rapidly changing may provide unreliable results and may be postponed or repeated within 4 hours after HCl concentrations return to below span levels. “

RESPONSE: The EPA thanks the commenter for their support of our modification to the span value.

The EPA agrees with the reasons stated by the commenter that a kiln operating without an inline raw mill may need a measurement span that exceeds 10 ppmv, as necessary to quantify all expected emissions, and we are modifying the rule to reflect this.

The EPA generally disagrees with the commenter’s concerns about option (l)(1)(ii)(A) for validating CEMS data above span. These optional procedures were added to the language as an additional option that allows for increased flexibility in handling such data and is clearly optional; meaning that if it isn’t
work able for a facility they may choose a different validation approach. We have found that some facilities may find this option useful, depending on their instrumentation and configuration.

The EPA agrees with changing “ug” to “ppm” since this is a typogr aphical error, and has modified the rule language accordingly.

The EPA agrees with the comment that wording changes to (2)(iii) and (l)(1)(ii)(C) were unclear and have taken steps to clarify that language in the rule. The use of the word “target” impli es flexibility which was our intent. The word “expected” is meant to include above span calibrations that were done before hand, and we have clarified that in the rule text.

The EPA agrees with the reasons provided by the commenter and we will add the word “consecutive” to the second sentence of (l)(1)(ii)(C) to align it with Hg monitoring section (2)(iii).

The EPA agrees with the commenter’s interpretation of (l)(1)(ii)(B) in that we did intend to allow the HCl CEMS operator to note a CEMS whose li nearity check surpassed the 10% level to switch to a 20% criteria by referencing (ii)(C) and proceeding down that path. We intend that a CEMS that does meet the 10% level under (ii)(B) would continue to follow the (ii)(B) pathway. We have clarified the la nguage in the
final version to reflect this intent.

The EPA agrees with the commenter’s request to align language of Hg section (2)(iii) and HCl monitoring section (ii)(C), for sake of consistency. We will align these two in the final rule, including the upscale certification value range, as suggested by the commenter.13

The EPA agrees with the reason provided by the commenter and will modify (ii)(B) to specify the use of a “reference gas with a certified value greater than your highest expected hourly concentration, or greater than 75% of the highest measured hourly concentration.”

The EPA agrees t hat the user of the option for above span validation provided in (l)(1)(ii)(B) may result in instances of HCl concentrations greater than the expected one

- hour average and might result in increased data availability concerns. This is the primary reason wh y this option is a weekly check and not a daily check. Where such checks result in unacceptable monitor availability for a facility they may wish to choose a different option for above span validation.

The EPA agrees with commenter’s interpretation of ( ii)(B) in that we did intend to allow the Hg CEMS operator to note a CEMS whose linearity check surpassed the 10% level to switch to a 20% criteria by referencing (ii)(C) and proceeding down that path. We intend that a CEMS that does meet the 10% level

un der (ii)(B) would continue to follow the (ii)(B) pathway. We have clarified the language in the final
version to reflect this intent.

The EPA agrees with the commenter’s statement that adjusting monitors based on low level calibration
checks done durin g mill

- off periods that might otherwise not require adjustments if conducted during
mill

- on periods, should be exempted from the requirements in the general provisions 63.8(c)(6): we agree with the commenter that this otherwise required adjustment is not n eeded and may create unnecessary corrective actions that are not generally helpful or serve to improve monitoring accuracy. We are modifying the rule language to reflect this change and provide the exception. This issue also applies to the Hg calibratio n check procedures and is discussed in comment response number 10 above.

The EPA disagrees with the commenter’s’ suggestion of excluding such periods from a daily calibration check in that we find sound value in requiring a daily upscale calibration ch eck and, where done during
mill

- off conditions, we will modify the rule language to reflect that we expect to see a higher upscale value during these periods, but without monitor adjustment as may be required through the more
standard mill

- on lower

- level d aily calibration. We are modifying the rule language to reflect this change.

And with respect to the issue of data substitution in (l)(1)(ii)(C), the EPA agrees with the reasons provided by the commenter and has removed the requirement for missing dat a substitution.



### After the close of the comment period, EPA also was made aware of a delay in vendor

provided HCl calibration gases. This delay, coupled with the delay in the promulgation of the

PS

- 18

, could result in the inability of sourc es to meet the September 9, 2015 compliance
date. As was suggested earlier in Section 10 of this Response to Comment document relative to delays experienced in acquiring NIST primary standards for Hg , we advised that sources could apply for an extension of one year for their HCl limit compliance demonstration under the General Provisions Section 63.6(i)(4(i)(A).



### 12. Typographical error in (l)(1)(ii)(A)14

Commenter 0861 states that the term “ug/m 3 ” should be replaced with “ppm” in the sentence, “This second span may be rounded as a multiple of 5 ug/m 3 ppm of total HCl”.

RESPONSE : The EPA agrees that this was a typographical error, and has made this change in the rule language.



### 13. Interim compliance method for HCl compliance demonstration.

Commenter 0861 stated that since the performance specification 18 (PS 18) is not yet final ized, sources should be allowed to use an alternative of certification with PS 15, and further that sources should be given an 18 month extension after PS 18 is promulgated, to demonstrate compliance using PS 18. This extension is requested so that the so urce can buy CEMS consistent with the PS 18 and perform the necessary installation and performance assessment of the CEMS.

RESPONSE: In the final rule (see eCFR 63.1350(l)), a source is required to either monitor HCl emissions continuously using an emis sions monitor certified with PS 15, or upon promulgation in accordance with any other performance specification. This language allows the source to either continue monitoring using PS

- 15 as the CEMS certification platform, or switch to PS

- 18, currently s cheduled to be promulgated in the spring of 2015. PS

- 18 allows the source more flexibility in their choice of technologies used to comply with these monitoring requirements. We want to allow sources the opportunity to use PS

- 18, even though the final ve rsion is not promulgated. Though we believe that the
final version of PS

- 18 will be published prior to September 9, 2015, sources may require additional time to review the final specifications and purchase equipment. Facilities who are concerned that swit ching
from PS

- 15 to PS

- 18 when PS

- 18 is available is not feasible, may also choose to apply for an extension of one year for their HCl limit compliance demonstration under the General Provisions Section 63.6(i)(4(i)(A).

14. Various typographical errors and clarifications

Commenter 0864 identified several typographical errors, needed clarifications, and misplaced equation terms that were located in both the February 12 2013 (see 78FR10036) and this proposed rule, related to the following sections:

40 CF R 63.1343(b)(2)

(40 CFR 63.1349(b)(1)(vi)

40 CFR 63.1349(b)(1)

40 CFR 63.1349(b)(4)(iii) and (6)(iv) 40 CFR 63.1349(b)

40 CFR 63.1343(b)(2)

40 CFR 63.1349(b)(1(vi)

40 CFR 63.1349(b)(1)

40 CFR 63.1349(b)(1) Table 115

40 CFR 63.1347(a)(1)

40 CFR 63.1348(b)(1)(iii)(A)(4)

40 CFR 63.1349(b)(1)(ix) (needs a cross reference for clarity)

40 CFR 63.1349(b)(4)(iii), (b)(1)(vi), and (6)(iv) (incorrect terms in denominator)

40 CFR 63.1349(b), (b)(7)(ii), (b)(3)(iv), (b)(7(iii)(B), (v), (b)(7)(vii ) and (ix), (b)(8)(viii)

40 CFR 63.1350(a)(2), (i)(2), (i)(1), (k)(2)(iii), (k)(5)(iv), (n), and (n)(4)

40 CFR 63.1354(b)(9)

RESPONSE: The EPA agrees that these are typographical errors, and in the case of 40 CFR 63.1349(b)(1)(ix), 40 CFR 63.1349(d)( 1)(ii) and 40 CFR 63.1354(b)(9)(ix) agrees that a cross reference and more consistent language would make these sections more clear, and thus has corrected or revised
these in the final rule.

15. Monitoring during startup and shutdown (SS) periods

Commen ter 0861 supports the proposed edit to remove the obligation to collect and average monitoring data during SS, since accurate monitoring data could not be compiled during SS events according to the recent amendments

RESPONSE: The EPA appreciates the sup port for this proposed change.

16. THC compliance test interval of 30 months

The commenter supports the amendment to the testing interval for coal mill stacks and alkali bypasses adopting an interval of 30 months.

RESPONSE: The EPA appreciates the supp ort for this proposed change.

17. Exclusion of data generated during malfunctions (40 CFR 63.1348(b)(1)(iii)

Commenter 0861 requested clarification on the term “operating level” whereas did the EPA mean to reference the data used to determine if an operating limit is being met, and also requested clarification relative to should the data for any given hour be excluded if any of the underlying monitoring devices malfunction? For example, if the mercury CEMS m alfunctions, but the production level monitor operates properly, is it correct to exclude both the CEMS data for the hour(s) of malfunction and the associated production data for the same hours? Conversely, if the production monitor fails, but the mercury CEMS is still operating, is the commenter correct to assume that both the CEMS and production data during the production monitoring malfunction are excluded?

RESPONSE: The operating level is the levels of parametric monitoring at the time of the malfunc tion. You may not use the emissions occurring at the time of the malfunction and also the operating levels of
the time of malfunction.

The malfunction discussed in 63.1348(b)(1)(iii) is the malfunction of the source operations or control device operabil ity and not the malfunction of the monitoring devices themselves. No exclusion is intended of any data associated with malfunctions of production monitors, or malfunctions of CEMS.16

The source is still responsible for reporting collected data from unaffec ted monitors, including measured emissions, during CEMS or process monitoring malfunctions, since the actual equipment (i.e. kiln) is still operating.

18. Acceptance of Performance Specification 8 or 8a

Commenter 0861 supports the addition of PS 8 as an acceptable standard for a THC monitor.

RESPONSE: The EPA appreciates the support for this proposed change.

19. Out of date regulation under 40 CFR 63.1355(d)

Commenter 0861 stated that the rule contains an out of date requirement to keep annual records of the amount of cement kiln dust (CKD) removed from the system. This requirement is no longer valid since the new rule utilizes mercury controls and compliance demonstrations for meeting the new mercury limit, and thus the CKD records are not relevant.

RESPONSE: The EPA agrees that 40 CFR 63.1355(d) is no longer relevant since the final rule utilizes mercury controls and the CKD records are not needed when compliance entails the procedures required in 63.1350, and thus is removing this requirement from the final rule.

20. Mercury Testing Frequency (40 CFR 63.1350(k)(5)(iv)



### Commenter 0861 supports the EPA’s proposed clarification of the mercury emissions testing frequency for alkali bypasses to be the same for coal mills, and that the frequency is r educed if the result is below the method detection limit. The commenter states that EPA should clarify that when the stack concentration is below the MDL, the emissions from the stack should be reported as zero.

RESPONSE: All values below the MDL sho uld be reported at the MDL level, and not reported as zero. Through the upper prediction limit (UPL) process, the MDL was considered when the limit was developed, and including MDL values in reported emissions will therefore not create a compliance

concer n. Sources using Method 30B for mercury emissions measurements have access to lower MDL values than sources who choose to demonstrate compliance with Method 29.

21. Flow monitoring requirement (40 CFR 63.1350(n))

Commenter 0861 supports proposed l anguage which clarifies that flow monitoring is only required when using a CEMS.

RESPONSE: The EPA appreciates the support for this proposed change.

22. Limits for raw material dryers

Commenter 0861 states that limits for materials dryers (40 CFR 63.1343(b)(1) and 40 CFR 63.1346) THC/OHAP emission limits for material dryers during operation, and work practices per 63.1346(g) during start

- up and shutdown could be applied when an in

- line raw mill with an external heat source is operated as a material dryer independently from the kilns, and thus could utilize the kiln stack THC CEMS. The commenter requests that EPA provide specific guidance regarding rule applicability for this situation, a nd whether this infrequent operation should be considered negligible.17

RESPONSE: T he commenter describes a unique situation whereby the source is utilizing an inline raw mill that is not receiving kiln exhaust, but rather is heated by an external heat source. In this situation, the raw mill would then be considered a raw material dryer, with THC limits as shown in 63.1343(b)(1)
and 63.1346.

23. Clarification needed on Note to Paragraph (a) for Section 63.1348

Several commenters through telephone communications (as recorded in the final docket) have requested clarification on the Note for Paragraph (a) of Section 63.1348 relative to whether you must complete the performance test prior to or on the compliance date. Also the commenters seek
clarifi cation on the actual compliance date, since the general provisions under 63. 7 allows 180 days after the compliance date to show compliance.

RESPONSE: The source must perform and report Relative Accuracy Test Audits (RATA) for the CPMS or
CEMS within 180 days after the compliance date, since according to the General Provisions, 40 CFR 63.7, the source has 180 days to demonstrate compliance. The Note to paragraph (a) was to provide clarification that a source’s 30 day operating day performance test cou ld start the day after the effective date, so that the rolling averages would begin to be developed following the first monitoring day after the compliance date. It is expected that existing sources have procured their monitoring equipment and
done their RATA for each emission source and is confident that they are in compliance on the compliance date, or within the time alloted per the General Provisions 40 CFR 63.7, including sufficient time, post RATA, to demonstrate compliance with a 30 day rolling aver age emission limit.

24. Dioxin Testing Temperature Limit During Startup/Shutdown

One commenter as listed in the docket, requested clarification that the temperature limit as listed in Section 63.1343(a), footnote (2), still applies during startup/shu tdown situations.

RESPONSE: The temperature shown in footnote (2) to Table 1 under Section 63.1343(a) is a decision point and ultimately a parametric limit measured during the performance test, whereby if the average temperature at the first PM contro l device inlet during the performance test is 400 degrees F or less, the limit is 0.40 ng/dscm (TEQ), but if it is greater than 400 degrees F, the limit is 0.20 ng/dscm (TEQ). The source must then comply with the limit recorded during that performance tes t. Once the limits are set during the dioxin compliance test, they apply at all times, and thus, to assure compliance, the temperature operating limit is to be continually monitored during startup and shutdown.

25. Clarification that startup and shutdo wn is part of Section 63.1348(b)(1)(iii)

One commenter as listed in the docket, requested clarification on this section that requires a source to not use data recorded during monitoring system malfunctions or repairs associated with monitoring
system ma lfunctions in calculations used to report emissions or operating levels, and whether this applies to startup and shutdown events.18

RESPONSE: This section was intended for both startup and shutdown as well as malfunction events, and thus the term “startup and shutdown” has been added to this section in the final rule.

26. Clinker coolers and the PM CPMS procedure

One commenter, through a c ommunication via telephone (and placed in the final docket) asked clarification as to whether a clinker cooler, which is subject to a PM limit for new and existing sources under Section 63.1343(b), is required to employ the PM CPMS procedures for measuring PM emissions.

RESPONSE: A source with a clinker cooler is required to employ the PM CPMS performance testing requirements and compliance monitoring procedures, but this requirement was inadvertently omitted from both the final rule and the proposed r ule amendments. Thus, the final rule has been corrected at 63.1349(b)(1).



## Subpart F (New Source Performance Standard for Cement Kilns)

27. Rolling Average Definition

Commenter 0861 stated that the rolling average definition is not clear.

RESPONSE : EPA agrees with the commenter and has revised this definition to be the same as the
revised definition under 63.1341.

28. Opacity Limits for Clinker Coolers

Commenter 0861 stated that opacity monitoring should be dropped for any clinker cooler that has a PM CPMS, since the PM CPMS is better suited for monitoring the PM. The commenter further states that the opacity provision was dropped under section 40CFR 60.62(a)(2) for this same reason.

RESPONSE: The EPA agrees with the commenter for the reasons s tated and has removed this provision
from the final rule.

29. Compliance date for revised monitoring and recordkeeping (40 CFR 60.62(e))

Commenter 0861 states that in the revised rule, EPA is clarifying that all of the new monitoring and recordkeeping provisions in the NSPS will apply to units triggering NSPS before 2008, and that they will apply on the effective date of the NESHAP through a cross reference to 40 CFR 63.1351(c). The commenter interprets that in doing this, EPA is indicating that units triggering NSPS before the latest changes are now subject to the newer monitoring and recordkeeping. The commenter states that this is
not ap propriate, and that the new provisions should only apply to kilns subject to the new emissions limits. The commenter further states that kilns subject to the old NSPS limits should remain subject to all of the previous requirements, including those for mo nitoring and recordkeeping that existed at the time NSPS became an applicable requirement. The commenter believes that it is not appropriate to change the applicable NSPS requirements at a later date, and the commenter asks that the prior monitoring and re cordkeeping provisions be reinstated and made applicable to the kilns that triggered NSPS under the old limits. The commenter also stated that if EPA does not make this correction, the new provisions should not apply until the 2015 NESHAP compliance date.19

RESPONSE : The EPA disagrees with the appropriateness of revising monitoring and recordkeeping as outlined by the commenter. Though it may not be appropriate to apply new emissions limits to kilns built before 2008 due to those kilns being designed to me et only the limits at the time, it is appropriate to apply monitoring and recordkeeping requirements to NSPS kilns prior to 2008. These requirements are independent of the emission limits: they do not affect the kiln design. In addition, EPA applied

revi sed monitoring and recordkeeping requirements in the 1988 NSPS review and thus had set a precedent for this practice. Also note there is no cost involved because NSPS sources have to meet the revised NESHAP monitoring and recordkeeping requirements, and th us there is no additional burden.

The EPA also disagrees with allowing the new provisions to not apply to NSPS sources that commence construction after June 16, 2008 until the 2015 NESHAP compliance date (September 9, 2015), since monitoring and recordkee ping requirements are in effect for NSPS sources at the date of final promulgation, which in this case was November 8, 2010.

30. Various technical clarifications and typographical corrections

Commenter 0861 noted the following technical clarifications and typographical corrections needed:

40 CFR 60.63(c) (Addition of the term “digital signal” is needed, as it was in other sections)

40 CFR 60.63(c)(1) (Cross references for clinker cooler limit should be added)

40 CFR 60.63(c)(7) (The term high load ca pacity removed in some sections and not others).

RESPONSE: The EPA agrees that these are typographical errors, and thus they will be revised in the final
rule.