$91M
                                  Annual Cost
Ductwork
                                                                          $315K
                                                                          $426K
ACI
                                                                          $6.7M
                                                                          $1.6M
WAS
                                                                           $32M
                                                                          $7.7M
RTO
                                                                           $57M
                                                                           $13M
Total Annual Cost
                                                                           $95M
                                                                           $22M
        Uncontrolled Emissions (ton/yr, unless otherwise indicated)[2]
Mercury (lbs/yr)
                                                                             60
                                                                            160
Nonmercury metal HAP
                                                                            1.5
                                                                            4.0
Acid Gases
                                                                            360
                                                                            956
PAH
                                                                         0.0034
                                                                         0.0091
Formaldehyde
                                                                           0.28
                                                                           0.74
          Emission Reductions (ton/yr, unless otherwise indicated)[2]
Mercury w/ ACI (lb/yr)
                                                                             57
                                                                            152
Nonmercury Metal HAP w/ WAS
                                                                            1.4
                                                                            3.8
Acid Gases w/ WAS
                                                                            359
                                                                            955
PAH w/ RTO
                                                                         0.0034
                                                                         0.0089
Formaldehyde w/ RTO
                                                                           0.27
                                                                           0.72
      Pollutant Cost Effectiveness ($/ton, unless otherwise indicated)[1]
Mercury w/ ACI ($/lb)
                                                                          $117K
                                                                           $11K
Nonmercury Metal HAP w/ WAS
                                                                           $22M
                                                                          $2.0M
Acid Gases w/ WAS
                                                                           $88K
                                                                          $8.1K
PAH w/ RTO
                                                                           $17B
                                                                          $1.4B
Formaldehyde w/ RTO
                                                                          $209M
                                                                           $18M
[1] Acid gases = HCl and HF; activated carbon injection = ACI. RTO = regenerative thermal oxidizer; WAS = wet alkaline scrubber
[2].The COE from bypass/waste heat stacks are broken down into the individual HAP that are able to be tested with EPA test methods. Once the COE pass through control devices, the emissions are no longer considered COE.

TABLE 6. ESTIMATED COSTS OF CONTROLS AND EMISSION REDUCTIONS FOR POTENTIAL BTF MACT STANDARDS FOR HNR COKE FACILITIES FOR TWO HAP: MERCURY AND NONMERCURY METALS UNDER BTF APPROACH 2.[1]
                                   Cost Item
                                HNR Facilities
                                  with HRSGs
                            (includes 4 facilities)
                                HNR Facilities
                    without HRSGs (includes one facility)
                                 Capital Cost
Ductwork
                                                                        $1,249K
                                                                          $540K
ACI
                                                                        $1,299K
                                                                          $314K
BH
                                                                           $30M
                                                                          $6.6M
Total Capital Cost
                                                                           $33M
                                                                          $7.5M
                                  Annual Cost
Ductwork
                                                                          $315K
                                                                          $426K
ACI
                                                                          $6.7M
                                                                          $1.6M
BH
                                                                          $5.7M
                                                                          $2.6M
Total Annual Cost
                                                                           $13M
                                                                          $4.7M
        Uncontrolled Emissions (ton/yr, unless otherwise indicated)[2]
Mercury (lbs/yr)
                                                                             60
                                                                            160
Nonmercury Metal HAP
                                                                          1.518
                                                                          4.035
          Emission Reductions (ton/yr, unless otherwise indicated)[2]
Mercury w/ ACI (lb/yr)
                                                                             54
                                                                            144
Nonmercury Metal HAP w/ BH
                                                                          1.517
                                                                          4.031
      Pollutant Cost Effectiveness ($/ton, unless otherwise indicated)[2]
Mercury w/ ACI ($/lb)
                                                                          $123K
                                                                           $11K
Nonmercury Metal HAP w/ BH+ductwork
                                                                          $4.0M
                                                                          $756K
[1] Activated carbon injection = ACI; baghouse = BH.
[2] The COE from bypass/waste heat stacks are broken down into the individual HAP that are able to be tested with EPA test methods. Once the COE pass through control devices, the emissions are no longer considered COE.

      Based on consideration of the estimated capital costs, annualized costs, reductions and cost effectiveness of the two approaches described above, we are proposing BTF emissions limits for the individual COE HAP, as nonmercury metals and mercury, consistent with BTF Approach 2 for the subcategory that includes HNR facilities without HRSGs, which includes one facility (Vansant). We are proposing this option because we estimate that BTF Approach 2 achieves similar reductions of mercury and nonmercury metals as compared to BTF Approach 1 but achieves those reductions more cost effectively. We conclude that both approaches are cost-effective for mercury. Regarding nonmercury metals, BTF Approach 2 is clearly cost-effective based on historical decisions regarding nonmercury HAP metals (for example, the EPA accepted cost effectiveness of $1.3 million per ton HAP metals in the 2012 Secondary Lead Smelters RTR final rule based on 2009 dollars). BTF approach 1 could also potentially be considered cost-effective for nonmercury metals. However, we conclude it is appropriate to propose the more cost-effective approach because it achieves similar reductions of the COE HAP metals at lower cost. With regard to the other three COE HAP from HNR without a HRSG subcategory (acid gases, formaldehyde and PAHs), based on consideration of capital costs, annual costs and cost effectiveness, we are proposing MACT floor limits (not BTF limits).
      For the nonrecovery facility without HRSGs subcategory, the potential BTF limits for COE HAP emitted as nonmercury HAP metals and mercury were calculated by assuming the addition of a baghouse (with estimated 99.9 percent reduction for metals) and ACI (with 90 percent reduction for mercury). We then compared the limits to the applicable 3xRDL value to ensure a measurable standard. For HAP metals, the 3xRDL value was greater than the BTF limit, and thus the proposed BTF standard was set at the 3xRDL value (a measurable value), which is 2 percent of the level of the MACT floor standard. For mercury, the 3xRDL value was less than the BTF UPL limit, and thus the proposed BTF standard was set at the BTF UPL limit. The results and proposed decisions based on the analyses performed pursuant to CAA sections 112(d)(2) and (3) for HNR bypass/waste heats stacks are presented in Table 7.
TABLE 7. MACT AND BTF STANDARDS DEVELOPED FOR EMISSIONS FROM COKE OVENS HNR HRSG BYPASS/WASTE HEAT STACKS SOURCES[27]
                               Source or Process
                                   Pollutant
                           Type of MACT Standard[1]

                                   Existing
                                      New
HNR bypass/ waste heat stack for 2 subcategories (for all 5 HNR facilities)
acid gases
0.13 gr/dscf [UPL]
0.070 gr/dscf [UPL]

formaldehyde
0.0011 gr/dscf
1.9E-05 gr/dscf

PAH
2.4E-06 gr/dscf [UPL]
2.4E-06 gr/dscf [UPL]
Heat recovery facilities (only) bypass/waste heat stack (with HRSGs) subcategory
Mercury
1.7E-05 gr/dscf [UPL]
7.8E-06 gr/dscf [UPL]

PM[28]
0.034 gr/dscf [UPL]
0.025 gr/dscf [UPL]
Nonrecovery facilities (only) waste heat stack (without HRSGs) (BTF) subcategory
Mercury
BTF 1.7E-06 gr/dscf [UPL]
BTF 7.8E-07 gr/dscf [UPL]

PM[28]
BTF 6.6E-04 gr/dscf [3xRDL]
BTF 6.6E-04 gr/dscf [3xRDL]
[1] gr/dscf = grains per dry standard cubic feet. RDL = representative detection level. UPL is the upper performance limit. PM is a surrogate for nonmercury metal HAP.
[2] Once the bypass/waste heat stacks COE pass through control devices, the emissions are no longer considered COE.

      We are proposing that testing for compliance with these proposed MACT and BTF limits be performed every 5 years. Annualized costs for testing, including recordkeeping and reporting, are estimated to be $3.2 million/year for the 11 operating facilities in the source category, or an average of $290,000 per year per facility.
      We are soliciting comments regarding other potential approaches to establish emissions standards for the HRSG main stacks and bypass stacks, including: (1) whether the EPA should consider the emission points all together (i.e., HRSG main stack plus HRSG bypass stack emissions) and establish standards based on the best five units or best five facilities including emissions from the HRSGs and their control devices, and emissions from the bypass over a period of time (e.g., per year or per month); or (2) a standard that is based in part on limiting the number of hours per year or per month that bypass stacks can be used.
      We are also soliciting comments regarding the use of bypass stacks. For the Coke Ovens: Pushing, Quenching, Battery Stacks source category, we understand that bypass of HRSGs is needed for maintenance and repair of HRSGs or their control devices. Furthermore, the facilities recover heat from coke oven exhaust and sell or produce power for sale, so they lose revenue when bypass is used; therefore, it is in the facilities' interest to not bypass HRSGs. For this source category's HNR subcategory, we have emissions tests data and, therefore, are able to propose numeric emissions limits for these emissions sources. We solicit comments regarding whether the EPA should consider other approaches to regulate bypass stacks.
      For details of how these MACT and BTF standards were developed and other BTF options that were considered see the MACT/BTF memorandum,[27] located in the docket for the proposed rule (EPA-HQ-OAR-2002-0085).
B. What are the results of the risk assessment and analyses for the Coke Ovens: Pushing, Quenching, and Battery Stacks source category?
1. Chronic Inhalation Risk Assessment Results
      The results of the chronic baseline inhalation cancer risk assessment indicate that, based on estimates of current actual emissions, the MIR posed by the Coke Ovens: Pushing, Quenching, and Battery Stacks source category is 9-in-1 million driven by arsenic emissions primarily from bypass/waste heat stacks. The total estimated cancer incidence based on actual emission levels is 0.02 excess cancer cases per year, or 1 case every 50 years. No people are estimated to have inhalation cancer risks above 100-in-1 million due to actual emissions, and the population exposed to cancer risks greater than or equal to 1-in-1 million is approximately 2,900 (see Table 8 of this preamble). In addition, the maximum modeled chronic noncancer TOSHI for the source category based on actual emissions is estimated to be 0.1 (for developmental effects from arsenic emissions).
TABLE 8. COKE OVEN PUSHING, QUENCHING, AND BATTERY STACKS SOURCE CATEGORY INHALATION RISK ASSESSMENT RESULTS
                                Risk Assessment
                             Number of Facilities
               Maximum Individual Cancer Risk (in 1 million)[1]
      Estimated Population at Increased Risk of Cancer >= 1-in-1 Million
                       Estimated Annual Cancer Incidence
                               (cases per year)
                        Maximum Chronic Noncancer TOSHI
                    Maximum Screening Acute Noncancer HQ[3]
                        Based on Actual Emissions Level
Source Category Emissions
                                      14
                                       9
                                     2,900
                                     0.02
                                      0.1
                                   (arsenic)
                             HQREL = 0.6 (arsenic)
Facility-Wide[2]
                                      14
                                      50
                                  2.7 million
                                      0.2
                                       2
                              (hydrogen cyanide)
                             HQREL = 0.6 (arsenic)
                      Based on Allowable Emissions Level
Source Category Emissions
                                      14
                                      10
                                    440,000
                                     0.05
                                      0.2
                                   (arsenic)
                                      --
1 Maximum individual excess lifetime cancer risk due to HAP emission.
 See "Facility-Wide Risk Results" in section III.C.6 of this preamble for more detail on this risk assessment.

Considering MACT-allowable emissions, results of the inhalation risk assessment indicate that the cancer MIR is 10-in-1 million, driven by arsenic emissions primarily from HNR pushing and bypass/waste heat stacks. The total estimated cancer incidence from this source category based on allowable emissions is 0.05 excess cancer cases per year, or one excess case every 20 years. No people are estimated to have inhalation cancer risks above 100-in-1 million due to allowable emissions, and the population exposed to cancer risks greater than or equal to 1-in-1 million is approximately 440,000. In addition, the maximum modeled chronic noncancer TOSHI for the source category based on allowable emissions is estimated to be 0.2 (for developmental effects from arsenic emissions).
2. Screening Level Acute Risk Assessment Results
As presented in Table 8 of this preamble, the estimated worst-case off-site acute exposures to emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category result in a maximum modeled acute HQ of 0.6 based on the REL for arsenic. Detailed information about the assessment is provided in Residual Risk Assessment for the Coke Ovens: Pushing, Quenching, and Battery Stacks Source Category in Support of the 2023 Risk and Technology Review Proposed Rule available in the docket for this action.
3. Multipathway Risk Screening Results
      Of the 14 facilities in the source category, all 14 emit PB-HAP, including arsenic, cadmium, dioxins, mercury, and POMs. Emissions of these PB-HAP from each facility were compared to the respective pollutant-specific Tier 1 screening emission thresholds. The Tier 1 screening analysis indicated 14 facilities exceeded the Tier 1 emission threshold for arsenic, dioxins, mercury, and POM; and two facilities exceeded for cadmium.
      For facilities that exceeded the Tier 1 multipathway screening threshold emission rate for one or more PB-HAP, we used additional facility site-specific information to perform a Tier 2 multipathway risk screening assessment. The multipathway risk screening assessment based on the Tier 2 gardener scenario resulted in a maximum cancer Tier 2 cancer screening value (SV) equal to 400 driven by arsenic emissions. Individual Tier 2 cancer screening values for dioxin and POM emissions were less than 1 for the gardener scenario. The maximum Tier 2 cancer SV, based on the fisher scenario, is equal to 10, with arsenic and dioxin emissions contributing to the SV, with a maximum individual Tier 2 SV of 10 for arsenic and a maximum Tier 2 SV of 5 for dioxin emissions. The maximum POM SV was less than 1. The multipathway risk screening assessment based on the Tier 2 fisher scenario resulted in a maximum noncancer Tier 2 SV equal to 6 for methyl mercury and less than 1 for cadmium emissions.
      A Tier 3 cancer screening assessment was performed for arsenic based on the gardener scenario as well as a Tier 3 noncancer screening assessment for methyl mercury based on the fisher scenario. The Tier 3 gardener scenario was refined by identifying the location of the residence most impacted by arsenic emissions from the facility as opposed to the worst-case near-field location used in the Tier 2 assessment. Based on these Tier 3 refinements to the gardener scenario, the maximum Tier 3 cancer screening value for arsenic was adjusted from 400 to 300. For the fisher scenario, we evaluated the Tier 2 noncancer SV for methyl mercury, to determine whether the results would change based on a review of the lakes, to determine if they were fishable. This review resulted in no change to the Tier 2 noncancer SV of 6 for methyl mercury.
      An exceedance of a screening threshold emission rate or SV in any of the tiers cannot be equated with a risk value or an HQ (or HI). Rather, it represents a high-end estimate of what the risk or hazard may be. For example, an SV of 6 for a noncarcinogen can be interpreted to mean that the Agency is confident that the HQ would be lower than 6. Similarly, a Tier 2 cancer SV of 300 means that we are confident that the cancer risk is lower than 300-in-1 million. Our confidence comes from the conservative, or health-protective, assumptions encompassed in the screening tiers. The Agency chooses inputs from the upper end of the range of possible values for the influential parameters used in the screening tiers, and the Agency assumes that the exposed individual exhibits ingestion behavior that would lead to a high total exposure.
      The EPA determined that it is not necessary to go beyond the Tier 3 gardener or Tier 2 fisher scenario and conduct a site-specific assessment for arsenic and mercury. The EPA compared the Tier 2 and 3 screening results to site-specific risk estimates for five previously assessed source categories. These are the five source categories, assessed over the past 4 years, which had characteristics that make them most useful for interpreting the Coke Ovens: Pushing, Quenching, and Battery Stacks screening results. For these source categories, the EPA assessed fisher and/or gardener risks for arsenic, cadmium, and/or mercury by conducting site-specific assessments. The EPA used AERMOD for air dispersion and Tier 2 screens that used multi-facility aggregation of chemical loading to lakes where appropriate. These assessments indicated that cancer and noncancer site-specific risk values were at least 50 times lower than the respective Tier 2 screening values for the assessed facilities, with the exception of noncancer risks for cadmium for the gardener scenario, where the reduction was at least 10 times (refer to EPA Docket ID: EPA-HQ-OAR-2017-0015 and EPA-HQ-OAR-2019-0373 for a copy of these reports).
      Based on our review of these analyses, if the Agency was to perform a site-specific assessment for the Coke Ovens: Pushing, Quenching, and Battery Stacks source category, the Agency would expect similar magnitudes of decreases from the Tier 2 and 3 SV. As such, based on the conservative nature of the screens and the level of additional refinements that would go into a site-specific multipathway assessment, were one to be conducted, we are confident that the HQ for ingestion exposure, specifically mercury through fish ingestion, is less than 1. For arsenic, maximum cancer risk posed by fish ingestion would also be reduced to levels below 1-in-1 million, and maximum cancer risk under the rural gardener scenario would decrease to 5-in-1 million or less at the MIR location. Further details on the Tier 3 screening assessment can be found in the Residual Risk Assessment for the Coke Ovens: Pushing, Quenching, and Battery Stacks, Source Category in Support of the 2023 Risk and Technology Review Proposed Rule.
In evaluating the potential for multipathway risk from emissions of lead, we compared modeled annual lead concentrations to the primary NAAQS for lead (0.15 microgram per cubic meter (ug/m[3])). The highest annual lead concentration of 0.014 ug/m[3] is well below the NAAQS for lead, indicating low potential for multipathway risk of concern due to lead emissions.
4. Environmental Risk Screening Results
As described in section III.A of this preamble, we conducted an environmental risk screening assessment for the Coke Ovens: Pushing, Quenching, and Battery Stacks source category for the following pollutants: arsenic, cadmium, dioxin, HCl, HF, lead, mercury (methyl mercury and divalent mercury), and POMs.
      In the Tier 1 screening analysis for PB-HAP (other than lead, which was evaluated differently), the maximum screening value was 80 for methyl mercury emissions for the surface soil No Observed Adverse Effects Level (NOAEL) avian ground insectivores benchmark. The other pollutants (arsenic, cadmium, dioxins, POMs, divalent mercury, methyl mercury) had Tier 1 screening values above various benchmarks. Therefore, a Tier 2 screening assessment was performed for arsenic, cadmium, dioxins, POMs, divalent mercury, and methyl mercury emissions. In the Tier 2 screen no PB-HAP emissions exceeded any ecological benchmark.
In evaluating the potential for multipathway risk from emissions of lead, we compared modeled annual lead concentrations to the primary NAAQS for lead (0.15 ug/m3). The highest annual lead concentration is well below the NAAQS for lead, indicating low potential for multipathway risk of concern due to lead emissions. We did not estimate any exceedances of the secondary lead NAAQS.
      For HCl and HF, the average modeled concentration around each facility (i.e., the average concentration of all off-site data points in the modeling domain) did not exceed any ecological benchmark. In addition, each individual modeled concentration of HCl and HF (i.e., each off-site data point in the modeling domain) was below the ecological benchmarks for all facilities.
      Based on the results of the environmental risk screening analysis, we do not expect an adverse environmental effect as a result of HAP emissions from this source category.
5. Facility-Wide Risk Results
An assessment of facility-wide (or "whole facility") risks was performed as described above to characterize the source category risk in the context of whole facility risks. Whole facility risks were estimated using the data described in section III.C of this preamble. The maximum lifetime individual cancer risk posed by the 14 modeled facilities, based on whole facility emissions is 50-in-1 million, with COE from coke oven doors (a regulated source in the Coke Oven Batteries NESHAP source category), driving the whole facility risk. The total estimated cancer incidence based on facility-wide emission levels is 0.2 excess cancer cases per year. No people are estimated to have inhalation cancer risks above 100 - in-1 million due to facility-wide emissions, and the population exposed to cancer risk greater than or equal to 1-in-1 million is approximately 2.7 million people. These facility-wide estimated cancer risks are substantially lower than the estimated risks in the 2005 Coke Ovens RTR rulemaking (see 70 FR 1992, April 15, 2005). For example, the facility-wide MIR in the 2005 final rule (based on estimated actual emissions) was at least 500-in-1 million. The facility-wide MIRs in 2005 also were driven by estimated COE from coke oven doors. The estimated cancer risks are lower in this current action largely due to the following: (1) the COE from coke oven doors in 2005 were based on an older equation and the current COE have been estimated using a revised equation (as described in section IV.D.6 of this preamble); and (2) the facility driving the risks in 2005 was a MACT track facility that is no longer operating.
Regarding the noncancer risk assessment, the maximum chronic noncancer HI posed by whole facility emissions is estimated to be 2 (for the neurological and thyroid systems as the target organs) driven by emissions of hydrogen cyanide from CBRPs, which are emissions sources not included within the source category addressed in the risk assessment in this proposed rule. Approximately 60 people are estimated to be exposed to a TOSHI greater than 1 due to whole facility emissions. The results of the analysis are summarized in Table 8 above.
6. Community-based Risk Assessment
      We also conducted a community-based risk assessment for the Coke Ovens: Pushing, Quenching, and Battery Stacks source category. The goal of this assessment is to estimate cancer risk from HAP emitted from all local stationary point sources for which we have emissions data. We estimated the overall inhalation cancer risk due to emissions from all stationary point sources impacting census blocks within 10 km of the 14 coke oven facilities. Specifically, we combined the modeled impacts from category and non-category HAP sources at coke oven facilities, as well as other stationary point source HAP emissions. Within 10 km of coke oven facilities, we identified 583 facilities not in the source category that could potentially also contribute to HAP inhalation exposures.
      The results indicate that the community-level maximum individual cancer risk is 100-in-1 million with 99 percent of the risk coming from a source outside the source category. Furthermore, there are no people exposed to cancer risks greater than 100-in-1 million. The population exposed to cancer risks greater than or equal to 1-in-1 million in the community-based assessment is approximately 1.1 million people. For comparison, approximately 2,900 people have cancer risks greater than or equal to 1-in-1 million due to the process emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category, and approximately 440,000 people have cancer risks greater than 1-in-1 million due to facility-wide emissions (see Table 8 of this preamble). The overall cancer incidence for this exposed population (i.e., people with risks greater than or equal to 1-in-1 million and living within 10 km of coke oven facilities) is 0.07, with 4 percent of the incidence due to emissions from Coke Ovens: Pushing, Quenching, and Battery Stacks NESHAP processes, 59 percent from emissions of non-category processes at coke oven facilities (that is, a total of 63 percent from emissions from coke oven facilities) and 37 percent from emissions from other nearby stationary sources that are not coke oven facilities.
C. What are our proposed decisions regarding risk acceptability, ample margin of safety, and adverse environmental effect?
1. Risk Acceptability
      As noted in section III.A of this preamble, we weigh a wide range of health risk measures and factors in our risk acceptability determination, including the cancer MIR, the number of persons in various cancer and noncancer risk ranges, cancer incidence, the maximum noncancer TOSHI, the maximum acute noncancer HQ, and risk estimation uncertainties (54 FR 38044, September 14, 1989).
      Under the current MACT standards for the Coke Ovens: Pushing, Quenching, and Battery Stacks source category, the risk results indicate that the MIR is 9-in-1 million, driven by emissions of arsenic. The estimated incidence of cancer due to inhalation exposures is 0.02 excess cancer case per year. No people are estimated to have inhalation cancer risks greater than 100-in-1 million, and the population estimated to be exposed to cancer risks greater than or equal to 1-in-1 million is approximately 2,900. The estimated maximum chronic noncancer TOSHI from inhalation exposure for this source category is 0.1 for developmental effects. The acute risk screening assessment of reasonable worst-case inhalation impacts indicates a maximum acute HQ of 0.6.
      Considering all of the health risk information and factors discussed above, including the uncertainties discussed in section III of this preamble, the EPA proposes that the risks for this source category under the current NESHAP provisions are acceptable.
2. Ample Margin of Safety Analysis and Proposed Controls
      The second step in the residual risk decision framework is a determination of whether more stringent emission standards are required to provide an ample margin of safety to protect public health. In making this determination, we considered the health risk and other health information considered in our acceptability determination, along with additional factors not considered in the risk acceptability step, including costs and economic impacts of controls, technological feasibility, uncertainties, and other relevant factors, consistent with the approach of the 1989 Benzene NESHAP.
      The proposed BTF limit for PM, as a surrogate for nonmercury HAP metals, which we are proposing pursuant to CAA sections 112(d)(2) and (3) for HRSG waste heat stacks in the Coke Ovens: Pushing, Quenching, and Battery Stack source category, described in section IV.A above, would achieve a reduction of the metal HAP emissions (e.g., arsenic and lead). This reduction in emissions also would reduce the estimated MIR due to arsenic from these units from 9-in-1 million to less than 1-in-1 million at a cost of $756,000 per ton nonmercury metals. The overall MIR for this source category would be reduced from a 9-in-1 million to 2-in-1 million, where the 2-in-1 million is due to arsenic emissions from the quench tower at U.S. Steel Clairton. We evaluated the potential to propose this same PM emission limit for the HNR waste heat stacks under CAA section 112(f); however, because the control technology would be infeasible to install, operate and implement within the maximum time allowed under CAA section 112(f), we are proposing the emission limit as a BTF standard under CAA sections 112(d)(2) and (3) only.
       We did not identify any other potential cost-effective controls to reduce the remaining risk (2-in-1 million) from quench towers (or from any other emission source). Therefore, based on all of the information discussed earlier in this section, we conclude that the current standards in the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP provide an ample margin of safety to protect public health.
      Although we are not proposing the BTF PM limit for waste stacks as part of our ample margin of safety analysis, as described earlier in this section, we note that once the proposed rule for Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP is fully implemented (within 3 years), the MIR would be reduced from 9-in-1 million to 2-in-1 million and the total population living within 50 km of a facility with risk levels greater than or equal to 1-in-1 million due to emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category would be reduced from 2,900 to 390 people due to the BTF PM limit. However, the total estimated cancer incidence would remain unchanged at 0.02 excess cancer cases per year, and the maximum modeled chronic noncancer TOSHI for the source category would remain unchanged at 0.1 (for respiratory effects from hydrochloric acid emissions). The estimated worst-case acute exposures to emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category would be reduced from a maximum acute HQ of 0.6 to 0.3, based on the REL for arsenic.
3. Adverse Environmental Effect
      Based on our screening assessment of environmental risk presented in section IV.B.4 of this preamble, we have determined that HAP emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category do not result in an adverse environmental effect, and we are proposing that it is not necessary to set a more stringent standard to prevent, taking into consideration costs, energy, safety, and other relevant factors, an adverse environmental effect.
D. What are the results and proposed decisions based on our technology review?
      We have reviewed the standards under the two rules, Coke Ovens: Pushing, Quenching, and Battery Stack and Coke Oven Batteries, and considered whether revising the standards is necessary based on developments in practices, processes, and control technologies. For the Coke Ovens: Pushing, Quenching, and Battery Stack source category, we did not identify developments in practices, processes, or technologies to further reduce HAP emissions from pushing coke from ovens and from quench tower sources in the source category. The pushing sources already are equipped with capture and control devices, and quench tower emissions are controlled by baffles inside of the quench towers and with limits on quench water dissolved solids. However, we are seeking information on emissions and on control options and work practice standards to reduce ByP battery stack emissions and to reduce soaking emissions from HNR ovens. These subjects are discussed in sections 1 and 2 below.
      For the Coke Oven Batteries source category, we did not identify any developments in practices, processes, or controls that would reduce charging emissions from ByP or HNR facilities regulated under the source category. The current rule requires the use of baghouses and scrubbers to minimize emissions from charging and to limit opacity from control devices used for charging emissions at HNR facilities. However, we identified improvements in control of ByP battery leaks, and we are proposing reduced allowable leak limits for leaks from doors, lids, and offtakes at ByP facilities. Also, we are asking for comments on the proposed revised monitoring techniques for leaks from HNR ovens. These proposed changes are discussed in sections 3 and 4 below. To address potential fugitive emissions at or beyond the fencelines of sources in the Coke Oven Batteries source category, in order to ensure that emissions remain at or below the levels required by the proposed leak standards and do not increase, we are proposing fenceline emission standards. This proposed standard is discussed in section 5 below.
      Lastly, we are proposing a revised equation for estimating leaks from ByP coke oven doors based on evaluating the historic equation developed from 1981 coke oven data. The discussion of this issue is in section 6 below.
1. ByP Battery Stack 1-hour Standards
      We acquired 1-hour battery stack opacity data as part of the 2022 CAA section 114 test request and also obtained information about work practices that are performed on ovens to maintain oven integrity which minimizes battery stack opacity, in general. We are considering whether an additional 1-hour battery stack standard is warranted to support the current 24-hour ByP battery stack standard in Coke Ovens: Pushing, Quenching, and Battery Stacks NESHAP. We are not proposing a 1-hour limit in this proposed action because of the processing of large quantities of data that would be needed to develop a 1-hour emissions limit for all coke facilities and also to analyze oven wall work practices reported by coke facilities in the CAA section 114 request responses to see if there is a correlation with the lower opacities in the 1-hour time data Therefore, we are soliciting comment and information regarding these issues, including comments regarding whether or not the EPA should include such a standard in the NESHAP in the final rule and an explanation as to why or why not; and what work practices would reduce high opacity on an hourly basis. The 1-hour opacity and work practice data collected as part of the 2022 CAA section 114 request are summarized in a memorandum titled Preliminary Analysis and Recommendations for Coke Oven Combustion Stacks, Technology Review for NESHAP for Coke Ovens: Pushing, Quenching, and Battery Stacks (40 CFR part 63, subpart CCCCC) that graphically shows the 1-hour data, located in the docket to this rule.
2. Soaking Emissions from ByP Coke Ovens
      The Coke Ovens: Pushing, Quenching, and Battery Stacks NESHAP regulates soaking COE from coke ovens via work practice standards. Under40 CFR 63.7294, coke oven facilities must prepare and operate according to a written work practice plan for soaking emissions. The plan must include measures and procedures to identify soaking COE that require corrective actions, such as procedure for dampering off ovens; determining why soaking COE emissions do not ignite automatically and, if not, then to manually do so; determining whether COE which are not fully processed in the ovens are leaking into the collecting main and if there is incomplete coking; and determining whether the oven damper needs to be reseated or other equipment needs to be cleaned.
      Soaking, for the purposes of the NESHAP, means the period in the coking cycle that starts when an oven is dampered off the collecting main and vented to the atmosphere through an open standpipe prior to pushing, and ends when the coke begins to be pushed from the oven. Visible soaking COE occur from the discharge of COE via open standpipes during the soaking period due to either incomplete coking or leakage into the standpipe from the collecting main.
      We are asking for comments on the feasibility of capturing and controlling soaking COE. Soaking COE are most pronounced with "green" coke, i.e., coke that has not completed the coking process. Work practice standards for soaking, covered in 40 CFR 63.7294, do not include opacity limits or control device requirements and rely on subjective observations from facility personnel. Furthermore, operational practices may prevent topside workers from seeing soaking COE, which is a prerequisite for the current soaking work practice standards to apply. Currently, EPA Method 303A observations do not consider soaking COE because intentional standpipe cap opening during pushing is not considered a leak from the oven and, therefore, is not included in the visible emissions observation field for oven testing.
      We are asking for estimates of COE from soaking to better understand the scope and scale of these emissions. In addition, we are asking for comments on options for capturing and controlling the soaking COE using a secondary collecting main that routes standpipe COE exhaust to a control device with or without an associated VE, opacity, or emissions limit. We are not proposing controls or an opacity limit in this current action; however, we solicit comment and information regarding soaking COE, including comments as to whether or not the EPA should include such a standard in the NESHAP in the final rule and an explanation as to why or why not. We also solicit comments on changes to the soaking work practice requirements currently in the rule.
3. ByP Door, Lids, and Offtakes Leak Limits
      Due to improvements in leak control at coke oven facilities, we are proposing to lower the door leak limits in the NESHAP under the technology review for the Coke Oven Batteries source category for both MACT track and LAER track ByP coke facilities. We are proposing for facilities with coke production capacity of more than 3 million tpy coke to lower the allowable leaking door limit from the current limit of 4 percent to 1.5 percent for tall leaking doors and from 3.3 percent to 1.0 percent for "not tall" leaking doors observed from the yard. These proposed standards would currently only apply to the U.S. Steel Clairton facility. For Coke Oven Batteries facilities that have coke production capacity less than 3 million tpy coke, we are proposing an allowable leaking door limit of 3.0 percent leaking doors observed from the yard for all sizes of doors (currently the NESHAP includes limits of 4.0 and 3.3 percent allowable leaking doors for tall and not tall doors, respectively, as described earlier in this preamble). Both proposed changes to the allowable limits would ensure continued low emissions from leaking doors. These reduced levels reflect improvements in performance of the facilities to minimize leaks from doors.
      Due to improvements in operation by the coke facilities, where actual emissions are much lower than allowable limits in many cases, we also are proposing to lower the lid and offtake leak allowable limits in the NESHAP under the technology review for the Coke Oven Batteries source category. The current NESHAP includes limits of 0.4 percent leaking lids and 2.5 percent leaking offtakes. We are proposing a revised leaking lid limit of 0.2 percent leaking lids and for offtakes a limit of 1.2 percent leaking offtakes. Both proposed changes to the limits would ensure continued low emissions from leaking lids and offtakes. These reduced levels reflect improvements in performance of the facilities to minimize leaks from lids and offtakes.
      Table 9 shows the estimated allowable emissions (tpy) before and after lowering the leak limits from doors, lids, and offtakes for each of eight ByP facilities.
TABLE 9. ESTIMATED ALLOWABLE EMISSIONS BEFORE AND AFTER PROPOSED CHANGES TO THE LIMITS FOR LEAKING DOORS, LIDS, AND OFFTAKES AT BYPRODUCT COKE OVEN FACILITIES (COKE OVEN BATTERIES NESHAP)
                                  Facility ID
                           Allowable Emissions (tpy)

                           With Current Leak Limits
                           With Proposed Leak Limits

                                 Doors[a][,b]
                                     Lids
                                   Offtakes
                                     Total
                                   Doors[c]
                                     Lids
                                   Offtakes
                                     Total
ABC-Tarrant-AL
3.4
0.076
0.11
3.6
3.0
0.038
0.052
3.1
BLU-Birmingham-AL
3.1
0.079
0.099
3.3
2.7
0.039
0.047
2.8
CC-Follansbee-WV
5.5
0.12
0.25
5.9
5.1
0.059
0.12
5.2
CC-Middletown-OH
1.8
0.030
0.12
2.0
1.7
0.015
0.060
1.8
CC-BurnsHarbor-IN
4.3
0.086
0.13
4.5
3.7
0.043
0.065
3.8
CC-Monessen-PA
1.3
0.029
0.092
1.4
1.3
0.015
0.044
1.3
CC-Warren-OH
2.0
0.034
0.14
2.2
1.9
0.017
0.067
2.0
EES-RiverRouge-MI
2.2
0.045
0.14
2.4
1.9
0.022
0.067
2.0
USS-Clairton-PA
17
0.38
1.1
19
11
0.19
0.53
12
Total
41
0.88
2.2
44
33
0.44
1.0
34
[a] Door emissions are calculated using the revised equation. See section IV.D.6 of this preamble.
[b] For doors, two limits apply in the current rule: 4 percent leaking doors for tall ovens (equal to or greater than 6 meters or 29 feet) and 3.3 percent leaking doors for all other shorter ovens (less than 6 meters). c For facilities with coke production capacity more than 3 million tpy coke, proposed limits from doors are 1.5 percent leaking doors for tall ovens and 1.0 percent leaking doors for all other shorter ovens; for facilities with coke production capacity less than 3 million tpy coke, proposed limits from doors is 3.0 percent leaking doors for all doors sizes.

      We are asking for comment on whether there are other methods available to reduce leaks from doors, lids, and offtakes, and from charging at coke oven batteries that are not discussed here. Additional information on the available methods is included in the memorandum Technology Review for the Coke Ovens: Pushing, Quenching, and Battery Stack and Coke Oven Batteries Source Categories (hereafter referred to as the Technology Review Memorandum), located in the dockets for the rules.
4. HNR Oven Door Leaks
HNR Leak-related Monitoring

      We are revising the Coke Oven Batteries NESHAP for new and existing HNR doors (40 CFR 63.303(a)(1) and (b)(1)) to require both monitoring of leaking doors at HNR facilities using EPA Method 303A, which relies on observing VE emanating from the ovens, and monitoring pressure in the ovens (and common tunnel), instead of choosing one or the other, as the current rule allows. We also are adding the requirement to measure pressure in the ovens during the main points in the entire oven cycle to include, at minimum, during pushing, coking, and charging (but not necessarily continuously throughout the oven cycle). We are asking for comment on these changes.
Alternative Monitoring Approaches  -  HNR Oven Doors
      The current method of assessing HNR oven doors for leaks under the Coke Oven Battery NESHAP (40 CFR 63.303(b)) is through the use of EPA Method 303 or 303A, methods based on observing VE emanating from the ovens and seen with the unaided eye, excluding steam or condensing water, by trained human observers. While VE has been used as an effective surrogate for monitoring door leaks in the past, especially for ByP facilities, the EPA is soliciting comments on whether there are other surrogates or practices which could be applied to HNR door leaks. For those alternative techniques that could be applied to measuring door leaks, the EPA is soliciting information on equivalency studies that have been performed against Method 303 and/or 303A, and any potential training requirements and/or associated monitoring procedures for the alternative techniques.
Use of Pressure Transducers  -  HNR Ovens and Common Tunnels
      As discussed earlier in this preamble, monitoring pressure in the ovens and common tunnel to establish negative oven pressure and establish leaks of 0.0 for HNR doors currently is allowed as an alternate method to observing leaks with EPA Method 303A under 40 CFR 63.303(b). We are proposing to require both methods, EPA Method 303A and pressure monitoring, to establish negative pressure in the ovens and 0.0 leaks. The current practice at HNR facilities is to operate one pressure monitor per common tunnel that may connect to 15 to 20 ovens and is, therefore, not very sensitive to pressure loss at one oven. Despite leaking emissions in one oven, a common tunnel with one pressure transducer may still show negative pressure within the tunnel. Also, facilities often only have one pressure transducer per oven, which might not be sufficient to monitor and establish negative pressure. We are considering a requirement for HNR facilities to develop and submit a monitoring plan to their delegated authority to ensure that there are sufficient pressure monitors in the ovens and common tunnels to be able to determine that all ovens are operated under negative pressure. We are not proposing this requirement at this time, however we are soliciting comment on this potential requirement and whether the EPA should allow each facility to suggest a site-specific number of monitors needed as part of the monitoring plan that they submit to the delegated authority for review and approval or whether EPA should establish a prescriptive minimum number of pressure monitors for each of the ovens and common tunnels in the NESHAP.
5. Fenceline Monitoring
      We are proposing a fenceline monitoring work practice standard (for benzene, as a surrogate for COE) under the technology review for the Coke Oven Batteries source category. Fenceline monitoring refers to the placement of monitors along the perimeter of a facility to measure fugitive pollutant concentrations. The fenceline monitoring standard requires owners and operators to monitor for benzene, as a surrogate for COE, and conduct root cause analysis and corrective action upon exceeding an annual average concentration action level of benzene as a work practice standard. Details regarding the proposed requirements for fenceline monitoring, the action level, and root cause analysis and corrective action are discussed in this section.
      The EPA recognizes that, in many cases, it is impractical to directly measure emissions from fugitive emission sources at coke manufacturing facilities. Direct measurement of fugitive emissions can be costly and difficult. The EPA is concerned about the potential magnitude of emissions from fugitive sources and the difficulty in monitoring actual fugitive emission levels.
      To improve our understanding of fugitive emissions and to potentially address fugitive emissions sources at coke facilities, we required fenceline monitoring for benzene and several other HAP through the 2022 CAA section 114 request that is described in section II.C in this preamble. In the 2022 CAA section 114 requests, five selected facilities (four ByP facilities and 1 HNR facility) were required to perform sampling using EPA Methods 325A/B for benzene, toluene, ethylbenzene, xylenes, and 1,3 butadiene and Compendium Methods TO-13A and TO-15A for VOC and PAHs to determine the facility fugitive HAP concentrations at the fenceline and interior on-site facility grounds.
      At the fenceline, facilities were required to sample for thirteen 14-day sampling periods (24 hours per day) at monitoring locations determined by EPA Method 325A, for a combined total of 182 days of sampling with analysis by EPA Method 325B. Facilities were also required to collect seven 24-hour samples at each fenceline TO monitor location for a total of at least 21 samples (3x7) for TO-13A and at least 28 samples (4x7) of TO-15A. In addition to fenceline monitoring, facilities were required to sample fugitive emissions within the interior facility grounds using methods TO-13A and 15A. Facility interior samples were collected at one location at the HNR facility and two locations at the ByP facilities for seven 24-hour periods at each location resulting in a total of 7 TO-13A and TO-15A samples at the HNR facility and 14 (2 times 7) TO-13A and TO-15A samples at each ByP facility.
      The requirements and decisions that we are proposing in this action are informed by the fenceline monitoring results reported by facilities in response to the 2022 Coke Ovens CAA section 114 request, consideration of dispersion modeling results, and consideration of the uncertainty with estimating emissions from fugitive emission sources. Based on the monitoring results and the other considerations, we determined that it is appropriate under CAA section 112(d)(6) to require coke oven facilities to monitor, and if necessary, take corrective action to minimize fugitive emissions, to ensure that facilities appropriately limit emissions of HAP from fugitive sources. More specifically, in this action, we are proposing that benzene concentrations be monitored in the ambient air at the fenceline of each coke oven facility using EPA Methods 325A/B. For each 2-week time-integrated sampling period, the facility would determine a delta c, calculated as the lowest benzene sample value subtracted from the highest benzene sample value. This approach is intended to subtract out the estimated contribution from background emissions that do not originate from the facility. The delta c for the most recent year of samples (26 sampling periods) would be averaged to calculate an annual average delta c. The annual average delta c would be determined on a 12-month rolling basis, meaning that it is updated with every new sample (i.e., every 2 weeks a new annual average delta c is determined from the most recent 26 sampling periods). This rolling annual average delta c would be compared against a benzene action level and owners and operators would be required to conduct root cause analysis and corrective action upon exceeding the benzene action level.
      We are proposing an action level of 3 ug/m[3] benzene. The proposed action level was determined by modeling fenceline benzene concentrations using the benzene emissions inventories used in the facility-wide risk assessment, assuming that those reported emissions represented full compliance with all standards, adjusted for additional control requirements we are proposing in this action.
      After modeling each facility, we then selected the maximum annual average benzene fenceline concentration modeled at any facility as the benzene action level. Thus, if the reported inventories are accurate, all facilities should be able to meet the benzene fenceline concentration action level. We note that this analysis does not correlate to any particular metric related to risk. This approach would provide the owner or operator with the flexibility to determine how best to reduce HAP emissions to ensure the benzene levels remain below the fenceline concentration action level. The details of this proposed approach are set forth in more detail in this section.
Siting, design, and sampling requirements for fenceline monitors.
      The EPA is proposing that passive fenceline monitors collecting 2-week time-integrated samples be deployed to measure fenceline benzene concentrations at coke oven facilities. We are proposing that coke oven facilities deploy passive samplers at a minimum of 12 points circling the coke oven facility perimeter according to EPA Method 325A.
      Fenceline passive diffusive tube monitoring networks employ a series of diffusive tube samplers at set intervals along the fenceline to measure a time-integrated ambient air concentration at each sampling location. A diffusive tube sampler consists of a small tube filled with an adsorbent, selected based on the pollutant(s) of interest, and capped with a specially designed cover with small holes that allow ambient air to diffuse into the tube at a small, fixed rate. Diffusive tube samplers have been demonstrated to be a cost-effective, accurate technique for measuring concentrations of pollutants (e.g., benzene) resulting from fugitive emissions in a number of studies[,] as well as in the petroleum refining sector. In addition, diffusive samplers are used in the European Union to monitor and maintain air quality, as described in European Union directives 2008/50/EC and Measurement Standard EN 14662 - 4:2005 for benzene. The International Organization for Standardization developed a standard method for diffusive sampling (ISO/FDIS 16017 - 2).
      We are proposing that the highest concentration of benzene, as an annual rolling average measured at any individual monitor and adjusted for background (see "Adjusting for background benzene concentrations" in this section), would be compared against the concentration action level (of 3 ug/m[3]) in order to determine if there are significant excess fugitive emissions that need to be addressed. We are proposing that existing sources would need to deploy samplers no later than 1 year after the effective date of the final rule which will enable facilities to begin generating annual averages after 2 years, and then within 3 years of the effective date the facilities would need to demonstrate that they meet the action level or would need to conduct the root cause analyses and corrective actions. New sources would be required to deploy samplers by the effective date of the final rule or startup, whichever is later, and generate the first annual average 1 year later. We are proposing that coke oven facility owners and operators would be required to demonstrate compliance with the concentration action level for the first time 3 years following the date the final rule is published in the Federal Register, and thereafter on a 1-year rolling annual average basis (i.e., considering results from the most recent 26 consecutive 2-week sampling intervals and recalculating the average every 2 weeks).
Benzene as an appropriate target analyte.
      Passive diffusive tube monitors can be used to determine the ambient concentration of a large number of compounds. However, different sorbent materials are typically needed to collect compounds with significantly different properties. Rather than require multiple tubes per monitoring location and a full analytical array of compounds to be determined, which would significantly increase the cost of the proposed fenceline monitoring program, we are proposing that the fenceline monitors be analyzed specifically for benzene. Coke oven facility owners or operators may elect to do more detailed speciation of the air at the fenceline, which could help identify the process unit that may be contributing to a high fenceline concentration, but we are only establishing monitoring requirements and action level requirements for benzene. We consider benzene to be a surrogate for organic HAP from fugitive sources at coke ovens facilities for multiple reasons. First, benzene is ubiquitous at coke oven facilities since it accounts for about 70 percent of all volatile compounds in the fenceline volatile emissions. Benzene is also present in emissions from CBRPs, where benzene is recovered from coke oven gas for sale along with other coke oven gas components. Second, the primary releases of benzene occur at ground level as fugitive emissions and the highest ambient benzene concentrations outside the facility would likely occur near the property boundary, also near ground level, so fugitive releases of benzene would be effectively detected at the ground-level monitoring sites. According to the emissions inventory we have relied on for this proposed action, 38 percent of benzene emissions from coke oven facilities result from fugitive emissions from coke batteries and CBRP equipment. See the emission inventory description in the document Residual Risk Assessment for Coke Ovens: Pushing, Quenching, and Battery Stacks Source Category in Support of the 2023 Risk and Technology Review Proposed Rule,[8] and the memorandum titled Fugitive Monitoring at Coke Oven Facilities (hereafter referred to as the Fugitive Monitoring memorandum), located in the dockets for the rules. Lastly, benzene is present in nearly all coke oven facility equipment exhaust. Therefore, the presence of benzene at the fenceline is also an indicator of other HAP emitted as part of COE or gas that is derivative of COE. For this reason and the reasons discussed earlier in this section, we believe that benzene is the most appropriate pollutant to monitor.
      We believe that other compounds, such as naphthalene and other PAH, would be less suitable indicators of total fugitive HAP for a couple of reasons. First, they are prevalent in stack emissions as well as fugitive emissions, so there is more potential for fenceline monitors to pick up contributions from nonfugitive sources. In contrast, almost all benzene comes from fugitive sources, so monitoring for benzene increases our confidence that the concentration detected at the fenceline is from fugitive emissions. Second, as compared to benzene, these other compounds are expected to be present at lower concentrations and, therefore, would be more difficult to measure accurately using fenceline monitoring. We request comments on the suitability of selecting benzene or other HAP, including naphthalene and other PAH, as the indicator to be monitored by fenceline samplers. We also request comment on whether it would be appropriate to require multiple HAP to be monitored at the fenceline, considering the capital and annual cost for additional monitors that are not passive/diffusion type, and if so, which pollutants should be monitored.
Adjusting for background benzene concentrations.
      Under this proposed approach, absolute measurements along a facility fenceline cannot completely characterize which emissions are associated with the coke oven facility and which are associated with other background sources outside the facility fenceline. The EPA recognizes that sources outside the coke oven facility boundaries may influence benzene levels monitored at the fenceline. Furthermore, background levels driven by local upwind sources are spatially variable. Both of these factors could result in inaccurate estimates of the actual contribution of fugitive emissions from the facility itself to the concentration measured at the fenceline. Many coke oven facilities are located in industrial areas that include facilities in other industries that also may emit benzene. With this spatial positioning, there is a possibility that the local upwind neighbors of a coke oven facility could cause different background levels on different sides of the coke oven facility.
      In this proposal, we are allowing the subtraction of offsite interfering sources (because they are not within the control of the owner or operators of coke ovens facilities) through site-specific monitoring plans, but we are not providing this option for onsite, non-source category emissions. The action levels described in this section are based on facility-wide emissions, and therefore these nonsource category sources have been considered in their development. We solicit comment on alternative approaches for making these adjustments for off-site contributions to the fenceline concentration of benzene.
Concentration action level.
      As mentioned above, the EPA is proposing to require coke oven facilities to take corrective action to reduce fugitive emissions if monitored fenceline concentrations exceed a specific concentration action level on a rolling annual average basis (recalculated every two weeks). We selected this proposed fenceline action level by modeling fenceline benzene concentrations using the benzene emissions estimates reported in response to the 2016 and 2022 CAA section 114 requests and estimated benzene emissions in the 2017 NEI for the CRBPs (see the model file description in Residual Risk Assessment for Coke Ovens: Pushing, Quenching, and Battery Stacks Source Category in Support of the 2023 Risk and Technology Review Proposed Rule). We estimated the long-term ambient benzene concentrations at each coke oven facility using the emission inventory and the EPA's American Meteorological Society/EPA Regulatory Model dispersion modeling system (AERMOD). Concentrations were estimated by the model at a set of polar grid receptors centered on each facility, as well as surrounding census block centroid receptors extending from the facility outward to 50 km. For purposes of this modeling analysis, we assumed that the nearest off-site polar grid receptor was the best representation of each facility's fenceline concentration, unless there was a census block centroid nearer to the fenceline than the nearest off-site polar grid receptor or an actual receptor was identified from review of the site map. In those instances, we estimated the fenceline concentration as the concentration at the census block centroid. Only receptors (either the polar or census block) that were estimated to be outside the facility fenceline were considered in determining the maximum benzene level for each facility. The maximum benzene concentration modeled at the fenceline for any coke oven facility is 3 ug/m[3] (annual average). For additional details of the analysis, see the Fugitive Monitoring memorandum.[37]
      Due to differences in short-term meteorological conditions, short-term (i.e., 2-week average) concentrations at the fenceline can vary greatly. Given the high variability in short-term fenceline concentrations and the difficulties and uncertainties associated with estimating a maximum 2-week fenceline concentration given a limited time period of meteorological data (one year) typically used in the modeling exercise, we determined that it would be inappropriate and ineffective to propose a short-term concentration action level that would trigger corrective action based on a single 2-week sampling event.
      One objective for this monitoring program is to identify fugitive emission releases more quickly, so that corrective action can be implemented in a timelier fashion than might otherwise occur without the fenceline monitoring requirement. We conclude the proposed fenceline monitoring approach and a rolling annual average concentration action limit (i.e., using results from the most recent 26 consecutive 2-week samples and recalculating the average every 2 weeks) would achieve this objective. The proposed fenceline monitoring would provide the coke oven facility owner or operator with fenceline concentration information once every 2 weeks. Therefore, the coke oven facility owner or operator would be able to timely identify emissions leading to elevated fenceline concentrations. We anticipate that the coke oven facility owners or operators would elect to identify and correct these sources early in efforts to avoid exceeding the annual benzene concentration action level.
      An "exceedance" of the benzene concentration action level would occur when the rolling annual average delta c, exceeds 3 ug/m[3]. Upon exceeding the concentration action level, we propose that coke oven facility owners or operators would be required to conduct analyses to identify sources contributing to fenceline concentrations and take corrective action to reduce fugitive emissions to ensure fenceline benzene concentrations remain at or below 3 ug/m[3] (rolling annual average).
Corrective action requirements.
      As described previously, the EPA is proposing that coke oven facility owners or operators analyze the fenceline samples and compare the rolling annual average delta c to the concentration action level. This section summarizes the root cause and corrective action requirements in this proposed rule. First, we are proposing that the calculation of the rolling annual average delta c must be completed within 30 days after the completion of each sampling episode. If the rolling annual average benzene delta c exceeds the proposed concentration action level (i.e., 3 μg/m[3]), the facility must, within 5 days of comparing the rolling annual delta c to the concentration action level, initiate a root cause analysis to determine the primary cause, and any other contributing cause(s), of the exceedance. The facility must complete the root cause analysis and implement corrective action within 45 days of initiating the root cause analysis. We are not proposing specific controls or corrections that would be required when the concentration action level is exceeded because the cause of an exceedance could vary greatly from facility to facility and episode to episode since many different sources emit fugitive emissions. Rather, we are proposing to allow facilities to determine, based on their own analysis of their operations, the action that must be taken to reduce air concentrations at the fenceline to levels at or below the concentration action level, representing full compliance with Coke Oven Batteries NESHAP requirements for fenceline emissions until the next fenceline measurement.
      If, upon completion of the root cause analysis and corrective actions described above, the coke oven facility subsequently exceeds the action level for the next two-week sampling episode following the earlier of the completion of a first set of corrective actions or the 45-day period commencing at initiation of root cause analysis ("subsequent exceedance"), the owner or operator would be required to develop and submit to the EPA a corrective action plan that would describe the corrective actions completed to date. This plan would include a schedule for implementation of additional emission reduction measures that the owner or operator can demonstrate as soon as practical. This plan would be submitted to the Administrator within 60 days after receiving the analytical results indicating that the delta c value for the 14-day sampling period following the completion of the initial corrective action is greater 3 ug/m[3], or if any corrective action measures identified require more than 45 days to implement, or, if no initial corrective actions were identified, no later than 60 days following the completion of the corrective action analysis.
      The coke oven facility owner or operator is not deemed out of compliance with the proposed concentration action level at the time of the fenceline concentration determination provided that the appropriate corrective action measures are taken according to the timeframe detailed in an approved corrective action plan.
      The EPA requests comment on whether it is appropriate to establish a standard time frame for compliance with actions listed in a corrective action plan.
      We expect that facilities may identify "poor-performing" sources (e.g., due to unusual or excessive leaks) using the fenceline monitoring data and, based on this additional information, would take action to reduce HAP emissions before they would have otherwise been aware of the issue through existing inspection and enforcement measures. By selecting a fenceline monitoring approach and by selecting benzene as the surrogate for COE, we believe that the proposed monitoring approach would effectively provide emissions information for all coke oven facility fugitive emission sources.
Additional requirements of the fenceline monitoring program.
      We are proposing that fenceline data at each monitor location be reported electronically for each quarterly period's worth of sampling periods (i.e., each report would contain data for at least six 2-week sampling periods per quarterly period). These data would be reported electronically to the EPA within 45 days of the end of each quarterly period and would be made available to the public through the EPA's electronic reporting and data retrieval portal, in keeping with the EPA's efforts to streamline and reduce reporting burden and to move away from hard copy submittals of data where feasible. We are proposing that facilities be required to conduct fenceline monitoring on a continuous basis at all monitors, in accordance with the specific methods described above.
      In light of the low annual monitoring and reporting costs associated with the fenceline monitors (as described in the next section), and the importance of the fenceline monitors as a means of ensuring the control of fugitives achieves the expected emission levels, we believe it is appropriate to require collection of fenceline monitoring data on a continuous basis. However, the EPA recognizes that fugitive benzene emissions at some monitors may be so low as to make it improbable that exceedances of the concentration action level would ever occur. In the interest of reducing the cost burden on facilities to comply with this rule, if a coke oven facility maintains the fenceline concentration below 0.3 ug/m[3] (a concentration that is 10 percent of the benzene action level) at any individual monitor for 2 years, the sampling frequency at that monitor can be reduced by 50 percent (e.g., 2 weeks of sampling for every 4-week period). For each sample location and monitor that continues to register below 0.3 ug/m[3] for an additional 2 years, the sampling may be reduced further to approximately once per quarter, with sampling occuring every sixth two-week period (i.e., five two-week periods are skipped between active sampling periods). If a monitor at the quarterly frequency continues to maintain a concentration of 0.3 ug/m[3] for an additional 2 years, sampling at that monitor may be reduced further to annual sampling. However, if the concentration at any sample location that is allowed a reduced frequency of testing increases above 0.3 ug/m3 at any time, sampling would need to immediately return to the original continuous sampling requirement.
      The EPA solicits comment on the proposed approach for reducing fenceline monitoring requirements for facilities that consistently measure fenceline concentrations below the concentration action level, and the measurement level that should be used to provide such relief. The proposed approach would be consistent with the fenceline alternate sampling frequency for burden reduction (40 CFR 63.658(e)(3)) as well as the graduated requirements for valve leak monitoring in Refinery MACT 1 and other equipment leak standards, where the frequency of required monitoring varies depending on the percent of leaking valves identified during the previous monitoring period (See e.g., 40 CFR 63.648(c). The EPA requests comment on the minimum time period facilities should be required to conduct fenceline monitoring; and the level of performance, in terms of monitored fenceline concentrations, that would enable a facility to reduce the frequency of data collection and reporting.
      Total costs for fenceline monitoring are estimated to be $116,000 per year per facility including reporting and recordkeeping and $1.3M annually for the industry including reporting and recordkeeping (11 affected facilities).
6. Revised Emissions Equation for Leaking Doors
      As part of the technology review under CAA section 112(d)(6), we are proposing to use an updated, revised version of the equation than that which has historically been used to estimate COE from leaking oven doors. The revised equation would provide more accurate estimates of COE from doors that reflects operation of any coke facility, not just the facility upon which the equation was derived, and includes facilities where advancements in preventing and reducing door leaks have occurred since 1981, which is when the equation was first developed.
      A summary of the revised equation and the rationale for its development follows here. A more detailed explanation can be found in the memorandum Revised Equation to Estimate Coke Oven Emissions from Oven Doors, located in the dockets for these rules. We are asking for comment on the revised equation to estimate coke oven door leaks.
      In the 2005 RTR for Coke Oven Batteries, COE from leaking oven doors were estimated using the following equation taken from the estimating procedures in AP-42 (Section 12.2: Coke Production, revised draft, July 2001).
COE-doors (lb/hr) = ND x (PLDyard/100) x (0.04 lb/hr) + ND x (PLDbench/100) x (0.023 lb/hr[41])
where:
ND = number of doors
PLD = percent leaking doors
Bench = walking platform running next to the ovens (and doors)
Yard = 50 to 100 feet from the oven doors
PLDyard = percent of doors with visible leaks observed from the yard
PLDbench= percent of doors with visible leaks only observable from the bench.
      Because of safety concerns, observations are not typically taken from bench and, therefore, this equation has historically included a default value of 6 percent for the percent leaking doors only able to be observed from the bench. As reported in the July 2008 update to AP-42 Chapter 12.2, this default value was derived from 1981 data, where the percent leaking doors from the yard was 6.4 percent and the total percent leaking doors visible from the bench was 12.4 percent, which included both leaks visible from yard and leaks visible only from the bench. The difference between 12.4 and 6.4 percent, equal to 6 percent, represented the percent leaking doors only able to be observed from the bench.
      In the current coke industry, the percent leaking doors measured from the yard is much lower, 2.5 percent or less, based on 2016 and 2022 source tests performed for the CAA section 114 request. The facility that was used in 1981 to establish the 6 percent leaking doors that were visible only from the bench was U.S. Steel Clairton-PA, which had 6.4 percent leaking doors visible from the yard at that time but now has a facility average of 0.54 percent leaking doors visible from the yard based on 2016 data and facility average of 0.46 percent leaking doors visible from the yard based on 2021 data. The default fixed value of 6 percent leaking doors visible only from the bench obviously does not reflect changes in practices for door leaks in the years since 1981 and should be reevaluated so that the total emissions from doors are not overestimated.
      Consequently, for the analyses conducted for this proposed rule, we revised the equation to include a bench-to-yard "ratio" instead of the 6 percent default value for doors seen leaking from the bench in the door leak emissions equation. The revised value in the equation (i.e., adjustment ratio) is still based on the historic values measured in 1981 but instead of using the 6 percent default value, the equation includes the ratio of the 1981 value for percent leaking doors visible only from the bench to the 1981 value for percent leaking doors visible from the yard. This adjustment ratio was used with current measured percent leaking doors from the yard to estimate the current percent leaking doors visible only from the bench. The ratio of bench-only emissions to yard emissions from 1981 is ((12.4-6.4)/6.4), equal to 6.0/6.4 or 0.94. The adjustment ratio (0.94) was multiplied by measured data for percent leaking doors measured from the yard to estimate the bench-only component of door emissions in the equation for COE for doors. Use of this adjustment ratio in the revised equation below is being proposed to better reflect operation of all coke ovens:
COE-doors (lb/hr) = ND x (PLDyard/100) x (0.04 lb/hr) +
      ND x (PLDyard x 0.94)/100) x (0.023 lb/hr)
E. What other actions are we proposing?
In addition to the proposed actions described above, we are proposing additional revisions to these NESHAP. We are proposing revisions to the startup, shutdown, and malfunction (SSM) provisions of these rules in order to ensure that they are consistent with the decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008), in which the court vacated two provisions that exempted sources from the requirement to comply with otherwise applicable CAA section 112(d) emission standards during periods of SSM. We also are proposing electronic reporting. Our analyses and proposed changes related to these issues are discussed as follows.
1. SSM
      In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the United States Court of Appeals for the District of Columbia Circuit (the court) vacated portions of two provisions in the EPA's CAA section 112 regulations governing the emissions of HAP during periods of SSM. Specifically, the court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 302(k) of the CAA, emissions standards or limitations must be continuous in nature and that the SSM exemption violates the CAA's requirement that some CAA section 112 standards apply continuously.
      With the issuance of the mandate in Sierra Club v EPA, the exemptions that were in 63.6(f)(1) and (h)(1) are null and void. The EPA amended 40 CFR 63.6(f)(1) and (h)(1)) on March 11, 2021, to reflect the court order and correct the CFR to remove the SSM exemption. In this action, we are eliminating any cross-reference to the vacated provisions in the regulatory text including 40 CFR 63.7310(a) and Table 1 of the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP and 40 CFR 63.300(e) and 63.310 for the Coke Oven Batteries NESHAP. Consistent with Sierra Club v. EPA, we are proposing standards in these rules that apply at all times. We are also proposing several revisions to Table 1 of the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP (the General Provisions applicability table) as is explained in more detail below. For example, we are proposing to eliminate the incorporation of the General Provisions' requirement that the source develop an SSM plan. We also are proposing to eliminate and revise certain recordkeeping and reporting requirements related to the SSM exemption as further described as follows.
      The EPA has attempted to ensure that the provisions we are proposing to eliminate are inappropriate, unnecessary, or redundant in the absence of the SSM exemption. We are specifically seeking comment on whether we have successfully done so.
      In proposing the standards in this rule, the EPA has taken into account SSM periods and, for the reasons explained as follows, has not proposed alternate standards for those periods. The coke oven industry has not identified (and there are no data indicating) any specific problems with removing the SSM provisions due to the nature of the coke process to operate continuously. If an oven is shut down, it has to be rebuilt before starting back up, which is the reason why coke ovens are put in idle mode when not operating. However, we solicit comment on whether any situations exist where separate standards, such as work practices, would be more appropriate during periods of startup and shutdown rather than the current standard.
      Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source's operations. Malfunctions, in contrast, are neither predictable nor routine. Instead they are, by definition, sudden infrequent and not reasonably preventable failures of emissions control, process, or monitoring equipment. (40 CFR 63.2) (definition of malfunction). The EPA interprets CAA section 112 as not requiring emissions that occur during periods of malfunction to be factored into development of CAA section 112 standards and this reading has been upheld as reasonable by the court in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016). Therefore, the standards that apply during normal operation apply during periods of malfunction.
 a. General Duty
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.6(e)(1)(i) and including a "no" in column 3 and revising 40 CFR 63.7310(c) text. In 40 CFR 63.6(e)(1)(i), the general duty to minimize emissions is described. Some of the language in that section is no longer necessary or appropriate in light of the elimination of the SSM exemption. With the elimination of the SSM exemption, there is no need to differentiate between normal operations, startup and shutdown, and malfunction events. Therefore, the language the EPA is proposing to revise for 40 CFR 63.7310(c) does not include that language from 40 CFR 63.6(e)(1). The EPA is also proposing to revise 40 CFR 63.300(e) in the Coke Oven Batteries NESHAP to reflect the elimination of the SSM exemption.
      We are also proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.6(e)(1)(ii) and including a "no" in column 3. In 40 CFR 63.6Euro(1)(ii), requirements are imposed that are not necessary with the elimination of the SSM exemption or are redundant with the general duty requirement being added at 40 CFR 63.7310(a). The EPA is also proposing to revise 40 CFR 63.300(e) in Coke Oven Batteries NESHAP to reflect the elimination of the SSM exemption.
 b. SSM Plan
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.6(e)(3) and including a "no" in column 3. Generally, the paragraphs under 40 CFR 63.6(e)(3) require development of an SSM plan and specify SSM recordkeeping and reporting requirements related to the SSM plan. The EPA is also proposing to revise 40 CFR 63.310(b) in 40 CFR part 63, subpart L to reflect the elimination of the SSM plan requirements. With the elimination of the SSM exemptions, affected units would be subject to an emission standard during such events. The applicability of a standard during such events would ensure that sources have ample incentive to plan for and achieve compliance and thus, the SSM plan requirements are no longer necessary.
 c. Compliance with Standards
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.6(f)(1) and including a "no" in column 3. Consistent with Sierra Club, EPA amended 40 CFR 63.6(f)(1) and (h)(1) on March 11, 2021, to reflect the court order and correct the CFR to remove the SSM exemption. However, the second sentence of 40 CFR 63.6(f)(1) contains language that is premised on the existence of an exemption and is inappropriate in the absence of the exemption. Thus, rather than cross-referencing 63.6(f)(1), we are adding the language of 63.6(f)(1) that requires compliance with standards at all times to the regulatory text at 40 CFR 63.7310(a). The EPA is also proposing to revise 40 CFR 63.300(e) in Coke Oven Batteries NESHAP: to reflect that standards apply at all times.
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.6(h)(1) and including a "no" in column 3. Consistent with Sierra Club, EPA amended 40 CFR 63.6(h)(1) on March 11, 2021, to reflect the court order and correct the CFR to remove the SSM exemption. However, the second sentence of 40 CFR 63.6(f)(1) contains language that is premised on the existence of an exemption and is inappropriate in the absence of the exemption. Thus, rather than cross-referencing 63.6(f)(1), we are adding the language of 63.6(f)(1) that requires compliance with standards at all times to the regulatory text at 40 CFR 63.7310(a). The EPA is also proposing to revise 40 CFR 63.300(e) in Coke Oven Batteries NESHAP to reflect that standards apply at all times.
 d. Performance Testing
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.7(e)(1) and including a "no" in column 3 and revising 40 CFR 63.7336(b) text. In 40 CFR 63.7(e)(1) performance testing is required. The EPA is instead proposing to add a performance testing requirement at 40 CFR 63.7322(a), 63.7324(a), and 63.7325(a). In addition, we are revising 40 CFR 63.309(a) and removing the citation to 40 CFR 63.7(e)(1) from 40 CFR 63.309(k). The performance testing requirements we are proposing to add differ from the General Provisions performance testing provisions in several respects. The regulatory text does not include the language in 40 CFR 63.7(e)(1) that restated the SSM exemption and language that precluded startup and shutdown periods from being considered "representative" for purposes of performance testing. The revised performance testing provisions require testing under representative operating conditions and exclude periods of startup and shutdown.
      As in 40 CFR 63.7(e)(1), performance tests conducted under these subparts should not be conducted during malfunctions because conditions during malfunctions are often not representative of normal operating conditions. The EPA is proposing to add language that requires the owner or operator to record the process information that is necessary to document operating conditions during the test and include in such record an explanation to support that such conditions represent normal operation. In 40 CFR 63.7(e), the owner or operator is required to make available to the Administrator such records "as may be necessary to determine the condition of the performance test" available to the Administrator upon request but does not specifically require the information to be recorded. The regulatory text the EPA is proposing to add to this provision builds on that requirement and makes explicit the requirement to record the information.
 e. Monitoring
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding entries for 40 CFR 63.8(c)(1)(i) and (iii) and including a "no" in column 3. The cross-references to the general duty and SSM plan requirements in those subparagraphs are not necessary in light of other requirements of 40 CFR 63.8 that require good air pollution control practices (40 CFR 63.8(c)(1)) and that set out the requirements of a quality control program for monitoring equipment (40 CFR 63.8(d)). In addition, the EPA is proposing to revise 40 CFR 63.305(f)(4)(i) in Coke Oven Batteries NESHAP to reflect changes to General Provisions due to general duty and SSM.
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.8(d)(3) and including a "no" in column 3. The final sentence in 40 CFR 63.8(d)(3) refers to the General Provisions' SSM plan requirement which is no longer applicable. The EPA is proposing to add to the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP at 40 CFR 63.7342(b)(3) text that is identical to 40 CFR 63.8(d)(3) except that the final sentence is replaced with the following sentence: "The program of corrective action should be included in the plan required under §63.8(d)(2)." We note that the revisions to 40 CFR 63.305(f)(4)(i) in Coke Oven Batteries NESHAP will also comport to this change.
 f. Recordkeeping
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP Applicability table (Table 1) by adding an entry for 40 CFR 63.10(b)(2)(i) and including a "no" in column 3. In 40 CFR 63.10(b)(2)(i), the recordkeeping requirements during startup and shutdown are described. In addition, the EPA is proposing to revise 40 CFR 63.311(f) in Coke Oven Batteries NESHAP. These recording provisions are no longer necessary because the EPA is proposing that recordkeeping and reporting applicable to normal operations would apply to startup and shutdown. In the absence of special provisions applicable to startup and shutdown, such as a startup and shutdown plan, there is no reason to retain additional recordkeeping for startup and shutdown periods.
      We are proposing to revise Table 1 of Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP by adding an entry for 40 CFR 63.10(b)(2)(ii) and including a "no" in column 3. In 40 CFR 63.10(b)(2)(ii), the recordkeeping requirements during a malfunction are described. The EPA is proposing to revise and add such requirements to 40 CFR 63.7342(a)(2)-(4). We are also revising the 40 CFR 63.311(f) to update the recordkeeping requirements in Coke Oven Batteries NESHAP. The regulatory text we are proposing to add differs from the General Provisions and other regulatory text it is replacing in that these provisions requires the creation and retention of a record of the occurrence and duration of each malfunction of process, air pollution control, and monitoring equipment. The EPA is proposing that this requirement apply to all malfunction events requiring that the source record the date, time, cause, and duration of the malfunction and report any failure to meet the standard. The EPA is also proposing to add to 40 CFR 63.7342(a)(3) and 40 CFR 63.311(f)(1)(iv) a requirement that sources keep records that include a list of the affected source or equipment and actions taken to minimize emissions, whether the failure occurred during a period of SSM, an estimate of the quantity of each regulated pollutant emitted over the standard for which the source failed to meet the standard, and a description of the method used to estimate the emissions. Examples of such methods would include product-loss calculations, mass balance calculations, measurements when available, or engineering judgment based on known process parameters. The EPA is proposing to require that sources keep records of this information to ensure that there is adequate information to allow the EPA to determine the severity of any failure to meet a standard, and to provide data that may document how the source met the general duty to minimize emissions when the source has failed to meet an applicable standard.
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(b)(2)(iv) and including a "no" in column 3. The EPA is proposing to revise 40 CFR 63.311(f) in the Coke Oven Batteries NESHAP. When applicable, the provision requires sources to record actions taken during SSM events when actions were inconsistent with their SSM plan. The requirement is no longer appropriate because SSM plans would no longer be required. The requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to record actions to minimize emissions and record corrective actions is now applicable by reference to 40 CFR 63.7342(a)(4) and 40 CFR 63.311(f)1(iv).
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(b)(2)(v) and including a "no" in column 3. The EPA is also proposing to revise 40 CFR 63.311(f) in Coke oven Batteries NESHAP. When applicable, the provision requires sources to record actions taken during SSM events to show that actions taken were consistent with their SSM plan. The requirement is no longer appropriate because SSM plans would no longer be required.
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(c)(15) and including a "no" in column 3. The EPA is proposing that 40 CFR 63.10(c)(15) no longer apply. When applicable, the provision allows an owner or operator to use the affected source's SSM plan or records to satisfy the recordkeeping requirements of the SSM plan specified in 40 CFR 63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10) through (12). The EPA is proposing to eliminate this requirement because SSM plans would no longer be required, and, therefore, 40 CFR 63.10(c)(15) no longer serves any useful purpose for affected units. The EPA is also proposing to revise 40 CFR 63.311(f) in Coke Oven Batteries NESHAP for similar changes.
 g. Reporting
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(d)(5)(i) and including a "no" in column 3. The EPA is also proposing to revise 40 CFR 63.311(b)(2), 63.311(b)(5), 63.311(d)(2), in Coke oven Batteries NESHAP to reflect similar changes. In 40 CFR 63.10(d)(5)(i), the reporting requirements for SSMs are described. To replace the General Provisions reporting requirement, the EPA is proposing to add reporting requirements to 40 CFR 63.7341(d)(4) and 40 CFR 63.311(f)(1)(iv) and revise reporting requirements in 40 CFR 63.311(b)(2), (b)(5), and (d)(2). The replacement language differs from the General Provisions requirement in that it eliminates periodic SSM reports as a stand-alone report. We are proposing language that requires sources that fail to meet an applicable standard at any time to report the information concerning such events in the semiannual reporting period compliance report already required under this rule. We are proposing that the report would contain the number, date, time, duration, and the cause of such events (including unknown cause, if applicable), a list of the affected source or equipment, an estimate of the quantity of each regulated pollutant emitted over any emission limit, and a description of the method used to estimate the emissions. Examples of such methods would include product-loss calculations, mass balance calculations, measurements when available, or engineering judgment based on known process parameters. The EPA is proposing this requirement to ensure that there is adequate information to determine compliance, to allow the EPA to determine the severity of the failure to meet an applicable standard, and to provide data that may document how the source met the general duty to minimize emissions during a failure to meet an applicable standard.
We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(d)(5)(i) and including a "no" in column 3 and revising the 40 CFR 63.7341(c)(4) text. We would no longer require owners or operators to determine whether actions taken to correct a malfunction are consistent with an SSM plan, because plans would no longer be required. The proposed amendments, therefore, eliminate the cross reference to 40 CFR 63.10(d)(5)(i) that contains the description of the previously required SSM report format and submittal schedule from this section. These specifications are no longer necessary because the events would be reported in otherwise required reports with similar format and submittal requirements.
      We are proposing to revise the Coke Ovens: Pushing, Quenching, Battery Stacks NESHAP General Provisions Applicability table (Table 1) by adding an entry for 40 CFR 63.10(d)(5)(ii) and including a "no" in column 3. The EPA is also proposing to revise 40 CFR 63.311(b)(2), 63.311(b)(5), 63.311(d)(2), in Coke Oven Batteries to reflect similar changes. In 40 CFR 63.10(d)(5)(ii) and 63.311, an immediate report is described for SSMs when a source failed to meet an applicable standard but did not follow the SSM plan. We would no longer require owners and operators to report when actions taken during a SSM were not consistent with an SSM plan, because plans would no longer be required.
2. Electronic Reporting
The EPA is proposing that owners and operators of coke oven facilities, under rules for both Coke Ovens Pushing, Quenching, and Battery Stacks NESHAP and Coke Oven Batteries NESHAP source categories, submit electronic copies of required performance test reports, periodic reports (including fenceline monitoring reports), and periodic certifications through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI). A description of the electronic data submission process is provided in the memorandum Electronic Reporting Requirements for New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, available in the docket for this action. The proposed rule requires that performance test results collected using test methods that are supported by the EPA's Electronic Reporting Tool (ERT) as listed on the ERT website at the time of the test be submitted in the format generated through the use of the ERT or an electronic file consistent with the xml schema on the ERT website, and other performance test results be submitted in portable document format (PDF) using the attachment module of the ERT.
For the quarterly and semiannual compliance reports of the Coke Ovens: Pushing, Quenching, and Battery Stacks NESHAP source category and the semiannual compliance certification of the Coke Oven Batteries NESHAP source category, the proposed rule requires that owners and operators use the appropriate spreadsheet template to submit information to CEDRI. A draft version of the proposed templates for these reports is included in the docket for this action. The EPA specifically requests comment on the content, layout, and overall design of the templates.
The electronic submittal of the reports addressed in this proposed rulemaking would increase the usefulness of the data contained in those reports, is in keeping with current trends in data availability and transparency, would further assist in the protection of public health and the environment, would improve compliance by facilitating the ability of regulated facilities to demonstrate compliance with requirements and by facilitating the ability of delegated state, local, tribal, and territorial air agencies and the EPA to assess and determine compliance, and would ultimately reduce burden on regulated facilities, delegated air agencies, and the EPA. Electronic reporting also eliminates paper-based, manual processes, thereby saving time and resources, simplifying data entry, eliminating redundancies, minimizing data reporting errors, and providing data quickly and accurately to the affected facilities, air agencies, the EPA, and the public. Moreover, electronic reporting is consistent with the EPA's plan to implement Executive Order 13563 and is in keeping with the EPA's agency-wide policy developed in response to the White House's Digital Government Strategy. For more information on the benefits of electronic reporting, see the memorandum Electronic Reporting Requirements for New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, referenced earlier in this section.
F. What compliance dates are we proposing?
      The proposed date for complying with the proposed SSM changes is no later than the effective date of the final rule with the exception of recordkeeping provisions. For recordkeeping under the SSM, we are proposing that facilities must comply with this requirement 180 days after the effective date of the final rule. Recordkeeping provisions associated with malfunction events shall be effective no later than 180 days after the effective date of the final rule. The EPA is requiring additional information for recordkeeping of malfunction events, so the additional time is necessary to permit sources to read and understand the new requirements and adjust record keeping systems to comply. Reporting provisions are in accordance with the reporting requirements during normal operations and the semi-annual report of excess emissions.
      The proposed date for complying with the proposed ERT submission requirements is 180 days after publication of the final rule. The proposed compliance date for the revisions to the allowable limits for leaking doors, lids, and offtakes under the Coke Oven Batteries NESHAP is 1 year after publication of the final rule. The proposed compliance date to begin fenceline monitoring is 1 year after the publication date of the final rule; facilities must perform root cause analysis and apply corrective action requirements upon exceedance of an annual average concentration action level starting 3 years after the publication date of the final rule.
      The proposed compliance date for the 15 new MACT limits (based on the MACT floor, as described in section IV.A of this preamble), in the NESHAP for Coke Ovens: Pushing, Quenching and Battery Stacks is 1 year after publication of the final rule. The proposed compliance date for the two new BTF emission limits for HNR waste heat stacks in the NESHAP for Coke Ovens: Pushing, Quenching and Battery Stacks is 3 years after publication of the final rule to allow time for the installation of ductwork to capture large volumes of battery COE and for acquisition and installation of control devices to treat the captured air. As described earlier in this section, the facility that is affected by the new BTF PM limit is located between three rivers, a state road, and a railroad track. Therefore, due to the unique configuration of facility, and the resulting space available to construct control devices and ductwork to reduce arsenic emissions from bypass stacks creates an impediment to a typical construction schedule. We estimate that the facility will need 3 years to complete all this work and comply with the new PM limit. Consequently, the proposed compliance date for the BTF PM limit for waste stacks in the Coke Ovens: Pushing, Quenching and Battery Stacks NESHAP is 3 years after publication of the final rule.
G. Adding 1-bromopropane to list of HAP
      On January 5, 2022, the EPA published a final rule amending the list of hazardous air pollutants (HAP) under the CAA to add 1-bromopropane (1-BP) in response to public petitions previously granted by the EPA. (87 FR 393). Consequently, as each NESHAP is reviewed, we are evaluating whether the addition of 1-BP to the CAA section 112 HAP list impacts the source category. For the Coke Ovens: Pushing, Quenching, and Battery Stacks and Coke Oven Batteries source categories, we conclude that the inclusion of 1-BP as a regulated HAP would not impact the representativeness of the MACT standard because, based on available information, we have no evidence that 1-BP is emitted from this source category. As a result, no changes are being proposed to the Coke Ovens: Pushing, Quenching, Battery Stacks and Coke Oven Batteries NESHAPs based on the January 2022 rule adding 1-BP to the list of HAP. Nevertheless, we are requesting comments regarding the use of 1-BP and any potential emissions of 1-BP from this source category.
V. Summary of Cost, Environmental, and Economic Impacts
A. What are the affected sources?
      These proposed amendments to the NESHAP for Coke Ovens: Pushing, Quenching and Battery Stacks affect sources of HAP emissions from pushing coke out of ovens, quenching hot coke with water in quench towers, battery stacks of oven combustion gas at ByP coke plants, and from HRSG and HNR bypass/waste heat stacks at HNR facilities. These proposed amendments also apply to the NESHAP for Coke Oven Batteries, where the affected sources are the visible leaks from oven doors, charging port lids, and offtake ducts; and from emissions from charging coal into the coke ovens.
B. What are the air quality impacts?
      There are no air quality impacts due to the proposed MACT floor limits for the Coke Ovens: Pushing, Quenching, and Battery Stacks NESHAP source category, although the 15 proposed MACT standards would ensure that air quality does not degrade over time. The proposed BTF MACT standards for waste heat stacks at nonrecovery facilities in the Coke Ovens: Pushing, Quenching, and Battery Stacks source category would reduce 237 tpy of PM, 14 tpy of PM2.5, 4.0 tpy of nonmercury metal HAP, and 0.072 tpy (144 pounds per year) of mercury.
      There are no air quality impacts due to proposed reduction in allowable emissions from coke oven doors in the Coke Oven Batteries source category, but the proposed standards would ensure that air quality does not degrade over time.
C. What are the other environmental impacts?
      Baghouses and ACI that are used to reduce air emissions of mercury and nonmercury HAP metals from bypass waste stacks at one HNR facility have the following environmental impacts: 15.1 million kilowatt-hour increased electricity use and 761 tons of hazardous dust for disposal. Baghouses and ACI are commonly used control devices for air emissions of PM and mercury. Consequently, there is a reduction in air emissions of 4.0 tpy nonmercury HAP metals and 144 pounds per year mercury.
D. What are the cost impacts?
      Cost impacts would occur due to the required source testing every 5 years to demonstrate compliance with the proposed MACT floor and BTF standards for Coke Ovens: Pushing, Quenching, and Battery Stacks. Testing costs are estimated to be $3.2 million annualized costs including reporting and recordkeeping for the 11 operating facilities in the source category, with an average of $290,000 per year per facility including reporting and recordkeeping.
      Cost impacts would occur due to the control device needed to reduce HAP emissions to meet the two BTF MACT standards. For the ACI and baghouses used to achieve the BTF standard for mercury, capital costs would be $314,000 for activated carbon and the injection systems and $7.2M for the baghouses along with necessary ductwork; annual costs for activated carbon and the injection systems would be $1.6M/yr and $3.0M/yr for the baghouses with necessary ductwork. For nonmercury metal HAP control, capital costs would be $7.2M for the baghouses along with necessary ductwork and annual costs would be $3.0M/yr. Total estimated capital costs for the BTF limit for waste heat stacks (nonmercury metal HAP and mercury) are $7.5M, with annualized costs of $4.7M (1 affected facility).
      Total costs for fenceline monitoring are estimated to be $116,000 per year per facility including reporting and recordkeeping and $1.3M annually for the industry including reporting and recordkeeping (11 affected facilities).
      Total capital costs for the industry (for 1 facility) are $7.5M and the estimated annual costs for the industry for all proposed requirements are about $9.1M/yr (including reporting and recordkeeping) for 11 affected facilities.
E. What are the economic impacts?
      The EPA prepared an Economic Impact Analysis (EIA) for the proposed rule, which is available in the docket for this action. This proposed rule is not a significant regulatory action under Executive Order 12866 Section 3(f)(1), as amended by Executive Order 14094, since it is not likely to have an annual effect on the economy of $200 million or more or adversely affect in a material way the economy, a sector of the economy, productivity, competition, jobs, the environment, public health or safety, or State, local, territorial, or tribal governments or communities. The EIA analyzes the cost and emissions impact under the proposed requirements, and the projected impacts are presented for the 2025-2036 time period. The EIA analyzes the projected impacts of the proposed rule in order to better inform the public about its projected impacts.
      If the compliance costs, which are key inputs to an economic impact analysis, are small relative to the receipts of the affected industries, then the impact analysis may consist of a calculation of annual (or annualized) costs as a percent of sales for affected parent companies. This type of analysis is often applied when a partial equilibrium or more complex economic impact analysis approach is deemed unnecessary given the expected size of the impacts. The annualized cost per sales for a company represents the maximum price increase in the affected product or service needed for the company to completely recover the annualized costs imposed by the regulation. We conducted a cost-to-sales analysis to estimate the economic impacts of this proposal, given that the equivalent annualized value (EAV), which represents a flow of constant annual values that would yield a sum equivalent to the present value, of the compliance costs over the period 2025 - 2036 range from $8.9 million using a 7 percent discount rate to $9.6 million using a 3 percent discount rate in 2022 dollars, which is small relative to the revenues of the steel industry (of which the coke industry is a part).
      There are five parent companies that operate active coke facilities: Cleveland-Cliffs, Inc. U.S. Steel, SunCoke Energy, Inc., DTE Energy Company, and the Drummond Company. Each reported greater than $1 billion in revenue in 2021. The EPA estimated the annualized compliance cost each firm is expected to incur and determined the estimated cost-to-sales ratio for each firm is less than 0.5 percent. James C. Justice Companies owns the idled Bluestone Coke facility, and the EPA estimated the compliance cost-to-sales ratio, if the facility were to resume operations, would be less than 0.1 percent. Therefore, the projected economic impacts of the expected compliance costs of the proposal are likely to be small. The EPA also conducted a small business screening to determine the possible impacts of the proposed rule on small businesses. Based on the Small Business Administration size standards and business information gathered by the EPA, this source category has one small business, which would not be subject to significant cost by the proposed requirements.
      Details of the EIA can be found in the document prepared for this rule titled Economic Impact Analysis for the Proposed National Emission Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks, Residual Risk and Technology Review; National Emission Standards for Hazardous Air Pollutants for Coke Oven Batteries Technology Review that is located in the dockets for these rules.
F. What are the benefits?
      The BTF MACT standards for waste heat stacks at nonrecovery facilities are expected to reduce HAP emissions (with concurrent control of PM2.5) and could improve air quality and the health of persons living in surrounding communities. These standards are expected to reduce 4.0 tpy of nonmercury HAP metal (including arsenic and lead) and 144 lbs per year of mercury. Due to methodology and data limitations, we did not attempt to monetize the health benefits of reductions in HAP in this analysis. The EPA remains committed to improving methods for estimating HAP benefits by continuing to explore additional aspects of HAP-related risk, including the distribution of that risk. These standards are also projected to reduce PM emissions by 237 tpy, of which 14 tpy is expected to be PM2.5.
G. What analysis of environmental justice did we conduct?
      Executive Order 12898 directs EPA to identify the populations of concern who are most likely to experience unequal burdens from environmental harms, which are specifically minority populations (people of color), low-income populations, and Indigenous peoples (59 FR 7629, February 16, 1994). Additionally, Executive Order 13985 is intended to advance racial equity and support underserved communities through Federal government actions (86 FR 7009, January 20, 2021). For this action, pursuant to the Executive Orders discussed in section VIII of this preamble, the EPA conducted an assessment of the impacts that would result from the proposed rule amendments, if promulgated, on various demographic groups living near coke oven facilities.
      The EPA defines EJ as "the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies." The EPA further defines fair treatment to mean that "no group of people should bear a disproportionate burden of environmental harms and risks, including those resulting from the negative environmental consequences of industrial, governmental, and commercial operations or programs and policies." In recognizing that people of color and low-income populations often bear an unequal burden of environmental harms and risks, the EPA continues to consider ways of protecting them from adverse public health and environmental effects of air pollution. For purposes of analyzing regulatory impacts, the EPA relies upon its June 2016 "Technical Guidance for Assessing Environmental Justice in Regulatory Analysis," which provides recommendations that encourage analysts to conduct the highest quality analysis feasible, recognizing that data limitations, time, resource constraints, and analytical challenges will vary by media and circumstance. The Technical Guidance states that a regulatory action may involve potential EJ concerns if it could: (1) create new disproportionate impacts on minority populations, low-income populations, and/or Indigenous peoples; (2) exacerbate existing disproportionate impacts on minority populations, low-income populations, and/or Indigenous peoples; or (3) present opportunities to address existing disproportionate impacts on minority populations, low-income populations, and/or Indigenous peoples through an action under development.
 Coke Ovens: Pushing, Quenching, and Battery Stacks Source Category Demographics
      The EPA examined the potential for the 14 coke oven facilities to disproportionately impact residents in certain demographic groups in proximity to the facilities, both in the baseline and under the control options considered in this proposal. Specifically, the EPA analyzed how demographics and risk are distributed both pre- and post-control under the Coke Ovens: Pushing, Quenching, and Battery Stack NESHAP, enabling us to address the core questions that are posed in the EPA's 2016 Technical Guidance for Assessing Environmental Justice in Regulatory Analysis. In conducting this analysis, we considered key variables highlighted in the guidance including minority populations (including Hispanic or Latino), low-income populations, and/or Indigenous peoples. The methodology and detailed results of the demographic analysis are presented in the document titled Analysis of Demographic Factors for Populations Living Near Coke Oven Facilities, which is available in the docket for this action.
      To examine the potential for disproportionate impacts on certain population groups, the EPA conducted a proximity analysis, baseline risk-based analysis (i.e., before implementation of any controls proposed in this action), and post-control risk-based analysis (i.e., after implementation of the controls proposed in this action). The proximity demographic analysis is an assessment of individual demographic groups in the total population living within 10 km (~6.2 miles) and 50 km (~31 miles) of the facilities. The baseline risk-based demographic analysis is an assessment of risks to individual demographic groups in the population living within 10 km and 50 km of the facilities prior to the implementation of any controls proposed by this action ("baseline"). The post-control risk-based demographic analysis is an assessment of risks to individual demographic groups in the population living within 10 km and 50 km of the facilities after implementation of the controls proposed by this action ("post-control"). In this preamble, we focus on the 10 km radius for the demographic analysis because it encompasses all the facility MIR locations and captures 99 percent of the population with baseline cancer risks greater than or equal to 1-in-1 million from coke ovens source category emissions. The results of the proximity analysis for populations living within 50 km are included in the document titled Analysis of Demographic Factors for Populations Living Near Coke Oven Facilities, which is available in the docket for this action.
      Under the risk-based demographic analysis, the total population, population percentages, and population count for each demographic group for the entire U.S. population is shown in the column titled "Nationwide Average for Reference" in Table 10 of this preamble. These national data are provided as a frame of reference to compare the results of the baseline proximity analysis, the baseline risk-based analyses, and the post-control risk-based analyses.
      The results of the category proximity demographic analysis (See Table 10, column titled "Baseline Proximity Analysis for Pop. Living within 10 km of Coke Oven Facilities") indicate that a total of 1.3 million people live within 10 km of the 14 Coke Oven facilities. The percent of the population that is African American is more than double the national average (27 percent versus 12 percent). The percent of people living below the poverty level is almost double the national average (22 percent versus 13 percent).
      The category baseline risk-based demographic analysis (See Table 10, column titled "Pre-Control Baseline"), which focuses on populations that have higher cancer risks, indicates that the population with cancer risks greater than or equal to 1-in-1 million due to emissions from the Coke Ovens: Pushing, Quenching, And Battery Stacks source category is predominantly white (86 percent versus 60 percent nationally). The population with cancer risks greater than or equal to 1-in-1 million is above the national average for percent of the population living below poverty (17 percent versus 13 percent) and the percent of the population that is over 25 without a high school diploma is almost 2 times the national average (21 percent versus 12 percent). The category post-control risk-based demographic analysis (See Table 10, column titled "Post-Control") shows that the controls under consideration in this proposal would reduce the number of people who are exposed to cancer risks greater than or equal to 1-in-1 million resulting from emissions from the Coke Ovens: Pushing, Quenching, and Battery Stacks source category by almost 90 percent, from approximately 2,900 to 400 people. The post-control population with risks greater than or equal to 1-in-1 million is predominately white (96 percent). Note that there are only 26 people with post-control risks greater than 1-in-1 million (MIR of 2-in-1 million) due to emissions from the Coke Ovens: Pushing, Quenching, And Battery Stacks source category within 10 km of the coke oven facilities.
TABLE 10. COKE OVENS: PUSHING, QUENCHING, AND BATTERY STACKS SOURCE CATEGORY: PRE-CONTROL AND POST-CONTROL DEMOGRAPHICS OF POPULATIONS LIVING WITHIN 10 KM OF FACILITIES WITH CANCER RISK GREATER THAN OR EQUAL TO 1-IN-1 MILLION COMPARED TO THE NATIONAL AVERAGE AND PROXIMITY DEMOGRAPHICS
                               Demographic Group
                       Nationwide Average for Reference
Baseline Proximity Analysis for Population. Living within 10 km of Coke Oven Facilities
      Cancer Risk >=1-in-1 Million within 10 km of Coke Oven Facilities

                             Pre-Control Baseline
                                 Post-Control
Total Population
                                     328M
                                     1.3M
                                      3K
                                      400
Number of Facilities
                                       -
                                      14
                                       3
                                       3
                Race and Ethnicity by Percent/Number of People
White
                                      60%
                                      59%
                                      86%
                                      96%

                                     197M
                                     789K
                                     2.5K
                                      400
African American
                                      12%
                                      27%
                                      11%
                                      2%

                                      40M
                                     364K
                                      300
                                    <100
Native American
                                     0.7%
                                     0.2%
                                     0.1%
                                     0.0%

                                     2.2M
                                     2.5K
                                    <100
                                       0
Hispanic or Latino (includes white and nonwhite)
                                      19%
                                      11%
                                      1%
                                      1%

                                      62M
                                     144K
                                    <100
                                    <100
Other and Multiracial
                                      8%
                                      3%
                                      2%
                                      1%

                                      27M
                                      44K
                                    <100
                                    <100
                      Income by Percent/Number of People
Below Poverty Level
                                      13%
                                      22%
                                      17%
                                      10%

                                      44M
                                     297K
                                      500
                                    <100
Above Poverty Level
                                      87%
                                      78%
                                      83%
                                      90%

                                     284M
                                      1M
                                     2.4K
                                      300
                     Education by Percent/Number of People
Over 25 and without a High School Diploma
                                      12%
                                      14%
                                      21%
                                      7%

                                      40M
                                     194K
                                      600
                                    <100
Over 25 and with a High School Diploma
                                      88%
                                      86%
                                      79%
                                      93%

                                     288M
                                     1.1M
                                     2.3K
                                      400
              Linguistically Isolated by Percent/Number of People
Linguistically Isolated
                                      5%
                                      3%
                                      1%
                                      0%

                                      18M
                                      39K
                                    <100