A. What are the proposed decisions and actions related to the Mineral Wool Production NESHAP?
      The following sections discuss the proposed decisions and actions regarding unregulated pollutants and emissions sources (i.e., the MACT floors), recordkeeping and notification, compliance and other proposed decisions and actions related to subcategorization of emissions sources and the findings of the SBAR Panel.
1. Addressing Unregulated Pollutants and Emissions Sources from Mineral Wool Production.
      In the course of evaluating the 1999 MACT rule, we identified certain HAP for which we failed to establish emission standards in the original MACT (i.e., COS, HF, HCl, phenol, and methanol) and certain unregulated processes (i.e., collection). Some of these HAP (COS, phenol, and methanol) were not regulated under the 1999 MACT rule because they were represented by surrogates (i.e., CO and formaldehyde). The EPA did not regulate HF and HCl in the 1999 rule although these HAP are emitted from cupolas. The 1999 MACT rule also did not regulate any HAP emitted from collection processes that occur on a bonded line even though these processes emit the HAP phenol, formaldehyde, and methanol. According to National Lime v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000), the EPA has a "clear statutory obligation to set emissions standards for each listed HAP". As a part of the information collected in 2010 to support this proposal, we specifically evaluated COS, HF, and HCl from cupolas and formaldehyde, phenol and methanol from collection and curing operations.
For the Mineral Wool Production source category, we are proposing MACT limits for: (1) COS, HF and HCl for existing, new and reconstructed cupolas; and (2) formaldehyde, phenol and methanol for existing, new and reconstructed combined collection and curing operations. The collection process emits HAP when a phenol-formaldehyde based binder is sprayed during collection. Such collection processes immediately precede curing ovens. Both processes emit HAP when they occur on bonded production lines, but of the two processes, only the curing oven was regulated under the 1999 MACT standard. This proposed rule regulates collection and curing as a combined process on bonded production lines under three subcategories (one subcategory for each combined process design). The proposed emissions limits were calculated using the 99 percent UPL method.
We considered beyond-the-floor options for COS, HF, and HCl standards for all cupolas, and for formaldehyde, phenol and methanol for all combined collection and curing operation designs, as required by section 112(d)(2) of the Act. However, we decided not to propose any limits based on the beyond-the-floor analyses for COS, HF, HCl, formaldehyde, phenol, and methanol for these sources because of the costs, potential disadvantages of additional controls (including the cost of RTO and unintended SO2 emissions), non-air environmental impacts, and adverse energy implications associated with use of these additional controls. The beyond-the-floor analyses are presented in the technical documentation for this action (see MACT Floor Analysis for the Mineral Wool Production Manufacturing Source Category and the MACT Floor Analysis for the Wool Fiberglass Manufacturing Source Category), and are available in the docket for this action.
In summary, we are proposing the following emissions limits for existing, new, and reconstructed cupolas in the Mineral Wool Production Source Category as presented in Table 2. We are not proposing changes to the PM emissions limits in the 1999 MACT rule for Mineral Wool Production, and for this reason they are not included in the proposed limits in Table 2 below.
Table 2. Mineral Wool Production Proposed Emissions limits for Existing, New, and Reconstructed Cupolas, pound of pollutant per ton of melt
Pollutant
Emission Limit (lb/ton of melt)

Existing Cupolas
New and Reconstructed Cupolas
COS
3.3
0.017
HF
0.014
0.014
HCl
0.0096
0.0096

      2. Subcategorization.
Under CAA section 112(d)(1), the EPA has the discretion to "...distinguish among classes, types, and sizes of sources within a category or subcategory in establishing..." standards. When separate subcategories are established, a MACT floor is determined separately for each subcategory. To determine whether the mineral wool production facilities warrant subcategorization for the MACT floor analysis, the EPA reviewed unit and process designs, operating information, and air emissions data compiled in the industry survey data set and other information collected by the agency for development of the NESHAP for this source category. Based on this review, the EPA concluded that there are significant design and operational differences in the collection operations at each of the three facilities that operate a bonded line in this source category.
For the unregulated process that emits HAP (i.e., collection and curing for facilities that operate a bonded line), we are proposing to subcategorize combined collection operations and curing ovens designs into three subcategories based on what the industry is currently using: vertical, horizontal and drum. When separate subcategories are established, a MACT standard is determined separately for each subcategory. To determine whether the mineral wool production facilities warrant subcategorization for the MACT floor analysis, the EPA reviewed unit and process designs, operating information and air emissions data compiled in the industry survey data set and other information collected by the agency for development of the NESHAP for this source category. Based on this review, the EPA concluded that there are significant design and operational differences in the collection operations at each of the three facilities that operate a bonded line in this source category. The combined collection and curing designs consist of three design types: vertical, horizontal and drum. For each existing, new, and reconstructed combined collection and curing operation, we are proposing the following emissions limits as presented in Table 3.
Table 3. Mineral Wool Production Proposed Emissions limits for Existing, New, and Reconstructed Combined Collection and Curing Operations, pound of pollutant per ton of melt
Design
Pollutant
Emission Limit (lb/ton of melt)
Vertical
Formaldehyde
0.46

Phenol
0.52

Methanol
0.63
Horizontal
Formaldehyde
0.054

Phenol
0.15

Methanol
0.022
Drum
Formaldehyde
0.067

Phenol
0.0023

Methanol
0.00077

3. Reporting and Recordkeeping Notifications.
      We are proposing to revise certain reporting and recordkeeping requirements of 40 CFR part 63, subpart DDD. Specifically, we are proposing that facilities maintain records and prepare and submit performance test reports on the frequency described below in Compliance Dates and Approaches to comply with the proposed emissions limits for COS, HF, HCl, formaldehyde, phenol, methanol and the existing PM limit. Although the PM limits in the existing MACT do not change as a result of this proposed rule we are proposing the same reporting, recordkeeping requirements for PM as for the other pollutants addressed under this proposed rule. We are also proposing language that would require the use of electronic reporting for all test methods that are supported by the ERT. Methods supported by ERT may be found at http://www.epa.gov/ttn/chief/ert/index.html.
4. Compliance Dates and Approaches.
      We are proposing that facilities that commenced construction or reconstruction on or before [INSERT DATE OF PUBLICATION OF THIS PROPOSED RULE IN THE FEDERAL REGISTER] must demonstrate compliance with the requirements of this subpart no later than 3 years after the effective date of this rule. Affected sources that commenced construction or reconstruction after the effective date of this rule must demonstrate compliance with the requirements of this subpart no later than the effective date of the rule or upon start-up, whichever is later.
We are proposing that compliance testing for PM, COS, formaldehyde, phenol and methanol be conducted using the same test methods as required by the 1999 MACT rule (i.e., Method 5 for PM and Method 318 for the organic HAP). We are proposing that sources can use either Test Method 26A or Test Method 320 to determine compliance for HF and HCl.
We are proposing both an initial performance test and repeat testing every 5 years or more often if the raw materials charged to the cupola change by more than 10 percent of that used for the initial performance test. Finally, we propose that continuous monitoring of appropriate operating parameters for control devices (e.g., RTO), cupolas, curing ovens and/or collection operations will be required as parametric monitoring. This is to ensure continuous compliance with the PM, COS, HF, HCl, formaldehyde, phenol and methanol emissions limits.
5. Other Decisions and Actions.
       In addition to the proposed decisions and actions discussed above, we are also proposing changes to the use of surrogates in the existing rule and to subcategorize the combined collection operations and curing oven designs from those facilities operating bonded lines. We also discuss here the findings of the SBAR panel.
      a. Surrogacy.
      As described in Sections III.B and VII.B of this preamble, the court, in the Brick MACT decision (Sierra Club v. EPA, 479 F. 3d 875 (D.C. Cir. March 13, 2007))[3], found that the EPA has a "clear statutory obligation to set emission standards for each listed HAP," which does not allow it to "avoid setting standards for HAP not controlled with technology." Because we did not conduct analyses that would support the use of CO as a surrogate for COS, or formaldehyde for methanol and phenol, we cannot demonstrate that we established emission limits for COS, methanol and phenol in the 1999 MACT standard. Therefore, the agency is proposing to add emission limits for both phenol and methanol. Similarly, the agency is proposing to discontinue the use of CO as a surrogate for COS, and to set emission limits for COS. The proposed emissions limits for formaldehyde, phenol, methanol and COS are presented in Tables 2 and 3, above. We are soliciting comment on our decisions to discontinue use of formaldehyde and CO as surrogates; any person wishing to establish or reestablish surrogacy relationships of one pollutant for others should provide emissions testing to support their conclusions.
      b. Small Business Advocacy Review Panel.
      For purposes of assessing the impacts of the proposed rule on small entities, the RFA defines small entities as including "small businesses," "small governments," and "small organizations" (5 USC 601). The regulatory revisions being considered by the EPA for this rulemaking are expected to affect a variety of small businesses, but would not affect any small governments or small organizations. The RFA references the definition of "small business" found in the Small Business Act, which authorizes the SBA to further define "small business" by regulation. The SBA definitions of small business by size standards using the NAICS can be found at 13 CFR 121.201. For the Mineral Wool Production source category (NAICS code 327993), the SBA size standard for a small business is 500 employees. Based on this size designation, there are currently 5 small businesses operating with a total number of 540 employees.

Under section 609(b) of the RFA, the Panel is to report its findings related to these four items:
         * A description of and, where feasible, an estimate of the number of small entities to which the proposed rule will apply;
         * A description of the projected reporting, recordkeeping and other compliance requirements of the proposed rule, including an estimate of the classes of small entities which will be subject to the requirement and the type of professional skills necessary for preparation of the report or record;
         * Identification, to the extent practicable, of all relevant federal rules which may duplicate, overlap or conflict with the proposed rule; and
         * A description of any significant alternatives to the planned proposed rule which would minimize any significant economic impact of the proposed rule on small entities consistent with the stated objectives of the authorizing statute.
The Panel's most significant findings and discussion with respect to each of these items are summarized below. To read the full discussion of the Panel findings and recommendations, see Section 9 of the Panel Report.
   1. Number and Types of Entities Affected
Six companies exist in this industry; five of the six companies are small businesses. All small businesses in the mineral wool production industry operate under NAICS code 327993.
   2. Recordkeeping, Reporting and Other Compliance Requirements
The proposed rule under consideration potentially impacts small businesses by requiring new emission limits on processes that were not regulated under the MACT standard promulgated in 1999, by requiring emission limits for pollutants that were not regulated under the MACT, or both processes and pollutants not regulated under the MACT. All companies are subject to Title V operating permits requirements, and as such will be required to add the newly regulated processes to their operating permits along with compliance demonstrations that the processes meet each pollutant emission limit in the rule. Compliance testing will be required to be conducted using EPA methods for each pollutant. Reporting and recordkeeping requirements are not expected to change from the MACT, with the exception of additional pollutants and processes included in such reports.
   3. Related Federal Rules
NAAQS: the most prevalent technology for reducing COS emissions will increase emissions of SO2. Under the current NAAQS, none of the small entities are in nonattainment areas, so installation of emissions control equipment should not subject them to additional permitting requirements under the SO2 NAAQS. However, the EPA cannot make such assurances about future NAAQS or future nonattainment zones, so there is a risk that future compliance with this rule could trigger additional emissions control requirements through the Title V/prevention of significant deterioration permit program.
GHG: Most emissions control strategies identified by the EPA during the Panel would increase the energy intensity of mineral wool production. Although the Panel does not have specific information about the GHG emissions of individual facilities in this industry, these facilities could be subject to GHG permitting as that program is phased in under the Tailoring Rule.
   4. Regulatory Flexibility Alternatives
The Panel agrees that the EPA does not have discretion in a number of areas that SER commented upon. Specifically, the EPA does not have the discretion to set the MACT floor emission limits at levels suggested by the SER. The Panel recognizes that EPA has the authority to review the MACT standard for completeness, risk, and technology improvements, and that the agency is currently under court order to conduct the risk and technology review for the mineral wool source category and propose amendments to the standard by October 31, 2011, and promulgate the amendments by October 31, 2012. However, whenever opportunities for regulatory flexibility arise, and when that regulatory flexibility can work to lessen impacts to small businesses, the Panel recommends that the EPA propose amendments to the mineral wool MACT that offer such regulatory flexibility to the maximum extent possible. Specifically, these opportunities arise in the following situations:
         * Selection of the averaging method in calculating the MACT floor for COS from cupolas and phenol, formaldehyde and methanol emissions from collection and curing processes; and
         * Subcategorization of regulated processes, when appropriate.
The Panel recommends that the EPA not require BTF emission limits for the mineral wool industry. Such limits are likely to have additional cost impacts to industry. In addition, the EPA did not identify BTF measures for consideration and has found that the results of the risk assessment show acceptable risks from this source category.
The Panel recommends subcategorization of collection along the lines described in Section 3 of the Panel Report, specifically, subcategorization for vertical collection and curing, horizontal collection and curing, and drum collection and curing. Based on available information, the Panel believes that emission standards based on the average emission limits across both collection and curing processes at each of the three subcategories would minimize the burden on small entities while fully complying with the EPA's obligations under section 112. The Panel also recommends setting MACT limits for new sources equal to MACT limits for existing sources.
The Panel recommends that the EPA allow the maximum amount of time within its discretion (3 years) and work with state permitting authorities to provide for the additional year permitted by the statute.
The Panel recommends that the EPA provide a detailed discussion in the preamble to the proposed rule that outlines the manner in which small entities may demonstrate compliance with the rule, when finalized, during start-up and shutdown. The Panel also recommends that the EPA propose allowing an affirmative defense against compliance actions for malfunction events, consistent with other section 112 rules recently promulgated. For more information on the SBAR Panel review process and findings, see Section IV.E of this preamble and the Final Report of the Small Business Advocacy Review Panel on the EPA's Planned Proposed Rule Risk and Technology Review (RTR) Amendments to the National Emission Standard for Hazardous Air Pollutants (NESHAP) for Mineral Wool Production October 2011 in the docket.
      c. Technical corrections to the rule.
We are also proposing revisions to certain terms in the existing NESHAP. Specifically, we are proposing to replace the term "incinerator" with "regenerative thermal oxidizer" to avoid confusion with rules promulgated under CAA section 129 and any new requirement that may be imposed on something called an "incinerator". We are also proposing to specify performance testing frequency for RTOs.
B. What are the proposed decisions and actions related to the Wool Fiberglass Manufacturing NESHAP?
      The following sections discuss the decisions proposed by this action with regard to the following topics: unregulated pollutants and emissions sources; the risk review; the technology review; our plans regarding area sources; recordkeeping, reporting and notification requirements; compliance requirements; and other proposed decisions and actions (i.e., changes in surrogacy and terminology cleanup).
1. Addressing Unregulated Pollutants and Emissions Sources.
      In the course of evaluating the 1999 MACT rule, we identified certain HAP for which we failed to establish emission standards in the original MACT (i.e., HF, HCl, phenol and methanol). As stated earlier, the EPA has "clear statutory obligation to set emissions standards for each listed HAP". National Lime v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000). The EPA specifically evaluated HF and HCl, from glass-melting furnaces and formaldehyde, phenol and methanol from RS manufacturing lines and FA manufacturing lines.
      a. Surrogacy.
As described in Sections III. B and VII.B of this preamble, the Court, in the Brick MACT decision, also found that the EPA erred when we did not establish emission limits for each HAPemitted from industrial processes regulated by the MACT standard. We are proposing to replace CO as a surrogate for COS with COS emissions limits. We are also proposing to discontinue use of formaldehyde as a surrogate for phenol and methanol. We are, therefore, proposing to add emission limits for COS, phenol and methanol. The proposed emissions limits can be found in Tables 4-6, below.
Table 4. Proposed Emissions limits for Rotary Spin (RS) Manufacturing Lines (pound of pollutant/ton of melt)
Pollutant
Existing RS Lines
New and Reconstructed RS Lines
Formaldehyde
0.17
0.020
Phenol
0.19
0.0011
Methanol
0.48
0.00067

Table 5. Proposed Emissions limits for Flame Attenuation (FA) Manufacturing Lines (pound of pollutant/ton of melt)
Pollutant
Existing FA Lines
New and Reconstructed FA Lines
Formaldehyde
5.6
3.3
Phenol
1.4
0.46
Methanol
0.50
0.50

Table 6. Proposed Emissions limits for Glass-Melting Furnaces (pound of pollutant/ton of melt)
Pollutant
Existing Furnaces
New and Reconstructed Furnaces
HF
0.002
0.00078
HCl
0.0015
0.00078

      b. Emission Limits for Unregulated HAPs.
For the Wool Fiberglass Manufacturing source category, we are proposing MACT limits for HF and HCl for glass-melting furnaces; formaldehyde, phenol and methanol from existing, new, and reconstructed RS manufacturing lines; and formaldehyde, phenol and methanol from existing, new, and reconstructed FA manufacturing lines. The proposed emissions limits can be found in Tables 4-6 above.
Section 112(d)(3)(B) of the CAA requires that the MACT standards for existing sources be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of sources (for which the Administrator has or could reasonably obtain emissions information) in a category with more than 30 sources. The Wool Fiberglass Manufacturing source category consists of 29 facilities with approximately 80 glass-melting furnaces. Since there are more than 30 furnaces, we based the MACT floor limit on the average emissions limitation achieved by the best performing 12 percent of furnaces.
The EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissions control that has been achieved by the best performing sources under variable conditions. It is recognized in the case law that the EPA may consider variability in estimating the degree of emissions reduction achieved by best-performing sources and in setting MACT floors. See Mossville Envt'l Action Now v. EPA, 370 F.3d 1232, 1241 - 42 (D.C. Cir 2004) (holding that the EPA may consider emissions variability in estimating performance achieved by best-performing sources and may set the floor at a level that a best-performing source can expect to meet "every day and under all operating conditions"). More details on how we calculate MACT floors and how we account for variability are described in the MACT Floor Analysis for the Wool Fiberglass Manufacturing Source Category which is available in the docket for this proposed action.
We considered beyond-the-floor options for the HF and HCl standards for all of the glass-melting furnaces and the formaldehyde, phenol and methanol standards for all RS manufacturing lines and FA manufacturing lines, as required by section 112(d)(2) of the Act. We decided not to propose any limits based on the beyond-the-floor analyses for any of these pollutants because of the costs, non-air environmental impacts, and adverse energy implications associated with use of these additional controls. The beyond-the-floor analysis is presented in the technical documentation for this action (MACT Floor Analysis for the Mineral Wool Production Source Category and the MACT Floor Analysis for the Wool Fiberglass Manufacturing Source Category).
2. Proposed decisions based on the Risk Review.
	Based on the results of our risk assessment and risk review (which are described in more detail in Section VIII of this preamble), we are proposing emission limits for chromium compounds under the authority of section 112(f)(2) of the CAA of 0.006 pounds of total chromium per thousand tons of glass pulled. As explained in Section VIII of this preamble, we are proposing these limits as an outcome of our ample margin of safety analysis.
3. Proposed decisions based on the Technology Review for the Wool Fiberglass Industry.
As explained in Sections VI.B and VIII.E of this preamble, we are proposing emissions limits for PM, under section 112(d)(6)(see Table 12 of Section VIII in this preamble). Furthermore, as explained in Section VIII.F of this preamble, we are proposing emissions limits for chromium compounds under section 112(d)(6) of the CAA as part of our technology review (see those sections for details) of 0.006 pounds of total chromium per thousand tons of glass pulled, which is the same limit we are proposing under Section 112(f)(2) of the CAA.
In our technology review for this industry, we discovered and evaluated two new technology developments that affect emissions from wool fiberglass manufacturing furnaces: furnace control technologies and high chrome refractories. These are discussed below.
Wool fiberglass furnaces are now equipped with air pollution control devices that achieve emissions of about 0.014 pounds PM per ton of glass produced. This is about 50 times lower than required under the MACT rule (0.5 lb PM per ton glass produced). In light of the record and additional data we received on PM emissions, we are proposing revised PM limits under the technology review of the wool fiberglass source category (as described in Section VIII of this preamble).
Glass-melting furnaces are constructed using refractories, which direct the heat of the furnace back into the melt. We are aware of a new technology that is used to significantly extend the life of the wool fiberglass furnace: refractories that are made of almost 100 percent chromium compounds and that are used to construct entire furnaces or very large parts of furnaces. Based on emission testing of one furnace, it appears that the levels of chromium compounds that can be emitted when glass-melting furnaces are constructed from high chrome refractories can be significant. This facility operates two furnaces. The total chromium compound emissions at this facility are estimated as 913 lb/yr assuming that both furnaces emit at a similar rate. This includes 840 pounds of hexavalent chromium. Industry information indicates that the furnaces emitting the highest levels of chromium compounds are constructed in whole or in part from these types of refractories. (Notes of April 14, 2011; Region 7 Certainteed Notes).[12,13]
It is our understandng that because of the corrosive properties of the molten glass, fresh refractory is continuously exposed to the molten glass along the metal/glass contact line in the glass-melting furnace process. This increases the surface area of the refractory that is exposed to the molten glass. As a result, when the glass furnace is constructed using high chrome refractories, the emission levels of chromium compounds continuously increase over the life of the furnace (Please refer to notes of April 14, 2011, telephone discussion between Susan Fairchild and Certainteed). One industry spokesperson estimated that 20,000 lb/yr of refractory are worn away from the inside walls of one wool fiberglass furnace and ducted to the control device before venting to the atmosphere.
On August 31, 2011, industry representatives met with the agency to provide data, in an attempt to improve our understanding of the levels of chromium content in refractory products used at wool fiberglass furnaces and their impacts on chromium complund emissions. In the meeting industry representatives stated the following:
 * the use of chromium in refractories is important to wool fiberglass operations because it extends the useful life of the furnace;
 * chromium content of furnaces vary from 0 to 95 percent
 * ; there is no distinction between the types of refractories used at the highest chrome emitting furnace and the refractories used to construct other glass furnaces that emit low levels of hexavalent chromium.
 * the type of furnace used at the high chromium emitting facility may may be responsible for increased hexavalent chromium emissions
 However, the information from the meeting appears to contradict other information on the reason for certain furnaces to have elevated chromium emissions. As previously discussed, emission test results from the 2010 testing and previous statements made to the EPA from owners/operators (Notes of April 14, 2011,Certainteed; Region 7 Certainteed notes) seem to inmly that the high chromium emissions are due to the chromium content of the refractory. Because of this contradictory information we are requesting additional emissions testing of wool fiberglass furnaces (discussed below). We are also soliciting comment on whether and how to subcategorize industry according to furnace type, or type of refractory. Commenters should also provide emissions test data to support their assertions regarding the correct manner in which to subcategorize the industry.

As shown in Table 12 of Section VIII of this preamble, we are proposing chromium compound emissions limits of 0.00006 lb/ton of glass produced. These limits would apply to wool fiberglass furnaces at major sources. However, there are no differences in furnaces at major sources and those at area sources. We are concerned about the levels of hexavalent chromium that can be emitted by area sources where furnaces may be constructed or reconstructed using high chrome refractories. We are announcing today our plans to regulate wool fiberglass area sources in a future action. We have issued a section 114 information collection request to the wool fiberglass industry to collect comprehensive information specific to the chrome content of the refractories used to construct their glass-melting furnaces and obtain complete chromium emissions test data. This information will enable us determine the scope of the source category (in terms of the universe of wool fiberglass producers that are area sources and that emit hexavalent chromium) to be regulated in the future action.
We are requesting information specific to wool fiberglass furnaces, including information on the chromium content of the refractories used in furnace construction, process rates and emissions testing. Nevertheless, we are soliciting comment from the public on our approach to limit emissions of chromium compounds as well as other alternatives to reducing emissions of chromium compounds, especially hexavalent chromium.
4. Reporting, Recordkeeping and Notification Requirements
      We are proposing to revise certain recordkeeping requirements of 40 CFR part 63, subpart NNN. Specifically, we are proposing that facilities maintain records and prepare and submit performance test reports to comply with the proposed emissions limits for PM, chromium compounds, HF, HCl, formaldehyde, phenol and methanol. Because refractory products can contain chromium compounds that can then be emitted to the ambient air during wool fiberglass manufacturing, we are proposing that owners/operators of glass manufacturing furnaces maintain records of the refractory brick composition from which the furnaces are constructed, including any rebricking or additional layers of refractory that are added to the outside furnace walls. In addition, owners and operators are required to keep records of the occurrence and duration of each malfunction or operation of the air pollution control equipment and monitoring equipment. We are also proposing requirements for the use of electronic reporting for all test methods that are supported by the ERT. Methods supported by ERT may be found at http://www.epa.gov/ttn/chief/ert/index.html.
5. Compliance Dates and Approaches.
      With regard to formaldehyde, HCL, HF, phenol and methanol, we are proposing that facilities that commenced construction or reconstruction on or before [INSERT DATE OF PUBLICATION OF THIS PROPOSED RULE IN THE FEDERAL REGISTER] must demonstrate compliance with the requirements of this subpart no later than 3 years after the effective date of this rule. Affected sources that commenced construction or reconstruction after the proposal date of this rule must demonstrate compliance with the requirements of this subpart no later than the effective date of the rule or upon start-up, whichever is later. We are proposing an initial performance test within 90 days of promulgation of the final rule.
      With regard to total chromium compounds, we are proposing that the requirements under CAA section 112(f)(2), if finalized, must be implemented no later than 90 days after the effective date of this rule, but the EPA may extend that timeframe for circumstances under which we believe the additional time is necessary for installation of air pollution control equipment or other measures to reduce HAP emissions. We are, therefore, allowing affected sources up to one year from the effective date of this rule to demonstrate compliance with the chromium emission limits. Consistent with CAA section 112(f)(4)(B), we are proposing that a one-year compliance period is necessary so that affected facilities have adequate time to install additional controls and demonstrate compliance, including the time necessary to purchase, install and test control equipment. Because these limits reflect the reductions from glass making furnaces required under both sections 112(d)(6) and 112(f)(2), we believe a one-year compliance timeframe is needed for the same reasons provided above. In addition, we are proposing that the PM emissions limit that would reflect reductions required for the glass making furnaces pursuant to CAA section 112(d)(6) must be met no later than one year after the effective date of this rule. We believe this time is needed to either enable installation of replacement bags, or if a facility decides to add a new baghouse in series with an existing baghouse, seek bids, select a vendor, install and test the new equipment; prepare and submit the reports in this proposed rule, if finalized.
Therefore, we are proposing that wool fiberglass facilities would be required to show compliance with both PM and the chromium limits within 1 year of promulgation of this standard. We are soliciting comments on this aspect of this proposed action.
Additionally, we propose that compliance with the proposed chromium compounds emissions limits be demonstrated by annual performance tests for all glass-melting furnaces subject to this rule as described in Section VI.B.2 of this preamble. We are proposing additional annual performance testing no later than 12 calendar months following the initial or previous performance or compliance test to demonstrate compliance with the chromium compounds emissions limit for furnaces.
We are proposing both an initial performance test and repeat testing every 5 years on the RS and FA lines and each time the binder formulation changes by more than 10 percent as compared to the binder formulation used in the initial performance test. We are seeking comment on whether the binder formulation variability of 10 percent as used here is appropriate.
We are proposing that compliance testing for PM, formaldehyde, phenol and methanol be conducted using the same test methods as required by the 1999 MACT rule (i.e., Method 5 for PM and Method 318 for formaldehyde, phenol and methanol). We are proposing Test Method 26A be used to determine compliance for HF and HCl and Test Method 0061 be used to ensure compliance with the chromium compounds emission limit.
We propose that continuous monitoring of temperatures of control devices (e.g., fabric filters, wet and dry ESP, scrubbers) for glass-melting furnaces, RS manufacturing lines, and FA manufacturing lines will be required as parametric monitoring to ensure continuous compliance with the PM, chromium compounds, HF, HCl, formaldehyde, phenol and methanol emissions limits.
Because the recent test data for glass-melting furnaces show a significant portion of the chromium compounds are hexavalent chromium, we are requiring Test Method 0061 be used to ensure compliance with the chromium compounds emission limit and as the most cost effective method to determine both total chromium and hexavalent chromium from wool fiberglass furnace stacks. Sources must report both total chromium and hexavalent chromium using this method or all chromium emissions are assumed to be hexavalent chromium.
6. Other Decisions and Actions.
In addition to the proposed decisions and actions discussed above, we are also proposing surrogacy changes and some general cleanup in terminology to the existing rule.
      a. Surrogacy.
As described in Sections III.B and VIII.B in this preamble, the Court found that the EPA has a "clear statutory obligation to set emission standards for each listed HAP." Because we did not conduct analyses that would support the use of formaldehyde as a surrogate for methanol and phenol, we cannot currently demonstrate that we established emission limits for the HAP methanol and phenol in the 1999 MACT standard. Therefore, we are proposing the emissions limits for phenol and methanol, which are presented in Tables 4-6, above.
      b. Technical corrections to the rule.
We are also proposing revisions to certain terms in the existing NESHAP. Specifically, we are proposing to replace the term "incinerator" with "RTO" and specify performance test frequency.
C. What are the proposed decisions and actions related to startup, shutdown and malfunction?
The United States Court of Appeals for the District of Columbia Circuit vacated portions of two provisions in the EPA's CAA section 112 regulations governing the emissions of HAP during periods of SSM. Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (U.S. 2010). Specifically, the Court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), that are part of a regulation, commonly referred to as the "General Provisions Rule," that the EPA promulgated under CAA section 112. When incorporated into CAA section 112(d) regulations for specific source categories, these two provisions exempt sources from the requirement to comply with the otherwise applicable CAA section 112(d) emissions standard during periods of SSM.
We are proposing the elimination of the SSM exemption in this rule. Consistent with Sierra Club v. EPA, the EPA is proposing standards in this rule that apply at all times. We are also proposing several revisions to Table 1 to subparts DDD and NNN of part 63 (the General Provisions Applicability table). 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 or revise certain recordkeeping and reporting that related to the SSM exemption. The EPA has attempted to ensure that we have not included in the proposed regulatory language any provisions that are inappropriate, unnecessary, or redundant in the absence of the SSM exemption. We are specifically seeking comment on whether there are any such provisions that we have inadvertently incorporated or overlooked.
In proposing the standards in this rule, the EPA has taken into account startup and shutdown periods and, for the reasons explained below, is proposing emissions limits for those periods. Information on periods of startup and shutdown received from the industry survey indicate that emissions during these periods are less than emissions during production. Control devices such as baghouses for PM and metal HAP particulate control and RTO for COS control are started up before the process units, and are operational during the shutdown phase of a process. Therefore, no increase in emissions is expected during these periods. Because the processes are ducted to the control device before startup and after shutdown, and because emissions during startup and shutdown are not more than emissions during production, startup and shutdown emissions limits should be equivalent to the emissions limits for production. Production based emissions limits are expressed in this rule on a pound of pollutant per ton melt basis. However, during startup and shutdown, there is no melt being produced. Therefore, separate standards for periods of startup and shutdown were developed by translating the production-based emissions limits from a pound per ton basis to a pound of pollutant per hour basis and are being proposed in this rule. Periods of startup, normal operations and shutdown are all predictable and routine aspects of a source's operations. However, by contrast, malfunction is defined as a "sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment or a process to operate in a normal or usual manner * * *" (40 CFR 63.2). The EPA has determined that CAA section 112 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 112 standards. Under CAA section 112, emissions standards for new sources must be no less stringent than the level "achieved" by the best controlled similar source and for existing sources generally must be no less stringent than the average emissions limitation "achieved" by the best performing 12 percent of sources in the category. There is nothing in CAA section 112 that directs the agency to consider malfunctions in determining the level "achieved" by the best performing or best controlled sources when setting emissions standards. Moreover, while the EPA accounts for variability in setting emissions standards consistent with the CAA section 112 case law, nothing in that case law requires the agency to consider malfunctions as part of that analysis. Section 112 of the CAA uses the concept of "best controlled" and "best performing" unit in defining the level of stringency that CAA section 112 performance standards must meet. Applying the concept of "best controlled" or "best performing" to a unit that is malfunctioning presents significant difficulties, as malfunctions are sudden and unexpected events.
Further, accounting for malfunctions would be difficult, if not impossible, given the myriad different types of malfunctions that can occur across all sources in the category and given the difficulties associated with predicting or accounting for the frequency, degree and duration of various malfunctions that might occur. As such, the performance of units that are malfunctioning is not "reasonably" foreseeable. See, e.g., Sierra Club v. EPA, 167 F. 3d 658, 662 (D.C.Cir. 1999) (the EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a problem. The court generally defers to the agency's decision to proceed on the basis of imperfect scientific information, rather than to "invest the resources to conduct the perfect study."). See also, Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) ("In the nature of things, no general limit, individual permit or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by `uncontrollable acts of third parties,' such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case-by-case enforcement discretion, not for specification in advance by regulation"). In addition, the goal of a best controlled or best performing source is to operate in such a way as to avoid malfunctions of the source and accounting for malfunctions could lead to standards that are significantly less stringent than levels that are achieved by a well-performing non-malfunctioning source. The EPA's approach to malfunctions is consistent with CAA section 112 and is a reasonable interpretation of the statute.
In the event that a source fails to comply with the applicable CAA section 112(d) standards as a result of a malfunction event, the EPA would determine an appropriate response based on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. The EPA would also consider whether the source's failure to comply with the CAA section 112(d) standard was, in fact, "sudden, infrequent, not reasonably preventable" and was not instead "caused in part by poor maintenance or careless operation" 40 CFR 63.2 (definition of malfunction).
Finally, the EPA recognizes that even equipment that is properly designed and maintained can sometimes fail and that such failure can sometimes cause an exceedance of the relevant emissions standard (see, e.g., State Implementation Plans: Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); Policy on Excess Emissions During Startup, Shutdown, Maintenance and Malfunctions (Feb. 15, 1983)). The EPA is, therefore, proposing to add to the final rule an affirmative defense to civil penalties for exceedances of emissions limits that are caused by malfunctions. See 40 CFR 63.542 (defining "affirmative defense" to mean, in the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding). We also are proposing other regulatory provisions to specify the elements that are necessary to establish this affirmative defense; the source must prove by a preponderance of the evidence that it has met all of the elements set forth in 40 CFR 63.552 (40 CFR 22.24). The criteria ensure that the affirmative defense is available only where the event that causes an exceedance of the emissions limit meets the narrow definition of malfunction in 40 CFR 63.2 (sudden, infrequent, not reasonable preventable and not caused by poor maintenance and or careless operation). For example, to successfully assert the affirmative defense, the source must prove by a preponderance of the evidence that excess emissions "[w]ere caused by a sudden, infrequent, and unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner...." The criteria also are designed to ensure that steps are taken to correct the malfunction, to minimize emissions in accordance with 40 CFR 63.543(j) and to prevent future malfunctions. For example, the source must prove by a preponderance of the evidence that "[r]epairs were made as expeditiously as possible when the applicable emissions limitations were being exceeded..." and that "[a]ll possible steps were taken to minimize the impact of the excess emissions on ambient air quality, the environment and human health...." In any judicial or administrative proceeding, the Administrator may challenge the assertion of the affirmative defense and, if the respondent has not met its burden of proving all of the requirements in the affirmative defense, appropriate penalties may be assessed in accordance with CAA section 113 (see also 40 CFR 22.27).
The EPA included an affirmative defense in the proposed rule in an attempt to balance a tension, inherent in many types of air regulation, to ensure adequate compliance while simultaneously recognizing that despite the most diligent of efforts, emission limits may be exceeded under circumstances beyond the control of the source. The EPA must establish emission standards that "limit the quantity, rate, or concentration of emissions of air pollutants on a continuous basis." 42 U.S.C. § 7602(k)(defining "emission limitation and emission standard"). See generally Sierra Club v. EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008). Thus, the EPA is required to ensure that section 112 emissions limitations are continuous. The affirmative defense for malfunction events meets this requirement by ensuring that even where there is a malfunction, the emission limitation is still enforceable through injunctive relief. While "continuous" limitations on the one hand are required, there is also case law indicating that in many situations it is appropriate for the EPA to account for the practical realities of technology. For example, in Essex Chemical v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973), the D.C. Circuit acknowledged that in setting standards under CAA section 111 "variant provisions" such as provisions allowing for upsets during startup, shutdown and equipment malfunction "appear necessary to preserve the reasonableness of the standards as a whole and that the record does not support the `never to be exceeded' standard currently in force." See also, Portland Cement Association v. Ruckelshaus, 486 F.2d 375 (D.C. Cir. 1973). Though intervening case law such as Sierra Club v. EPA and the CAA 1977 amendments undermine the relevance of these cases today, they support the EPA's view that a system that incorporates some level of flexibility is reasonable. The affirmative defense simply provides for a defense to civil penalties for excess emissions that are proven to be beyond the control of the source. By incorporating an affirmative defense, the EPA has formalized its approach to upset events. In a Clean Water Act setting, the Ninth Circuit required this type of formalized approach when regulating "upsets beyond the control of the permit holder." Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977). But see, Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an informal approach is adequate). The affirmative defense provisions give the EPA the flexibility to both ensure that its emission limitations are "continuous" as required by 42 U.S.C. §7602(k), and account for unplanned upsets and thus support the reasonableness of the standard as a whole.
D. What are the proposed decisions and actions related to electronic reporting?
Records must be maintained in a form suitable and readily available for expeditious review, according to 63.10(b)(1). Electronic recordkeeping and reporting is available for many records, and is the form considered most suitable for expeditious review if available. Electronic recordkeeping and reporting is encouraged in this proposal and some records and reports are required to be kept in electronic format. Records required to be maintained electronically include the output of continuous monitors and the output of the BLDS. Additionally, standard operating procedures for the BLDS and fugitive emissions control are required to be submitted to the Administrator for approval in electronic format.
VII. Rationale for the Proposed Actions for the Mineral Wool Production Source Category
As discussed in Section VI.A of this preamble, we evaluated emissions limits for PM, COS, HF, HCl, formaldehyde, phenol and methanol at mineral wool production facilities. This section of the preamble provides the results of the RTR, our rationale for the proposed actions and decisions concerning changes to the 1999 MACT rule for the Mineral Wool Production source category.
A. What data were used for the NESHAP analyses?
To perform the technology review and residual risk analysis for the Mineral Wool NESHAP, we created a comprehensive dataset based on existing and new test data provided by the 7 mineral wool facilities. As described in Section IV.C of this preamble, the voluntary industry survey requested available information regarding process equipment, control devices, point and fugitive emissions, practices used to control fugitive emissions, and other aspects of facility operations. In addition to the industry survey, each owner/operator was asked to submit reports for any recent emissions tests conducted at their facility and to conduct additional emissions tests in 2010 for certain HAP from specific processes. Pollutants tested for the mineral wool source category in 2010 included most HAP metals, CO, PM and certain organic HAP (formaldehyde, phenol, methanol and carbonyl sulfide).
B. What are the proposed decisions regarding surrogacy relationships?
In the 1999 MACT rule, PM serves as the surrogate for metal HAP at existing and new cupolas, CO serves as the surrogate for COS at new cupolas and formaldehyde serves as the surrogate for phenol and methanol from curing ovens. The 1999 MACT standard does not have emissions limits for COS, HCl or HF from existing cupolas; limits for phenol or methanol from curing; or emissions limits for any pollutants from collection operations. We are proposing HAP-specific emission limits for these pollutants under CAA section 112(d)(3)in this action.
 The agency is retaining use of PM as a surrogate for HAP metals. As discussed in Sections III.B and VII.B. of this preamble, the Court found that the EPA must set emission limits for each listed HAP (Sierra Club v. EPA, 479 F. 3d 875 (D.C. Cir. March 13, 2007))[3], and agreed with the EPA that nothing in the CAA suggests that it is prohibited from resetting the MACT floors in order to correct our own errors. They also agreed that the approach our petitioners labeled "MACT-on-MACT" would be more accurately described as "MACT-on-Unsupportable-Standards-Erroneously-Labeled-as-MACT".
 With regard to the evaluation of potential MACT limits for HAP metals from this source category, consistent with the explanation presented in the proposal of the 1999 MACT rule (NESHAP for Mineral Wool Production, Proposed Rule, June 1, 1997, 64 FR 29490) for this source category describing the appropriateness of PM as a surrogate for HAP metals, we continue to consider PM as an appropriate surrogate for HAP metals in the proposed amendments to the NESHAP in this action.
The agency is proposing emissions limits for phenol and methanol because the concentration of formaldehyde in a specific binder formulation is independent of phenol and/or methanol. The mineral wool industry commented during the small business advocacy review that the binder ingredients and formulation can vary from one mineral wool company to the next, and that the test data from one company is not necessarily relevant for or representative of another company.
In summary, under 112(d)(3) we are proposing emission limits for COS, HF and HCl from cupolas; and for formaldehyde, methanol and phenol from bonded lines.
C. What are the proposed decisions regarding certain unregulated emissions sources?
In the course of evaluating the Mineral Wool Production source category, we identified certain HAP for which we failed to establish emission standards in the original MACT. See National Lime v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000) (the EPA has "clear statutory obligation to set emissions standards for each listed HAP"). Specifically, we evaluated emissions standards for COS, HF and HCl for cupolas and formaldehyde, phenol and methanol for curing ovens and collection operations at mineral wool production facilities, that are not specifically regulated in the existing 1999 MACT standard. We are proposing emissions limits for these pollutants and processes pursuant to 112(d)(2) and 112(d)(3) as discussed in Section V.A of this preamble.
D. What are the proposed decisions regarding subcategorization?
The EPA collected information from the mineral wool companies that operate bonded lines to better understand the different equipment designs and whether all collection processes are the same, or whether design and manufacturing process differences warranted consideration of subcategories for the collection process. This process led to the identification of three distinct process design subcategories: vertical, horizontal and drum. Because collection processes only emit HAP if they occur on a bonded line, we are proposing to bundle collection operations and curing ovens together for each of three subcategories and propose new emissions limits for formaldehyde, phenol, and methanol at combined collection/curing on bonded lines. The following discussion involves the rationale for subcategorization of collection operations into three subcategories:
1. The Vertical Collection Design.
During the production of wool fiberglass on a bonded production line using a vertical collection design, the molten rock/slag mixture is poured from the cupola spout onto a group of stainless steel drums spinning in opposite directions. The spinning drums form fine fibers of the mineral mixture. High air volume directs the fibers off the fiberization spinners toward a fast-moving porous vertical conveyor belt. A strong vacuum is drawn on the opposite side of the belt causing the fibers to lie against the vertical belt as it moves upward. At the top of the conveyance, the belt travels around a curve, the vacuum is released, and the fibers are moved onto a second belt that conveys the layer of binder-sprayed mineral wool fibers into the curing oven. Because the conveyor belt is vertical, the air volume drawn through the belt and fiber layer must be very high and the resulting fiber layer that is collected on the belt is thin. In this design, `shot' (BB-sized black granules that are high in iron as a result of using slag from the iron and steel industry) falls out of the fiber layer. The vertical design is used to produce a specific type of mineral wool that is low in `shot' and may be used in the hydroponic gardening market as well as in a specialized market of insulation products in which shot is undesirable.
Currently, only one facility operates this type of collection design. Formaldehyde, phenol and methanol MACT floors for existing, new and reconstructed sources in this subcategory were based on emissions test runs for combined curing and collection operations from this facility.
2. The Horizontal Collection Design.
Horizontal collection is similar to vertical collection, but because the conveyor belt is horizontal it works with gravitational forces. The layer of mineral wool collected on a horizontal belt is thinner than that collected on a vertical belt, and the `shot' is not selectively removed. The air volume that is drawn through the fiber layer is much lower than in the vertical design, and therefore the air stream is conducive to thermal oxidation at the hottest part of the cupola exhaust stack or the existing thermal oxidizer on the curing oven.
Currently, only one facility operates this type of collection design. Formaldehyde, phenol and methanol MACT floors for existing, new and reconstructed sources in this subcategory were based on emissions test runs for combined curing and collection operations from this facility.
3. The Drum Collection Design.
In the drum collection design, fibers are drawn using a very high volume air flow into the center of a rotating drum. The sides of the rotating drum have small holes that allow the air flow to exit, but which trap the fibers. The angle of the drum and the use of a vacuum and centrifugal force pull the fibers against the inside wall of the drum and out the end. The entire drum is enclosed and the air flow may be vented to the hottest part of the cupola exhaust stack or to the existing thermal oxidizer on the curing oven.
Currently, only one facility operates this type of collection. Formaldehyde, phenol, and methanol MACT floors for existing, new, and reconstructed sources in this subcategory were based on emissions test runs for combined curing and collection operations from this facility.
E. What are the results from the risk assessments performed and the proposed decisions for the Mineral Wool Production Source Category?
As described in Section V.A of this preamble, we conducted an inhalation risk assessment for all HAP emitted from the Mineral Wool Production source category. We also conducted multipathway screenings for cadmium, mercury, and lead. Details of the risk assessments and additional analyses can be found in the draft residual risk documentation referenced in Section V.A of this preamble, which is available in the docket for this action. The agency considered the available health information - the MIR; the numbers of persons in various risk ranges; cancer incidence; the maximum non-cancer HI; the maximum acute non-cancer hazard; the extent of non-cancer risks; the potential for adverse environmental effects; and the distribution of risks in the exposed population (54 FR 38044, September 14, 1989)  -  in developing the proposed CAA section 112(f)(2) standards for the Mineral Wool Production source category.
1. Inhalation Risk Assessment Results for the Mineral Wool Production Source Category.
Table 7 of this preamble provides an overall summary of the results of the inhalation risk assessment.
Table 7. Mineral Wool Production Inhalation Risk Assessment Results
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 Non-cancer
TOSHI[2]
Maximum Screening Acute Non-cancer HQ[3]
Based on Actual Emissions Level
Based on Allowable Emissions Level

Based on Actual Emissions Level
Based on Allowable Emissions Level

4
10
1,650
0.0004
0.04
0.1
8 (REL)
0.4 (AEGL-1, ERGP-1)
[1] Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
2 Maximum TOSHI. The highest TOSHI for the Mineral Wool Production source category is for the respiratory system.
[3] The maximum HQ acute value of 8 is driven by emissions of formaldehyde. It is also based on a refined emissions multiplier of 3 which was used to estimate the peak hourly emission rates from the average rates. See section V.A. of this preamble for explanation of acute dose-response values.

The results of the chronic inhalation cancer risk assessment indicate that, based on estimates of current actual emissions, the MIR could be up to 4-in-1 million, with formaldehyde primarily driving these risks. The total estimated cancer incidence from this source category based on actual emission levels is 0.0004 excess cancer cases per year or one case in every 2,500 years, with emissions of formaldehyde and arsenic compounds contributing 64 percent and 33 percent, respectively, to this cancer incidence. In addition, we note that no persons are estimated to have cancer risks greater than 10-in-1 million, and approximately 1,650 people are estimated to have risks greater than 1-in-1 million as a result of emissions from 1 facility. When considering the risks associated with MACT-allowable emissions, the MIR could be up to 10-in-1 million. The maximum modeled chronic non-cancer TOSHI value for the Mineral Wool Production source category could be up to 0.04 with emissions of formaldehyde dominating those impacts, indicating no significant potential for chronic non-cancer impacts.
Our screening analysis for worst-case acute impacts indicates the potential for only one pollutant, formaldehyde, to exceed an HQ value of 1 at only one facility in this source category, with a potential maximum HQ up to8. A refined emissions multiplier of 3 was used to estimate the peak hourly emission rates from the average rates. Refer to Appendix 7 of the draft residual risk document in the docket for a detailed description of how the refined emissions multiplier was developed for the Mineral Wool Production source category. The worst-case acute impact estimate occurs at a facility that is located in a rural area with a small population. Since the acute modeling scenario is worst-case because of its confluence of peak emission rates and worst-case dispersion conditions, and since the HQ estimates for formaldehyde based on the AEGL-1 and ERPG-1 values for this facility are well below 1, we are proposing to find that acute noncancer health impacts of concern are unlikely.
With respect to the potential for adverse environmental effects from non PB-HAP, we note that that there is a lack of information about specific adverse environmental effects occurring at given concentrations of the HAP emitted by this source category. However, given that all chronic non-cancer HQ values considering actual emissions are less than 1 using human health reference values, we believe that it is unlikely that adverse environmental effects would occur at the actual HAP concentrations estimated in our human health risk assessment.
2. Multipathway Risk Assessments and Results.
There were no exceedances of screening emissions rates for the PB HAP emitted by the facilities in the Mineral Wool Production source category, thus we have no concerns about potential multi-pathway risks from this source category.
3. Facility Wide Risk Assessment Results.
For all facilities in this source category, there are no other significant HAP emissions sources present beyond those included in the source category. All significant HAP sources have been included in the source category risk analysis. Therefore, we conclude that the facility wide risks are essentially the same as the source category risks.
F. What are our proposed decisions for the Mineral Wool Production source category based on risk acceptability and ample margin of safety?
1. Risk Acceptability
As noted in Section V.A of this preamble, we weigh all health risk factors in our risk acceptability determination, including the MIR; the numbers of persons in various risk ranges; cancer incidence; the maximum noncancer HI; the maximum acute noncancer hazard; the extent of noncancer risks; the potential for adverse environmental effects; and distribution of risks in the exposed population; and risk estimation uncertainty (54 FR 38044, September 14, 1989) in developing the proposed CAA section 112(f)(2) standards for this source category.
Based on the inhalation risk assessment, we estimate that the cancer risks to the individual most exposed could be up to 4-in-1 million due to actual emissions and up to 10-in-1 million due to MACT-allowable emissions, mainly due to formaldehyde stack emissions. We estimate that the incidence of cancer based on actual emissions is 0.0004 excess cancer cases per year or one case every 2,500 years, and that about 1,650 people face a cancer risk greater than 1-in-1 million due to HAP emissions from this source category. Our assessments also indicated a low potential for HAP emissions from these sources to pose any significant adverse environmental effects or human health multi-pathway risks or chronic noncancer human health risks due to inhalation. While our acute risk screening ruled out the possibility of acute impacts of concern for all pollutants except for formaldehyde at one facility, we ultimately concluded that the potential for acute impacts of concern at this facility is low. The risk assessment for this source category was largely based on facility-specific stack test data and emissions estimates, indicating a high degree of confidence in the results. Considering all of the above information, we are proposing that the current risks due to actual HAP emissions from this source category are acceptable.
While the estimated chronic risks associated with MACT-allowable emissions from this source category are slightly higher than risk estimates based on actual emission levels, they are still well below 100 in one million and there are no other significant risks. Therefore, we propose the risks due to allowable emissions are also acceptable.
2. Ample Margin of Safety.
As explained earlier in Section V of this preamble, the agency again considers all of the health risks and other health information considered in the first step. Beyond that information, we evaluate the cost and feasibility of available control technologies and other measures (including the controls, measures and costs reviewed under the technology review) that could be applied in this source category to further reduce the risks due to emissions of HAP identified in our risk assessment.
Based on our research and analyses as discussed in Section V.C of this preamble, we have not identified any feasible control options beyond what we are requiring in our proposed standards for emissions sources described above, and are therefore not proposing additional controls, under section 112(f)(2). Therefore, we are proposing that the MACT standards for the mineral wool production source category, as revised per above, provide an ample margin of safety to protect public health and prevent adverse environmental effects.
Nevertheless, we are soliciting comments and information regarding additional control measures and work practices that may be available and their feasibility in further reducing stack emissions of COS, HF, HCl, formaldehyde, phenol, and methanol, or additional monitoring that may be warranted to ensure adequate control of these emissions.
G. What are the results from the technology review and proposed decisions?
Based on our technology review, we believe that the reductions in HAP emissions since promulgation of the 1999 Mineral Wool Production MACT rule are directly related to improvements in two areas: (1) improvements in fabric filter control technology (e.g., improved bag materials, replacement of older baghouses) and (2) addition of regenerative thermal oxidizers (RTOs) and oxygen injection to control emissions from cupolas. Additional reductions have been achieved due to the use of low-sulfur raw materials at one facility. The RTOs and lower sulfur raw materials are discussed above (in Section VII.C of this preamble) since these controls and measures are relevant to development of the MACT standards for COS and other organic HAPs under Section 112(d)(2) of the CAA, and in the beyond the floor analyses (described in Section VII.C of this preamble) that we also do as part of the MACT standard evaluations under Section 112(d)(2) and 112(d)(3).
In this section, as part of our technology review, we describe developments in development in fabric filter technologies and the relationship to PM emissions.
Slight improvements in fabric filter control technology are reflected in the emissions test data collected under the industry survey. The emissions limit for PM under the 1999 MACT rule is a production-based limit of 0.1 pounds of PM per ton of melt for new and existing cupolas. Based on our analysis of survey responses and test data collected under the industry survey, this industry primarily uses fabric filters to control emissions of metal HAP, and sources affected by the current PM limit are achieving PM concentrations at control device outlets that are only slightly below the current limit (see Technology Review for the Mineral Wool Production Manufacturing Source Category). Given fluctuations in control device performance and mineral wool production fluctuations, we do not believe that developments in practices, processes, and control technologies warrant revisions to the PM limit in the 1999 MACT rule to reflect HAP metal emissions levels achieved in practice.
Moreover, the RBLC did not identify any practices, processes, or control technologies applicable to the emission sources in this source category that were not identified and evaluated during the original MACT development.
In summary, we have not identified any additional relevant cost-effective developments in technologies, practices or processes since promulgation of the MACT rule to further reduce HAP emissions. Therefore, we are not proposing any changes to the MACT standards in this action as a result of our technology review under Section 112(d)(6) for Mineral Wool Production.
Additional details regarding these analyses can be found in the following technical document for this action which is available in the docket: Technology Review for the Mineral Wool Production Manufacturing Source Category.

VIII. Rationale for the Proposed Actions for the Wool Fiberglass Manufacturing Source Category
As discussed in Section VI.B of this preamble, we evaluated emissions limits for PM, chromium compounds, HF, HCl, formaldehyde, phenol, and methanol at wool fiberglass manufacturing facilities. This section of the preamble provides the results of the RTR, our rationale for the proposed actions for the Wool Fiberglass Manufacturing source category, and our proposed decisions concerning changes to the 1999 MACT rule.
A. What data were used for the NESHAP analyses?
To perform the technology review and residual risk analysis for the Wool Fiberglass Manufacturing NESHAP, we created a comprehensive dataset based on existing and new test data provided by 26 of the 29 wool fiberglass facilities. As described in Section IV.C of this preamble, the voluntary industry survey requested available information regarding process equipment, control devices, point and fugitive emissions, practices used to control fugitive emissions, and other aspects of facility operations. In addition to the ICR survey, each facility was asked to submit reports for any recent emissions tests conducted and to conduct additional emissions tests in 2010 for certain HAP from specific processes. Pollutants tested for the wool fiberglass source category in 2010 included most HAP metals, PM, and certain organic HAP (HF, HCl, formaldehyde, phenol, and methanol).
As discussed in Section IV.C above, in the emissions testing for the survey, industry requested to conduct emission testing on furnaces they believed were representative of the other furnaces in operation. The EPA and industry agreed that the bases for representativeness would include a variety of factors such as processing the same materials, producing the same products and being the same type of furnace. Furnace construction and refractory composition were not factors that were presented by industry as having an effect on HAP emissions, and those factors were not used as a basis of representativeness for the resulting data set. During analysis of the test data, the EPA discovered high emissions of chromium compounds, including hexavalent chromium, and that these emissions were mostly from certain furnaces constructed of high chrome refractories.
The Wool Fiberglass Manufacturing source category consists of 29 facilities with 80 furnaces, 54 RS manufacturing lines and less than 30 FA manufacturing lines. Since there are more than 30 furnaces and RS lines, we based the MACT floor limits on the average emissions limitation achieved by the best performing 12 percent of sources. Therefore, the MACT floor for HF and HCl from glass-melting furnaces was based on the 10 best performing furnaces; the 7 best performing RS lines; and the 5 best performing FA lines.
The stack test data were used to calculate the MACT floors using the 99 percent UPL for glass-melting furnaces, RS manufacturing lines, and FA manufacturing lines from wool fiberglass manufacturing plants. The UPL analysis is explained in more detail in MACT Floor Analysis for the Wool Fiberglass Manufacturing Source Category, which is available in the docket for this proposed action. The results from the MACT floor analysis are presented in Section VI.B of this preamble.
B. What are the proposed decisions regarding surrogacy relationships?
A surrogate approach is used to allow for easier and less expensive measurement and monitoring requirements. In the 1999 MACT rule for this source category, PM serves as the surrogate for metal HAPs at existing and new glass-melting furnaces and formaldehyde serves as the surrogate for phenol and methanol from forming and curing at RS manufacturing lines and forming and curing at FA manufacturing lines. As described in Sections III.B and VIII.B in this preamble, the court found that the EPA erred when we did not set emission limits for each HAP emitted by industry processes in the MACT standards. Therefore, the agency is proposing HAP-specific emissions limits for phenol and methanol.
C. What are the proposed decisions regarding certain unregulated emissions sources?
As discussed earlier in Section VI.B of this preamble, we identified certain HAP for which we failed to establish emission standards in the original 1999 MACT. In the 1999 MACT rule, we used formaldehyde as a surrogate for phenol and methanol, and we did not establish HAP-specific emission limits for phenol, methanol, HF and HCl. For this action we evaluated emissions standards for HF, HCl, phenol, and methanol at wool fiberglass manufacturing facilities, described below, that are not specifically regulated in the existing 1999 MACT standard. The EPA is therefore proposing to set emissions limits for these HAP emissions, under CAA section 112(d)(3) in this action.
D. What are the results from the risk assessments and analyses and the proposed decisions for the Wool Fiberglass Manufacturing Source Category?
An inhalation risk assessment was completed for all HAP emitted for the Wool Fiberglass Manufacturing source category. Details of the risk assessments and additional analyses can be found in the residual risk documentation referenced in Section V.A of this preamble. The agency considered the available health information -- the MIR; the numbers of persons in various risk ranges; cancer incidence; the maximum non-cancer HI; the maximum acute non-cancer hazard; the extent of non-cancer risks; the potential for adverse environmental effects; and distribution of risks in the exposed population (54 FR 38044, September 14, 1989)  -  in developing the proposed CAA section 112(f)(2) standards for the Wool Fiberglass Manufacturing source category.
1. Inhalation Risk Assessment Results for the Wool Fiberglass Manufacturing Source Category.
Table 8 of this preamble provides an overall summary of the results of the inhalation risk assessment.
Table 8. Wool Fiberglass Manufacturing Inhalation Risk Assessment Results
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 Non-cancer
TOSHI[2]
Maximum Screening Acute Non-cancer HQ[3]
Based on Actual Emissions Level
Based on Allowable Emissions Level

Based on Actual Emissions Level
Based on Allowable Emissions Level

40
60
849,000
0.05
0.2
0.5
30 (REL)
2 (AEGL-1, ERPG-1)
[1] Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category. Hexavalent chromium is the primary driver for cancer risk.
2 Maximum TOSHI. The highest TOSHI for the Wool Fiberglass Manufacturing source category is for the respiratory system.
3 The maximum HQ acute value of 30 is driven by emissions of formaldehyde. See section V.A. of this preamble for explanation of acute dose-response values.

The results of the chronic inhalation cancer risk assessment indicate that, based on estimates of current actual emissions, the maximum individual lifetime cancer risk (MIR) could be up to 40-in-1 million. The major contributor to this cancer risk is hexavalent chromium that is emitted from the furnace refractory brick. The greatest amount of hexavalent chromium emitted from a single source is from a facility that currently uses a type of refractory brick that is made almost entirely of chromium compounds. In addition, we note that approximately 12,000 people are estimated to have cancer risks greater than 10-in-1 million as a result of formaldehyde and hexavalent chromium emissions at 2 facilities, and approximately 849,000 people are estimated to have risks greater than 1-in-1 million as a result of formaldehyde and hexavalent chromium emissions from 15 facilities. The maximum estimated chronic non-cancer TOSHI value for the Wool Fiberglass Manufacturing source category is 0.2 with emissions of formaldehyde dominating those impacts, indicating no significant potential for chronic non-cancer impacts.
Based on the acute REL to assess possible acute non-cancer effects due to emissions of formaldehyde, our analysis indicates that the maximum acute HQ value could exceed a value of 1 at a total of 7 facilities due to formaldehyde emissions, with one facility in this source category indicating the potential to create a maximum worst-case HQ value up to 30. This maximum worst-case acute impact corresponds to a maximum HQ of 2 based on the AEGL-1 and ERPG-1 levels for formaldehyde. Altogether, these results indicate that we cannot rule out the potential for formaldehyde emissions from this source category to cause acute impacts of mild concern, such as eye and nose irritation. Repeated exposures to these levels (i.e., at or above the AEGL-1 and ERPG-1) could cause further health concerns.
With respect to the potential for adverse environmental effects from non PB-HAP, we note that that there is a lack of information about specific adverse environmental effects occurring at given concentrations for the HAP emitted by this source category. However, given that all chronic non-cancer HQ values considering actual emissions are less than 1 using human health reference values, we believe that it is unlikely that adverse environmental effects would occur at the actual HAP concentrations estimated in our human health risk assessment.
2. Auxiliary Risk Characterization.
      As indicated in Section VIII.D.1 above, the MIR for the Wool Fiberglass Manufacturing source category could be up to 40-in-1-million based on actual emissions. The major contributor to this cancer risk is hexavalent chromium. The greatest amount of risk is from one facility that uses a type of refractory brick that is described by the company as "high chrome"[12][,13].( (Notes of April 14, 2011, Certainteed); (Region 7 Certainteed Notes).
      Because the use of high chrome refractories extends the life of the furnace from a maximum of 10 years to at least 15 years, and the cost of furnace construction is increased by about 15 percent when it is reconstructed using high chrome refractories[1][2] (Notes of April 14, 2011, Certainteed) we believe that there is a financial incentive for other facilities to switch to this high chromium refractory at the time they rebuild their furnaces. For this reason, we performed an auxiliary risk characterization analysis to assess the potential maximum individual lifetime cancer risks in the event that the other 28 Wool Fiberglass facilities switch to the high chromium brick. For the auxiliary risk characterization analysis it was assumed that the hexavalent chromium emissions for each facility would be the same as that for the facility with annual emissions of 420 lbs of hexavalent chromium per furnace. Table 9 of this preamble provides a summary of the results of this auxiliary inhalation risk assessment.
Table 9. Wool Fiberglass Manufacturing Auxiliary Inhalation Risk Assessment Results
Potential Maximum
Individual
Cancer Risk
(in 1 million)[1]
Estimated Population
at increased Risk of cancer >= 1-in-1 Million
Estimated Population
at increased Risk of cancer >= 10-in-1 Million
Estimated Population
at increased Risk of cancer >= 100-in-1 Million
Estimated Annual
Cancer
Incidence (cases per year)
Based on Actual Emissions Level

900
7,300,000
460,000
8,100
0.46
[1] Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category.

The results of the auxiliary analysis indicate that, under this scenario, the estimated emissions from 14 facilities could lead to maximum individual lifetime cancer risks greater than 100-in-1-million, with the highest emitting facility posing a potential maximum individual risk of 900-in-1-million. Under this scenario, 8,100 people would be exposed to risks greater than 100-in-1-million, 460,000 people would be exposed to risks of greater than 10-in-1-million, and over 7 million people would be exposed to cancer risks of greater than 1-in-1-million.
In summary, the auxiliary risk analysis indicates that if other facilities switch to high chromium refractory, emissions of hexavalent chromium could potentially pose unacceptable risks to public health due to inhalation exposures resulting from stack emissions of hexavalent chromium.
3. Multipathway Risk Assessments and Results.
None of the facilities in the Wool Fiberglass Manufacturing source category reported emissions of PB HAP that were greater than the screening emission rates. Therefore, multi-pathway exposures and environmental risks were deemed negligible.
4. Facility Wide Risk Assessment Results.
For this source category, there are no other significant HAP emissions sources present beyond those included in the source category. All significant HAP sources have been included in the source category risk analysis. Therefore, we conclude that the facility wide risk is essentially the same as the source category risk and that no separate facility wide analysis is necessary.
E. What are our proposed decisions for the Wool Fiberglass Manufacturing source category based on risk acceptability and ample margin of safety?
1. Risk Acceptability.
As noted in Section VIII.D of this preamble, we weigh all health risk factors in our risk acceptability determination, including the MIR; the numbers of persons in various risk ranges; cancer incidence; the maximum noncancer HI; the maximum acute noncancer hazard; the extent of noncancer risks; the potential for adverse environmental effects; and distribution of risks in the exposed population; and risk estimation uncertainty (54 FR 38044, September 14, 1989) in developing the proposed CAA section 112(f)(2) standards for this source category.
Based on the inhalation risk assessment, we estimate that the cancer risks to the individual most exposed could be up to as 40-in-1 million due to actual emissions and up to as 60-in-1 million due to MACT-allowable emissions, mainly due to formaldehyde and chromium stack emissions. We estimate that the incidence of cancer based on actual emissions is 0.05 excess cancer cases per year or one case every 20 years, and that about 850,000 people face a cancer risk greater than 1-in-1 million due to the HAP emissions from this source category.
Our assessments also indicate a low potential for HAP emissions from these sources to pose any significant adverse environmental effects, human health multi-pathway effects, or chronic noncancer human health risks. Our acute risk screening ruled out the possibility of acute impacts of concern for all pollutants but one, formaldehyde, at seven facilities, with a maximum worst-case HQ estimated to be 30 based on the REL and 2 based on the AEGL-1 (or ERPG-1, which is equivalent). While this means we cannot rule out the potential for acute concerns due to formaldehyde emissions from these facilities, we note that the use of formaldehyde is being phased out in this industry, and will be eliminated from all but 2 facilities in the source category. Since the cancer risks due to actual and allowable emissions (based on the current composition of refractory bricks used by this source category) are well within the acceptable range (i.e., less than 100-in-1 million) and since we have no additional significant concerns regarding other potential human health or environmental impacts, we are proposing that the current risk levels due to actual and MACT-allowable emissions are acceptable.
2. Ample Margin of Safety Analysis and Proposed Decisions.
As described above, we are proposing that the risks associated with the actual and MACT-allowable stack emissions from this source category are acceptable based on the current composition of refractory bricks used by this source category. However, as discussed in Section VIII.D(2) of this preamble, if other wool fiberglass facilities reconstructed their furnaces with high chromium refractory bricks, the maximum individual cancer risks would be higher and likely result in a finding of unacceptable risks.
According to our 2-step process for assessing risks, after we evaluate whether risks are `acceptable' we evaluate whether cost effective measures are available to reduce risks further, to provide an `ample margin of safety'. As stated in Section VIII.F of this preamble, both NaOH scrubbers and a furnace rebuild are considered cost effective when hexavalent chromium levels are high. NaOH scrubbers achieve at least 95 percent reduction in hexavalent chromium emissions at other industries. Transferring this technology to the wool fiberglass industry is reasonable and would reduce hexavalent chromium to levels that would achieve an ample margin of safety. Therefore, we are proposing emission limits of 0.06 lb of total chromium compounds per thousand tons (or 60 lb of total chromium compounds per million tons) of glass pulled in this action (as presented in Table 10) under Section 112(f)(2) of the CAA in this action. We believe this limit would achieve an ample margin of safety to protect public health and prevent adverse environmental effects.
Table 10. Proposed Emissions limits for Glass-Melting Furnaces based on Risk Review
Pollutant
Pounds of pollutant per thousand tons of melt

Chromium Compounds
0.06

These emission limits apply to furnaces at major sources in the wool fiberglass manufacturing source category. However, there are no differences in furnaces at major sources and area sources. We are concerned about the levels of hexavalent chromium that can be emitted by area sources where furnaces may be constructed using high chrome refractories. Therefore we plan to collect additional information from industry to inform regulation of area sources in a future action.
The emission limits we are proposing for chromium compounds under 112(f)(2) are identical to the chromium compounds limits we are proposing under 112(d)(6), as described in Section VIII. F of this preamble.
Our assessments also indicate a low potential for HAP emissions from these sources to pose any significant adverse environmental effects, human health multi-pathway effects, or chronic noncancer human health risks. Our acute risk screening ruled out the possibility of acute impacts of concern for all pollutants but one, formaldehyde, at seven facilities, with a maximum worst-case HQ estimated to be 30 based on the REL and 2 based on the AEGL-1 or ERPG-1, which is equivalent (formaldehyde). While this means we cannot rule out the potential for acute concerns due to formaldehyde emissions from these facilities, we note that the worst-case acute HQs are based on conservative assumptions (e.g., worst-case meteorology coinciding with peak short-term one-hour emissions from each emission point, with a person located at the point of maximum concentration during that hour). Moreover, the use of formaldehyde is being phased out in this industry, and will be eliminated from all but 2 facilities in the source category. Since the cancer risks due to actual emissions are well within the acceptable range (i.e., less than 100-in-1 million) and since we have no additional significant concerns regarding other potential human health or environmental impacts, and since we have not identified any additional cost-effective controls to further reduce formaldehyde emissions, we are proposing that the MACT rule along with all the proposed amendments described above (including the emissions limits for chromium and formaldehyde) will provide an ample margin of safety to protect public health and prevent adverse environmental effects.
We are soliciting comments and information regarding additional control measures, work practices that may be available, and their feasibility in further reducing emissions of formaldehyde, chromium compounds, HCl, and HF, or additional monitoring that may be warranted to ensure adequate control of stack emissions. We specifically request information on other criteria on which a chromium compounds emission limit should be based that would reduce risks from hexavalent chromium.
3. Analysis of the resulting risk after the proposed requirements are in place.
      We conducted an assessment to estimate the risks based on a post-control scenario reflecting all the proposed requirements for the emissions described above (including the proposed emissions limit for chromium compounds). Details are provided in the Draft Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories, EPA's Office of Air Quality Planning and Standards Office of Air and Radiation, September 2011, which is available in the docket to this rule.
Table 11 of this preamble provides an overall summary of the results of the post-control inhalation risk assessment. As compared to Table 8, the MIR decreased from 40-in-1 million to 20-in-1 million, primarily as a result of one facility replacing the high chrome refractory bricks at the facilities that currently exceed the proposed chromium standard. These estimates are based on the dataset compiled using the industry's emissions test data from their 2010 industry survey responses, which show three furnaces would have to reduce chromium emissions to meet the limit in the proposed rule.
Table 11. Post Control Inhalation Risk Estimates for Wool Fiberglass (result of Chromium control)
Maximum
Individual
Cancer Risk
(in 1 million)
Based on Actual Emissions Level[1]
Estimated Population
at increased Risk of cancer >= 1-in-1 Million
Estimated Annual
Cancer
Incidence (cases per year)
Maximum Chronic Non-cancer TOSHI Based on Actual Emissions Level[2]
Maximum Screening Acute Non-cancer HQ[3]
20
282,000
0.02
0.2
30

In addition, we estimated that the formaldehyde emissions would be at or below the MACT standard for all facilities once this rule is fully implemented and we are not proposing that additional control options be implemented.
In a letter dated June 8, 2011, the industry trade association (NAIMA) stated that "NAIMA can provide documentation that all major sources have already converted or have announced plans to convert to non-phenol formaldehyde binders. Essentially non-formaldehyde binders are or will be used industry-wide." A copy of this letter has been placed in the docket for this action (see NAIMA's Response for the Fiberglass Industry to EPA's Formaldehyde and Collection Questions). Based on this information and the information provided by the industry in their 2010 survey, we estimate that 27 of the 29 wool fiberglass manufacturing facilities will have HAP emissions below the 10 and 25 tpy thresholds and will not be subject to the major source MACT requirements. We further estimate that there may be two facilities manufacturing pipe insulation or heavy density insulation products that will be major sources of HAP emissions on the compliance date of these proposed amendments to subpart NNN.
 If NAIMA is correct in that formaldehyde will be phased out by the compliance date of these proposed amendments, we anticipate that the estimated inhalation risks due to formaldehyde would further decrease.
      In summary, we are proposing that the MACT standard, with the changes we are proposing in this action, will provide an ample margin of safety and prevent adverse environmental effects.
F. What are the results from the technology review and proposed decisions?
Based on our technology review, we determined that there have been advances in emissions control measures since the Wool Fiberglass Manufacturing NESHAP was originally promulgated in 1999. Since promulgation, we estimate that industry-wide metal HAP emissions from process sources have been reduced by approximately 76 percent. Due to industry's efforts to replace phenol-formaldehyde binders, more than 95 percent of formaldehyde, phenol, and methanol emissions have been reduced (or will be by 2012). As a result actual PM (metal HAP), formaldehyde, phenol, and methanol emissions from process sources at all wool fiberglass manufacturing facilities are significantly lower than are allowed under the 1999 MACT rule.
We believe that the reductions in metal HAP emissions since promulgation of the 1999 MACT rule are mainly directly related to improvements in two areas: (1) improvements in fabric filter control technology (e.g., improved bag materials, replacement of older baghouses) and (2) the use of electrostatic precipitators (ESPs). Our review also indicates that high chrome refractories are a new technology used in wool fiberglass furnaces that the available data indicate result in an increase in emissions of chromium compounds. The results of our analyses and our proposed decisions for these areas under CAA section 112(d)(6) are presented in the following sections. Based on these data, we believe that developments in practices, processes, and control technologies warrant revisions to the 1999 NESHAP. Additional details regarding these analyses can be found in Technology Review for the Wool Fiberglass Manufacturing Source Category.
The improvements in fabric filter control technology are reflected in the emissions test data collected under the industry survey. Two types of PM control are used in the wool fiberglass manufacturing industry: fabric filters (baghouses) and electrostatic precipitators. Electrostatic precipitators (ESP) may be configured as either wet ESPs or dry ESPs. The emissions limit for PM under the 1999 MACT rule is a production-based limit of 0.5 pounds of PM per ton of glass pulled applicable to all glass melting furnaces. Based on our analysis of survey responses and test data collected under the industry survey, this industry primarily uses fabric filters to control emissions of metal HAP, and the vast majority of sources affected by the current PM limit are achieving PM emissions at control device outlets that are far below the current limit. Id.
Most, if not all, sources reported PM emissions (coming out of the stacks after the control devices) that are less than 10 percent of the current limit, with several sources achieving PM emissions that are two to three orders of magnitude lower than the current limit. Based on these data, we believe that developments in practices, processes, and control technologies warrant revisions to the 1999 MACT rule, under section 112(d)(6). Our analysis of emissions data provided in the survey conducted by industry indicates that stacks equipped with a well-performing fabric filter or ESP can achieve exhaust PM concentrations of less than 0.014 lb/ton of glass pulled. We estimate that all of the wool fiberglass facilities would be able to comply with this revised limit without additional controls. We estimate that this would result in small reductions of metal HAP emissions since there will only be a couple of facilities subject to the PM limits and the available data on some of the furnaces at those facilities indicates they are currently meeting the proposed PM emission limit. We do not anticipate additional energy use associated with this revised limit. Furthermore, we do not anticipate any adverse non-air environmental impacts associated with the implementation of this revised limit. Therefore, we are proposing that reducing the PM limit in the NESHAP from 0.50 lb of PM per ton of glass pulled to 0.014 lb of PM per ton of glass pulled (see Table 12) is both feasible and cost effective. Therefore, we are proposing a revised PM limit in the NESHAP of 0.014 lb of PM per ton of glass pulled in this action. We have based these statements on information we received from the industry in their survey responses; nevertheless, we are seeking comment on our estimation that all wool fiberglass manufacturers can meet the PM emission limits without additional controls.
We conducted a review of the available test data for chromium compounds including hexavalent chromium emissions from glass furnaces. We found that for most furnaces, measured emissions were near or below detection limits of the methods used for testing (EPA Method 29 followed by EPA Method 0061). In contrast, the chromium emissions for a few furnaces were several orders of magnitude higher than the rest of the industry. The facility emitting the highest level of hexavalent chromium, at 840 lb/yr, advised us that the reason chromium tested very high was due to the refractory products, high chrome refractories, from which the furnaces are constructed (Notes of April 14, 2011, Certainteed)[1][2]. Based on the emissions testing and information on high chrome refractories, we believe changes to the 1999 MACT rule are warranted under CAA section 112(d)(6).
The data indicate that well performing wool fiberglass furnaces emit small amounts of chromium compounds, that is, they emit less than 0.06 pounds of chromium compounds (Cr) per thousand tons of glass pulled. However, three facilities currently operate furnaces that emit chromium in excess of this rate. Chromium emissions from these high emitters range from 9 to 840 lb/yr. Furnaces operating below this rate generally emit less than 1 pound per year; many of these tested below the detection level of the test method. The data indicate that there is a `break' between the furnaces emitting less than the proposed limit and those emitting greater amounts of chromium. Data further indicate there are no wool fiberglass manufacturers with low glass production rates but high levels of chrome emissions. We are therefore proposing to set a chromium compounds emission limit of 0.06 lb of chromium per thousand tons of glass pulled as shown in Table 12.
Under section 112(d)(6), we are proposing this emission limit for chromium compounds taking into account the developments in practices, processes and technology by the wool fiberglass industry since promulgation of the 1999 MACT standard. The emission limits we are proposing for chromium compounds under 112(d)(6) are identical to the chromium compounds limits we are proposing under 112(f)(2), as described in Section VIII.E of this preamble.
We estimate that the 2 remaining major source wool fiberglass facilities would be able to comply with this chromium compounds emission limit. We estimate that if the high chromium emitting facilities remain major sources, these new emission limits would result in annual reductions of 1,155 pounds of chromium compounds, specifically hexavalent chromium and there will be no reductions at the remaining facilities because data indicate they are currently meeting the proposed chromium emission limit.
Wet scrubbers are not generally in use in this industry. However, we evaluated their use to achieve reductions in hexavalent chromium for furnaces emitting chrome above the levels being proposed. Sodium hydroxide (NaOH) scrubbers are in use for furnace operations at other industries for chromium compounds reduction. We have evaluated the use of NaOH scrubbers for the wool fiberglass manufacturing industry and find that the control technology can be adapted for use in the wool fiberglass industry from the chromium electroplating industry and from certain high temperature metallurgical industries.
We do anticipate an additional energy use associated with this revised limit if sources choose to install NaOH scrubbers to remove hexavalent chromium from the furnace gases. We anticipate the affected sources may incur disposal costs of hexavalent chromium contaminated materials associated with the implementation of this emission limit. We anticipate that two sources which currently emit chromium at levels slightly higher than the proposed limit will be able to meet it by installing NaOH scrubbers (which selectively remove the hexavalent form of chromium from the exhaust air). This cost is about $300 per pound hexavalent chromium removed if these companies install a NaOH scrubber in series with the existing furnace control. A wool fiberglass facility could also choose to rebuild the glass furnace using refractories with low chromium contents. The cost of that option would be prorated to consider the remaining useful life of the existing high chromium furnace and would cost about $12,000 per pound chromium compounds removed. We expect that for the highest chromium emitting wool fiberglass furnace emitting 500 lb chromium per year, this option would be used to meet the proposed limit. We base this estimate on two factors: 1) the furnace is at the end of its useful life and is expected to be reconstructed in 2013 (Notes of April 14, 2011; Region 7 Certainteed Notes)[12,13] and 2) the NaOH scrubber achieves about 95 percent reduction (NaOH Scrubber Information)[4][2], which is not quite enough to meet the proposed chromium emission limit.
The cost of the control equipment to wool fiberglass plants is about $225,000 for installation and annual operation and maintenance costs of about $5000 per year. We compared the cost of the controls to the sales or revenues of the companies that would incur costs to comply with the chromium emission limits. The economic impact on these firms, measured in annual compliance costs as a percent of sales or revenues, is less than 0.001 percent for each of the affected firms.
 We therefore, we propose that requiring the 0.06 lb chromium per thousand tons of melt limit in the NESHAP is both feasible and cost effective. We solicit comment on this comparison and the use of this value as a reasonable cost to reduce chromium.
Table 12. Proposed Emissions limits for Glass-Melting Furnaces based on Technology Review
Pollutant
Pounds pollutant per ton of melt

PM
0.14
Chromium Compounds
0.00006

This proposed limit for chromium compounds (of 0.06 lb per thousand tons chromium limit) under CAA Section 112(d)(6) is the same limit being proposed under Section 112(f)(2) that was described earlier in this notice. We believe that these proposed revisions for chromium and PM are cost effective revisions and reflect the current developments in processes and technology by this industry. (i.e., well performing air pollution control).
IX. Summary of Cost, Environmental, and Economic Impacts for the Mineral Wool Source Category
      Here we discuss the anticipated air, water, solid waste and energy impacts in addition to the cost and economic impacts to the industry as a result of the proposed amendments to the 1999 MACT rule.
A. What are the affected sources in the Mineral Wool Production source category?
We anticipate that the 7 mineral wool production facilities currently operating in the United States will be affected by these proposed amendments.
B. How are the impacts for this proposal evaluated?
	 For the proposed amendments to the Mineral Wool Production source category, the air quality, water quality, solid waste, and energy impacts were determined based on the need for additional control technologies and actions required to meet the proposed emissions limits. The Economic Impact Analysis considered annual sales and revenue data from the facilities within this source category and their ability to meet the proposed amendments. The following sections discuss the cost, environmental, and economic impacts to the Mineral Wool Production source category. (Economic Impact Analysis for the Mineral Wool and Wool Fiberglass RTRs. US EPA. October 2011.)
C. What are the air quality impacts for the Mineral Wool Production source category?
The EPA estimated the emissions reductions that are expected to result from the proposed amendments to the 1999 MACT rule compared to the 2010 baseline emissions estimates. A detailed documentation of the analysis can be found in: Cost Impacts of the Revised NESHAP for the Mineral Wool Production Manufacturing Source Category.
Emissions of formaldehyde from mineral wool production facilities have declined over the last 12 years as a result of federal rules, state rules and on the industry's own initiative. The current proposal would not reduce formaldehyde, phenol, or methanol emissions from their current levels. Under the proposed emissions limits for cupolas, COS, HF, and HCl emissions would be reduced by a combined 23 percent compared to 2010 levels reported in the industry survey responses. We estimated that the COS emissions reductions would be 41 tpy from cupolas.
Based on the emissions data available to the EPA, we believe that all facilities will be able to comply with the proposed emissions limits for COS, HF, HCl, formaldehyde, phenol, and methanol without additional controls because they can reduce emissions using raw material substitution or oxygen injection as discussed previously in Section VII.F of this preamble.
D. What are the water quality and solid waste impacts?
	We do not anticipate any adverse water quality or solid waste impacts from the proposed amendments to the 1999 MACT rule because the requirements proposed would not change the existing requirements that impact water quality or solid waste.
E. What are the secondary impacts?
	Indirect or secondary air quality impacts include impacts that will result from the increased electricity usage associated with the operation of control devices, as well as water quality and solid waste impacts (which were just discussed) that might occur as a result of these proposed actions. We anticipate that the mineral wool production facilities will be able to comply with the proposed amendments without having to install additional control technologies such as RTOs. In addition, those facilities that switch to low-sulfur raw materials will most likely reduce air emissions of SO2.
F. What are the energy impacts?
	Energy impacts in this section are those energy requirements associated with the operation of emission control devices. Potential impacts on the national energy economy from the rule are discussed in the economic impacts section. There would be little national energy demand increase from the operation of any of the control options analyzed under the proposed NESHAP amendments.
G. What are the cost impacts for the Mineral Wool Production source category?
Each facility was evaluated for its ability to meet the proposed emissions limits for PM, COS, HF, and HCl emissions from cupolas and formaldehyde, phenol, and methanol emissions from combined collection operations and curing designs. The memorandum, Cost Impacts of the Revised NESHAP for the Mineral Wool Production Manufacturing Source Category, includes a complete description of the cost estimate methods used for this analysis and is available in the docket.
We identified several ways in which mineral wool producers reduce the COS emissions from cupolas, enabling them to comply with the proposed emission limit of 3.3 lb COS per ton of melt. These methods include raw material substitution, oxygen injection, and installation of an RTO. We found two approaches to raw material substitution: slag and rock. One mineral wool manufacturer purchases low-sulfur slag, a waste product from a local steel plant. Another plant owns and operates a local quarry from which they obtain rock that does not contain sulfur. The low-sulfur slag or rock is used in the cupola in place of high-sulfur slag. Because sulfur is not added into the cupola with the raw materials, it is not emitted as sulfur compounds from the stack in the form of COS or SO2 during production. As shown in their title V permit, another plant uses oxygen injection to accelerate the reaction of COS to CO2 and SO2, thereby reducing that company's COS emissions.
However, most mineral wool plants have installed regenerative thermal oxidizers to convert the high concentrations of COS in the cupola exhaust gas to energy that is returned to the cupola. This technology reduces the consumption of coke up to 30 percent and, because of the cost of coke, this technology pays for itself over a period of several years. Emissions of COS are below 0.04 lb COS per ton melt when an RTO is installed for energy reclamation and new source MACT is based upon the use of this technology.
One facility is expected to incur an incremental annualized cost of $360,000 for low-sulfur raw materials (rock) if they use that option to comply with the COS requirement for cupolas. That cost would be lessened to no more than $20,000 for installation of oxygen injection, which is another alternative. We do not anticipate this plant would install an RTO to comply with the rule. The total industry-wide costs for monitoring for COS, HF, and HCl from the cupolas is $146,000, while the total costs for monitoring for formaldehyde, phenol, and methanol from the combined collection and curing operations is $42,000.
The total annualized costs for the proposed rule are estimated at $548,000 (2010 dollars). Table 13 provides a summary of the estimated costs and emissions reductions associated with the proposed amendments to the Mineral Wool Production NESHAP presented in this action.
Table 13. Estimated Costs and Reductions for the Mineral Wool Production Proposed Standards in this Action

                              Proposed Amendment

                         Estimated Capital Cost ($MM)

                          Estimated Annual Cost ($MM)
                Total HAP Emissions Reductions (tons per year)
             Cost Effectiveness in $ per ton total HAP reduction
COS limit; Low-Sulfur Materials
0
0.360
41
8,780
Additional testing and monitoring
0
0.243
N/A
N/A

H. What are the economic impacts for the Mineral Wool Production source category?
We performed an economic impact analysis for mineral wool producers nationally using the annual compliance costs estimated for this proposed rule.(Economic Impact and Initial Regulatory Flexibility Analysis. October 2011)[4][3]. The impacts to most producers affected by this proposed rule are annualized costs of less than one percent of their revenues using the most current year available for revenue data. One producer will experience an annualized cost of 6.7 percent of its revenue, however. Both demand and supply in this sector are inelastic to price changes. Thus, if producers could pass through the entire cost of the rule to consumers, we would expect prices to increase by less than one percent, with no change in output. Conversely, if producers could not pass through any of the cost by increasing the price, we would expect output to decline by less than one percent.
 Hence, the overall economic impact of this proposed rule should be low on most of the affected industry and its consumers. For more information, please refer to the Economic Impact Analysis for this proposed rulemaking that is available in the public docket. Id.
I. What are the benefits for the Mineral Wool Production source category?
The proposed Mineral Wool Production NESHAP amendments are expected to result in approximately 23 percent reduction in COS; HF, and HCl are not reduced. We have not quantified the monetary benefits associated with these reductions.
J. What demographic groups might benefit the most from this regulation?
The worst-case nature of our acute screening assessment suggests that the potential for adverse effects carries a relatively low probability of occurrence. The EPA concludes that, based on our analyses, the risks associated with MACT-allowable and actual emissions (primarily due to formaldehyde emissions from stacks) from this source category are acceptable. Thus, a demographic analysis was not conducted.
X. Summary of Cost, Environmental, and Economic Impacts for the Wool Fiberglass Manufacturing Source Category
A. What are the affected sources in the Wool Fiberglass Manufacturing source category?
We evaluated the impacts to the affected sources based on all available information, including two significant sources: the 2010 emissions testing and subsequent conversations with NAIMA and individuals operating industry facilities. According to the 2010 emissions test data, there are 3 furnaces at 3 facilities that do not meet this proposed chromium emission limit. In their responses to the survey conducted by the industry, facilities stated the tested furnaces were representative of the untested furnaces. However, furnace construction materials (refractory composition) were not one of the factors considered in determining representativeness.
After the completion of the survey conducted by industry, we received information that emissions testing for chromium may not necessarily be representative of other furnaces that were not tested. Therefore, we based our assessment of the impacts upon the tested furnaces only, and did not include in that assessment untested furnaces.
Based on this approach, we anticipate that all 29 wool fiberglass manufacturing facilities currently operating in the United States will be affected by these proposed amendments, 2 of the 29 wool fiberglass manufacturing facilities currently operating in the United States will install air pollution controls, and that one facility will reconstruct a furnace to comply with these proposed amendments. Additionally, industry has stated that no major wool fiberglass residential insulation sources will still exist in this source category by the time the proposed rules are promulgated. If their predictions come to pass, we estimate that two facilities will be affected by these proposed amendments; these are pipe insulation facilities. However, any major sources still in operation at the time the amendments are promulgated will be affected by this rule. One new facility was recently built, but no facilities are expected to be constructed in the foreseeable future.
B. How are the impacts for this proposal evaluated?
	For the proposed Wool Fiberglass Manufacturing NESHAP amendments, the air quality, water quality, solid waste, and energy impacts were determined based on the need for additional control technologies and actions required to meet the proposed emissions limits. The Economic Impact Analysis considered annual sales and revenue data from the facilities within this source category and their ability to meet the proposed amendments. The following sections discuss the cost, environmental, and economic impacts to the Wool Fiberglass Manufacturing source category. (Economic Impact Analysis for the Mineral Wool and Wool Fiberglass RTRs. US EPA. October 2011.)
C. What are the air quality impacts?
The EPA estimated the emissions reductions that are expected to result from the proposed amendments to the 1999 MACT rule compared to the 2010 baseline emissions estimates. A detailed documentation of the analysis can be found in: Cost Impacts of the Revised NESHAP for the Wool Fiberglass Manufacturing Source Category. We expect reductions of formaldehyde, phenol and methanol, and chromium compounds.
Emissions of formaldehyde, PM, and HAP metals from wool fiberglass manufacturing have declined over the last 12 years as a result of federal rules, state rules and on the industry's own initiative. The current proposal is not expected to yield emission reductions for formaldehyde, phenol, or methanol from their current levels. However, the proposed amendments are expected to discourage facilities in the wool fiberglass industry from reintroducing formaldehyde to their production lines. In addition, the proposed chromium compound emission limit would prevent emissions of chromium compounds in the future and discourage the replacement of currently operating furnaces with those constructed of high chromium refractory bricks.
Based on the emissions data available to the EPA, we believe that all affected facilities will be able to comply with the proposed emissions limits for formaldehyde, phenol, methanol, HF, and HCl without additional controls. Additional controls are required for major sources with high-chrome refractories. Additionally, as discussed in Section X.J of this preamble, the EPA has determined that the proposed rule will not have disproportionately high and adverse human health or environmental effects on minority or low-income populations.
D. What are the water quality and solid waste impacts?
We anticipate water quality and solid waste impacts may result from the disposal of high chrome refractories in landfills or in other areas that are not designed or permitted to receive hexavalent chromium waste. Water quality and solid waste impacts are also possible from potential reuse of spent high chrome refractory products. Because of their durability, we believe that use of refractory bricks made with high chrome content are becoming widespread[,] (Chromium in Refractories)[11], as their use can nearly double the life of glass furnaces (Notes of April 14, 2011, Certainteed; Region 7 Certainteed Notes; August 31, 2011 Meeting)[12,13,3][5]. When glass furnaces reach the end of their useful life and must be rebuilt, the high chrome refractory brick from demolition of the old furnace is typically discarded, as it typically cannot be used in new furnace construction.
As for any industrial waste, the bricks from an old glass furnace would, when discarded, potentially be subject to the Resource Conservation and Recovery Act (RCRA) and its regulations.

      Additionally, NaOH scrubber solids are expected to contain high levels of hexavalent chromium removed from furnace emissions. The proper disposal procedures for hexavalent chromium-contaminated waste are provided under RCRA regulations (40 CFR 262.11).
E. What are the secondary impacts?
	Indirect or secondary air quality impacts include impacts that will result from the increased electricity usage associated with the operation of control devices, as well as water quality and solid waste impacts that might occur as a result of these proposed actions. We estimate the proposed amendments will not result in any significant secondary impacts from the requirements of the Mineral Wool MACT amendments because facilities can meet the COS limits without installing RTOs. We do not anticipate significant secondary impacts from the proposed amendments to the Wool Fiberglass MACT.
F. What are the energy impacts?
	Energy impacts in this section are those energy requirements associated with the operation of emission control devices. Potential impacts on the national energy economy from the proposed amendments to the Wool Fiberglass MACT are expected to be minimal and will not result in a significant increase in national energy demand.
G. What are the cost impacts?
The capital costs for each facility were estimated based on the ability for each facility to meet the proposed emissions limits for PM, chromium compounds, HF, HCl, formaldehyde, phenol, and methanol. The memorandum, Cost Impacts of the Revised NESHAP for the Wool Fiberglass Manufacturing Source Category, includes a complete description of the cost estimate methods used for this analysis and is available in the docket.
Under the proposed amendments, the majority of wool fiberglass facilities are not expected to incur any capital costs to comply with the proposed emissions limits. The total costs estimated for compliance with the amendments proposed in this action are $60,000 for compliance testing on glass-melting furnaces and $52,000 for compliance testing on the FA manufacturing line for pipe insulation products. The total annualized costs for the proposed rule are estimated at $112,000 (2010 dollars). Table 14 provides a summary of the costs and emission reductions associated with the proposed amendments if the three facilities with high levels of hexavalent chromium install controls or reconstruct furnaces to meet the emission limits of the proposed rule. Because the industry is undergoing the phaseout of HAP binders, no major sources are expected to exist by the compliance deadline for this proposed rule, and no costs to industry beyond testing would be incurred. However, in the event that the three facilities that do not now meet the chromium compounds limit were to remain major sources, we estimated the annualized control costs as between $100,000 to $300,000 per furnace, depending on which of two options is used. Eleven hundred (1100) pounds of chromium compounds per year would be reduced at three major sources in the industry, 913 pounds of this from a single facility. Hexavalent chromium is 92% of the total chromium compounds emitted from wool fiberglass furnaces. Actual facility costs would be determined by the number of furnaces, the associated level of Cr emissions, and the major source status of the facility.
Table 14. Estimated Costs and Reductions for the Proposed Wool Fiberglass Manufacturing Standards in this Action

                              Proposed Amendment

                            Est.Capital Cost ($MM)

                            Est. Annual Cost ($MM)
               Total HAP Emissions Reductions (pounds per year)
                       Cost Effectiveness in $ per pound
                                No. Facilities
Change out of refractory brick lining
6.0
0.3
900
 333
1
Installation of NaOH scrubber
.25
.1
70
1400
2
Additional testing and monitoring for glass-melting furnaces
0
0.06
N/A
N/A

Additional testing and monitoring for FA lines for pipe insulation products
0
0.052
N/A
N/A

H. What are the economic impacts?
We performed an economic impact analysis for the wool fiberglass industry using the annual compliance costs estimated for this proposed rule (Economic Impact and Initial Regulatory Flexibility Analysis for the Proposed Mineral Wool and Wool Fiberglass Risk and Technology Review)[4][3]. The impacts to producers affected by this proposed rule are annualized costs of less than 0.1 percent of their revenues using the most current year available for revenue data. With the responsiveness of wool fiberglass demand and supply at less than 1:1 compared to a price change, and with the change in product price as approximated by the cost to revenue ratio at less than 0.1 percent, for this ratio is the maximum price change that producers may face, it is expected that wool fiberglass price and output changes will be less than 0.1 percent. Hence, the overall economic impact of this proposed rule should be low on the affected industry and its consumers. For more information, please refer to the Economic Impact Analysis for this proposed rulemaking that is available in the public docket. (Economic Impact Analysis for the Mineral Wool and Wool Fiberglass RTRs. US EPA. October 2011.)
I. What are the benefits?
As stated in section X.C., we expect emissions reductions of PM, phenol, formaldehyde, methanol, and chromium compounds. We have not quantified the monetary benefits associated with these reductions.
J. What demographic groups might benefit the most from this regulation?
      For the proposed wool fiberglass rule, the EPA has determined that the current health risks posed to anyone by emissions from this source category are acceptable. However, there are about 849,000 people nationwide that are currently subject to health risks which are non-negligible (i.e., cancer risks greater than 1-in-1 million) due to emissions from this source category. We performed an analysis of the demographic makeup of these 849,000 people. The demographic distribution of this "at-risk" population is similar to the national distribution of demographics for all groups except for the "minority" group (defined as total population minus the white population), which is 11 percent greater than its corresponding national percentage. See the Risk and Technology Review  -  Analysis of Socio-Economic Factors for Populations Living Near Wool Fiberglass Facilities in the docket for additional details on the demographic analysis.
The EPA has determined that the current health risks posed to anyone by emissions from this source category are acceptable. Therefore, the EPA has determined that the proposed rule will not have disproportionately high and adverse human health or environmental effects on minority or low-income populations.