MEMORANDUM
Date:	October 2021
Subject: 	Summary of Comments and EPA's Responses on the National Emission Standards for Hazardous Air Pollutants: Cyanide Chemicals Manufacturing Residual Risk and Technology Review Proposed Rule 
From:	Nathan Topham, Sector Policies and Programs Division (SPPD), Office of Air Quality Planning and Standards (OAQPS), U.S. Environmental Protection Agency (EPA)
To:	EPA Docket No. EPA-HQ-OAR-2020-0532
1.0	Introduction
      On January 15, 2021 (86 FR 3906), the U.S. Environmental Protection Agency (EPA) proposed amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Cyanide Chemicals Manufacturing source category. The proposal addressed (1) the results of the residual risk and technology review (RTR) for the major source category as required under the Clean Air Act (CAA); (2) the addition of process wastewater emissions standards; (3) amendments related to startup, shutdown, and malfunction (SSM) provisions; (4) the addition of electronic reporting requirements, and (5) amendments to reporting and recordkeeping requirements.
	The purpose of this memorandum is to present a summary of the public comment submissions received on the proposed action and the EPA's responses to those comments not discussed in the preamble to the final rule. For each comment summary, the EPA provides the unique Docket ID number(s) representing the commenter public submission to the docket for the action (see Docket No. EPA-HQ-OAR-2020-0532). Individual comments from the public (and attachments submitted with comments) submitted to the docket are assigned a unique 4-digit docket number that follows the base docket number (i.e., EPA-HQ-OAR-2020-0532-XXXX, where "XXXX" represents the unique 4-digit document docket number). The unique document docket numbers presented in this memo represent that "XXXX" unique docket number. For example, docket number EPA-HQ-OAR-2020-0532-0059 is presented as "0059" within the text of this memo.
      Eight comment letters were received on the EPA's proposal:
          Docket ID - EPA-HQ-OAR-2020-0532-0059; Commenter  -  A. Trejo.
          Docket ID - EPA-HQ-OAR-2020-0532-0061; Commenter  -  Texas Commission on Environmental Quality (TCEQ).
          Docket ID - EPA-HQ-OAR-2020-0532-0062; Commenter  -  Etheridge.
          Docket ID - EPA-HQ-OAR-2020-0532-0063; Commenter  -  A. Kochan.
          Docket ID - EPA-HQ-OAR-2020-0532-0064; Commenter  -  K. Larkin.
          Docket ID - EPA-HQ-OAR-2020-0532-0065; Commenter  -  The Dow Chemical Company. 
          Docket ID - EPA-HQ-OAR-2020-0532-0066; Commenter  -  Earthjustice (submitted comments on behalf of Sierra Club).
          Docket ID - EPA-HQ-OAR-2020-0532-0067; Commenter  -  Anonymous.
            
The EPA Docket contains all comment letters submitted, and the comments are available for viewing at the EPA Docket Center Reading Room, or electronically through https://www.regulations.gov by searching Docket ID No. EPA-HQ-OAR-2020-0532 by docket number.
      The following sections of this memorandum contain summaries of comments received on the proposed amendments to the standards for the Cyanide Chemicals Manufacturing source category for all comments not discussed in the preamble to the final rule, as well as the EPA's responses to the comments. The comments are organized under the following general topics:
 Standards (Section 2)
             Equipment Leaks
 Risk Assessment (Section 3)
             Risk Assessment Quality/Communication
             Co-Located Emission Source Risk
             Environmental Justice/Demographic Analysis
             Environmental Impacts
 Technology Review (Section 4)
 Fenceline Monitoring (Section 5)
 Compliance Requirements (Section 6)
             Electronic Reporting Requirements
             Extension for Compliance Reporting for Force Majeure Events
             Other Compliance Requirements
 Administrative Procedures Act (Section 7)
 Other Miscellaneous Comments (Section 8)
2.0 Equipment Leak Standards
2.1 Technology Review  -  Equipment Leak Requirements
	Comment: Commenter (0066) states that EPA has ignored developments in equipment leak detection and repair (LDAR). The commenter contends that EPA must recognize the need to strengthen the equipment leak requirements under the rule for similar reasons as discussed in the commenter's Miscellaneous Organic Chemical Manufacturing NESHAP (MON) comments. The commenter asserts that the EPA may not allow indefinite repair or unlimited leaks as such allowances are equivalent to a malfunction exemption and violate the Act's requirement for continuous emission standards. According to the commenter, EPA's own Technical Support Document (TSD) that purports not to acknowledge equipment leak control developments refers to a Texas rule that it also says is more stringent -- and that rule is an example of a "development" that EPA has ignored here. The commenter states that EPA must evaluate other developments based on the most current information on equipment LDAR, including optical remote sensing and monitoring requirements.
	Response: EPA disagrees with the commenter's claim that the types of equipment leaks addressed in the NESHAP are "malfunctions." Equipment leaks typically occur from equipment such as pumps, compressors, agitators, sampling collection systems, open-ended valves or lines, valves, and connectors. At the time we developed the MACT standards for this source category, we recognized that these emission points even at the best performing facilities regularly emit small quantities of hazardous air pollutants (HAP), and we promulgated work practice standards regulating equipment leaks from these components based on the performance of the best performing sources. These provisions require Cyanide Chemicals Manufacturing facilities to monitor for leaks and to repair any detected leaks. While equipment leaks may not be predictable, the types of equipment leaks addressed by these regulations are fairly routine emissions from sources; these leaks are not what EPA generally considers to be malfunctions  -  the type of unpredictable or infrequent event for which we cannot anticipate.
      With respect to the TCEQ equipment leak rule mentioned by the commenter, we stated in our proposed rule that based on our review of this Texas rule that the specific facilities impacted in the Houston-Galveston-Brazoria area are still conducting a leak detection and repair (LDAR) program using EPA Method 21. The vast majority of equipment, including almost all pieces of equipment in gas and vapor service that would tend to highly contribute to the overall equipment leak air emissions are complying with the same leak definition as in the cyanide NESHAP, and that the TCEQ HRVOC Rule generally requires quarterly monitoring whereas the cyanide rule has varying degrees of monitoring frequencies depending on the percentage of leaking equipment that could lead to either more stringent, the same, or less stringent amount of times for which an EPA Method 21 measurement and repair of a leaking component (if measured) must occur. We determined at proposal that there were few, if any, substantive differences between the TCEQ rule and the NESHAP for this source category and therefore do not consider the TCEQ rule a development for Cyanide Chemicals Manufacturing NESHAP. 
      Cyanide Chemicals Manufacturing facilities currently have an option to use optical gas imaging (OGI) through an alternative work practice to detect leaks from equipment at 40 CFR 63.11(c), (d), and (e). This alternative work practice includes provisions for using OGI in combination with annual monitoring using Method 21 (and not as an alternative). Since there is not a standardized method for monitoring with OGI, it was not further evaluated as an alternative to EPA Method 21. This standardized method is critical to ensuring that the same (or better) emissions reductions are achieved with OGI that are currently achieved with Method 21 of Appendix A-7 to 40 CFR part 60 ("Method 21"). A standardized method would ensure equivalent emissions reductions through prescribing specifications OGI instruments must meet; verification procedures for ensuring instruments meet these specifications; procedures for proper instrument use and operator practices during field surveys; necessary operator training; and appropriate quality assurance/quality control (QA/QC) procedures. EPA believes that these issues are of paramount importance to resolve before OGI would be allowed as an alternative to Method 21. No change is being made to the final rule.
2.2 Applicability
2.2.1 Concentration-Based Threshold for Equipment in Cyanide Service
	Comment: Commenter (0065) states that EPA should clarify the equipment that is subject to the equipment leak provisions by making the applicability of the equipment leak provisions consistent with the Subpart YY regulation for the ethylene production source category. The commenter suggests that EPA clarify that only equipment that contains or contacts > 5 weight-percent organic HAP plus cyanide compounds should be subject to the requirements.
	Response: The EPA has not made the change requested by the commenter. The NESHAP for Cyanide Chemicals Manufacturing did not include a threshold for cyanide chemicals concentration to determine applicability when establishing the MACT floor for equipment leaks. We have not reopened that MACT floor determination to establish a threshold for cyanide chemicals or organic HAP as requested by the commenter.
2.2.2 Equipment in Vacuum Service
	Comment: Commenter (0065) requests that EPA clarify that equipment in vacuum service is not subject to the requirements.
	Response: The language requested by the commenter already exists in 40 CFR part 63, subpart TT, which contains the requirements related to equipment leaks for Cyanide Chemicals Manufacturing facilities. We have concluded that it is unnecessary to add that same language to the Cyanide Chemicals Manufacturing NESHAP. 
3.0 Risk Assessment
3.1 Risk Assessment Quality/Communication
Comment: Commenter (0066) asserts that EPA's proposed lack of action under CAA section 112(f)(2) is illegal and arbitrary due to EPA's failure to fully assess the health risk based on the best available science. According to the commenter, all of EPA's risk numbers are likely to be significant underestimates because of the many ways in which EPA's Residual Risk Assessment fails to follow the best available science, including: 
 EPA underestimates health threats to children and from early-life exposure, including by ignoring increased risk in childhood and from prenatal exposure;
 EPA underestimates health threats to communities exposed to multiple sources by refusing to add factors to account for the increased risks caused by such exposure; 
 EPA underestimates the multipathway cancer, chronic non-cancer, and acute health risks by using modeling assumptions that ignore real-world exposures underestimating risk due to EPA's refusal to follow the best available science and refusing to aggregate cancer inhalation and multipathway risks.
	The commenter (0066) contends that in view of these substantial health threats, it is unlawful, arbitrary and capricious for EPA to do nothing to reduce any of these emissions or resulting health threats. EPA may not lawfully or rationally find health risks to be "acceptable" under CAA section 112(f)(2) when the record shows the opposite, and EPA has ignored significant health impacts. 
	The commenter (0066) states that EPA proposes no changes at all to reduce the health and ecological risks, and to assure the requisite "ample margin of safety to protect public health," and prevent an adverse environmental effect. Additionally, the commenter maintains that EPA's proposal not to strengthen the standards at all pursuant to CAA section 112(f)(2) is also unlawful and arbitrary, because it is incomplete and based on analyses that underestimate and ignore the health risks from the toxic pollution that Cyanide Chemicals Manufacturing facilities emit into communities.
	Response: The risk assessment demonstrated that health risks due to air emissions from Cyanide Chemicals Manufacturing sources are acceptable and after considering available control options and all available risk information, EPA concluded that the current standards provide an ample margin of safety to protect public health. The documentation for this decision (which includes assumptions, inputs, and uncertainties associated with the analyses) is provided in the technical report, Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in the docket for this action (EPA-HQ-OAR-2020 - 0532-0005). 
	The approach incorporated into the CAA and used by the EPA to evaluate residual risk and to develop standards under CAA section 112(f)(2) is a two-step approach. In the first step, the EPA determines whether risks are acceptable. This determination "considers all health information, including risk estimation uncertainty, and includes a presumptive limit on maximum individual lifetime [cancer] risk (MIR) of approximately 1 in 10 thousand." If risks are unacceptable, the EPA must determine the emissions standards necessary to reduce risk to an acceptable level without considering costs. In the second step of the approach, the EPA considers whether the emissions standards provide an ample margin of safety to protect public health "in consideration of all health information, including the number of persons at risk levels higher than approximately 1 in 1 million, as well as other relevant factors, including costs and economic impacts, technological feasibility, and other factors relevant to each particular decision." The EPA must promulgate emission standards necessary to provide an ample margin of safety to protect public health or determine that the standards being reviewed provide an ample margin of safety without any revisions. After conducting the ample margin of safety analysis, we consider whether a more stringent standard is necessary to prevent, taking into consideration costs, energy, safety, and other relevant factors, an adverse environmental effect. After considering available control options and all available risk information, EPA concludes that the standards provide an ample margin of safety to protect public health.
      Comment: Commenter (0064) contends that there is public concern about the current standards regarding cyanide chemicals and potential pollutants. The commenter also references the National Academies of Science, Engineering, and Medicine's (NASEM) 2018 review of EPA's guidance material for the systematic review of risk materials that found inconsistencies with EPA and its systems used to evaluate risks. The commenter states that there is a divide between concerned parties and EPA and recommends that a conversation be facilitated to satisfy both parties. According to the commenter, the proposed rule could potentially provide the material necessary to do so, given the ambiguous nature of the language in the proposal.	 
	Response: We carefully considered available information and followed our established approach for the residual risk review for this source category. The EPA has determined that the risk from emissions of air toxics from this source category is acceptable, and that the current standards provide an ample margin of safety to protect public health. The documentation for this decision is provided in the technical report, Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in the docket for this action (EPA-HQ-OAR-2020 - 0532-0005).  
	The commenter references the NASEM review of The Use of Systematic Review in EPA's Toxic Substances Control Act Risk Evaluations, which reviewed the guidance outlining the approach used by the EPA's TSCA program. Commenter notes that the NASEM review raised concerns with aspects of that approach. This comment is out of scope of this action or its associated risk assessment, as the risk assessment in support of this rulemaking did not rely on the TSCA systematic review approach. 
	Comment: Commenter (0066) contends that the risk assessment and proposed determination are unlawful and arbitrary because EPA has presented numbers in the abstract, making it difficult for communities and the public to understand the risk assessment and what the risks mean for people's lives. The commenter notes that EPA provides only the results of its facility-wide risk assessment and acute risk modeling and refined assessment and does not provide the emission totals it used, or the data it used to calculate the facility-wide risk numbers. 
	Response: The risk assessment demonstrated that health risks due to air emissions from Cyanide Chemicals Manufacturing sources are acceptable and after considering available control options and all available risk information, EPA concluded that the current standards provide an ample margin of safety to protect public health. The documentation for this decision (which includes assumptions/inputs/uncertainties associated with the analyses) is provided in the technical report, Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in the docket for this action (EPA-HQ-OAR-2020 - 0532-0005). Risk modeling input files used for the acute and facility-wide assessments are also available in the docket for this action (EPA-HQ-OAR-2020-0532-0010). 
	Comment: Commenter (0063) recommends that EPA continue to reassess and update data pertaining to the Inhalation Reference Concentration (RfC) and Oral Reference Dose (RfD) of cyanide compounds as a result of low confidence in the past.
	Response: The EPA acknowledges the need to update assessments with newly available data. The need to update assessments with newly available data as well as the need to complete toxicological assessments for all HAP lacking dose-response assessments increases the importance of Agency activities to streamline and fully utilize the EPA's already overloaded Integrated Risk Information System (IRIS) program. To that end, the EPA has always prioritized for future IRIS assessments those HAP without dose-response values but with the greatest potential for public exposure. As a result of this prioritization, while not all HAP have scientifically accepted dose-response values that can be used in residual risk assessments, it is clear that the vast majority of HAP that carry the potential to significantly impact the results of residual risk assessments do, in fact, have credible dose-response values. Thus, while we are not yet at the point where all HAP have dose-response values, we are generally capable of deriving reasonable risk estimates for those HAP that dominate the risks from any one source category. In general, we strive to strike a balance in our assessments, meaning that while some factors likely lead to underestimates of risk, others likely lead to overestimates of risk. We conclude that the risk assessment for this source category is sufficient to support a decision on the acceptability of the risk and ample margin of safety.
3.2 Co-Located Emission Source Risk
      Comment: Commenters (0061, 0066) express concern related to the EPA's assessment of emission sources co-located at facilities that manufacture cyanide chemicals. In particular, commenters reference coke oven and ethylene oxide (EtO) emissions. 
      Commenter (0066) notes the assessment points to EtO emitters and coke ovens but fails to provide additional information on those collocated sources to which it attributes the high facility-wide risk, or to provide any information on how EPA plans to reduce the carcinogenic emissions from those sources. According to the commenter, EPA's cryptic and incomplete risk assessment therefore violates public notice-and-comment and participation requirements, and fails to meet EPA's commitment to public transparency and a process that provides information and access to the most affected fenceline community members.
      Commenter (0066) states that EPA recognizes high facility-wide cancer risk -- 200-in-1 million due in part to EtO and coke oven emissions from collocated sources. According to the commenter, EPA ignored the facility-wide risk in deciding that the risk from cyanide chemical manufacturing is "acceptable." The commenter contends that, based on the record the Agency has created and the evidence before it, EPA can have no lawful basis for refusing to recognize and find that the cancer risk from these facilities is unacceptable as it is twice EPA's own presumptive benchmark.
	As the D.C. Circuit held in interpreting the same language in the prior version of §7412: 
      We find that the congressional mandate to provide "an ample margin of safety" "to protect the public health" requires the Administrator to make an initial determination of what is "safe." This determination must be based exclusively upon the Administrator's determination of the risk to health at a particular emission level. 
	The commenter (0066) states that in finding unsafe risk, EPA must determine that the risk is unacceptable at these facilities. The commenter states that at a minimum, EPA must recognize that the level of emissions from cyanide chemical manufacturing facilities is currently unsafe and requires regulatory reduction. Further, the commenter adds that as cancer risk of 1-in-1 million is the "aspirational goal" of the statute, EPA must also describe what it will do to reduce emissions and risks, yet it does neither.
	According to the commenter (0066), EPA's statement that it plans to address the EtO and other cancer risk driving emissions at collocated sources in future rulemakings fails to satisfy the Act here and now and is arbitrary. The commenter provides that EPA should stop delaying the required health protection at these facilities and require reductions from all parts of these facilities that are needed to prevent all unacceptable cancer risk and satisfy the Act's requirement for an "ample margin of safety to protect public health." 
	Commenter (0061) references the proposal's statement that the "cancer risk is driven by emissions sources that are not in the Cyanide Chemicals Manufacturing source category; specifically, emissions of ethylene oxide and coke oven emissions from noncategory sources account for 95 percent of the cancer incidence" and states that EPA did not critically review all relevant and available carcinogenic EtO dose-response assessments for the proposed rules. The commenter provides that scientific due diligence for the risk assessment requires that EPA conduct a formal critical review of the relevant and available carcinogenic EtO dose-response assessments and unit risk factors (URFs). According to the commenter, EPA has a duty to use the most scientifically supported approach and URF to inform its risk assessment and decision making, instead of assuming that its most recent IRIS assessment is the most scientifically defensible assessment available. The commenter provides that the scientific credibility of the EtO cancer risk estimates in the proposed rule is contingent upon this. In addition, the commenter notes that EPA states in this proposed rule that, "[i]n cases where new, scientifically credible dose-response values have been developed in a manner consistent with EPA guidelines and have undergone a peer review process similar to that used by the EPA, we may use such dose-response values in place of, or in addition to, other values, if appropriate." According to the commenter, such a value has been developed that was consistent with EPA guidelines and underwent a peer review process similar to EPA's process, which was presented in the final Texas Commission on Environmental Quality (TCEQ) Development Support Document (DSD). The commenter states that this information was inappropriately excluded from the proposed assessment and further points out scientific issues with EPA's 2016 IRIS assessment on which the proposal relies.
	Response: Because the facility-wide risks due to EtO are emitted by sources that are not part of the Cyanide Chemicals Manufacturing source category, this comment is not within the scope of this action. Therefore, EPA will address any new epidemiological data or analyses (e.g., the final TCEQ Development Support Document) in separate rulemakings for which EtO is a driver for the regulated source category.  
      The whole facility risk analysis is intended to help EPA understand the context of the risks posed by the source category being regulated. As such, the whole facility results are not used to determine whether or not risks from the source category are acceptable. The results can, however, inform the agency about source categories that may be of concern from a public health standpoint, and can be used to establish priorities for future information collection and regulatory actions. Regarding the facility-wide risks due to EtO, which are emitted by sources that are not part of the Cyanide Chemicals Manufacturing source category, we intend to evaluate those facility-wide estimated emissions and risks further and may address these in a separate future action, as appropriate.
      The EPA is taking steps to address ethylene oxide emissions by: (1) reviewing and, as appropriate, revising CAA regulations for facilities that emit ethylene oxide -- starting with air toxics emissions standards for miscellaneous organic chemical manufacturing facilities (85 FR 49084, August 12, 2020) and commercial sterilizers; and (2) working with industry and state, local, and tribal air agencies to achieve near-term emission reductions. The EPA posts updates on its work to address ethylene oxide at: https://www.epa.gov/ethylene-oxide. 
	Comment: Commenter (0061) states that epidemiological data are insufficient to demonstrate that EtO is a known human carcinogen. The commenter maintains that it is important to recognize that despite a large population of workers being exposed long-term to EtO concentrations up to millions of times higher than typical environmental concentrations, epidemiological data are insufficient alone to establish EtO as a known human carcinogen. The commenter notes that the EPA IRIS assessment (EPA 2016) considered the human study evidence of EtO carcinogenicity to be substantial but inconclusive. The commenter concurs with the EPA 2016 IRIS assessment that the human epidemiological evidence showing that EtO is carcinogenic is inconclusive (despite occupational exposure to EtO concentrations that were up to millions of times higher than environmentally relevant levels). According to the commenter, EPA's calculated hypothetical risks based on the 2016 URF are simply too overestimated and uncertain for regulatory use given both: (1) the inconclusive epidemiological data; and (2) the fact that the TCEQ has demonstrated that EPA's model is inaccurate at predicting cancers. By contrast, the TCEQ's standard Cox proportional hazards model is demonstrated to accurately predict cancers in both the key worker cohort as well as a model validation cohort.
	Commenter (0061) adds that the weight of epidemiological evidence does not sufficiently support breast cancer as an endpoint that should be included in EtO risk estimates due to the weakness of the epidemiological data for EtO-associated breast cancer. The commenter presents studies by Marsh et al. and Vincent et al. to support this.[,] According to the commenter, URFs should not include breast cancer, and the scientific creditability of the EtO cancer risk estimates in the proposed rule is contingent upon risk estimates being based only on lymphoid cancer as the endpoint.
	Response: The EPA acknowledges the commenter's input. The EPA classified ethylene oxide as a human carcinogen in December 2016. Studies of workers show that their exposures to ethylene oxide are associated with an increased risk of cancers of the white blood cells (the infection-fighting cells of the immune system). Studies also showed an increased risk of breast cancer in females. While this comment is not within the scope of this action, the EPA posts updates on its work to address ethylene oxide on its website at: https://www.epa.gov/ethylene-oxide.
3.3 Environmental Justice/Demographic Analysis
	Comment: Commenter (0063) states that, outside of environmental effects, the proposal does not include or address community concerns. According to the commenter, this proposal, under the rules set by Section 112 of the CAA, only addresses concerns from a numerical perspective. The commenter states that while effective in monitoring changing levels and requirements, the proposed revisions do not provide any requirements for community monitoring of the situation. The commenter asserts that outdated, inaccessible data has allowed for corporations to emit more than what the limit calls for, as seen in Colorado and Texas. The commenter suggests that EPA create future resources to maintain transparency with communities on data collection and levels of cyanide compounds.
      Response: In the Urban Air Toxics Strategy Report to Congress, we acknowledge that national rules and standards can address part of the risk to communities, but because the assessments did not include background risks or contributions to risk from sources outside the facilities, more needs to be done at the community level with other tools available within the CAA and within state, local, and other federal programs. EPA is committed to our efforts to make a difference in communities of concern and is developing an integrated strategy focusing work in communities with the most need for EPA's assistance. This effort to enhance coordination across our EPA programs and with other federal agencies will improve how we support community needs. We will focus on those communities where we think we have opportunities to leverage resources and actions to make a real difference. As we learn lessons on coordinating and focusing our efforts, we will use these lessons to help more communities in the future.
      Additionally, the final rule includes the electronic reporting of performance tests and the semiannual compliance report. After processing, these reports become publicly accessible through the EPA's WebFIRE portal (https://cfpub.epa.gov/webfire/).
3.4 Environmental Impacts 
      Comment: Commenter (0063) contends that the proposal does not fully address the adverse effects of cyanide chemicals on the environment, wildlife populations, and human health. According to the commenter, both the Center for Disease Control (CDC) and the EPA recognize that all residual risks of cyanide, ranging from health to environmental, have not fully been researched. The commenter suggests that there is low to medium confidence in several of the available studies on the environmental and wildlife effects of cyanide chemicals. 
      The commenter (0063) states that in aquatic ecosystems, fish, invertebrates, and some plant species are severely impacted by cyanide concentration exposure leading to decreased performance and death. The commenter also notes that cyanide exposure also results in decreased performance in birds. The commenter adds that as wastewater emissions pass through the soil, cyanide has a toxic effect on soil microorganisms. The commenter maintains that the lack of data and complete research in these areas allow for regulations to be passed without full consideration of the impacts.
      As such, the commenter (0063) suggests that to protect the interests of both the public and environmental populations, the EPA should further investigate cyanide impacts on wildlife populations such as aquatic species, birds, and mammals to fully understand the residual risks to species outside of human health risks. 
      Response: Based on the results of our environmental risk screening analysis, we do not expect an adverse environmental effect as a result of HAP emissions from this source category. The documentation for this decision is provided in the technical report, Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in the docket for this action (EPA-HQ-OAR-2020 - 0532-0005). 
      The EPA focuses on eight HAP, which are referred to as "environmental HAP," in its screening assessment: six persistent and bio-accumulative (PB) - HAP and two acid gases. For the environmental risk assessment, the following environmental HAP for the Cyanide Chemicals Manufacturing source category were identified and assessed: hydrochloric acid, cadmium compounds, lead compounds, arsenic compounds, mercury compounds, and polycyclic organic matter (POMs) (of which polycyclic aromatic hydrocarbons (PAH) is a subset). 
      EPA's 2006 Ecological Risk Workshop identified cyanide compounds as being highly toxic, but, based upon a refined analysis, it was determined that releases of cyanide compounds were neither persistent nor bioaccumulated. Based upon its ability to degrade in the atmosphere, this pollutant was not recommended to be included as an "environmental HAP" by the EPA for purposes of this regulatory review under the CAA.
      A review of the environmental screening assessment did not identify any exceedances of any Tier 1 ecological benchmarks for all the PB-HAPS (arsenic compounds, cadmium compounds, mercury compounds and POMs). For lead, we did not estimate any exceedances of the secondary lead national ambient air quality standards (NAAQS). For hydrochloric acid, each individual concentration (i.e., each off-site data point in the modeling domain) was below the ecological benchmarks for all facilities. For specific information on how the environmental risk screening assessment was conducted, including a discussion of the risk metrics used, how the environmental HAP were identified, and how the ecological benchmarks were selected, see Appendix 9 of Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in docket ID: EPA-HQ-OAR-2020-0532.
4.0 Technology Review 
      Comment: Commenter (0066) states that EPA recognizes that some of the emission standards here are cloaked as alternative "performance standards." The commenter contends that performance standards that do not satisfy §7412(d)(2)-(3) cannot be allowed to remain as an alternative compliance method under §7412(d)(6). The commenter provides that section 7412 does not allow EPA to satisfy the section 7411 test only. The commenter notes that it is "necessary" under §7412(d)(6) for EPA to review those alternative "performance" standards and revise them as needed to ensure they comply with §7412 and assure the "maximum achievable" degree of emission limitation -- that is at least as stringent as the average emission limitation "achieved" by the relevant best-performing sources. According to the commenter, this would likely mean deleting the alternative "performance" standard, and ensuring that section 112-compliant emission standards apply at all times.
      Response: The commenter erroneously suggests that EPA must reopen the MACT floors established for various emission sources in the 2002 NESHAP. Contrary to the commenter's assertion, EPA does not have an obligation to review prior MACT determinations and recalculate MACT floors as part of the CAA section 112(d)(6) review. Notably, this argument has been repeatedly rejected by the courts. See, e.g., Nat'l Ass'n of Surface Finishing v. EPA, 795 F.3d 1 (D.C. Cir. 2015); Association of Battery Recyclers v. EPA, 716 F.3d 667, 673 (D.C. Cir. 2013), NRDC v. EPA, 529 F.3d 1077 (D.C. Cir. 2008). The MACT standards were expressed in multiple forms representing equivalent levels of control and we have not reopened these MACT floor determinations. 
      Comment: Commenter (0066) contends that EPA has ignored developments in flare operational and monitoring requirements and equipment leaks in this rulemaking, even though this source category has sources that use flares and equipment leaks are a source of HAP emissions. EPA's MON, ethylene production, and refinery rules all recognize "developments" in flare operation, monitoring and emission reductions. The commenter adds that EPA must similarly recognize such developments here and require revisions to the cyanide chemical manufacturing rules that include the improvements in these other similar rules. According to the commenter, refusing to revise the cyanide chemical manufacturing standards to require improvements in flare efficiency and resulting emission reductions would violate §7412(d)(6) and would be irrational based on the strong record showing these developments exist. 
	Response: The EPA has not made the changes requested by the commenter. The flare requirements cited by the commenter were developed based on data available for those industries that the EPA does not possess for the cyanide chemicals manufacturing source category. The commenter references other NESHAPs that were revised based on data collected to support those rulemakings. We do not possess the same information regarding flare operation or monitoring for the cyanide chemicals manufacturing source category. The issues identified with assisted flares in reviews of other source categories have not been identified for the cyanide chemicals manufacturing source category. Responses to comments on the stringency of standards for equipment leaks are located in section 2.1 of this document.    
 Fenceline Monitoring
      Comment: Commenter (0066) provides that EPA must consider and "take into account" fenceline monitoring as a "development" for this type of source and facility to satisfy §7412(d)(6) and (f)(2).
	The commenter (0066) states that monitoring for EtO and other toxic air pollutants contributing to the unacceptable cancer and other health risks here would help provide the requisite "ample margin of safety to protect public health" by ensuring EPA has accurate information on the HAPs emitted from cyanide chemical manufacturing and collocated EtO-emitters and other sources -- and would help ensure that EPA could set fenceline corrective action concentrations for the carcinogens emitted here, to reduce the overall cancer risk. The commenter contends that EPA must evaluate this as a needed §7412(f)(2) revision and finalize fenceline monitoring requirements. 
	In addition, the commenter (0066) notes that fenceline monitoring is a "development" under §7412(d)(6) for chemical manufacturing facilities that emit EtO and other HAP through leaks, flares, and other sources. The commenter references EPA's recognition that in the petroleum refinery rulemaking, the organic liquids distribution rulemaking, and most recently, in the ethylene production rulemaking, fenceline monitoring is a "development" in pollution control, technologies, and methods under section 7412(d)(6) for chemical and petrochemical sources that have significant fugitive emissions that can be hard to measure and control, like cyanide chemical manufacturing sources. 
	The commenter (0066) also provides that the record shows fenceline monitoring is a development EPA must "tak[e] into account," demonstrating revisions are "necessary" under §7412(d)(6). The availability of this method to monitor and to require a corrective action concentration level to control fugitive emissions illustrates additional emission reductions are "achievable," such that EPA can and should strengthen the standards to ensure they satisfy §7412(d)(2). According to the commenter, where a development demonstrates the achievability of further emission reductions or control improvements, EPA must revise the standards to reflect that development and ensure the "maximum" degree of emission reductions that is "achievable." The commenter maintains that if EPA declines to revise the standards based on those developments, EPA must demonstrate that implementation of the developments is not "achievable," or would not result in any further source category emissions reductions.
	The commenter (0066) provides several examples in their comment letter of advancements and updates to fenceline monitoring practices that would demonstrate further toxic emission reductions are "achievable", highlighting EPA test methods to monitor for EtO and other major developments in real-time monitoring of pollutants.
	Response: Fenceline monitoring in the refinery regulation cited by the commenter is used to monitor emissions of benzene from fugitive sources, such as leaks from pumps and pipeline valves and connectors handling volatile organic compounds. At refineries, these fugitive sources of HAP are potentially a significant contributor to the facility's overall HAP emissions. Fugitive emissions at refineries are difficult to measure due to the large number of valves, connectors, pumps, etc. Fenceline monitoring, as discussed in the preamble to the proposed refinery rule may identify significant increases in emissions, but small increases in emissions are unlikely to impact the fenceline concentration. We have no knowledge of any facilities in the Cyanide Chemicals Manufacturing source category currently conducting fenceline emissions monitoring. EPA is not incorporating fenceline monitoring into the final rule due to these considerations. 
	The ethylene oxide emissions of concern are not emitted from the Cyanide Chemicals Manufacturing source category and controlling or monitoring those emissions are not within the scope of this action. See section 3.2 (Co-Located Emission Source Risk) of this comment response document for related comments expressing concern regarding ethylene oxide emissions and exposure and the EPA's responses to those comments.
6.0 Compliance Requirements
6.1 Electronic Reporting Requirements
6.1.1 Requiring Electronic Reporting Using the Compliance and Emissions Data Reporting Interface (CEDRI) System
      Comment: Commenter (0066) supports requiring electronic reporting to assure and account for compliance.
      Response: The EPA acknowledges the commenters' support for electronic reporting. The final rule requires electronic reporting for all Cyanide Chemicals Manufacturing facilities subject to subpart YY, as proposed.
      Comment: Commenter (0065) generally supports the proposed timing and implementation of EPA's new periodic reporting Excel workbook. The commenter notes, however, that EPA's assertion that electronic reporting eliminates paper-based, manual processes, thereby saving time and resources, simplifying data entry, eliminating redundancies, minimizing data errors, and providing data quickly and accurately to the affected facilities, air agencies, the EPA, and the public is not necessarily the case. The commenter provides that state reporting requirements, such as TCEQ's, or even local requirements will generally require additional versions of the same report. The commenter supports an electronic reporting system by which reports to all agencies could be satisfied by using the CEDRI system in the future.
	Response: The EPA's electronic reporting system provides quick and easy access to submitted data for state, local, and tribal agencies in two convenient locations: CEDRI and WebFIRE. EPA works with state, local, and tribal agencies to encourage and implement the use of CEDRI for electronic delivery of reports within their jurisdiction. As more information is provided through EPA's electronic reporting system, EPA expects more state, local, and tribal agencies to adopt the use of the EPA's electronic reporting system. Electronic reporting minimizes submission of unnecessary or duplicative reports in cases where facilities report to multiple government agencies and the agencies opt to rely on EPA's electronic reporting system to view report submissions. Where air agencies continue to require a paper copy of these reports and will accept a hard copy of the electronic report, facilities will continue to have the option to print paper copies of the electronic report to submit to the air agencies, and, thus, minimize the time spent reporting to multiple agencies.
	Additional information required to be submitted by a state, local, or tribal agency may be easily submitted with the required template as either additional files within the zipped file (further details on the procedures are contained in the Welcome tab of the template) or within the optional "Additional Data" fields within the template itself.
6.1.2 Proposed Periodic Report Template
      Comment: Commenter (0065) provides several comments and improvement suggestions for several tabs of the Report Template provided below:
       Welcome Tab and General Comments
          There is a typo in the description on Row 15; "Storrage" should be spelled storage; and
          There is a missing tab entry for process wastewater source information (future) 
       Applicable standard detail Tab
          Column E cannot be modified; error message states that value doesn't match data validation;
          Columns E-L references §63.1111(c)(2)  -  (c)(5) SSM reporting although §63.1110(a)(7) specifically excludes §63.1111 for cyanide. Note, if the form is released more than 6 months after the rule is finalized, then these columns will not be needed because the SSM provisions will no longer apply; and
          This tab should also include a field for a redetermination of predominate use for recovery operations, if necessary (§63.1100(f)(6))
       Closed vent Leaks Tab
          EPA should consider adding the following to the citation on this form:
             Date Leak Detected should include the reference §63.998(d)(1)(iii)(B);
             Date Leak Repair First Attempted should include the reference §63.998(d)(1)(iii)(B);
             Date Leak Successfully Repaired should include the reference §63.998(d)(1)(iii)(C);
             Maximum Instrument Reading should include the reference §63.998(d)(1)(iii)(D);
             Was Repaired Delayed etc. should include the reference §63.998(d)(1)(iii)(E); and
             Reason for Delay if Repair was Delayed should include the reference §63.998(d)(1)(iii)(E)
       Closed vent valves Tab
          Columns E through I heading states "maintenance" only as the only reason for removing the car seal, but should note that there are other reasons for a by-pass for car-sealed valves: 1 - the car seal was broken, 2- the bypass line valve position changed, 3- or the key to unlock the bypass line valve was checked out
       Storage vessel Tab
          EPA should add a data entry field for "redetermination of predominate use for storage vessels, §63.1100(e)(4)"
       LDAR initial UU TAB
          This form is missing a field for the Certification of Unsafe to Monitor Components, 63.1103(g)(5)(i), §63.1039(b)
       LDAR UU general Tab
          This tab allows for grouping valves but does specify listing components ID and arithmetic average for leaking valves from last two monitoring periods
       LDAR UU summary Tab
          This form is missing dropdown list items for agitators, connectors;
          This form does not have a field or entry for pressure testing for testing options §63.1039(b)(7), §631036(f); and
          This form does not have an entry in form for revisions to method of compliance §63.1039(b)(8)
	Response: EPA has made the suggested changes with the exception of or modification to the following;
 The EPA disagrees that, on the Applicable_Standard_Detail tab, the SSM revisions remove the need for columns E through L. Section §63.1110(a)(7) specifically excludes the SSM reporting of §63.1111(b), the provisions of §63.1111(c) continue to apply. Columns E through L remain in the final version of the template. 
 The EPA disagrees that the change in predominant use reporting specified in §63.1100(e)(3) and §63.1100(f)(6) belongs on the Storage Vessel and the Applicable_Standard_Detail tabs respectively, and has included the change in predominant use data field on the Affected_Sources tab. 
 EPA has added the indicated citations to Closed_Vent_Leaks tab in addition to the reporting citation of §63.999(c)(2)(i) as only referencing the recordkeeping citation is insufficient to indicate the reason for reporting and has caused confusion in other templates.
 On the Closed_Vent_Valves tab, the header of column D indicates that the selection is for the "Maintenance Activity" which consist of all of the cited reasons in the dropdown. EPA has however removed "Maintenance" from the headers of columns E through I for clarity as maintenance per se is not the sole reason for bypass of a car-sealed valve.
 For the LDAR_UU_General tab, the listed requirements of §63.1039(b)(4)(iv) are not easily contained within the spreadsheet format of the template. The EPA is not specifying the form or format of the listing and average, but as noted in column G, they are to be attached to the report, and the filename noted in the appropriate row.
 The EPA disagrees that the certification of unsafe to monitor components belongs in the LDAR_Initial_UU tab as it is applicable to both Subpart TT and UU LDAR options. A new tab, LDAR_Unsafe_Certification tab has been added for the required information.
 Rather than incorporating pressure test requirements into LDAR_UU_Summary tab, the requirements of §63.1036(f) are included in a new tab, LDAR_UU_Pressure_Test.
 The EPA disagrees that the template does not have an entry in the form for the details required by §63.1039(b)(8) in the event of a change in the method of compliance, however there may be some confusion. The requirement of §63.1039(b)(8) is to, in the event of a change in method of compliance to report any revisions to items reported in an earlier Initial Compliance Status Report, which may be reported on the LDAR_Initial_UU tab. To clarify, we have amended the citations to also reflect §63.1039(b)(8) and added a column to indicate that a particular row is meant as a revision to previously submitted report.
6.2 Extension for Compliance Reporting for Force Majeure Events
      Comment: Commenter (0066) contends that EPA may not create an unlawful exemption, labeled as an extension for compliance reporting, as it proposes to do for web outages or so-called "force majeure events," as this violates the requirement for standards to be continuous and would allow unreported exceedances to go unchecked, indefinitely, as explained in the referenced comment on Integrated Iron and Steel Manufacturing (pp. 94-97). The commenter recommends that if there is a need for a reporting extension, EPA should ensure that EPA reviews, grants, and requires a report by a prompt, enforceable deadline, instead of providing the open-ended, indefinite exemption the proposed rule would allow. According to the commenter, force majeure events are simply another term for a malfunction, and providing an exemption for reporting only worsens the harm from releases by removing any deadline to report them in a timely manner.
	Response: The EPA disagrees with the commenter's assertion that the extension for reporting allowed through the force majeure or CEDRI outage provisions are an exemption from reporting, as discussed in detail in response to the commenters original comment in the Summary of Public Comments and Responses for Risk and Technology Review for Integrated Iron and Steel Manufacturing Facilities (https://www.regulations.gov/document/EPA-HQ-OAR-2002-0083-1100 pp. 5-1 through 5-4). The concept of force majeure has been implemented by the EPA in this context since May 2007 within the CAA requirements through the performance test extensions provided in 40 CFR 63.7(a)(4) and 60.8(a)(1) regarding the time granted for conducting a performance test and such language has not undermined compliance or enforcement. There is no exception or exemption to reporting, much less an exemption from compliance with the numerical emission standards, only a method for requesting an extension of the reporting deadline. Reporters are required to justify their request and identify a reporting date. There is no predetermined timeframe for the length of extension that can be granted, as this is something best determined by the Administrator (i.e., the EPA Administrator or delegated authority as defined in 40 CFR 63.2) when reviewing the circumstances surrounding the request. Different circumstances may require a different length of extension for electronic reporting. For example, a tropical storm may delay electronic reporting for a day, but a Hurricane Katrina scale event may delay electronic reporting much longer, especially if the facility has no power, and as such, the owner or operator has no ability to access electronically stored data or to submit reports electronically. Like the performance test extensions, the approval of a requested extension of an electronic reporting deadline is at the discretion of the Administrator. The Administrator will be the most knowledgeable of the events leading to the request for extension and, after reviewing the information submitted in the request for extension under 40 CFR 63.7841(f), will assess whether an extension is appropriate, and if so, a reasonable length for the extension. The Administrator may even request that the report be sent in hardcopy until electronic reporting can be resumed. While no new fixed duration deadline is set, the regulation requires that the report be submitted electronically as soon as possible after the CEDRI outage or after the force majeure event resolves.  
6.3 Other Compliance Requirements
	Comment: In addition to supporting electronic reporting, commenter (0066) supports requiring recordkeeping and repeat performance testing to assure and account for compliance. The commenter states that EPA has long recognized that electronic reporting, testing, and recordkeeping are necessary to assure compliance and for public transparency and accountability. The commenter considers these changes "necessary" to assure compliance with the Clean Air Act and should be finalized under §7412(d)(6).
	Response: The EPA acknowledges the commenter's support for electronic reporting.
7.0 Administrative Procedures Act (APA)
      Comment: Commenter (0066) states that EPA's proposal fails to satisfy the CAA's public participation requirements. According to the commenter, the CAA requires EPA to publish "notice of proposed rulemaking," that "shall be accompanied by a statement of its basis and purpose," and include "a summary of ... the major legal interpretations and policy considerations underlying the proposed rule." 42 U.S.C. §7607(d)(3). The commenter provides that here, EPA did not publish the actual "proposed rule" or proposed regulatory language at all, or some of the explanation for such changes. The commenter notes that instead, EPA placed the regulatory language and explanations of it in a separate PDF in the docket. The commenter contends that EPA has violated public notice and comment requirements of the CAA and APA by failing to publish notice in the Federal Register of the proposed rule itself. 
	The commenter (0066) states that EPA's failure is prejudicial to the ability of the public to be able to find and comment on the proposed regulatory changes because they are not part of the notice in the Federal Register. The commenter provides that the notice format is extremely unusual compared to EPA's regular practice.
	The commenter (0066) contends that the CAA and the APA do not allow an Agency to hide the core regulatory language in this way. The commenter adds that the proposed and final regulatory language must be published in the Federal Register to satisfy the core public notice requirements and allow for meaningful comment. The commenter states that EPA has also failed to ensure that there is a permanent, public record documenting the proposed and final changes to the Code of Federal Regulations, because only the Federal Register notices are also published in legal databases like Westlaw.
	The commenter (0066) states that EPA should publish the proposed language and necessary basis for public comment in the Federal Register, to remove the prejudicial effect on the public's ability to comment before it finalizes the rule. The commenter provides that failing to do so will violate core procedural requirements of the CAA and contravene the Biden-Harris Administration's commitment to good government and transparency and the public's right to know about and have a meaningful opportunity to participate in EPA's rulemaking process.
	Response: The proposal met all APA and CAA notice and comment requirements.  Nothing in the APA or the CAA, including the language the commenter cites, requires EPA to publish proposed rule text in the Federal Register. Commenter suggests that because EPA did not publish the proposed rule text, EPA failed to meet the CAA 307(d)(3) requirement to publish a notice of proposed rulemaking. However, the requirement to publish a notice of proposed rulemaking is not a requirement to publish proposed rule text. Section 307(d)(3) specifies the required elements of a notice of proposed rulemaking and proposed rule text is not a required element. The elements commenter cites that are required to be included in the notice of proposed rulemaking (a "statement of basis and purpose," "a summary of... the major legal interpretations and policy considerations underlying the proposed rule, etc...") were included and commenter does not suggest otherwise. 
      The APA does not require publication of proposed rule text in the Federal Register either. Section 553(b)(3) of the APA provides that a notice of proposed rulemaking shall include "either the terms or substance of the proposed rule or a description of the subjects and issues involved." (emphases added). Thus, the APA clearly provides flexibility to describe the "subjects and issues involved" as an alternative to inclusion of the "terms or substance" of the proposed rule. See also Rybachek v. U.S. E.P.A., 904 F.2d 1276, 1287 (9th Cir. 1990). (EPA's failure to propose in advance the actual wording of a regulation does not make the regulation invalid where EPA's discussion of the regulatory provisions "clearly describe `the subjects and issues involved.'")
      Commenter claims that EPA did not publish "some of the explanation" for the proposed amendatory regulatory text. However, commenter does not identify any specific regulatory text that was not explained or specify any deficiency in any explanation of regulatory text in the Federal Register notice. Such a generalized objection is not sufficiently specific. See Appalachian Power Co. v. E.P.A., 251 F.3d 1026, 1036 (D.C. Cir. 2001) ("`An objection must be made with sufficient specificity reasonably to alert the agency.'" (quoting Tex Tin Corp. v. EPA, 935 F.2d 1321, 1323 (D.C.Cir.1991)).  
      Commenter makes a vague assertion that EPA's approach was prejudicial to the ability of the public to be able to find and comment on the proposed regulatory changes, but does not claim any actual difficulty in finding or commenting on the proposed rule language. EPA's approach was not prejudicial to the commenter or any member of the public. The notice of proposed rulemaking clearly explained that the proposed amendatory language and a redline strikeout version of the subpart YY showing proposed changes were available in the docket and on EPA's website:
      The proposed changes to the CFR that would be necessary to incorporate the changes proposed in this action are set out in an attachment to the memorandum titled Proposed Regulation Edits for 40 CFR part 63, subpart YY, available in the docket for this action (Docket ID No. EPA - HQ -  OAR - 2020 - 0532). The document includes the specific proposed amendatory language for revising the CFR and, for the convenience of interested parties, a redline version of the regulation. Following signature by the EPA Administrator, the EPA will also post a copy of this memorandum and the attachments to https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.
National Emission Standards for Hazardous Air Pollutants: Cyanide Chemicals Manufacturing Residual Risk and Technology Review, 86 FR 3908 (Jan. 15, 2021).  
      Although EPA's recent practice has generally been to publish proposed amendatory regulatory text, EPA's practice has varied. See Hazardous Air Pollutants: Proposed Regulations Governing Constructed, Reconstructed or Modified Major Sources, 59 FR 15504 (April 1 , 1994) ("The proposed regulatory text is not included in the Federal Register notice, but is available in Docket No. A-91-64 or by request from the EPA contact persons designated earlier in this note. The proposed regulatory language is also available on the technology Transfer Network (TTN), of EPA's electronic bulletin boards."), Federal Standards for Marine Tank Vessel Loading and Unloading Operations and National Emission Standards for Hazardous Air Pollutants for Marine Tank Vessel Loading and Unloading Operations, 59 FR 25004 (May 13, 1994) ("The proposed regulatory text and other materials related to this rulemaking are available for review in the docket."). Even when EPA does include the proposed text in the Federal Register, we often include a redline version of proposed regulations in the docket for rulemakings to assist the public in understanding the proposed regulatory changes. In our experience, stakeholders find the redline version far more useful than the proposed amendatory language in the format required by the Office of the Federal Register. Although appropriate for the task of revising the Code of Federal Regulations, this language can be difficult to assess without the accompanying full regulatory text. Given this, and given that we rarely receive comments on the proposed amendatory language or on proposed regulatory language at all, we determined that for rulemakings such as these it would be more efficient to take the approach here of making both easily accessible but not including the proposed amendatory text in the notice.
      Comment: Commenter (0066) provides that EPA has failed to satisfy the public notice-and-comment requirements by failing to discuss the specific standards it is proposing other than by reference to the HON (related to proposed process wastewater provisions). Additionally, the commenter holds that EPA has failed to present the information on which it purports to rely on that 2008 rule in the record for public notice-and-comment, a critical error in violation of 42 U.S.C. §7607(d)(3). According to the commenter, the public cannot attempt to evaluate or show how EPA's purported floor analysis is flawed when it is unclear what it is relying on -- and the way the Act requires EPA to ensure the public has this information by directing EPA to place it into the public docket for this rule.
      Response: The EPA disagrees with the commenter that we did not adequately support the decision to establish the wastewater provisions of the HON as the MACT level of control for process wastewater at existing Cyanide Chemicals Manufacturing sources. The EPA reviewed title V permits for all facilities in the source category and determined that wastewater operations at all facilities in the category are subject to the wastewater provisions of the HON or substantively equivalent provisions in other NESHAPs. Therefore, we concluded that these provisions represent the level of the MACT floor for process wastewater at existing sources. We did not identify any other technologies available for use at these facilities for process wastewater at existing sources beyond the technology required for process wastewater at new sources. We did not receive any data before proposal or from public comments regarding changes in the cost or emissions impact of the level of control required for new sources and therefore the conclusion reached when we developed the NESHAP initially regarding this technology's use at existing sources has not changed.  
8.0 Other Miscellaneous Comments
      Comment: Commenter (0059) states that there is an urgency to protect air quality, as the effects of poor air quality are of great importance and repercussions are fatal. According to the commenter, the quality of air is affected more commonly due to cyanide because it is in our daily household items and the rate of society consuming or inhaling such chemicals is more than common. The commenter provides that it is a danger to those who work around it and those who live with the items at home. The commenter continues in stating that cyanide is harmful to the environment and there are other resources that can replace it that are safer for everyone. The commenter maintains that cyanide is one of the deadliest chemicals to ingest and should have been banned a long time ago as research has long supported this conclusion.
      Response: The EPA acknowledges the commenters' concerns. The risk assessment demonstrated that health risks due to air emissions from Cyanide Chemicals Manufacturing sources are acceptable and, after considering available control options and all available risk information, EPA concluded that the current standards provide an ample margin of safety to protect public health. The documentation for this decision (which includes assumptions/inputs/uncertainties associated with the analyses) is provided in the technical report, Residual Risk Assessment for the Cyanide Chemicals Manufacturing Source Category in Support of the Risk and Technology Review 2020 Proposed Rule, available in the docket for this action (EPA-HQ-OAR-2020 - 0532-0005).
      Comment: Commenter (0062) asserts that there is a lack of responsibility on the part of environmental protection agencies, as well as those in charge of petroleum refineries and plants that process toxic chemicals in that they fail to consider the risks and impacts to health from the emissions they seek to increase in our communities. The commenter supports the need for more regulation on this pollution and that producers of these air-borne toxins must be reviewed.
      Response: The EPA acknowledges the commenters' concerns. The statutory authority for this action is provided by sections 112 and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of the CAA establishes a two-stage regulatory process to develop standards for emissions of HAP from stationary sources. Generally, the first stage involves establishing technology-based standards and the second stage involves evaluating those standards that are based on maximum achievable control technology (MACT) to determine whether additional standards are needed to address any remaining risk associated with HAP emissions. This second stage is commonly referred to as the "residual risk review." In addition to the residual risk review, the CAA also requires the EPA to review standards set under CAA section 112 every 8 years and revise the standards as necessary, taking into account any "developments in practices, processes, or control technologies." This review is commonly referred to as the "technology review." These periodic reviews are ongoing to meet the EPA's mission to protect human health and the environment.
      Comment: Commenter (0067) expresses dissatisfaction with EPA's past standing on standard enforcement and suggests for the rule to be strengthened accordingly. The commenter contends that the impacts of this chemical on wildlife and marine biology and data warehousing systems that prove how these systems are working and what the levels are needed to be addressed or further investigated. The commenter also states that this rule is a step in the right direction, even though it does not fully assess the risks.
      Response: The EPA acknowledges the commenters' dissatisfaction. See EPA's response to comments in section 3.4 (Environmental Impacts) of this document.
