Document o9ax42dQzMnNZa1a6KR49wYvo

will necessitate a significant investment. Such an investment cannot he undertaken if it is not fully developed to ensure compliance with the more stringent fPM standard. Additionally, the economic burden of these upgrades would impose financial strain on the facility. potentially leading to operational disruptions. The financial burden of implementing the required upgrades, alongside the necessary feasibility studies, within the compliance deadline is prohibitive. The estimated cost of the upgrades, including procurement, installation, and operational adjustments, could exceed our current financial capabilities. the immediate financial strain of these upgrades could jeopardize our ability to continue operations and place a significant burden on the local economic community, which provides the labor force for PUS. Therefore, an extension to the compliance deadline is necessary to allow for a comprehensive evaluation and careful execution of the necessary upgrades. PM CENS Technology is Not Available There arc technological limitations that also make PM CEMS "not available" and make demonstrating continuous compliance with an fl'M limit of 0.010 lb/MMBtu via CEMS nearly impossible. CEMS for fPM does not provide direct measurements; instead, it uses correlation curves to indirectly calculate estimated emissions levels based on the measurement of some other value. However. the low IPM limit in the Rule makes developing this correlation curve "virtually impossible." PGEN Comments on EPA 's Proposed Rule: NESHAP ('oal- and Oil-Fired Electric attain Generating Units Review of the Residual Risk and Technology Review, Docket No. EPA-I IQ-OAR-2018-0794-5994, at 22 (June 28, 2023) [hereinafter "PGFN Comments"] (citing and attaching Ralph L. Roberson. Technical Comments on EPA 's Proposed Ride: Mercury and Air Toxics,S"tandards Risk and Technology Review, at 3 (2023) [hereinafter "PM CEMS Technical Memo"]). EPA admits as much--it explains that 0.010 lb/MMBtu is the "lowest achievable fPM limit that allows for the use of PM CEMS for compliance." 89 Fed. Reg. at 38,530. And EPA's analysis ignores the need for a compliance margin below 0.010 lb/MMBtu in order to "implement" that limitation in practice. Similarly, the quality assurance/quality control ("QA/QC") criterion for fPM CFMS arc extremely difficult to meet at such low levels. See Comments of the ('lass of '85 Regulatory Response Group on the Proposal on National Emission .Standards for Hazardous Air I'ollutanis: Coal- and Oil-Fired Electric [MIR; Steam Generating Units Review of. the Residual Risk and Technology Review, Docket No. EPA-IIQ-OAR-2018-0794-5989, at 16 (June 28, 2024) 1 hereinafter "Class of. '85 Comments"]. In fact. at the time ofthe proposed MATS revisions, no commercially available FPM CEMS would have been able to meet the tight confidence and tolerance intervals associated with the low proposed fP11/1 limitation. PC-1EN Comments at 23 (citing PM CFMS Technical Memo at 5). EPA was, thus, forced to address these issues in the final MATS revisions by adjusting the QA criterion and correlation procedures. See 89 Fed. Reg. at 38,528-29 ("PM CEMS currently correlated for the 0.030 lbiMMBtu fi'M emission limit may experience difficulties should re-correlation be necessary ... those concerns are also ascribed to yet-to-be installed PM CEMS"). Iowever, those changes arc not enough to address the fundamental issue: that fPM CFMS is simply not able to reliably measure such low IPM levels the error rates of the instrument prohibit it. See PGEN Comments at 23 (finding insurmountable the "uncertainties inherent in the measurement device" and the "problems associated with relative size of the uncertainty to the limited data range of fPM concentrations and the confidence levels and tolerances"); see also Class of '85 Comments at 3 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000201-00003 SC_EVERSPLIT0005975