Document 93nDXXG8kBgqgqnjK67Jyw857

depending on location. Ash content of the coal being fired may impact the ability of units to comply with the fPM limit, regardless of the effectiveness of the control technologies in place. Other operational factors such as cleaning frequency, operational duration, and filter change-out frequency of baghouses impact the performance of controls and, thus, the facility's ability to comply with the proposed limit. These concerns are exacerbated by the companion requirement to measure compliance using monitors that have not been demonstrated to be reliable. CENTS Technology is Not Available by the Rule's Compliance Date The MATS R TR also requires coal-fired units to implement the revised IPM limit of 0.010 lb/MMBtu using CEMS. rather than periodic stack testing. There are technological limitations, as well as costs and market limits, that make adoption of CFMS by July 2027 unattainable. PM CFMS does not provide direct measurements; it uses correlation curves to calculate emissions levels. However, the low fPM standard in the Rule makes developing this con-elation curve "virtually impossible." PGLA Comments on EPA Proposed Rule: ATSHAP Coal- and Oil-Fired Electric Utility Steam Generating Units Review of the Residual Risk and "Iechiu Review, Docket No. FPA-11Q-OAR-2018-0794-5994, at 22 (June 28, 2023) [hereinafter "PCIF.N Comments"' (citing and attaching Ralph I.. Roberson, lechnical Cointnents on EPA .s Proposed Me: Mercury and Air Toxics .9andards Risk wul Technology Review, at 3 (2023) [hereinafter "PM CEMS Technical Memo"]). Similarly, the QA/QC criterion for CFMS are extremely difficult to meet at such low levels. See Conuncuits ()film? Clas.s of '85 Regulatory Response Group on the PrOpO.SaI on National 1,..nussion ,S'tandards fOr HUIIIYIOUS Aii' Pollutants: Coal- and O11-Fired Electric I 'tilily .9eath Generating Units Review ()film? Residual Risk and Fechnology Review. Docket No. EPA-HQ-OAR-2018-0794-5989, at 16 (June 28, 2024) [hereinafter "Class of '85 Comments"]. In fact, at the time of the proposed MATS RTR, no commercially available PM CEMS would have been able to meet the tight confidence and tolerance intervals associated with the low proposed fPM standard. PGFN Comments at 23 (citing PM CFMS Technical Memo at 5). FPA was, thus, forced to address these issues in the final MATS RTR by adjusting the QA criterion and correlation procedures. See 89 Fed. Reg. at 38,528-29. However, it has not yet been shown that these changes are enough to address the fundamental issue that PM CFMS has difficulty reliably measuring such low fPM levels due to the error rates of the instrument. See PCIFN Comments at 23 (finding insurmountable the "uncertainties inherent the in the measurement device" and the "problems associated with relative size of the uncertainty to the limited data range of IPM concentrations and the confidence levels and tolerances"); see also Class of '85 Comments at 18. And, in reality, units would need to target emissions below 0.010 lb/MMBtu in order to ensure continuous compliance. See Perrs' Brief at 72. Therefore, the CEMS technology to demonstrate compliance with the revised WPM standard is unavailable. Second. there are significant costs and market limitations associated with PM CEMS, which make it "not available." Installing and operating CEMS is more costly than stack testing. See PCiEN Comments at 25-26. Costs include purchasing and installation of CF.MS, as well as potential modifications to the units to accommodate CEMS, extended correlation testing, and annual operational costs. See id. at 26; see also Class of '85 Comments at 18 (estimating $180,000 to 5400,000 for site preparation and engineering analysis, analyzer equipment and installation 3 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000172-00003 SC_EVERSPLIT0005949