Document 6w1GVGG9kEdXY91VgEkRObnGE

The proposed sampling frequency reduction level of 0.3 ug/m-' highlights the challenges associated with M325 benzene sampling and analysis: the proposed level not only exceeds the lowest point on laboratory benzene calibration curves, it also fails to take into account sample-tosample variability in the effective detection limit for benzene. As a result, the proposed 0.3 ug/m3 regulatory sample reduction level inevitably will be influenced by background benzene levels, which would contribute up to 0.1 ugim' of benzene that is not associated with the ambient air, but rather germane to laboratory bias. These technical shortcomings would render the data inaccurate and over-inclusive (i.e., it would include other sources' emissions) and have unreasonable adverse effects on a facility's ability to be relieved of unnecessary monitoring. For example, even after a successful six-year effort and stepwise reductions in sampling frequency, a single unreliable sample location reporting above 0.3 ug/m3 could cause the facility to immediately return to the original continuous sampling requirement. If, despite SunCoke's comments, EPA proceeds with requiring fenccline monitoring for I INR facilities, SunCoke submits that the appropriate reduction level should be 0.9 ug/m3, which would be equivalent to that in the Refinery MACT, and should be based on an annual average similar to EPA's proposed corrective action threshold rather than a single sampling period. This would help mitigate against laboratory measurement bias and minimize decision outcome risk. In the Refinery MACT, EPA acknowledged the monitoring technology limitations, i.e., those related to equipment detection limits and the need to ensure reliable data quality, and set 0.9 ug/m3 as the appropriate level, including because it facilitated using alternative monitoring approaches (e.g., gas chromatographs and open path monitoring systems) EPA's reasoning with respect to the reduction level in the Refinery MACT applies here as well. Moreover, if EPA were to set the reduction level at 0.3 ug/m3, the Agency effectively would eliminate the option to use non-M325 approaches to demonstrate compliance with the action level and make it exceedingly difficult to meet the sample reduction level due to non-ambient air contributions associated with analytical results at such a low level. 8. EPA Should Not Establish A One-Size-Fits-All Time Frame for Corrective Action or Require Corrective Action in Absence of Violation of Subpart I. EPA is proposing to require coke oven facilities to take corrective action to reduce fugitive emissions if monitored fcncelinc concentrations exceed the action level on a rolling annual average basis (recalculated every fourteen (14) days) With respect to the requirement to perform corrective action after exceeding the action level, EPA should not require a "one size fits all" timeline. Corrective actions are facility- and cause-specific, and it would be untenable for EPA to predetermine and dictate a timcframe for corrective action without any information on what may -1' See EPA, Presentation, Vaiiona/ f ir Tones Atoniioring and Da a :1haIrsis Workshop, Oct 28th, 2015, available at https "www3 epa.gov ttnamtil"filesiambientiairtox 12015workshop"Petrolcum%20Refinciy pdf Several of the example root cause analyses identified by EPA in the redline version of MACT I. do not represent root cause analysis of an event that has already occurred Instead, they reference an event is ongoing (e.g "employing progressively more frequent sampling, analysis and meteorology (c g. "using shorter sampling periods for Methods 325.A and 325B of appendix A of this part, or using active sampling techniques)." EPA-IIQ-OA R-2003-0051-0753, EPA, Memorandum, Coke NEVI 1P Redline rs ref Proposed Rule ( 'hanges fo,..1O FR par, (3, svrhprirf L, at S4--S5 (Jul. 1, 2023) (amending 50 C, F.R. 63.3 l4(g)). 45 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000109-00046 SC_EVERSPLIT0005720