MEMORANDUM

SUBJECT: Bounding Anal ys is for Portland Cement MACT Floors TO: Docket No. EPA - HQ - OAR- 2011 - 0817 DATE: May 14 , 2012 EPA re - evaluated the floor calculations used in the final NESHAP for the Portland cement source category . 75 FR 54970 (Sept. 9, 2010). This analysis is a bounding anal ys is which removes from the Portland cement database any cement kiln which combusts a non - hazardous secondary material. This anal ys is is not intended to determine which kilns are CISWIand which remain cement kilns. Rather, it determines what floors would be on the extreme hy pothetical assumption that any

cement kiln which combusts a non - hazardous secondary material is not a cement kiln. The analysis then determines what the floors would be under this extreme as sumption, bounding the possible floors which could result from the data set. The result s of this anal ys is are presented below:

**Pollutant Kilns that do not combust** 

**non -**  **hazardous secondary materials**  **Promulgated –**  **All Kilns Existing**  **New Existing**  **New Hg**  No. of Kilns 26 26 89 89 No. in Floor 4 1 11 1 UPL (lb/MM tons clinker ) 66.60 46.48 54.10 20.30 Average (lb/MM tons clinker ) 44.75 35.20 31.70 13.90 **HCl** No. of Kilns 11 11 21 21 No. in Floor 2 1 3 1 UPL (ppm) 0.56 0.34 0.52 0.34 Average (ppm) 0.40 0.34 0.41 0.34 **PM** No. of Kilns 18 18 45 45 No. in Floor 3 1 6 1 UPL (lb/ton clinker ) 0.05 0.01 0.04 0.01 Average (lb/ton clinker ) 0.03 0.01 0.00 0.01 **THC**No. of Kilns 10 10 15 15 No. in Floor 2 1 2 1 99 th percentile (ppm) 14.98 10.84 24.00 24.00 Average (ppm) 5.69 5.68 5.20 4.70 The attachment to this memo (Attachment A) contains the calculations supporting these results . Attachment A - 9 details the kilns identified as CI SWIat reconsideration. These kilns were removed from all MACT floor calculations as part of the bounding anal ys is . Additionally, any kilns identified as combusting non - hazardous secondary material from the 2007 portland cement ICR were removed from the MACT floor calculations. Attachment A - 10 details the kilns that were identified as combusting non - hazardous secondary materials. We note further that although the HCl floor ostensibly changes (slightl y) in this analysis, in fact there is no reason that the HCl floor would change . This is because the floor is effectivel y determined b y the anal ytic detection limit, and there are a large group of cement kilns which performed identicall y to the best performers. See 76 FR at 28322 n. 11. The reason for the (slightly) different value in this bounding anal ys is is due to the different number of sources in the database , not to any

difference in measured performance . Since there is no actual difference in kiln performance for HCl, there is no reason that the floor should be altered . We also note that no cement kilns are reclassified as incinerators in this bounding anal ys is due to processing non - hazardous secondary materials as ingredients. This is bec ause none of the non - hazardous materials identified by cement kilns as being used as ingredients are combusted, as explained at 76 FR 28322. Even under the extreme assumptions of this analysis, EPA does not believe that the technology

basis for the PM, HCl, THC or mercury standards would change were these bounding anal ys is floors to be adopted as standard s .