Response to Comments  -  EPA-R03-OAR-2017-0509  -  Approval and Promulgation of State Air Quality Plans for Designated Facilities and Pollutants; City of Philadelphia; Control of Emissions from Existing Sewage Sludge Incineration Units

Comment: The commenter stated that EPA must confirm that no additional SSI units exist or have been constructed since the time of Philadelphia's certification letter, citing the amount of time between receipt of the negative declaration and the proposed approval.

Response: EPA does not agree with the commenter's assertion that EPA must ensure that no additional SSI units have been constructed since Philadelphia AMS submitted the negative declaration in order to finalize this action.  As stated in the technical support document for the NPR and in the EG for existing SSI units (40 CFR 60, subpart MMMM), the designated facilities to which the EG apply are SSI units that: 1) commenced construction on or before October 14, 2010; 2) meet the definition of a SSI unit as defined in 40 CFR 60.5250; and 3) are not exempt under 40 CFR 60.5065.  Thus, for EPA approval of Philadelphia AMS' negative declaration regarding existing SSI, Philadelphia only needed to assert no SSI units exist that commenced construction on or before October 14, 2010.  Because Philadelphia's negative declaration was submitted on March 28, 2012  -  after the October 14, 2010 deadline to be considered an existing SSI unit  -  there is no need to revisit the initial determination of Philadelphia AMS that no existing SSI units exist within the jurisdictional boundaries of the local air pollution control agency.  Prior to Philadelphia's submission, EPA worked with Philadelphia AMS and reviewed Philadelphia's inventory of sources to ensure no existing SSI units existed within Philadelphia, and the commenter has not provided any information to the contrary that would cause EPA to reconsider the assessment of Philadelphia AMS's negative declaration.  EPA's acceptance of Philadelphia's negative declaration therefore is appropriate.  SSI units constructed after the above cited date (i.e., October 14, 2010) would be considered "new," as opposed to "existing," and therefore would be subject to a separate rule - 40 CFR 60 subpart LLL, "Standards of Performance for new Sewage Sludge Incineration Units."  EPA is therefore finalizing the negative declaration for existing SSI units in this action.

