Where are the NAICS/ SIC and SCC codes changes that have been implemented for the 2017NEI?

Please refer to the NEI webpage for 2017 documentation, and follow the link for Appendix 2 - 2017 NEI Plan Code Changes. That Excel file described changes for the SCCs and NAICS and includes a helpful read me spreadsheet. Note that all SCC and NAICS changes for use in the 2017 NEI are in EIS and that some NAICS code changes, not reflected in Appendix 2, are also in EIS, consistent with their non-EPA dataset.