Section 096-100-91 - Modification or modified source"Modification or modified source" means any physical change in or change in the method of operation of a source that would result in the emission increase of any regulated pollutant excluding GHGs, except that:
A. Routine maintenance, repair, and replacement shall not be considered a physical change;B. The following shall not be considered a change in the method of operation:(1) An increase in the production rate at an existing source, unless such change is prohibited under any federally enforceable permit condition which was established after January 6, 1975, pursuant to 40 C. F. R. 52. 21 or under regulations approved pursuant to 40 C. F. R. Part 51, Subpart I or 40 C. F. R. 51. 166, and if such increase does not exceed the operating design capacity of the source;(2) An increase in the hours of operation, unless such change is prohibited under any federally enforceable permit condition which was established after January 6, 1975, pursuant to 40 C. F. R. 52. 21 or under regulations approved pursuant to 40 C. F. R. Part 51, Subpart I or 40 C. F. R. 51. 166; or(3) Use of an alternative fuel or raw material if prior to January 6, 1975, the source is designed to accommodate and is licensed to use such alternative fuel; andC. Replacement of pollution control apparatus at steam electrical utility generating units or other source determined by the Department to be equally or more effective than the apparatus being replaced shall not be considered a physical change or change in the method of operation for the purposes of this definition, but shall be governed consistent with the CAA and federal regulations.06-096 C.M.R. ch. 100, § 91