"Maximum Achievable Control Technology (MACT) emission limitation" means the MACT emission limitation required for new and existing Part 70 HAP sources. This emission limitation is either promulgated by EPA pursuant to Section 112 of the CAA, or is determined by the Department on a case-by-case basis pursuant to Section 112(g) or (j) of the CAA.
06- 096 C.M.R. ch. 100, § 85