"Normal operation" for existing sources or emission units, means the level of operation that actually occurred or can be reasonably anticipated to occur in meeting the source's needs or demand under typical operating conditions over a reasonable period of time. Emissions units that are under construction or are going through initial start-up procedures (refractory curing, tube boilout, etc.) have not begun normal operations. Factors that change the source's operation (i. e. , market changes) will change the normal operation.
06-096 C.M.R. ch. 100, § 101