"Modified thermal unit that emits mercury" means a thermal unit that emits mercury for which an application is submitted on or after May 4, 2006, to change the method of operation of or to physically change the thermal unit that emits mercury in a manner which results in an increase in the amount of mercury that will be or has the potential to be emitted into the atmosphere.
Nev. Admin. Code § 445B.3627
NRS 445B.210, 445B.300