Radiation Portal Monitors (RPMs) based on polyvinyl toluene (PVT) scintillators have been in use since the 1970s. Recently it has been discovered that under certain conditions PVT scintillators can fog at low temperatures. In collaboration with researchers at national laboratories, Eljen Technology has developed methods for the production of Intrinsic Anti-Fogging Scintillators. The production methods have been scaled up to allow for castings of rods and large sheets of scintillators that are deployable in RPMs and other extreme locations. The work is ongoing. The presentation will focus on the properties of the new scintillators and on the ongoing testing results from exposure to extreme environmental conditions.