We focus on the interference between mobile stations as they attempt to gain access to an OFDMA-based WiMAX/IEEE 802.16 network. We propose a set of strategies that enable base stations to 1) reduce or eliminate the interference between emergency and non-emergency mobile stations and 2) provide prioritized access to emergency mobile stations. Our strategies include introducing a sliding contention window, redistribution of ranging codes and the ability of base stations to delay the entry process of any mobile station. We give an analysis of our strategies and some simulated results.