The E.P.A._base.esp file you have requested: Modifications / Factions / EPA Base v1.1 - 675.44kb is not available. Perhaps try browsing all files for the game Fallout 3 and upload any files you want to share or are missing. This is the only information we could locate:
A small base with armory near Bigtown. The key to the armory is hidden at the Bridge Ruins. Just open your pipboy and the two places are marked on the world map.