I would not lower the _risk_, just put something in to help contain, control, and eventually eliminate them. "Bucket Brigades" from a nearby well/fountain, or Firehouses, for example.
From game play and design, I am guessing the game is modelled along the lines of the Anno game series (Ubisoft/Blue Byte) [or the open source remake called Unknown Horizons (UH)], with some influences from The Settlers series (Blue Byte) [and the open source remake, Widelands (WL)]. It has been awhile since I played them, but UH, IIRC, has Firehouses which can be built. Do something similar. Most likely a Tier II building, since many early history settlements did not have such until it became apparent that fires could wipe out entire communities.
In a similar manner, UH lumberjacks have a button to plant new trees in every empty space of it's work area (which I am not fond of because of it's "all-or-nothing" mechanics). The WL game has Foresters which can go plant new trees in their work area. (And in some "Tribes", Game Keepers which go release new animals or Fisheries which can go replenish Fishing spots--which are not infinite like this game or Anno/UH).
I am really hoping this game will continue to develop and grow! UH development has stalled while switching to a new underlying game engine, leaving me missing the game. :-(