Thank you for the response! For Central Land, I have about 1784 residences total (estimating on peasant since it says 1.1k) and 12 detoxification centers. At one point I had 24 before I destroyed some, and the risk was constantly rising, maybe because I needed to have so many extra residences to support that many centers? For comparison, I have 20 hospitals since they were more affordable, and those incidents happen far less frequently. For Islands, I have 3 detox centers and 492 residences, and it has quite frequent poison incidents, though I don't know how many would be considered a normal rate. Hope that's helpful!