Sump Sea Badzone Collapse Disaster

After a seemingly momentary respite from the otherwise ongoing violence, the underhive has one again sprung into action.  Tectonic disturbance from a large-scale industrial disaster deep below the inhabited levels of the hive city has caused widespread panic amongst the populace.  Gasses, molds, and fungal spores have clogged the filters and mechanisms of the Hive's air purifiers, causing ecological disaster and economic collapse.  Many people lost their lives or livelihoods or domiciles.  Now that most of the dust has settled, newly doomed souls have been sent by their houses, clans, guilds, or masters to claim the abandoned regions - and new, unknown territories below.