The response of an organisation to stress is strikingly similar to the response of a ductile metal to stress. For a ductile metal, as load (or stress) is increased, it is able to recover or return to its original form when the load is removed, up to a point.
This point is the yield point. After the yield point, as load is applied, the material begins to permanently deform until it reaches the point where it fractures. For an organisation, as demand or load on people increases, they can respond well or handle stress up to a certain point. Beyond this point, the risk of loss increases as people reach a limit where they are overloaded and working beyond their capacity; their mental functioning is degraded and errors are more likely. They may even reach a point where they are no longer able to cope.
Resilience Engineering in Practice: a guidebook, Ashgate 2011, page 91