Another Normal Accident

The explosion on the Deepwater Horizon, the oil platform leased by BP from Transocean, seems to be another or Chuck Perrow's "Normal Accidents" - that is something catastrophic that arises when a number of smaller errors and problems compound. According to Mike Williams, an electrical engineer on board the rig when the explosion occurred, who was interviewed on 60 Minutes, there were a variety of factors, "a series of mishaps", that together seem to have lead to the disaster. The drill string was raised accidentally while the BOP (blow-out preventer) was being tested, causing damage to the "annular" rubber seal at the top of the BOP. Chunks of rubber were coming up in the drilling fluid, but this dismissed as not "not out of the ordinary - not a big deal"; presumably, this may not have been and unusual occurrence. One of the BOP control pods was partly inoperative - but then there are two for exactly that reason and the second was thought to be operating properly. Because the drilling operation had been delayed by unexpectedly tough going , the project was 200% over time, and there was increase pressure to speed up the end of project. This lead to a decision to withdraw the mud from the bore hole before the third and final plug was set. Each element on its own was clearly serious, but not catastrophic; their albeit improbable coincidence was.