The Sunday Times's Science editor, Jonathan Leake, has revealed further details of the failure suffered by the Large Hadron Collider, at CERN, on the 27th March. According to Dr Lyn Evans, who leads the accelerator construction project, "There was a hell of a bang, the tunnel housing the machine filled with helium and dust and we had to call in the fire brigade to evacuate the place...The people working on the test were frightened to death but they were all in a safe place so no-one was hurt."
The magnet assemblies responsible for the explosion were designed and manufactured by CERN's main rival, Fermilab. The director of Fermilab, Pier Oddone, has apparently written to his staff, accusing them of causing "a pratfall on the world stage". Oddone said: "We are dumb-founded that we missed some very simple balance of forces. Not only was it missed in the engineering design but also in the four engineering reviews carried out between 1998 and 2002 before launching the construction of the magnets."
An article on the Scientific American website further quotes Oddone as saying: "[E]ven though every magnet was thoroughly tested individually, they were never tested with the exact configuration that they would have when installed at CERN—thus missing the opportunity to discover the problem sooner." This means that the magnets underwent unit testing, but didn't undergo system testing. In engineering terms, this is an elementary error.