Damon and Carlton recently announced that the Finale of this season will be titled "The Incident". I guess its fair to say that the episode will explain the Incident that Chang refers to in the Swan orientation film. Now I have to credit Dinsdale42's post about something Miles said for the trigger of this theory I have. Miles mentions that Widmore has been looking for the Island for 20 years. If Miles and the science team come to the Island in late 2004/early 2005 then 20 year earlier would be around 1985. Isn't that the time of the year that the Incident occurred according to the blast door map?
I think we'll see that Ben does trick Widmore into turning the wheel and in so doing they inadvertently cause the incident to happen at the Swan station. I posted a previous theory about the Jughead being buried where the Swan was built. Perhaps the radiation leaking from the bomb mixed with the electromagnatism present in that area of the island mixed with the wheel being turned causes some catastrophic event.
I'm not sure about all this being correct but I think I may be onto something here with Widmore leaving the island (if that did in fact happen with him turning the wheel) coinciding with the Incident. We may find out by the end of this season.