mickk I have dived Truk and all over PNG - dived MANY reef passes that were created by the use of explosives during WW2 - yes the reef pass doesn't 'grow back' in a human life time although it will on longer time scales - but the coral that forms the sides of the reef pass is anything but dead. And do you think they blew out a passage from solid coral or widened a natural existing passage? I can assure you it was the later.
I have seen huge brain corals terribly damaged by vandals carving their name/date into them and gone back a year later and the damage is repaired - we swam around certain we had the right coral formation but unable to see ANY evidence.
Its a stupid analogy anyway - a ship running aground is nothing like VAST amounts of high explosive blasting a passage through a reef 100+ feet deep and 1/2nm wide.
A better comparison would be what Truk Lagoon looked like after the US finished wiping out the Jap fleet there in 1945, a real mess that was NEVER even looked at from an ecological damage point of view. Never any attempt made to clean up all the oil spilled from bombed ships laying on the bottom - and now its a pristine environment with numerous 'artificial reefs' covered in colourful corals and teeming with fish.
By 1950 you'd have been hard pressed to see any signs of the battles of 1945 from a boat crossing the lagoon. Oil spills are an ecological non event but a political opportunity that cannot be missed.