DandyDon:I thought it was one of the easier of the deeper Keys wreck dives, much easier than it's sister The Bibb. Our buddy posted this on another thread here...
My first hunch would be medical with little connection to the dive...?
From the article, I'm inclined to agree with DandyDon. I dove the Duane recently and it's not a particularly dangerous dive, although the current can be pretty stiff. Depending upon your dive operator (six/eight pack or cattle car) and how well organized they are, you might end up with a mob ascending simultaneously on the hang line and waving like flags in strong current, but I've seen worse.
The Duane itself isn't particularly dangerous or challenging as far as wrecks go, but I'm inclined to agree also that the sheer numbers of divers on these wrecks increase the odds of injury/death. It's always sad to hear of such a thing, and I also extend sympathies to the family of the lost diver.
SeaKat