As this thread was brought back to live, I did read it again, and found that the initial info was off about the wood that was turned and flew apart, as I still have a picture to a part of that wood I thought it was important to bring that up here, mentioned was that they thought it was Cedar that do tend to split, it is not quit right, it was Mequite and it had big splits in it before starting to turn.
To me it was asking for trouble, if you look at the picture you can see where there was a long split going from the rim well past the centre, there is another short split in this part of the wood, these splits are easily seen, deciding to turn that kind of wood anyway is just plain dumb.
Taking the heavy weight of that wood species and the velocity of that large piece, I can imagine the damage that it can do and did, and here is another problem we have with wood turners wanting to turn dry wood, they try to first dry large pieces of wood and than turn it.
By doing this turners end up with wood that has splits in it, that is basically guaranteed to happen (but for one or two species we can partially dry without splitting).
Turning fresh green wood after a close examination, it will give you safer wood, and can be dried after without it splitting, it can even be turned without the need to re-turn it.
Also high speed turning is another hazard that even wood without splits in it already can have it fly apart, don't do it and make sure you examine the wood closely before and even while turning it.