If you're interested in a commercial diving career I recommend reading the novel "Louisiana Blue" by David Poyer. Parts of the plot are a bit silly, but it's a fun read and the descriptions of oil field divers are (from what I'm told) fairly realistic. http://www.esva.net/~davidpoyer/tiller.htm

Besides the immediate risks of drowning and dismemberment, a lot of experienced commercial divers end up with chronic damage from repeated decompression and being in the water all the time. And in the long run it looks like human divers are increasingly being replaced by ROVs.