There’s an article in the Austin American Statesman about the ongoing Gulf oil spill. It talks about the effects of the spill throughout the water column. The massive use of dispersants at depth is noted as being experimental: nobody knows exactly what outcomes you get by doing that. Well, other than that less of the oil washes ashore where it is convenient for photographers to document the pathetic demise of many a bird and marine mammal because of the oil. It is a lot harder to get cameras on the pathetic demise of benthic, nektonic, and pelagic animals, but those deaths count no less because they pass unseen. Nor is most of the problem going to be at the level of charismatic megafauna, as the authors point out. This spill is disrupting the food web from the lowest levels right up to the top predators. Further, they note that the bacteria that are relied upon to consume the oil over time do so in the presence of oxygen. As they metabolize the oil, they deplete the oxygen. High levels of methane gas are not helping, either. It doesn’t take much to make the inference that “dead zones” with low to no oxygen in the water will expand. What’s worse is that given the toxicity of what we’re dumping into the Gulf, they may well persist over time scales we have not experienced before.
It seems to me to be only common sense that off-shore oil drilling at any depth, if done at all, should be conditional on the principals demonstrating that they have the capacity on-hand to deal with even worst-case problems within a short time window. Turning loose the machinery and hoping for the best is no way to safeguard the public welfare.
As usual, this is only personal opinion.