Turns out, 1 cubic mile is about 1,000,000,000,000 (trillion) gallons.
Therefore, 62,500 cubic miles of ocean have been/will be adversely affected and/or polluted (as of today!). Of course, the reality is that the oil doesn't mix well with water, and it floats, so the average of 1ppb is not achieved, far fewer cubic miles have been affected (so far) but the intensity of oil in water probably is wiping out all life in many, many cubic miles already, and many more to come.
And each day it is left uncontrolled, the spill in the gulf (1.25 million gallons times 1,000,000,000) is spoiling 1,250 (potentially, if it were being distributed equally) cubic miles of ocean.
There are 326,000,000 cubic miles of water on the planet, so don't be concerned, there is PLENTY left for us to pollute.
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