The actuality is exactly as I stated, chemical dispersants are themselves toxic - they're not just lots of bulk Fairy Liquid. They work just like dishwashing liquid because they break down the surface oil into millions of tiny droplets which become suspended in the top 30 - 50 foot layer under the surface. Shell then, of course says that the leak has dispersed, but it didn't just vanish to nowhere.
In the SkyTruth article, which you so helpfully label, "Oil Pollution Off Nigeria - Other Sources" it's actually a Shell spokesman who claims part of the spill is from another vessel
The country chair for Shell Nigeria, Mutiu Sunmonu, has said that the cleanup efforts have been hampered by oil spilled by another vessel in the area. “Our teams witnessed oil on the surface of the water that they are sure did not come from Bonga,” he said. “We have taken samples of this oil to understand where it came from.”
Here's another quote from SkyTruth
Assuming Shell, like most successful companies, is fanatical about inventory control they should be able to provide an accurate measurement by comparing the amount pumped out of the FPSO with the amount that actually ended up in the shuttle tanker. Flow meters on the pumps and transfer lines, and gauges in the tanks, should allow them to calculate the spill with precision. Let's ask them for those numbers and settle the question.
Regardless of the specific amount spilled, we're left with some troubling questions, most notably: how could up to 1.7 million gallons of oil steadily leak into the ocean before anybody noticed and took action? The crack in one of the transfer lines that Shell blames for this leak looks like it could only divert about 5-10% of the flow through that line. How long would that take to amount to 1.7 million gallons? This is just the latest example of the many mundane, low-tech ways that modern offshore oil production still poses risks -- even when it's being done by one of the biggest, technically accomplished, retail-brand-sensitive multinational oil companies (hmm, that sounds familiar...).
And finally, well done to all the Caverton personnel who have been flying to support the clean up operation
Presumably all the DanCopter personnel and non-flying staff are totally irrelevant to important safety managers such as yourself then
