That certainly doesn't excuse their (much larger) mess but they are correct: satellite images of the west coast of Africa, like some other coastal regions around the world, routinely show signs of oil pollution from other sources, especially bilge-dumping by vessels large and small. We don't know if it's legal in this area; it is not legal in US or Canadian waters. Radar satellite imagery is an excellent tool for detecting bilge-dumping.
This Envisat ASAR image taken on December 18, 2011 shows a 100-mile-long slick caused by bilge dumping from a large vessel that was traveling toward the southeast on a course taking it very close to the Bonga FPSO (we've inferred the location of the FPSO from multiple radar satellite images; if anyone has the exact lat/lon coordinates please pass them along to us):
|Envisat ASAR image taken December 18, 2011 showing oily bilge dump from a passing vessel northwest of the Bonga oil field off Nigeria. Image courtesy European Space Agency.|
At 1 micron thick this bilge slick holds about 80,000 gallons of oily material. Projecting the vessel track back to the northwest, we land near the city of Aneho on the Togo coast. There is an industrial facility in the area that appears to have an offshore loading system. It could be the point of origin for the suspect vessel, but we really have no way of knowing:
|Projecting backward along bilge slick to shore. Envisat ASAR image courtesy European Space Agency.|
Here's what it looks like in Google Maps. Does anyone have any information about this facility?