SkyTruth, a conservation technology nonprofit, has detected a likely oil slick of more than 250km long in Sudan waters, which was probably discharged from a moving vessel. SkyTruth is now trying to track down the responsible ship for the oil slick.  

On May 19, 2023, Sentinel-2 satellite images detected the slick, more than 250 kilometers long, in the Red Sea to the east of Dungunab.

According to SkyTruth, rough preliminary estimates of the slick volume equates to a volume of at least 120,000 gallons, assuming a 1-micron-thick slick on average.

The strong spectral signature of this slick on the Sentinel-2 image indicates that in many places it is actually much thicker than 1 micron.

“The unusually large size and volume of this slick suggests it could be the result of tank washing by a petrochemical tanker, rather than bilge discharge from a cargo ship,” SkyTruth suggested in a post on social media.

Out of 94 AIS vessel tracks transiting the region in the 12 hours preceding the slick, SkyTruth winnowed the potential sources down to four ships.

SkyTruth based its analysis on the following assumptions:

1. The polluting vessel was not running dark; it was broadcasting Automatic Identification Systems (AIS) signals.

2. The vessel AIS track closely follows the slick as it appears on image and a Sentinel1 radar image taken just 4.5 hours earlier. The slick has not drifted appreciably since it was discharged from the vessel.

3. The AIS track shows it had moved beyond the footprint of the images when the satellite passed overhead. The vessel responsible for this slick is not visible on the image, as SkyTruth says.

SkyTruth is a conservation technology nonprofit that “inspires people to protect the planet by using satellite imagery, big data, and the latest technological innovations to reveal environmentally damaging actions,” as it is described in social media.