Satellite imagery shows a slick of oil stretching from the site of an FPSO explosion that has killed at least three crew members off Nigeria.

The image from the European Space Agency’s Copernicus Sentinel-2 mission shows an oil slick extending at least 20 km, according to Antoine Halff, chief analyst at satellite data analytics company Kayrros.

He said on Twitter that imagery from Earth observation company Capella Space also shows the slick.