Following a sabotage operation led by a whale protection group, Ibsa I and Ibsa II went on fire and sank in the port of Vigo in Galicia. The sabotaged vessels released 143 tonnes of bunker fuel into the port.

Source:
Name: Ibsa I and Ibsa II
Date: 27 April 1980
Location: Spain
Accident area: Vigo, Galicia
Cause of spill: sabotage
Type of pollutant: bunker fuel
Quantity spilled: 143 tonnes
Ship type: whaler
Flag: Spanish
Last update: May 2011