The 100,000 bpd No.1 crude distillation unit (CDU) has been shut since May 7 for a maintenance shutdown, and the 120,000 bpd No.2 CDU has been shut since May 3 for a turnaround.

Cosmo had been considering restarting the two CDUs from July, but the restart was been delayed due to an investigation into the asphalt leak from the refinery into the sea in late June.