Indonesia's state-owned oil company Pertamina has finally admitted it is responsible for a major oil spill on the coast of Borneo.
Pertamina said one of its undersea pipelines was severed last week, causing crude oil to pour into Balikpapan Bay.
Five fishermen died when the oil spill ignited last week.
The pollution spread throughout the bay killing local marine life including protected dugongs and dolphins, and has caused an overpowering stench across Balikpapan, a city of 700,000 people.
The admission by Pertamina follows four days of denials by the company.
Until Tuesday the company continued to claim that Pertamina's own testing showed the oil was marine fuel, not the crude oil that runs through the company's pipelines.
The company also claimed that it had sent down divers and they had not spotted any damage to their pipes.
The refinery continued operating as normal for several days after the initial leak.
But now Pertamina says its sonar equipment revealed a punctured pipeline as the source.
It said it knew this information on Tuesday but it did not make it public until late on Wednesday.
"When we checked on the first day it all looked normal," said refinery director Togar.
The tests showed that one of its pipes had shifted 100 metres from its original position.
Togar said the pipeline had been dragged out of position and ruptured "by a heavy force".
He didn't elaborate but the bay is used by bulk coal vessels.
Before Pertamina's admission, the crew of one of the bulk vessels, the MV Ever Judger, had been questioned about whether the oil had come from the ship.
Indonesian police say a criminal prosecution may follow.
