No physical evidence of at least 500 litres of diesel that spilt into Coromandel Harbour last week remains in the area.
The diesel was spilt after a mussel barge sank near Te Kouma boat ramp.
Environment Waikato’s Coromandel harbour master monitored the spill over the weekend to track the diesel’s movements and check any potential impacts on sea life.
The diesel has now evaporated and dispersed naturally as expected.
“Most of it will have evaporated, and the rest has been broken down by the ocean into less complex substances that are not hazardous,” said Regional On-Scene Commander Scott Fowlds.
“From our observations, the diesel slick drifted out to sea where it broke down naturally and never reached the shore.”
Environment Waikato has received no reports of harm to birds or marine life from members of the public as a result of the spill.
The Maritime Safety Authority will be investigating the incident.