The Department of Mineral Resources has finalised its reports on the substance which was found in a river near Barotu village in Ra in December last year.
A spokesperson for the department says the samples collected from the river last year were tested and identified as oil although initial reports said it was crude oil.
He says initial indications lead to the substance being waste fuel.
It has been confirmed that a separate team has been tasked to look into the report before villagers are informed about it.
The official findings in the report are yet to be released.
Some of the media outlets had reported that the substance was crude oil.
