The City of Lethbridge has given the all-clear for the Oldman River.
That oily substance discovered in the water last week has been all cleaned up and is no longer entering the river.
It’s believed the substance was cooking oil and there was lots of it, between 3500 and 4500 litres.
Crews will be removing clean-up equipment from the river over the next few days.
Alberta Environment is conducting the investigation.