The regulator says the 12 geese were found after Imperial reported Monday that it had accidentally released an estimated 900 litres of crude oil into a process water lagoon at its Mahihkan plant.
The AER says all of the geese have been removed from the lagoon and taken to a specialist site for cleaning and rehabilitation.
The recovery of oil is ongoing, and the AER says it has directed Imperial to provide daily updates about its cleanup efforts.
Imperial has deployed additional wildlife deterrents such as wildlife cannons and flagging around the lagoon.
The regulator says it continues to monitor the situation and has notified communities in the area of the incident.
This report by The Canadian Press was first published July 26, 2023.
Companies in this story: (TSX:IMO)