Toronto Wildlife Centre spokeswoman Julia Pietrus says they still have 104 ducks and two sandpipers at the facility.
Thousands of litres of transformer oil leaked into Mimico Creek after a transport truck rolled over on a highway Monday and eventually covered the birds.
Ontario Provincial Police have charged an Alberta man with careless driving.
Pietrus says they have several ducklings that will have to remain with them until they are able to fly, which will be several more weeks.
She says the charity needs more towels, paper towels and donations to help fund the large-scale rescue.