A transport-truck crash was the source of the mineral oil spill that covered 60 ducks in Mimico Creek on Tuesday, the Ontario Provincial Police confirmed today.

In a statement, police said the driver of the flatbed did not properly negotiate the curve on the southbound Hwy. 427 ramp to westbound Hwy. 401 and rolled over shortly after 6:30 p.m. ET.

"The load on the trailer contained three electrical transformers that contained approximately 2,878 litres of oil each," the OPP said. "As a result of the rollover, at least two of the three transformers spilled the oil onto the roadway and surrounding area."

Police say a 54-year-old man from Sherwood Park, Alta., sustained minor injuries and was charged with careless driving.

The centre is cleaning the ducks that were found covered in mineral oil — a sticky black substance which makes the birds appear black — near the intersection of Martin Grove and Rathburn roads.

An oily duck is cleaned at the Wildlife Centre. People were showing at Mimico Creek to help the ducks when news broke on Tuesday. (Toronto Wildlife Centre)

In a tweet posted this morning, the Toronto Wildlife Centre said, "Staff and volunteers worked until 4am last night bathing 60 oiled ducks, and more expected today."

The oil is not toxic, but damages the birds' feathers, according to wildlife rescue workers.

Any witnesses to the accident are asked to call the Toronto OPP detachment at 416-235-4981.