The City of Lethbridge has confirmed that no oil entered the Oldman River after contaminated water was found at its Wastewater Treatment Plant on Monday, April 28. (Photo: City of Lethbridge)

By David Opinko

Contamination at Lethbridge Wastewater Treatment Plant resolved, no leakage into river

Apr 29, 2025 | 9:42 AM

The City of Lethbridge says all is good at the Wastewater Treatment Plant.

On Monday, April 28, it reported a “significant level of contamination” of what appeared to be vegetable oil.

That overloaded the facility’s processing capabilities, putting extra strain on the system that treats water before returning it to the Oldman River.

As a precautionary measure, staff installed containment booms on the river to minimize any risk of spillover.

Crews monitored the situation overnight, and the City now tells LNN that the contamination has passed and no oil entered the waterway.

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Normal operations at the plant have resumed.

It is currently unknown where the source of the contamination was, but an investigation is underway.