Canadian mining company Teck Resources has confirmed that up to 25,000 liters of chemical solution have leaked into the Columbia River from its smelter located in Trail, British Columbia, according to media reports.

Canadian Manufacturing quoted Teck's spokesman Richard Deane as stating that the chemical solution most likely contained sodium hydroxide — a chemical commonly known as lye or caustic soda, used in the smelter to de-mineralize water for its boilers. He said that the solution was drained to a domestic sewage plant by accident, instead of being treated.

RELATED: Chemical spill contaminates drinking water in nine West Virginia counties

Just two weeks prior to the spill, Teck Resources made it to the list of the Global 100 Most Sustainable Corporations for 2014, published by media company Corporate Knights, for the second year in a row. But despite being widely recognized as a sustainable business, this is not the first time that Teck has been involved in a similar accident, the website noted. It is currently facing legal action over previous instances of its Trail smelter allegedly polluting the Columbia River. The company has been ordered by a Washington state judge to pay all costs for the cleanup of the river south of the Canadian border for apparently dumping slag and effluent from its Trail smelter in the river for decades.

Teck has also been accused of heavy metals pollution in parts of Lake Roosevelt close to the Canadian border, Canadian Manufacturing reported.