In 2008, more than 209 million litres of effluent containing "black liquor" — a byproduct from pulp processing used as fuel in the plants — gushed into the Columbia River over two days.
In a written release, Environment Canada described the material spilled as "acutely lethal effluent."
The provincial and federal environment departments investigated and charged the company with one offence under the federal Fisheries Act and five charges under the provincial Environmental Management Act.
The court ordered Zellstoff Celgar to pay a $150,000 fine, $120,000 of which will go to the Habitat Conservation Trust Foundation.
That money will to back into river conservation programs, says the trust's CEO, Brian Springinotic.
"We will marry this money up with high-quality proposals that seek to improve conditions for fish and wildlife in the Columbia drainage," said Springinotic.
The judge hearing the case found there was no noticeable harm done by the spill, and the company can still appeal the decision.