Judges at the Supreme Court of Canada are still deciding. They heard arguments at the end of March about who will be responsible for clean-up costs at the Dryden mill, but there's no date for the release of the court's decision.

The province has been challenging the validity of an agreement with forestry companies reached in 1985, which was later transferred to a new buyer for the property. The deal meant Queen's Park would take on the environmental liability, in return for a new company buying the mill and providing upgrades. However, the province is challenging the deal.

Hearings on March 28 looked at whether the Court of Appeal erred, when it failed to find the terms of the 1985 Indemnity meant that Resolute FP Canada Inc. is entitled to benefit from the 1985 Indemnity, as the corporate successor of Great Lakes Forest Products Limited.

In 2011, the province ordered the companies to remediate the former mill site in Dryden, where some 9,000 kg of toxic effluent was dumped in the English-Wabigoon River system in the 1960s.

Researchers have since found mercury is still leaking from the site into local waterways.

Domtar currently operates the mill in the community. However, the company has said responsibility for cleaning up mercury from previous owners was transferred to the province in 1985.

Along with studies to determine the best way to clean up mercury from local waterways, the province has also agreed to look into ongoing sources of mercury leaking into the water.

The federal government is also being pushed to commit to a medical clinic specializing in treatment for those impacted by the contamination.

The 1986 settlement agreement covered the polution from the mill between 1963 and 1970. The mill stopped using mercury in 1975, but there's research to suggest the heavy metal may be leaking from landfill sites near the mill.

For more information:

Supreme Court of Canada - Case docket

Court of Appeal - Decision