A dispute has broken out over who should pay to search for possible mercury contamination on and near the pulp and paper mill property upstream from Grassy Narrows First Nation.

On Monday, Ontario’s Ministry of the Environment and Climate Change said it intends to order Domtar, the current mill owner, to find out whether mercury is still leaking from the mill property into the nearby Wabigoon River in northern Ontario.

Domtar fired back, saying it will start legal proceedings to halt the order and adding it is concerned the province is “seeking to transfer its responsibilities for the management of historical mercury contamination associated with the mill site in Dryden to an innocent bystander.”

Grassy Narrows Chief Simon Fobister said he is worried that “a fight over the bill” will distract from the effort to find what is causing elevated mercury levels.

“We need to know right away whether the Dryden mill site is leaking mercury and poisoning the fish that our families eat,” he said.

Between 1962 and 1970, the Dryden paper plant, then owned by Reed Paper, dumped 10 tonnes of mercury into the river. The mercury, a potent neurotoxin, contaminated the fish, which poisoned the people of Grassy Narrows and nearby Whitedog First Nation who live about 100 kilometres downstream.

High levels of mercury in soil, fish and sediment today suggest the site is still leaking, about 50 years on.

There is no suggestion that Domtar, a pulp manufacturer several owners removed from Reed Paper, is responsible for any source of mercury. The company said Monday that the provincial government has consistently recognized that Domtar has never used mercury on the Dryden mill property.

The proposed “director’s order” from the Environment Ministry, which calls for Domtar to install monitoring wells and analyze groundwater and soil, comes nearly six months after the Star and an environmental group reported finding soil on mill property that had mercury levels up to 80 times normal levels. Scientists have reported that sediment in the stretch of the Wabigoon River that flows past the plant had mercury levels up to 130 times normal levels. The Star has also revealed that walleye downstream are the most mercury-contaminated in the province.

In February, Environment Minister Glen Murray and Indigenous Relations Minister David Zimmer said they were “completely committed” to finding areas near Grassy Narrows contaminated with mercury and creating a plan to clean it up. This new proposed order is part of that commitment, the Environment Ministry said Monday.

There is now a 30-day period for public comment and review before a final decision is made on the order.

“This is occurring as part of Ontario’s commitment to identify mercury-contaminated sites, and to develop and implement a comprehensive action plan to remediate these sites,” the proposed order said.

Domtar said it is the province’s job to look for possible mercury and that this proposed order will only delay finding answers.

“Domtar is left with no choice but to appeal and seek a stay of this order,” a company statement said. “Domtar encourages the government to provide the leadership it promised and reconsider its decision to issue an order that risks delaying and distracting from the important work of addressing mercury contaminated sediment in the river.”

The Star began its investigation into mercury contamination in Grassy Narrows last year with the story of retired mill worker Kas Glowacki, who said that in 1972 he was part of a group who “haphazardly” dumped drums filled with salt and mercury into a pit behind the mill. The soil samples subsequently tested by the Star were taken from an area circled on a map by Glowacki.

Though it will resist this proposed order, Domtar said it will continue to allow the ministry “the access necessary to assess the veracity” of Glowacki’s claim.

The province’s proposed order also says that once Domtar finishes the work, it should submit a final report to the ministry detailing whether mercury is coming from the mill land or is present in sediments of the Wabigoon River near the mill, and whether mercury could affect downstream water, sediment and fish.

It comes as another legal fight is playing out over whose responsibility it is to monitor the area.

In 2011, Ontario’s Environment Ministry issued an order against two former owners of the mill — paper companies Weyerhaeuser and Resolute — to monitor a separate, official mercury disposal site on the property. The companies have argued in court that the monitoring was not their financial burden to carry, because the government gave all future owners of the land indemnity when it struck a deal in 1979 with Reed Paper and its successor in order to facilitate the sale of the plant and protect industry in Dryden.

In a July 2016 ruling by Ontario’s Superior Court, a judge agreed: taxpayers, not the companies, should foot the bill for the monitoring costs.

The province appealed. A decision on that appeal is due to be released soon.

An Environment Ministry spokesperson said Monday’s proposed order “will complement ongoing environmental work also underway with First Nations and ministry scientists in the English Wabigoon River, as part of Ontario’s commitment to identify mercury-contaminated sites and to develop and implement a comprehensive action plan to remediate these sites.”