As Lake Coeur d’Alene’s overall health continues to deteriorate, Idaho Gov. Brad Little ordered a third-party review of the data on Wednesday.

The request could set the stage for a more concerted effort to protect the lake, or it could simply “kick the can down the road,” said Phil Cernera, director of the Coeur d’Alene Tribe’s lake department.

Either way, Cernera welcomed the review, noting that a decade of data collected by both the Coeur d’Alene Tribe and the state of Idaho has shown continued declines in the lake’s health.

“The lake management plan is obviously not working,” he said. “Our water quality is declining.”

Since the 1990s, the volume of phosphorus flowing into the lake has roughly doubled, according to a 2017 presentation on the topic. That’s a troubling development for a lake that has roughly 75 million metric tons of sediment polluted with lead and other heavy metals, the toxic legacy of more than a century of mining in Idaho’s Silver Valley.

Those toxins are mostly concentrated in the lake’s sediment. However, increased plant growth in the lake, spurred by higher levels of phosphorous, threatens to ultimately reduce the lake’s oxygen to a point at which the heavy metals could become resuspended in the lake water.

Oxygenated water acts like a cap on the metals, keeping them locked in the sediment. At the same time, a warming climate will increase the likelihood of those metals resuspending as snowpack levels decrease and water temperatures rise during the summer months.

Little announced the request, through a representative, at the annual Our Gem Symposium, a conference about Lake Coeur d’Alene’s water quality. Little directed the Idaho Department of Environmental Quality to arrange a third-party review of the state and tribe’s data and management efforts.

“The report must include an assessment of the sufficiency of our current data and identify any additional information that may be needed,” a statement signed by the governor states. “It must also offer recommendations to address any identified concerns.”

This year, nearly 200 people attended the conference, the best turnout in the history of the event, according to organizers. That turnout, in conjunction with Little’s announcement, indicates a shift, said Andy Dunau, the Spokane River Forum’s executive director and an organizer of Our Gem.

“The governor is trying to meet them half way and say, ‘No, if these scientists validate this we will start to take action,’ ” he said.

Staff and scientists from the state of Idaho agreed with that assessment and said the announcement indicated support and concern from the governor’s office.

“Independent reviews are essential parts of the scientific process,” said Craig Cooper, the senior lake scientist with the Idaho Department of Environmental Quality. “That review will build the credibility. To me, it shows the government is taking it seriously.”

Not everyone at the symposium agreed.

“I find it amusing that there will be another study,” Paul Woods told attendees. “The National Academy of Sciences report has all of this in it. All you have to do is look in it. … It doesn’t need to be done again.”

In 2005, the NAS published a massive report finding that the U.S. Environmental Protection Agency’s cleanup plan for the Silver Valley was based on “generally sound” scientific and technical principals and that the agency ought to expand its effort to protect residents and wildlife in the basin.

Lake Coeur d’Alene is included in the federal Superfund site but does not receive Superfund money. Instead, the state of Idaho and the Coeur d’Alene Tribe were given water-quality management authority by the federal government.

Woods, who is retired after a career studying lakes, pointed out that between 1975 and the early 1990s phosphorous levels were decreasing in Lake Coeur d’Alene.

Those successes have not continued. Human development and logging have led to increased levels of phosphorous and plant growth in the lake, said Cernera.

In response to those increased levels and a perceived lack of action, the Coeur d’Alene Tribe withdrew from the lake management plan in September.

“Our response was, ‘Hey we’re out of this,’ ” Cernera said. “Until we see something else happening we ain’t a part of this game.”

He believes that decision prompted the Governor’s call for a third-party review.

“We had to do this to make things happen,” he said. “The only reason we have the state saying we need a third-party review … is because we walked away from this lake management.”

CORRECTION: Lake Coeur d’Alene is included in the federal Superfund site but does not receive Superfund money. A previous version of this story incorrectly described that arrangement. It has been corrected.