PRIEST RIVER — The Selkirk Conservation Alliance is opposing the proposed silicon smelter as an affront to the watershed it has vowed to protect for the past 31 years.

The alliance joins a chorus of other groups including Citizens Against the Newport Silicon Smelter, Responsible Growth North East Washington and Kalispel Tribe of Indians which have taken positions against PacWest Silicon’s silicon refining facility south of Newport. Opponents of the smelter contend impacts from the project jeopardize the health and economic vitality of the area.

“These include air pollution, odor, acid rain, increased truck and train traffic, and decreased property values in homes located near and downwind of the smelter,” the alliance’s board of directors said in a letter outlining its position.

The alliance notes that the smelter is expected to generate 706 tons of sulfur dioxide and 700 tons of nitrogen oxide, making it the fifth largest emitter of sulfur and the 15th largest emitter of nitrogen oxide in the Evergreen State. The alliance fears those emissions will only increase as production at the smelter ramps up its production.

Also concerning to the conservation group is the annual emission of 85 tons of ultra-fine particulates which cannot be filtered by human lungs and can be deposited directly into a person’s bloodstream.

“Most of the prevailing winds blow from the south and southwest, which will carry this pollution directly into the Priest River Basin. Even in the winter when northeast winds are prominent, a passing weather system will invariably result in winds veering to the southwest,” the alliance’s board said.

Precipitation, meanwhile, will fall through the pollution-laced atmosphere, resulting in the formation of sulfuric and nitric acid.

“This will then fall on our environment, increasing the acidity of the soil and waters,” the alliance said.

Acid soil can have a detrimental effect on plant and tree growth, placing further strain on forests already straining from 100 years of fire suppression, increased insect infestation and climate change, according to the alliance. The group is also concerned that atmospheric pollution will negatively impact on lichen, the primary source of food for a dwindling population of mountain caribou.

The Selkirk Conservation Alliance also rues the prospect of combining the region’s increasingly smoke-filled wildfire season with the emissions from the plant, which will disproportionately affect those who work or recreate outdoors. There is further concern that acid rain will kill off fish or prevent their eggs from hatching.

“The Lower Priest River was once prime habitat for trout and Dolly Varden. The recovery of this cold-water fishery may substantially impaired by acid rain,” the alliance said in a statement.

The group acknowledges the need for economic development and a steady customer for the Pend Oreille Public Utility District’s power, but said the “PacWest smelter is not the right industry for our region for the long haul.”

Keith Kinnaird can be reached by email at kkinnaird@bonnercountydailybee.com and follow him on Twitter @KeithDailyBee.