An EPA assessment of a hypothetical large-scale mine on the shores of Bristol Bay, Alaska concluded there is potential to hurt future salmon runs and habitats.
The study was launched when concerns were raised about the Pebble Mine project, an effort to potentially mine large deposits of copper and gold around Bristol Bay.
The preliminary assessment concluded habitats such as streams and wetlands in the mine footprint could be damaged, killing off millions of salmon that annually run through the Bristol Bay watershed. Jobs and revenue generated from the area's ecological resources could also be negatively impacted.
The entire 339-page draft of the study is provided online in PDF form. To download it, click here.
EPA Regional Administrator Dennis McLerran said the study is not aimed at any one mining effort.
"Our primary intent is to understand the salmon...how large scale mining might affect those salmon," McLerran said.
Supporters of the mine argue it would bring thousands of jobs to an economically depressed area. Critics have said they are not willing to lose one of the world's premiere salmon runs as a cost.
This week, developers from Pebble Limited Partnership set aside $107 billion to prepare the area for permits. Though the permit process is expected to take several years, Pebble officials said they hope to begin it this fall.
Alaska Attorney General Michael Geraghty rejected the EPA's decision to conduct the assessment, calling it premature.
While the agency does not recommend any regulatory decision, the EPA has opened a public comment period for the next 60 days, that will include a series of meetings held throughout Alaskan villages. Online comments are also welcome on the EPA Bristol Bay website, which can be found here.