The U.S. Environmental Protection Agency’s (EPA) Office of Inspector General (OIG), an independent watchdog of the agency, said it found no evidence of bias or predetermination in the agency’s effort to review the potential impacts of the proposed Pebble Mine on the Bristol Bay watershed in Alaska, according to a new report.

However, the inspector general did raise questions about potentially inappropriate efforts by one EPA employee to aid opponents of the mine.

The Alaska Post-Dispatch reported that the report marks a major step in a years-long fight over the potential mine that has been subject to calls of federal overreach by the company hoping to mine the massive deposits of gold and copper in Southwest Alaska. The inspector general reviewed EPA’s actions from May 2014 to October 2015, including an assessment of more than 8,000 emails involving EPA officials, the report said.

“Based on the information available to us, we found no evidence of bias in how the EPA conducted its Bristol Bay watershed assessment, or that the EPA pre-determined the assessment outcome” to allow the agency to bar mining in parts of the watershed, said Randy Holthaus, of the inspector general’s office, in a podcast released with the report.

The EPA followed the rules in its scientific process for assessing the potential impacts to the watershed and the subsequent peer review, the report found.

Pebble Limited Partnership chief executive officer Tom Collier struck back against the inspector general's findings, asserting the EPA reached a decision to block the mine before undertaking the scientific inquiry. He said the EPA “inappropriately colluded with environmental activists, [and] that it had manipulated the scientific process and lied about its intentions.”

Collier called the report “an embarrassing failure.” 

The IGO set out to find out why EPA did the review; if it was done in a biased manner or had a predetermined outcome; and if the agency followed correct policies, processes and procedures during the watershed assessment and the peer review that followed.

After ongoing requests and concerns about the project, and Pebble’s repeated unfulfilled promises to submit a permit application, EPA agreed to launch a scientific study, based largely information about mine plans Northern Dynasty submitted to the U.S. Securities and Exchange Commission in 2011. That information is required to be accurate.

In July 2014, EPA issued a proposed decision to restrict certain parts of the watershed from mining activities, but that decision has not been made final due to ongoing litigation.

In its report, the EPA inspector general found that Philip North, a former employee in EPA’s Alaska office, used his personal email account to help Alaska Native tribes write their petition for the EPA to block the project in 2010.

But investigators couldn’t conclude whether North’s actions violated rules or the law. The EPA lost years of North’s email records, and the investigators could not locate him for an interview, nor would his attorney send him a subpoena the IG drafted.

“We are by no means through making our case that EPA acted inappropriately and perhaps illegally with respect to Alaska’s Pebble Project,” Collier said in response to the report.