One of the newest members of the Mackenzie Valley Environmental Impact Review Board has excused himself from the review of the Giant mine clean up.

The move came after John Curran questioned a social justice group and two First Nations during hearings on the cleanup.

Curran called Alternatives North a "clandestine" organization because an official would not provide the names of individual members, and he criticized the group for a report it did on the cleanup, suggesting it could harm property values in the city. He went on to aggressively question the two First Nations about what faith they have in the wisdom and authority of the board.

Immediately after the questions, the board's lawyer and other members expressed concerns to Curran, who then publicly apologized for the tone of his questioning.

The concern was that Curran's questions could be perceived as a sign of bias that could call the fairness of the hearing into question.

"There was certainly a discussion about the line of questioning and the potential for an apprehension of bias was raised," said Verne Christensen, executive director of the Mackenzie Valley Environmental Impact Review Board.

"It's really difficult to tell how these things might play out if these things are challenged. But out of concern for caution, Mr. Curran came back later and wrote a note to the chair indicating he was resigning himself from the Giant Mine [environmental assessment] file."

Curran was appointed to the board by the federal government in July. The former executive director of the NWT Chamber of Commerce had little experience in environmental matters but was the campaign manager for the Conservative Party's failed bid to win the Western Arctic seat in the last federal election.