ST. PAUL, Minn. (AP) — Enbridge Energy and its supporters have accused Minnesota regulators of imposing unreasonable and unlawful procedures that they say will delay construction of a $2.6 billion pipeline to carry North Dakota crude oil across northern Minnesota.

Enbridge in a regulatory filing Monday says the Public Utilities Commission’s requirement that a final environmental study be submitted before the pipeline route is formally reviewed will delay the project another four to six months. That would be nearly four years after Enbridge filed its application.

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The Star Tribune reports the pipeline company cites 17 other projects in which regulators addressed environmental risks in tandem with the permit review.

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Environmental groups and Indian tribes are concerned the pipeline could damage pristine northern waterways. The Minnesota Chamber of Commerce and labor groups support Enbridge’s challenge.

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