Minnesota utility regulators Thursday rejected a request by the state's Ojibwe bands to require a comprehensive tribal cultural analysis for Enbridge's proposed pipeline across northern Minnesota.

The tribes have asked the Minnesota Public Utilities Commission (PUC) to include a full state study of tribal historic sites as part of the state's Environmental Impact Statement for Enbridge's proposed new Line 3. The controversial pipeline would ferry Canadian oil to Enbridge's terminal in Superior, Wis.

The PUC declined to include such a survey in the environmental review, essentially saying that it isn't the state's responsibility but that of the U.S. Army Corps of Engineers. A Corps-led cultural survey began last fall but is unlikely to be completed before the PUC makes a final decision on Line 3, which is expected in June.

The PUC has acknowledged that the timing is a problem. It decided in December that if it approves Line 3, construction can't start until the federal tribal cultural survey is completed.

"We understand there's another point of view that that's not enough," PUC member Dan Lipschultz said at Thursday's meeting.

Two Minnesota House members expressed that viewpoint at the meeting.

"It defies logic to approve something before we have the results and the full implications of the [tribal cultural] survey," said Rep. Jamie Becker-Finn, DFL-Roseville, who grew up on the Leech Lake Reservation.

"How can you approve something if you don't have all of the information?" added Rep. Peggy Flanagan, DFL-St. Louis Park, who is member of the White Earth Nation.

Indian bands and environmental groups oppose Line 3, saying it would open up a new region of lakes, rivers and streams to possible contamination from an oil spill. The new Line 3 would follow old Line 3's path to Clearbrook, Minn., but would then jog south to Park Rapids, Minn., before heading east to Superior.

Calgary, Alberta-based Enbridge said the new pipeline is a much-needed safety upgrade over the current 1960s-vintage Line 3, which is corroding.

The new Line 3 — unlike the current pipeline — would not cross any Indian reservations. But it would traverse the tribes' historical homeland, where they have treaty rights for hunting, fishing and gathering.

The environmental review, which was done by the Minnesota Department of Commerce, contains an analysis of tribal properties. But it includes only known archaeological and historic resources.

The full tribal cultural survey is broader, searching for sites of historical importance that aren't necessarily known.

"The standard interpretation of the archaeological record usually does not recognize sites of cultural and religious significance to tribes," said a recent PUC filing by the Fond du Lac Band of Lake Superior Chippewa.

As an example, the filing noted an incident last year in which highway construction in Duluth inadvertently dug up human remains, desecrating an American Indian burial ground.