ST. PAUL — An Enbridge Energy official kicked off a 12-day hearing by testifying that the company’s aging Line 3 crude oil pipeline across northern Minnesota is increasingly subject to corrosion and cracking. Laura Kennett said its maintenance needs are expected to grow exponentially unless the company can replace it.

The trial-like “evidentiary hearing” opened Wednesday before Administrative Law Judge Ann O’Reilly in St. Paul. The 60 witnesses scheduled to testify range from Enbridge officials and labor and oil industry allies that support the replacement, to representatives of environmental, tribal and climate change groups that oppose it.

Line 3 runs from Alberta across North Dakota and Minnesota to Wisconsin.

Enbridge hopes to persuade O’Reilly to recommend that the state Public Utilities Commission approves the replacement. The PUC is scheduled to decide in April.