Although it’s too early to say for certain, action taken late last week by a key state agency involved in the Line 5 controversy and potential construction of a tunnel underneath the Straits of Mackinac appears to have moved the process ahead a step or two.

On Friday, the Michigan Public Service Commission OK’d a $500 million plan to encase in a protective tunnel that portion of Line 5 that runs beneath the channel connecting two Great Lakes.

That means just one more regulatory hurdle for the contentious project remains: The plan still needs approval from the U.S. Army Corps of Engineers, which is still compiling an environmental impact statement. A final decision may not come until 2026, the Associated Press reported.

Just say the words Line 5 and the hackles of many environmentalists and, indeed, interested others, are raised.

The decades-old pipeline, which runs from Superior, Wisconsin to Sarnia, Ontario, carries up to 23 million gallons of crude oil and natural gas liquids daily.

And therein lies the problem.

Operated by Enbridge, a Canadian corporation, the pipeline is considered an environmental disaster waiting to happen.

People and organzations who oppose the pipeline in general and tunnel construction in particular want the line shut down and construction plans scrapped.

Fair enough. But about the product that flows through the pipeline and the role it plays in people’s lives? Enbridge officials, and many others not connected with the company, claim the line meets 55% of Michigan’s propane needs, including 65% used in northern Michigan and the Upper Peninsula. Refineries served by Line 5 also supply a large portion of the aviation fuel at Detroit Metro Airport.

The state of Michigan has invested significant resources opposing the line and tunnel project.

We would argue the state should also invest in finding ways to replace the petroleum products the line carries each day.

Thousands of Upper Peninsula residents, many residing in remote locations, depend on propane from the line. Turning the spigot off, so to speak, without a well-conceived plan to address at least the propane issue is, at minimum, wrong and could ultimately prove dangerous.

In the meantime, the legal and regulatory process moves forward, inch by painful inch.