The S.S. Badger may need to clean up its act.

But the Environmental Protection Agency needs to be flexible so this historic and fun car ferry across Lake Michigan doesn’t financially sink.

The S.S. Badger is the only coal-fired steamship still in operation on the Great Lakes, according to its owners. Every summer, the ship that’s 410 feet long and 7 stories high hauls up to 600 passengers and 180 vehicles across the lake between Manitowoc and Ludington, Mich.

Each departure and arrival includes crowds of happy travelers excitedly waving from the deck and shore, like a trip back in time to the glory days of transatlantic ocean liners. The nearly 60-year-old ship is on both state and national registers for historic places.

It’s a slice of Americana that specializes in family fun, boosting tourism dollars and jobs on both sides of the lake.

But the EPA has warned the Lake Michigan Carferry Service, which owns and operates the S.S. Badger, that it can no longer discharge coal ash from the ship’s boilers after next year’s season, which runs from May to October.

The owners are exploring the viability of using compressed natural gas instead of coal, according to the Manitowoc Herald Times Reporter. They also have indicated a willingness to spend millions on an upgrade but insist more time is needed to study and plan for the transition.

The ship is already equipped with technology to reduce smoke and increase fuel efficiency. But 3.8 tons of coal ash still fall into the lake each day the ship operates, according to the Manitowoc newspaper.

A solution is needed soon. Yet given the challenging economy, some kind of time extension is justified.

The lake carried more than 50 coal-fired steamships in the ’70s, according to the Lake Michigan Carferry Service. So it’s hard to imagine the one remaining steamship causing much damage by comparison.

Yet with so many threats facing the Great Lakes, a cleaner fuel makes sense. The EPA should give the S.S. Badger more time to comply – assuming the owners can clearly demonstrate they are seriously advancing toward an upgrade.