Even though it did not change to a cleaner fuel source, or come up with an alternative to coal ash dumping into Lake Michigan in the four years that regulators gave the ship's owners to comply.
More than 30 posts on this blog about the matter, back to the spring of 2009:
...the pollution has been tolerated even though its reality has been known for years. I began checking into this a few years ago, and learned that the Wisconsin legislature gave the Badger a permanent exemption from the Clean Air Act - - but not the Clean Water Act.
See applicable state statute section 285.27 (3) here.
Why the exemption, and the long delay in any regulatory action to hold the ship to the same standards that one would apply to a coal-fired boiler on land forbidden from dumping its ash into the lake everyday - - for years, no doubt measured in tons.