Michigan’s pioneering ballast water law was challenged in March by a coalition of international shipping company interests in federal court.

The shippers sued the state’s Department of Environmental Quality, claiming the law requiring ocean ships to sanitize ballast tanks with one of four approved technologies before discharging water is unconstitutional.

The rule, the first of its kind in the U.S., was enacted by Michigan as a start toward controlling the invasive species that hitchhike in the ballast water of ocean-going vessels before being dumped in the lakes. The invaders—including zebra mussels, the round goby fish and the spiny water flea—disrupt the freshwater ecosystems with often-devastating results.

The voracious goby creates veritable biological deserts in parts of the lower lakes by out-competing native fish species for food. The zebra mussel fouls municipal water intakes and is blamed for crashing populations of plankton that form the base of the Great Lakes food chain. It is also implicated in a resurgence of the algae blooms that foul shorelines along Lake Erie, Lake Huron’s Saginaw Bay and Lake Michigan’s Traverse Bay region.

All told, the invaders result in economic losses of $5 billion annually in damage and control costs, according to the Great Lakes Regional Collaboration study.

Shippers say such rules should be created federally, rather then piecemeal by individual states. They point out that ships could simply dock at ports in other states or provinces, or discharge ballast water in other states’ waters to avoid the rule.

But decades of lobbying at the federal level has not resulted in significant remedies, say Great Lakes advocates and Michigan regulators. Michigan’s law is being closely watched by other states and provinces, several of which are expected to enact similar rules if Michigan’s is effective.

The Michigan Environmental Council supports full implementation of the ballast water law and is working with the state to make it effective. Three of MEC’s allies—the National Wildlife Federation, Michigan United Conservation Clubs and the Alliance for the Great Lakes—are seeking to join the lawsuit on the state’s side.

“What’s wrong with this picture?” National Wildlife Federation Michigan Director Andy Buchsbaum told the Muskegon Chronicle when the suit was filed. “The same shippers that brought us zebra mussels are now suing Michigan to stop us from protecting ourselves from invasive species.”

A more pithy response was offered by State Sen. Patricia Birkholz (R-Saugatuck), who told the Detroit News: “If anything, we ought to be suing them.”