(GREAT LAKES REGION) Midwest groups have entered a legal fight to keep ocean ships from dumping contaminated ballast water into the Great Lakes.

Law firms and environmental groups are challenging an EPA rule that exempts certain water transfers from one water body to another from permit requirements under the Clean Water Act. In some parts of the nation, the fight is over partly draining lakes to supply rivers to help farmers. Along the Great Lakes, there's an ongoing battle over restricting ocean ship ballast water from being dumped into the lakes and releasing invasive species.

Attorney Karen Schapiro represents the Clean Water Action Council of Northeastern Wisconsin. She says the dispute is important. She and others have just filed a petition, asking a federal appeals court to halt EPA's water transfer rule.

The agency says its taking action on many fronts to prevent the spread of invasive species from ballast water and other vessel discharges. EPA also says it will continue to use available tools under the Clean Water Act to protect the nation's lakes, rivers, and streams from potential impacts from water transfers. The agency says it will review the challenge to the regulation and “looks forward to working with Congress and the states on this issue."