A federal agency has completed an eight-year study of potential damage to human health from industrial pollution in the Great Lakes region.
It includes extensive environmental and health data from 26 heavily polluted "areas of concern" along streams, rivers and lakes. But it acknowledges the data is insufficient to draw firm conclusions about possible links between pollution and health effects.
The report calls for more study to determine what threats may exist and how to deal with them.
The agency released two preliminary versions of the report after drawing accusations of a cover-up from some members of Congress.