In 1990, Congress amended the Great Lakes (GL) Critical Programs Act, also known as the Fed. Water Pollution Control Act, mandating that the EPA and the ATSDR and the GL states submit a research report assessing the harmful human health effects of water pollutants in the GL basin. ATSDR developed the GL Health Effects Research Strategy to identify human populations residing in the GL basin that may be at greater risk of exposure to chemical contaminants, and to help prevent any adverse health effects. This report provides insight into ATSDR efforts to assess the adverse effects of water pollutants in the GL system on the health of people in the GL states.