Potential implications of new information concerning manganese Ohio community health effects studies

Several epidemiology studies have been conducted in Ohio communities where industrial facilities with manganese emissions are located. New information not addressed in the published papers for this research has been disclosed by U.S. federal agencies pursuant to the Freedom of Information Act. This paper describes the newly available information, presents statistical analyses of the new summary data, and explores how this information potentially impacts the conclusions of the published research. Based on a statistical analysis of the newly available data, we found very few, and no consistent, statistical differences for various illnesses, self-reported symptoms, and neuropsychological/neuromotor test results between one community with a manganese emission source and a control town that were part of the initial research. Further, we determined that the distribution of total suspended particulate manganese air concentrations did not correlate with the distribution of the more biologically relevant respirable manganese concentrations when data from two communities with potential manganese emissions were combined. These results are important, particularly in determining whether the studies should influence regulatory reference values related to manganese. We recommend that the full health effects data set associated with the published research be made available and re-evaluated to address the issues identified in this paper.