Gwendolyn Glenn travels to Iberville Parish in Louisiana to report on a landmark EPA investigation into charges of environmental racism. For years, Iberville residents have suffered health problems traced to numerous chemical plants in the predominantly black community. Activists in Iberville have argued that the siting of such plants in their neighborhoods is an example of environmental racism . . . but in the past they've had little luck in proving it. Now, an EPA civil rights investigation may support their charge.