Lawmakers and the NAACP are calling for an investigation into reports that federally funded scientific experiments in 2000 spread sewage sludge on yards in poor black neighborhoods to test if it could fight lead poisoning in children. The Associated Press reported Sunday that researchers spread a mix of human and industrial wastes from sewage treatment plants on the lawns of nine low-income families in Baltimore and a vacant lot next to an elementary school in East St. Louis, Illinois. We speak with John Heilprin, the AP reporter who broke the story. [includes rush transcript]