Under pressure from Congress, the government has released a controversial draft report on pollution in the Great Lakes states.
The report suggests pollution in some areas is causing health problems, including cancer and premature births. The document was produced by scientists at the Centers for Disease Control and Prevention.
But CDC administrators quickly backpedaled, saying some of the science is weak, and that they released it after accusations of a cover-up.
CDC officials also said they have asked the Institute of Medicine to review the drafts and give its own assessment of the work's quality. The Institute of Medicine is an independent scientific advisory organization.