The 2002 biosolids study from the National Academy of Sciences (NAS) did not reference research into health impacts by Environmental Protection Agency (EPA) whistleblower David Lewis, as reported in our News story 'Raking through sludge exposes a stink' (Nature 453, 262–263; 2008). The citation was included in a prepublication draft that is still posted on the EPA's internet site, but the NAS panel voted to remove the reference before final publication. An NAS spokesman said the panel decided the information was not relevant as the panel was not charged with evaluating health impacts.