A letter report issued by the Government Accountability Office with an abstract that begins "In February 2004, the Centers for Disease Control and Prevention (CDC) was asked to assess the effects of elevated lead levels in tap water on Washington, D.C., residents. In April 2004, CDC published the results. However, an inaccurate statement and incomplete descriptions of the limitations of the analyses resulted in confusion about CDC's intended message. GAO was asked to examine (1) CDC's actions to clarify its published results and communicate current knowledge about the contribution of lead in tap water to elevated blood lead levels (BLL) in children and (2) CDC's changes to its procedures to improve the clarity of the information in its public health communications. GAO reviewed CDC communication policies and procedures and interviewed CDC officials."