The Government Accountability Office, the investigative arm of Congress, has faulted federal health officials for failing to address flaws in a 2004 article on exposure to lead in District of Columbia tap water.

The continuing confusion over elevated blood lead levels in Washington, D.C., residents, the GAO said in a report, reflects the fact that the Centers for Disease Control and Prevention “does not have a policy to monitor the use of or clarify information in public health publications.”

Responding to concerns about high levels of lead in the city’s tap water, CDC scientists analyzed blood samples from residents taken between January 1998 and December 2003. The CDC article published in April 2004, concluded that although lead in tap water “contributed to a small increase” in blood lead levels, no children were identified with levels above the CDC’s level of concern for children, “even in homes with the highest water lead levels.”

Since the article was published, CDC officials have said that some children were, in fact, identified with lead in their blood above the level of concern.

The CDC has taken some incremental actions to address the confusion. But the GAO noted that “as of January 2011, the CDC had no plans to publish an overview of the current knowledge about the contribution of elevated lead levels in tap water to BLLs [blood lead levels] in children.”

Separately, a congressional subcommittee found in May 2010 that the CDC had made “scientifically indefensible” claims in its 2004 article. Dr. Thomas R. Frieden, the agency’s director, has said that “in its urgency to rapidly assess the situation, the CDC communicated scientific results poorly.”

Lead levels in the District of Columbia’s tap water increased in 2000 when the U.S. Army Corp of Engineers, which controls the Washington Aqueduct, stopped using chlorine to disinfect water and switched to chloramine, a chemical later found to increase erosion from lead pipes in homes.