WASHINGTON, DC—A House subcommittee report released last month accuses CDC of using flawed data in basing its assertion in 2004 that the drinking water in Washington, DC did not contain harmful levels of lead.

In January of 2004 local DC residents were alarmed by media reports that revealed that authorities in the nation’s capital had found that two-thirds of the homes they tested had tap water lead levels above the EPA limit of 15 ppb. High levels of lead in drinking water are known to be particularly dangerous for children.

In response, CDC’s Agen-cy for Toxic Substances and Dis- ease Registry (ATSDR) conducted a preliminary investigation published in an April 2, 2004 Morbidity and Mortality Weekly Report. A cross-sectional study included in its investigation found that even in homes that it tested with tap water lead levels greater than 300 ppb, all of the children had blood lead levels below CDC’s levels of concern. The findings reassured many DC residents that the water was safe to drink.

A House Committee on Science and Technology panel said that its own investigation found that CDC knowingly left out key data in its report by omitting that many of the residents had stopped drinking their tap water months prior. The subcommittee’s investigation also reported that the principal author of the CDC report knew that thousands of blood lead level test results were missing from its data for the years 2002 and 2003.

The subcommittee noted that it found in its own investigation that the number of children with elevated blood lead levels in 2002-03 was at least three times greater than reported by the CDC. “The authors knew there were problems with their studies, but in their disclosure on the limits of their data, they said not one word about missing data or confounding variables,” said Rep Brad Miller, D-NC, chairman of the House Committee on Science and Technology Subcommittee on Investigations and Oversight.

Committee Examines MMWR Report

Robin Ikeda, MD, deputy director in CDC’s Office of Noncommunicable Diseases, Injury and Environmental Health, told subcommittee members that CDC published a new analysis of the data from its original study on lead in DC’s water last month.

She explained that the new analysis includes data from specimens from 2003 that were not included in the original 2004 report. Still, she maintained the new data did not change the original results. “Our more comprehensive analysis did not fundamentally change our findings from 2004.”

Ikeda said that CDC published a new analysis in MMWR last month to let people know that CDC “understood that our comments in the MMWR in 2004 were ambiguous” and that CDC wanted to make sure that people understood the principal message intended from 2004 is that “no lead level is safe.”

Marc Edwards, PhD, a professor of civil and environmental engineering at Virginia Tech, told the subcommittee that he believed that the new analysis CDC published was still flawed because it only corrected data from 2003 and did not correct other data.

GAO Calls for Changes

Members of the subcommittee were also interested in what steps should be taken to assure that reports and products that come from ATSDR have undergone the appropriate reviews prior to release.

Cynthia A Bascetta, director of Health Care for GAO, testified that a GAO review of ATSDR found that the policies and procedures established for public health product preparation “lack some of the critical controls needed to provide some
reasonable assurance of product quality.”

The GAO’s recommendations include revising existing policies and procedures, or developing new guidance, “to provide documented direction for various levels of management on their roles and responsibilities in the monitoring of all products prior to review and clearance.”

Ikeda also testified that ATSDR has efforts underway to improve its processes for review of all documents that are prepared for public dissemination.

Members of the panel also questioned whether the agency’s products should be required to undergo peer review. ATSDR is exempt from mandated peer review of its products by law. “I see no reason that they should be exempted from peer review,” said Rep Paul Broun, R-GA, the ranking Republican of the subcommittee.

John Wargo, PhD, a professor of environmental risk analysis and policy at Yale, agreed that peer review was needed. “That exemption has created serious problems of credibility for the agency.”

When Ikeda was asked about whether there is a need for a mandated peer review process, she said that “peer review is a pillar of good science,” but that “the rigor of peer review and the time it takes to conduct a review must be balanced against the need to get information out quickly.”

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