TRAVERSE CITY, Mich. -- Substandard science has hurt a federal agency's seven-year effort to document possible links between industrial pollution and health problems in the Great Lakes region, an independent review panel said Friday.
The Institute of Medicine said drafts of a report still under development by the federal Centers for Disease Control and Prevention were deeply flawed. Shortcomings included use of questionable data and conclusions that were overstated or not backed by sufficient evidence, the institute said.
"The problems we found in the drafts would limit the ability of officials and others to draw conclusions from them about whether any health risks are associated with living in or near certain places around the Great Lakes," said Robert Wallace, a professor of epidemiology at the University of Iowa and chairman of the 11-member committee that conducted the review.
The CDC said the report confirms what it had said previously -- that the document simply isn't ready yet.
The agency asked the institute -- a scientific advisory organization and part of the National Academies -- to evaluate the report's quality after some members of Congress accused the agency of a cover-up for delaying its release.
Versions made public earlier this year noted elevated levels of cancer, premature births and infant mortality in some of the U.S. counties where 26 "areas of concern" are located. Those sites are heavily tainted with toxins such as PCBs, mercury and dioxins. About 9 million people live near the sites in cities such as Detroit, Chicago, Cleveland and Milwaukee.
The CDC released drafts from 2004 and 2007 last March after a not-for-profit group posted an unauthorized copy on its website. But administrators acknowledged they were acting under pressure from Congress and that some of the science was weak.
The institute's report echoed those concerns, and Wallace said in a telephone interview he believed CDC bosses were right to delay its release.
"We think a lot of refinements could be made," he said.
CDC spokesman Glen Nowak said, "It's heartening to see the IOM report reaffirmed that our concerns were valid ones and our decision not to release the report was a wise one."
The study was requested in 2001 by the International Joint Commission, a U.S.-Canadian agency that advises both nations about the Great Lakes and other boundary waters. The CDC's Agency for Toxic Substances and Disease Registry conducted the study.
It produced no new statistics, but pulled together information from a variety of government health and environmental databases.
In a letter to the CDC, the Institute of Medicine questioned why and how certain data sets were used in the study while other potentially helpful ones were excluded.
A particular issue, also raised by ATSDR directors and some peer reviewers, was that environmental data from specific contaminated sites were lumped together with health data taken from entire counties -- and at different times.
The report did not make clear how particular contaminants could have caused the identified health problems, the institute said in a news release.
"This juxtaposition of data without explanation or support could lead readers to assume links between contamination and health problems regardless of whether they actually exist," it said.
The agency released a third draft in April that removed the countywide health statistics and made other adjustments. But the Institute of Medicine said the slimmed-down version shed little light on the original question of how the contamination might be affecting human health.
U.S. Rep. Bart Stupak, one of the lawmakers who criticized the CDC for withholding the report, said the institute had identified shortcomings in the documents but hadn't explained "why it took seven years for a draft of this report to see the light of day."
"CDC now has a blueprint for perfecting this report and presenting Congress and the American people with a clear picture of what our greatest public health risks are along the Great Lakes," said Stupak, a Michigan Democrat and chairman of a House subcommittee investigating the CDC's handling of the matter.
A number of scientists outside the agency also had called for the report to be made public, saying that even if it is flawed it could provide useful information to the affected communities.
Nowak, the CDC spokesman, said the agency still intends to produce a final document but had no deadline. "The issues we are being asked to address are challenging ones," he said.