A public health study about the effects of Great Lakes pollution by the U.S. Centers for Disease Control and Prevention has been delayed, prompting speculation from health experts about its findings.

The study, Public Health Implications of Hazardous Substances in 26 U.S. Great Lakes Areas of Concern, was to have been released by the CDC last summer. The CBC has learned that excerpts of leaked parts of the report are available on the Internet.

The study, which has been reviewed by experts over the past three years, suggests that people living in 26 polluted areas around the Great Lakes — including Chicago, Cleveland and Detroit — face higher rates of lung, breast and colon cancer.

Researchers also found low birth weights and high infant mortality in some Great Lake areas.

Canadian scientists said they are concerned the findings have important health ramifications for Canadians. "When you have persistent toxic substances, like the organic chlorine chemicals such as DDT and dioxins and PCBs, the essential aspect is the chemicals. The Great Lakes are not static," Canadian biologist Mike Gilbertson told CBC News.

Gilbertson said that, as a peer reviewer, he has seen the entire study and scrutinized the data on how many Americans face elevated health risks.

Peer review found report ready to release

Gilbertson is now calling on the CDC to release the study. So, too, is Herb Gray, the Canadian chair of the International Joint Commission, a bilateral organization that monitors the use and quality of boundary waters between the U.S. and Canada.

"They claim that there are some gaps in the scientific analysis," said Gray. "The original draft report was apparently peer-reviewed by a number of experts who felt the original report was satisfactory to be released."

The still-secret study has also got the attention of some Democrats in the U.S. Congress, who feel the document is being suppressed.

The CDC has rejected that charge and said the report will likely be released in four months time but that more revisions are necessary.

Gilbertson said he worries about what will be missing in the final draft. Money may be the core issue, he said.

"Really, the concern is that there may be costs, very high costs, associated with remedial action to try to counter the effects of that pollution having got into the environment," he said.