Scientists could further study the public health consequences of nuclear weapons testing, but questions remain about how worthwhile such a project would be, a new federal report says.

The U.S. Centers for Disease Control and Prevention and the National Cancer Institute report explores the feasibility of looking more deeply into the health effects from atomic weapons tests in the 1950s and '60s.

Its answer is that "yes, it is feasible and possible," said Stephanie Creel, spokeswoman for the CDC's National Center for Environmental Health.

But whether it ranks as a high public health priority must be determined before any such study is considered, she added.

The study's results proved discouraging to "downwinders," people who lived downwind of above-ground nuclear testing in Nevada. They believe the government is dragging its feet on such research.

"We didn't need a study to tell us it was possible," said Mary Dickson, a Salt Lake City downwinder advocate and author.

Dickson said skepticism exists about whether the government that conducted the nuclear tests in Nevada is the best entity to study the health consequences of the testing.

Part of the new study, first requested by Congress in 1998, discusses a canceled University of Utah study on radioactive fallout and thyroid disease. The $8 million CDC-funded study ended last year after being granted several extensions.

Joseph Lyon, the U. researcher running the study, said government delays in delivering timely funding prevented him from completing the study on deadline. CDC officials later questioned the calculations used to determine how much fallout individuals were exposed to in areas downwind of the Nevada Test Site.

"Their decision was not based on science," he said.

At the time the study stopped, researchers had examined 1,700 people, falling short of the 3,500 goal. Lyon had estimated it would have taken another two years with full funding to finish.

The new federal report was written when the U. study was still under way, and referenced Lyon's work, saying it would help clarify the extent to which the Nevada tests increased the risk of thyroid cancer and other diseases of the thyroid.

J. Preston Truman, head of an Idaho-based advocacy group called Downwinders, called that reference "a really strong statement."

But Creel said the CDC/NCI study's finding that additional research would be feasible has not changed the CDC's position on canceling the U. research program.

Truman said the decision to cancel the study is a source of continuing frustration. He said the study was just beginning to find useful information when it was canceled.

"This was to be the definitive study," Truman said.

The U. study investigated the long-term health effects of radioactive fallout, in particular Iodine 131. After above-ground nuclear tests, particles including Iodine 131 were carried by weather patterns to other parts of the country.

Most of the exposure for those downwind of the tests is believed to be through ingestion. Fallout landed on fields of grass where dairy cattle grazed. Radioactive particles concentrated in the cows and entered their milk.

Children drinking this milk in the 1950s also drank radioactive particles, which ended up concentrated in the thyroid gland. Research shows that this likely led to an increase in cases of thyroid cancer, but questions remained about other thyroid conditions.

The CDC/NCI report specifically notes that little research has been conducted to understand how fallout and radiation affect the risk of noncancer diseases.

While the new report indicates more work is needed, there are cautions about how to move forward.

"Significant resources would be required to implement this detailed study, however, and careful consideration should be given to public health priorities before this path is taken," the authors wrote. Creel said the CDC has not decided on a course of action based on this report.

The study -- known as the "Report on the Feasibility of a Study of the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations" -- lists several potential options, ranging from conducting no additional work to undertaking a detailed study that looks at dose estimation, risk analysis and communication of the results to the public.

Though the authors finished the report in May 2005, it has only become recently available on the Internet at www.cdc.gov/nceh/radiation/fallout.

Congress requested the report in 1998, following the release of a 1997 NCI study that looked at radioactive fallout estimates for each county of United States.

Source: Knight Ridder/Tribune Business News