Anyone alive in the United States in the 1950s was exposed to radioactive iodine-131 fallout from atomic bomb tests - and 10,000 to 75,000 of them may develop thyroid cancer from it.

That's according to a 14-year study by the National Cancer Institute that was released, in part, on Friday amid howls by activists who complained that the entire report, although completed, was not to be released until September or later.Somewhat surprisingly, it said Utah was not the nation's hardest-hit area - even though it was directly downwind from the Nevada tests, and Congress already chose to compensate some victims in some counties there for some types of cancer.

Still, eight counties in Montana and Idaho actually suffered worse overall iodine-131 fallout doses than Utah's hardest hit area, a part of Washington County (around St. George).

And only Utah's Washington and Kane counties finished among the worst 25 "hot spot" counties in the nation.

Also surprisingly, some of the higher estimated doses in Utah came in northern counties where residents likely never dreamed it was a problem. For example, residents of Utah County had higher average fallout doses than part of "hot spot" Kane County.

Also, some southern counties where people may think fallout was a big problem actually suffered little. For example, Iron County had the lowest average fallout dose of any county in Utah - even though it is adjacent to hard-hit Washington County.

The study used complicated procedures to compute likely doses based on where people lived, where fallout blew after each of 90 atomic tests, people's age and how much milk they likely drank - and what the source of that milk was.

Iodine-131 is most easily absorbed in humans by drinking milk contaminated when cows ate feed fouled by fallout. Children and people who drank more milk had higher doses. People who drank milk from a family cow had higher doses than those who drank processed milk.

It found that iodine-131 was spread in every county in the nation. And the average estimated dose for the 160 million Americans alive in the 1950s was 2 rads.

That's about five times the radiation from a modern mammogram, said Richard Klausner, director of the National Cancer Institute.

Klausner said scientists do not yet have firm proof that iodine-131 actually causes thyroid cancer.

"We do not feel that we have the data to support the idea that there was a large risk. On the other hand, we cannot rule it out," Klausner said.

However, if it causes cancer similar to other external radioactivity sources, the study estimates that dose rates were high enough that 10,000 to 75,000 people exposed will develop thyroid cancer from it in their lifetime - and that about a third have already developed it.

Klausner said the real question is determining what exposure levels can cause the cancer.

While the average estimated exposure in America was only 2 rads nationally, Klausner noted that members of even the same family in the same place could have had wide variances in doses because of their age, size and milk-drinking habits.

To illustrate, the study looked at a hypothetical family living in Salt Lake City in the 1950s.

The father born, say, in 1927 would have absorbed an estimated 1.3 rads. His wife, two years younger, would have had 1.4 rads.

Their first child born in October 1951, would have had a relatively whopping 10 rads because it was drinking more milk during some of the worst tests and was small so its thyroid held more of the iodine.

A second child born in September 1952 would have had less - only 8.9 rads because of the timing of tests. A third child born in 1956 would have had 5.5 rads. And a child born in 1958 would have had only 0.1 rads as the tests neared an end.

The long study was ordered by Congress in 1982 after Deseret News stories showed fallout had spread nationwide, and showed higher-than-expected cancer rates in areas immediately downwind of the tests - bringing howls from Utah politicians.

After press reports last week that the study was finally completed but was not scheduled for release until at least September, several activist groups and politicians called for quick release and wondered aloud if the government was hiding something.

On Friday only a short synopsis of findings was released. Klausner said the full 100,000 page report with a 1,000-page narrative of findings will be released by October on the Internet.

Some politicians were still not pleased that the data were not more quickly released.

Rep. Chris Cannon, R-Utah - who blames the cancer that killed his father on atomic tests - said the slow data release broke trust with the public, and that the federal government "should be on notice that this breach of trust is not taken lightly, and that appropriate compensatory measures are expected."

Some cancer victims in Utah are also not convinced that the study accurately estimates radiation exposures.

For example, Alfred H. Rosenhan of Salt Lake City tells how he was prospecting for uranium on Aug. 31, 1957, near Preston, Franklin County, Idaho - and made his lunch on top of a flat rock. After lunch, his group turned on their geiger counters, and they went off the scale because, he says, of an atomic test earlier that day.

Rosenham said he figures his lunch was contaminated by radiation because of the foul metallic taste he couldn't get rid of that night. He soon lost part of his tongue to cancer, had cancer on his nose, lost much of his feeling below his waist - "and my life has been a hell ever since."

Documents released Friday are available on the Internet at (http://rex.nci.nih.gov).

*****

ADDITIONAL INFORMATION

Atomic testing

Examples of how cumulative fallout doses of iodine-131, measured in rads, varied depending on location and age during 1950s atomic tests - even within the same family in the same city.

......................Salt Lake Los Angeles New York Denver Chicago

Father, born 9/15/1927 1.3 0.03 0.5 1.1 0.7

Mother, born 10/10/1929 1.4 0.03 0.6 1.1 0.7

Child, born 10/1/1951 10.0 0.3 5.0 10.0 6.6

Child, born 9/15/1952 8.9 0.06 3.8 8.9 5.8

Child born 11/28/1956 5.5 0.02 2.2 5.5 2.9

Child born 9/5/58 0.1 0.002 0.01 0.1 0.04

Source: National Cancer Institute Study of Radioactive Fallout from Nuclear Tests

*****

Fallout doses

Estimated average dose of radioactive iodine-131 per person in Utah counties from atomic bomb testing in the 1950s.

County Rads* Population

Beaver 3.1 4,633

Box Elder (subarea 1) 2.8 438

Box Elder (subarea 2) 4.1 21,561

Cache 3.7 34,494

Carbon 4.5 23,300

Daggett 3.9 703

Davis 4.2 45,270

Duchesne 3.5 7,725

Emery 4.7 5,980

Garfield 8.9 3,904

Grand 3.2 3,791

Iron (subarea 1) 1.7 605

Iron (subareas 2&3) 1.6 9,530

Juab 5.5 5,391

Kane (subarea 1) 7.8 1,516

Kane (subarea 2) 10.0 941

Millard 8.7 8,739

Morgan 4.4 2,654

Piute 5.0 1,711

Rich 3.4 1,678

Salt Lake 4.0 320,858

San Juan 2.5 6,897

Sanpete 5.0 12,688

Sevier 4.8 11,433

Summit 4.5 6,288

Tooele (subarea 1) 4.5 3,278

Tooele (subarea 2) 4.0 12,733

Uintah 3.6 10,845

Utah 6.2 92,569

Wasatch 5.7 5,462

Washington (subarea 1) 6.3 887

Washington (subarea 2) 11.3 5,702

Washington (subarea 3) 9.2 3,430

Wayne 2.6 2,001

Weber 4.2 94,981

*A rad is a unit of measurement that stands for radiation absorbed dose. In comparison, radiation from a modern mammogram is about 0.4 rads.

Source: National Cancer Institute Study of Radioactive Fallout from Nuclear Tests.