Between 1951 and 1963, while Americans...

For generations, it was the Big Fear: The eye-searing fireball that might shatter any dream; anxiety shuddering unexpectedly through the most tranquil moments; the billowing threat of disease and death hanging gloomily over the happiest occasions.

Photographer and author Carole Gallagher is among the millions of Americans who grew up haunted by atom-bomb Angst .

But now, as the world heaves a collective sigh of post-Cold War relief, Gallagher, 43, finds herself burdened by a dreadful “secret.”

As a nation cowered in fear of Armageddon, she says, a nuclear holocaust of sorts did indeed rumble across the American landscape.

She bears witness to that horror in a book which, by focusing more intimately than previous accounts on the people affected, is triggering gentle shock waves nationwide: “American Ground Zero--The Secret Nuclear War.”

Had the attack Gallagher documents occurred in a single burst, had a foreign enemy launched it, the headlines would have thundered:

100 A-BOMBS BLAST AMERICA! DAMAGE INCALCULABLE!

But the flames and fallout of the 100 or more atmospheric explosions on the Nevada desert--each of which released as much radiation as the Chernobyl disaster--dragged on for more than a decade, from 1951 to 1963. And the government that triggered the tests--and has sinceconducted another 800 such blasts underground--was our own.

So, while terror of a Soviet first strike overshadowed most Americans’ fear of testing, Gallagher became obsessed with the blasts and their effects.

In 1983, after reading everything she could find on nuclear testing and radiation’s health risks--which the government continues to downplay--she left her New York City home to live with two polygamist widows, in the basement of their St. George, Utah, home.

For the next decade, she became an unusual war correspondent on a battlefield that she contends is littered with carnage no one wants to acknowledge: cancer of every variety, neurological disorders, reproductive abnormalities, sterility, birth defects, diseases from genetic mutations and other afflictions she and others believe radiation-related .

“I got sucked into it,” she says. “I feel I was meant to do (the book) and I don’t know what that means. . . . This thing was getting done because there was a body here to do it and a mind here to do it. They happened to be mine.”

During the next decade, she interviewed more than 1,000 of the tens of thousands of citizens most directly affected by the tests: test site workers, military veterans who participated in the tests, and those who lived immediately downwind of ground zero in Nevada, Utah, Arizona, Idaho and South Dakota--from a brothel owner to an Episcopal priest.

Slowly, she gathered accounts of residents from towns just miles from the site, who had watched in awe as the bombs mushroomed, their pressure breaking store windows. She spoke to folks from relatively distant towns that had been dusted with pink fallout, into which children who had never seen snow gleefully scrawled their names.

Their testimony and an understated narrative--based in part on reams of recently released government documents--combined with Gallagher’s compelling black-and-white portraits and landscapes, have been fashioned by MIT Press into a wrenching look at what Gallagher swears are the effects of atomic test radiation, despite what she characterizes as the U. S. government’s lies about the matter.

Living with so much disease was grim, Gallagher says, and her own “abject poverty” didn’t make things any cheerier. Depression gnawed at her like a cancer: “Sometimes I didn’t want to go to sleep at night--I thought I’d die of loneliness.” Then there was “the fact that my work was being denied--that I was covering a war and no one believed it was happening.”

Now, as she sprawls casually on the couch in an acquaintance’s house in the San Gabriel foothills, her face has the serene, almost cheerful glow of a recovering bodhisattva.

But her exuberance is fragile.

The moment talk touches on the people in “Ground Zero,” tears flow like a southwestern flash flood.

A 1950s military film, “produced for the armed forces and the American people,” features an Army chaplain reassuring soldiers who are about to witness an early nuclear test at the Nevada Test Site, north of Las Vegas.

Gallagher quotes: “Actually, there is no need to be worried. . . . You look up and you see the fireball as it ascends up into the heavens. It contains all of the rich colors of the rainbow, and then as it rises up into the atmosphere it assembles into the mushroom. It is a wonderful sight to behold.”

Claudia Boshell Peterson, then age 3 or 4, was swinging in the yard with her brother when a sight not unlike that described by the chaplain--”this great big red ball”--appeared on the horizon.

One of 80 people who appear in Gallagher’s book, Peterson lived then on a little farm outside Cedar City, Utah, just downwind of the test site at Frenchman Flat.

Like others in the book, Peterson remembers the government workers who showed up to monitor radiation and assure the populace. “When I was in fourth grade,” she says, “they came to school with Geiger counters . . . when the Geiger counter was near my face it just went bananas, and I said, ‘What does this mean?’ ”

The worker told her, “It means you had dental X-rays.”

Peterson had never had one.

Years later, doctors were equally patronizing when Peterson’s young daughter, Bethany, complained of stomach problems. She was “overreacting,” they said.

Peterson had considerable experience with such dismissals, though, beginning when the family’s sheep delivered two-headed lambs after a test.

Peterson finally took her little girl to a Salt Lake City hospital. Having watched several of her own classmates die, the mother knew even before she heard the words that the doctors’ diagnosis would be cancer and that the prognosis would be “fatal.”

“It was like my whole body was being altered,” she recalls. “It was like I was being sucked down a tunnel . . . I said, ‘I don’t want to hear it, I don’t want to hear it!’ I curled up on the bed and put the pillow over my head, and rocked back and forth and screamed. And it was just like he was screaming it in my ear, ‘She’s got stage four neurobastoma.”

Peterson’s sister, Cathy, who’d also been exposed to radiation, also got sick--liver tumors, breast tumors, bone tumors, brain tumors, lung tumors. She left six small children when she died.

Peterson was--and is--intensely patriotic, as are so many in the region inhabited predominantly by Mormons--who believe the U.S. government is divinely blessed and that authority is to be obeyed.

But, like other reporters before her, Gallagher came across previously classified government documents demonstrating that more often than not, agencies were at best insensitive, at worst downright deceitful in handling the testing.

While Gallagher believes that the downwind landscape is among the most beautiful on Earth, a 1950s armed forces publication for soldiers being sent to the test site described it as “a damn good place to dump used razor blades.”

She also mentions what she calls a recently reclassified “top secret” Atomic Energy Commission report that refers to people downwind of the test site as “a low-use segment of the population.”

Such contempt made it easier for the government to justify misleading the public, say some scientists quoted in the book.

During much of the aboveground testing, Dr. Melvin W. Carter worked with and later served as director of the Public Health Service’s National Environmental Research Center in Las Vegas.

He monitored radiation levels and supervised others during the tests.

A professor emeritus of health physics at Georgia Tech, Carter says he hasn’t heard of Gallagher’s book. But while he acknowledges that the controversy on the effects of testing probably has the half-life of plutonium (about 250,000 years), he disputes the charge Gallagher and her subjects make about government duplicity:

“Speaking for the agencies I was involved in, we . . . never concealed any information from the public. Any information we had about the tests, the health and safety effects, all that information was essentially public information and was made available.”

“Downwinder” Martha Bordoi Laird has a different view.

Four years after the tests began, in 1954, Laird’s 7-year-old son died of leukemia. Another baby lived just a couple of hours--”from the hips down, her legs were all shriveled up and black.”

No longer willing to buy what she had come to view as the government’s pro-testing propaganda, Laird got up a petition and had it signed by 75 neighbors in Twin Springs, Nev.

“We believe . . . that it is both undemocratic and un-American to subject one group of citizens to hazards which others are not called upon to face, particularly when the adverse effects may be reflected in future generations yet unborn,” the petition read. “We are not excitable or imaginative people, most of us coming from rugged ranch families, but neither are we without deep feeling for each other and our children.”

A 1957 reply from her U. S. senator pooh-poohed warnings about the dangers of fallout as the work of “a minority group of scientists,” and suggested that these “scare stories” might have been planted by communists.

“If they could get us to agree not to use the only weapon with which we could win a war, the conquest of Europe and Asia would be easy,” the letter said.

Gallagher doesn’t outright reject the notion that sometimes only horrible means can prevent more horrifying ends.

But if that were the case with the nuclear deterrent, she says, there came a point, fairly early on, when honest scientists knew the tests were unnecessary and would have tragic consequences.

Word of “Ground Zero” began to rumble along the Southwest’s literary, environmental and political grapevines well before publication, and its message is now mushrooming in the national media, gaining praise from snobby book reviews and such middle-brow publications as Entertainment Weekly--which awarded it an A+.

In its review, The Times said the coffee table-sized volume “does not constitute legal or scientific proof of anything.” But the power of the personal testimony Gallagher records, it continued, “is pervasive and damning enough for anyone to understand.”

Chris West, director of external affairs at the Department of Energy’s Nevada Operations Office in Las Vegas, says he keeps the book on his night stand and reads a page or two each night.

Every plant, animal and human on the planet carries traces of plutonium and other fallout from the United States’ and other nations’ atmospheric nuclear tests, he says. But those traces are so slight, in most cases, that researchers cannot link it to health problems.

He also doubts any link to fallout in many of the medical problems Gallagher’s book attributes to testing in Nevada.

“The book certainly presents one side of the story, an extremely emotional side that presents lots of people’s feelings,” he says. While emphasizing that he doesn’t want to discount those testimonials, he adds: “Our technical people and people familiar with the history take exception with many of the facts.”

As for the charge in “Ground Zero’s” preface, that atmospheric testing constituted “the most prodigiously reckless program of scientific testing in American history,” he says: “We certainly wouldn’t do it the same way, given today’s environmental standards. But . . . I don’t think that by any stretch of imagination could we say it was reckless. From what I know of the history, I’m firmly convinced that the government and people associated with the tests did take precautions and did believe there was no harm to those people.”

Gallagher recently handed to Atty. Gen. Janet Reno a copy of “Ground Zero,” in which she had inscribed: “These are crimes to be prosecuted, not ignored.”

Meanwhile, she just received her first Geiger counter as a birthday present. She’ll take it with her as she heads back into the desert with an ABC crew to film a television documentary, recording some of the people who appear in her book.

Whenever Gallagher and her subjects get together now, “it’s a fabulous occasion.”

That said, tears stream from Gallagher’s eyes, and she whispers: “The ones who are still alive.”

Regaining her composure, she adds, “They love me because I understand and take them seriously; I love them because they stood up and spoke up in a culture that tells them to sit down and shut up. They’re very courageous.”

Gallagher writes that the time she spent shooting in the contaminated area around ground zero “surely bestowed upon me an honorary degree in denial, thus drawing me closer to understanding the culture of the downwinders.”

But if there’s one bombshell Gallagher’s book drops on the American populace, it is the point made by a map that she says shows the patterns of fallout from the tests.

The same point is made by an Air Force colonel who, the book says, flew radiation monitoring missions during the tests: “There isn’t anyone in the United States who isn’t a downwinder.”