Butrico telephoned a radiation official at the Nevada Test Site, who told him to wait. Butrico called again at 9:45 a.m., but the official had no concrete plan other than to wash cars and get people indoors.

Butrico met with the mayor of St. George, who arranged for a Cedar City radio station to announce that people should go indoors. The announcement came about 10:15 a.m.

"No other effort was made to reach towns to the east," wrote U.S. District Judge Bruce S. Jenkins. Butrico estimated a level of 320 milliroentgens per hour could have hit St. George for 20 minutes.

In 1984, Jenkins ruled that fallout caused human deaths and the federal government was negligent in failing to warn residents. However, on appeal the government won a reversal on national security grounds.

Later, Congress ordered some relief. It has paid compensation for thousands killed by fallout from the above-ground tests of the 1950s and 1960s, or who were injured by unsafe uranium mining. But it has rejected many claims.

For decades, the government denied responsibility for a massive sheep kill in the spring of 1953, when herds from southern Utah grazed in winter pastures 60 miles from the Nevada Test Site.

That was the year of the dirtiest nuclear explosions ever set off in the open air at the site: tests Annie, 16 kilotons; Nancy, 24 kilotons; Badger, 23 kilotons; Simon, 43 kilotons; Harry, 32 kilotons.

Fallout rained down on sheep and actually burned holes in their fleece; they grazed contaminated grass.

"You'd think they'd be all right, and the next day there'd be 30 or 40 of them dead," rancher Kern Bullock, Cedar City, recalled years later.

In the last two weeks of May 1953, of 11,000 sheep and lambs in the region, 4,300 died or were born dead.

Government veterinarians investigated, finding the sheep had high levels of radiation in organs, particularly their thyroids, and that bones, livers and lungs also registered high readings.

One federal vet wrote that he believed "the Atomic Energy Commission has contributed to great losses." Another specialist wrote that the sheep's facial sores made him suspect they had come into contact with "material on the bushes, grass and etc. that would cause these lesions."

A June 9, 1953, radiation measurement in sheep thyroid glands, an expert wrote, exceeded "by a factor of 250 to 1,000 times the maximum permissible concentration of radioactive iodine for humans."

But the AEC claimed the sheep died because of poor vegetation.