A Nobel Peace Prize-winning group of doctors says the open-air atomic and nuclear bomb tests in Nevada - which ended in the 1960s - may continue to kill hundreds of thousands of people downwind for decades to come.

It said Thursday that the tests created long-life radioactive particles scattered over vast distances that continue to spread through the food chain and will continue to cause cancer and death.Worse, it said the government knew that use of the Nevada Test Site would spread radiation nationwide - but used it anyway because it was more convenient than safer locations.

International Physicians for the Prevention of Nuclear War - which won the Nobel Peace Prize in 1985 - has released a book, "Radioactive Heaven and Earth," by a commission it set up to investigate the health and environmental consequences of nuclear weapons production.

"Our estimate is that the radiation and radioactive material from atmospheric testing that is taken in by people up until the year 2000 will cause 430,000 cancer deaths, some of which have already occurred," said Arjun Makhijani, principal technical consultant for the project.

"Over the centuries to come, we estimate that 2.4 million people will die from cancer as a result of the legacy of atmospheric testing," he added.

Roughly half of the 430,000 cancer deaths expected from poisoning by the year 2000 may come from tests at the Nevada Test Site, Anthony Robbins, director of the commission, estimated.

Of course, Congress last year passed a bill by Rep. Wayne Owens, D-Utah, and Sen. Orrin Hatch, R-Utah, to apologize to downwind cancer victims of Nevada testing in Utah and other Western states, and to compensate some victims.

Makhijani said, "The long-lived radioactive residues of atmospheric testing, such as plutonium-239, cesium-137 and strontium-90 still pollute the Earth, increasing cancer risk.

"About 10 million curies of carbon-14 from testing (worldwide) are in the atmosphere, small portions of which are continually being incorporated into our food supply."

Makhijani added, "Military documents cited in our book establish that Nevada was chosen in spite of knowledge that nuclear testing in the West would spread fallout over most of the rest of the country.

"For precisely this reason, the U.S. considered an alternative site in North Carolina to be safer. Ultimately, however, the federal government selected Nevada because it already controlled the land (which has long been claimed by the Shoshone people) and because it was logistically more convenient than the North Carolina site."

Makhijani added, "Perhaps, not surprisingly, some of these same reasons have dominated Nevada's selection as the only state to be considereed as a host for a nuclear waste repository for high-level wastes."

Makhijani said that environmental problems were not solved by moving nuclear tests underground.

"The problems were only shifted out of sight, and the main risk transferred to future generations. Underground testing is leaving behind large quantities of long-lived radioactive materials at test sites around the world."

Makhijani added, "In essence, this testing has created and is continuing to create unstudied, uncharacterized and unlicensed dumps for high-level radioactive wastes. Today, after nearly 30 years of underground testing, there still has been no serious, detailed assessment or study of its environmental impact."

He said the Nevada Test Site, for example, has large residues of plutonium-239, a radioactive toxin with a half-life of 24,400 years.

"The total amount of this deadly material at the Nevada Test Site approximates 110,000 curies - about four times the combined total quantity of plutonium in all 51 high-level waste tanks from three decades of plutonium production at the U.S. government's Savannah River nuclear weapons plant.

"In addition, almost 3 million curies of strontium-90 and over 4 million curies of cesium-137 . . . remain as the radioactive legacy of underground testing. The Soviet test sites collectively contain comparable quantities of materials."

Katherine Yih, of the commission, called for all underground testing to be halted to allow "the long-term environmental effects of weapons testing underground to be studied, understood and democratically debated."

Makhijani said that especially makes sense because U.S. policy requires expensive studies to determine whether Yucca Mountain - near the Nevada Test Site - is a suitable disposal site for high-level wastes and spent fuel from nuclear power.

He said waste there would be put in special containers surrounded by multiple barriers to prevent the migration of radioactivity.

"In the meantime, this same type of radioactivity is being routinely and explosively injected into the underground environment at the test site just a few miles away. Clearly, this makes no sense," he said.

Other key findings of the new book include:

- Fallout due to Soviet atmospheric testing at the Kazakhstan test site cause very high radiation levels downwind, seriously increasing the risk of fatal cancer for many people. Between 1,000 and 40,000 people may have received doses as high as 160 rems, while the current standard for U.S. civilians is 0.1 rem per year.

- Testing by all nuclear weapons powers appears to have disproportionately affected rural, minority and tribal peoples and those under colonial rule, as test sites have been located nearest such populations.

- The French government failed to evacuate Polynesian natives after one presumably high-fallout incident, although it evacuated French workers.

Makhijani concluded, "Secrecy and the cover of national security provided the conditions in which officials in all nuclear weapons states have shown a readiness to harm people if that was necessary or even merely convenient to testing.

"That dangerous legacy is being perpetuated by the continuation of underground testing without any systematic examination of its implications for the safety of generations far into the future."