Decades after residents of this remote coral atoll left to make way for U.S. atomic bomb tests, work has begun to clean up lingering radiation and bring the "nuclear nomads" of Bikini home to stay.

Some 50 Bikini leaders and a delegation of U.S. officials gathered on the windswept island of Eneu last week to mark the start of the cleanup and resettlement project.Eneu is now the only inhabited island of the approximately two dozen islands that comprise the Bikini atoll. It is on the southeast tip of the island ring, about five miles south of the island of Bikini.

Officials say it could take seven years of work before the Bikinians can safely repopulate Bikini island, and estimates of the cleanup cost range from $130 million to $200 million.

Tomaki Juda, mayor of the Marshall Islands' Kili Island, where many Bikinians now live, said Thursday's groundbreaking "isn't a day of great happiness."

"A day of great happiness for the Bikinian people will be coming back to an island that is free of radiation and which we can stay on without being afraid," Juda said through an interpreter.

"The ceremony this afternoon marks the beginning of a great effort, but we cannot celebrate until the radioactivity has been removed from the coral soil of our home island," said Henchi Balos, a senator representing the Bikinians and acting president of the Marshall Islands.

Juda and Balos were among 146 people who left Bikini in 1946, when U.S. officials told them the western Pacific atoll was needed for testing the atom bomb. The Americans promised to return the islanders to Bikini when tests were completed.

Between 1946 and 1958 the United States detonated 23 nuclear bombs at Bikini, an atoll of islands surrounding a lagoon 24 miles long and 11 miles wide.

The American promise was something the Bikinians wanted the delegation including Rep. Barbara Vucanovich, R-Nev., and congressional staff members to remember.

"There are only a few elders left who know our traditional customs, and it will not be long until they are gone also," Juda said. "We hope it will not be long before we can restore our traditions."

Vucanovich, a member of the House Subcommittee on Energy and Environment, told the Bikinians the time had come for the United States to fulfill its promise to return them home.

A small group of Bikinians returned in the early 1970s when radiation levels were thought safe. But tests in 1978 found they were ingesting dangerous amounts of radioactive materials drawn up from the soil by food plants, and they were evacuated.