A silent killer that stalked Nikita Khrushchev, Yasser Arafat, Fidel Castro and other world leaders as they gave historic speeches has been exhumed from the UN headquarters. Enough asbestos to cover a football field more than five metres deep with lethal blue dust has been extracted from the building during a US$2-billion-plus renovation aiming to turn it into a clean, green Manhattan landmark, according to the chief architect. World leaders who gather at the annual UN debate next week will see a gleaming modernist skyscraper, far from the gutted building they visited last year. The East River tower, designed by an international team including Brazil's Oscar Niemeyer and French-Swiss legend Le Corbusier, is marking its 60th anniversary. A white plastic sheet covers the leaking General Assembly dome, which will be the next stage of the project. The headquarters was built at a time when asbestos was ubiquitous, said Michael Adlerstein, the preservation architect leading the diplomatic and technical exploit. "It was put on like mayonnaise. It was put on every pipe, every wall," he said. Had Khrushchev banged his shoe a bit harder during his angry 1960 speech to the General Assembly, had Palestinian icon Arafat fired the gun he held in his landmark 1974 address, the asbestos might have loosened. But Adlerstein, who has also worked on the renovation of the nearby Statue of Liberty and of the Taj Mahal in India, stressed that the dust has been taken out in an "absolutely safe" operation that passed thousands of air quality tests. The dust notorious for causing mesothelioma cancer is just one of many challenges tackled. There was also the task of getting debris out and hundreds of construction workers in each day, all while presidents and ministers carried on daily meetings. "The Statue of Liberty and Ellis Island are wonderful monuments, but unlike the UN you could close them, you could do the work," said Adlerstein. The Security Council moved to a temporary home in the basement. UN Secretary General Ban Ki-moon was exiled to a prefabricated office. Now some 3,300 UN staff are moving back into the 39-floor skyscraper floor by floor. By next week, some 1,100 will be in place. Ban should be back in his 38th floor office in November. The Security Council will return to its historic chamber in February. Norway, which decorated the 1952 Security Council chamber, is again providing fabric and wood for the refurbishment of the horseshoe-shaped venue where wars have been started and averted. The table and UN and national flags will go back in their same places. "It will have new electronics, there will be video-conferencing and other hi-tech opportunities, but basically it will be the same room," said the architect. Russia is renewing the council consultations room that it paid for in 1952 and where decades of secret talks have since been held. China, Turkey, the Netherlands, Denmark and more than a dozen other countries are decorating lounges, hallways and other rooms in the building.