UN staff worry about asbestos exposure, security

* Concerns voiced over renovation of UN headquarters

* 60-year-old NY skyscraper getting $2 billion overhaul

By Louis Charbonneau

UNITED NATIONS, April 16 (Reuters) - Many people at U.N. headquarters worry about security risks and exposure to toxic asbestos during the upcoming renovation of the 60-year-old New York skyscraper, its staff union chief said on Thursday.

The $2 billion renovation project is intended to make the blue-green tinted 40-story building along Manhattan's East River safer, more comfortable and greener.

During the renovation, which is already underway and is expected to take several years, U.N. employees, contractors and accredited media representatives will be moved to temporary office spaces inside or near the U.N. complex.

Stephen Kisambira, president of the United Nations staff union, held a rare news conference at U.N. headquarters to voice staff concerns about the so-called Capital Master Plan.

"Asbestos abatement is a serious issue," he told reporters. "The risk is there ... They are saying that nothing can go wrong. How can they be sure?"

Removal of the cancer-causing flame-retardant asbestos lining the ceiling tiles of the U.N. building is one of the most sensitive aspects of the renovation.