NEW YORK -- Anyone who watched Rudolph Giuliani preside over ground zero in the days after the terrorist attacks of Sept. 11, 2001, glimpsed elements of his strength -- decisiveness, determination, self-confidence.

Those qualities were also on display over the months he directed the cleanup of the collapsed World Trade Center. But today, with evidence that thousands of people who worked at ground zero have become sick, many regard Giuliani's triumph of leadership as New York's mayor as having come with a human cost.

An examination of his handling of the extraordinary recovery operation during his last months in office shows that he seized control and largely limited the influence of experienced federal agencies. In doing that, according to some experts and many of those who worked in the trade center's ruins, Giuliani might have allowed his sense of purpose to trump caution in the rush to prove that his city was not crippled by the attack.

Administration documents and thousands of pages of legal testimony filed in a lawsuit against New York City, along with more than two dozen interviews with people involved in the events of the last four months of Giuliani's administration, show that while the city had a safety plan for workers, it never meaningfully enforced requirements that those at the site wear respirators, even long after the last survivor was rescued.