Deborah Reeve got a cold, a cough and a fever that wouldn't go away. It was more than two years after she had left recovery efforts at ground zero.

A month later, the nonsmoker was diagnosed with mesothelioma, an asbestos-related cancer. By last spring, the 41-year-old mother of two was dead.

"My wife got killed on Sept. 11 and she didn't die until March 15, 2006," said her husband, David, a paramedic like his wife who also spent months breathing in toxic dust at the World Trade Center site after the 2001 attacks. "She got killed and didn't know it."

After five years, doctors have definitively established a link between work at ground zero and chronic respiratory illness; a study published last fall by the largest monitoring program for post-9/11 workers found nearly 70 percent were likely to have lifelong breathing problems.

But experts have been slower to officially link deaths to the exposure, saying it is easy to misinterpret some diseases, like cancer, as being connected to ground zero when other factors may be at play.

So far, two deaths have been firmly connected to exposure to the toxic cloud that enveloped lower Manhattan after the twin towers collapsed, killing almost 3,000 people. The family of Felicia Dunn-Jones, who died of sarcoidosis an inflammation of the lungs a year after escaping the twin towers was paid a $2.6 million death benefit by Kenneth Feinberg, who oversaw the compensation fund for Sept. 11 victims. And last April, a New Jersey medical examiner concluded that the January 2006 death of retired police Detective James Zadroga was "directly related" to his work at ground zero.

Feinberg, who issued more than 2,000 payments to people sickened after the attacks, said he rejected many claims of cancer.

"We were not satisfied that based on the medical documentation submitted, that the cancers would have represented itself so soon after 9/11," he said.

But an unofficial, anecdotal death toll of post-Sept. 11 workers is rising rapidly. In 2006, the number of deaths tracked by a lawyer suing the city and contractors overseeing the cleanup of ground zero more than quadrupled to 90 people, up from about 20, said attorney David Worby.