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.

The plaintiffs, who all worked at ground zero in one form or another, died of diseases now familiar to the thousands who are sick: sarcoidosis, mesothelioma, and pulmonary disease. They include Reeve, who spent four months working at the site and at the city morgue; and a nun, Sister Cynthia Mahoney, 54, who served as a chaplain for six months at the site, often blessing the remains of the dead pulled from the rubble.

Many experts studying post-Sept. 11 illness say research hasn't proven yet that all the deaths are connected — particularly cancer, a leading cause of death in the nation, could be falsely linked to trade center exposure, they say.

Doctors at Mount Sinai Medical Center, which has screened 19,000 of the believed 40,000 ground zero workers, say they still need to rule out cases of people whose exposure simply triggered an illness they were already predisposed to contract.

Last fall, the National Institute for Occupational Safety and Health scrapped autopsy guidelines for the nation's medical examiners weeks after drafting them. The institute made the decision after experts said the guidelines could lead to misinterpretation and false links to ground zero deaths.

U.S. Sen. Hillary Clinton and other lawmakers joined ailing recovery workers at ground zero on Monday to demand more federal funding to treat those workers with chronic breathing problems.

"We have been given a slow, slow death sentence, and that's simply not right," said Marvin Bethea, a paramedic who said he has suffered everything from asthma to post-traumatic stress disorder after his work at ground zero.

David Reeve says it may take decades to prove what should be obvious right now. His wife's primary doctor, Reynaldo Alonso, wrote a letter nine months before his wife died stating that Reeve's only exposure to asbestos and other carcinogens came from her work at the trade center site.

"Why do you have such a disproportionate number of people developing cancer at an earlier age?" he asked. "The only thing these people have in common is that they were in southern Manhattan on Sept. 11, 2001. Now argue that."