The federal screening program found that 52 percent of workers suffered from ear, nose and throat ailments, 46 percent showed pulmonary symptoms and 52 percent reported such mental health problems as post-traumatic stress disorder as a result of their work in and around the dusty, smoky rubble.
The findings are alarming, said Dr. Robin Herbert, co-director of Mount Sinai Medical Center's screening program for World Trade Center workers.
"Our preliminary findings clearly demonstrate the need for the immediate screening of the WTC responders, as well as the provision of medical follow-up," he said.
More than 3,500 workers of the estimated 30,000 who toiled at the ruins of the trade center have been examined under the program. The findings were based on a random sample of 250 people from the first 500 patients who were seen from July 16, 2002, to Aug. 29, 2002.
The $12 million program has offered free medical screening to anyone who worked at ground zero, including volunteers. It is scheduled to conclude in July.
Sen. Hillary Rodham Clinton, D-N.Y., said that the program can only afford to screen about 9,000 workers. She said she plans to ask President Bush for $90 million more.
"This is absolutely critical to finish the job," Clinton said.
The health screening includes pulmonary function tests, blood tests, chest X-rays, psychological questionnaires and general physical exams. If doctors detect problems, patients are referred for treatment not covered by federal funding.
"We're here like beggars, asking the federal government, 'Please come and help us,'" said Thomas Scotto, president of the Detectives' Endowment Association, a police union.
Since Sept. 11, there have been increasing concerns that the initial toll of the attack would be exacerbated by its environmental impact. Some worried that the collapse of the twin towers released asbestos and other chemicals into the air, and that the Environmental Protection Agency was lax in its response.
But in a December report, scientists said the thick layer of irritating dust that blanketed lower Manhattan after the Sept. 11 terrorist attacks probably will not cause alarming increases in cancer, emphysema and other serious long-term health problems.
The analysis found that most of the potentially toxic dust particles collected in the week after the attacks were too large to lodge deep in people's lungs. Only 1 percent of the dust samples was composed of finer particles, researchers said.
A new study will follow as many as 200,000 people exposed to ash and dust from the collapse to determine patterns of illness and recovery.
New York City and federal health officials are finishing the details of the $20 million project, which they say would be the largest such study ever conducted, The New York Times reported.
The registry, to be paid for by federal disaster relief money, will track the health of residents and employees in Lower Manhattan, rescue and recovery workers, people evacuated from their homes and passers-by.