Rescue workers and firefighters in New York City contracted a serious lung-scarring disease called sarcoidosis at a much higher rate after the Sept. 11 attacks than before, said a study that is the first to link the disease to exposure to toxic dust at Ground Zero.

The study, published by nine doctors including the medical officer monitoring city firefighters, Dr. David Prezant, found that firefighters and rescue workers contracted sarcoidosis in the year after Sept. 11, 2001, at a rate more than five times higher than the years before the attacks.

Unlike previous studies that have linked exposure to the toxic dust cloud that enveloped lower Manhattan after the World Trade Center's collapse to many different respiratory illnesses, this study zeroes in on one disease.

Sarcoidosis, which can be life-threatening, causes an inflammation in the lungs that deposits tiny cells in the organs, leaving scar tissues that damage them. Several rescue workers and others exposed to WTC dust have claimed they contracted the disease from their work at Ground Zero.

The study compared the rates of sarcoidosis among fire department employees for 15 years before Sept. 11 and for five years since. It said firefighters who showed symptoms of the disease on chest X-rays underwent more intensive exams.

After the WTC attack, 26 firefighters were diagnosed with sarcoidosis, the study found. Thirteen were diagnosed in the first year after the attacks, which represents a rate of 86 per 100,000. In the 15 years before the attack, the rate of sarcoidosis was 15 per 100,0000, the study found.

None of the 26 rescue workers, who are in their 30s and 40s, has died of the disease, and about 10 have improved or recovered since their diagnoses, the study found. Two of the firefighters were former smokers, the study found.

The study was published this week in the May issue of CHEST, a journal published by the American College of Chest Physicians.