NEW YORKThe death toll associated with the World Trade Center disaster of September 11 may rise 20 or 30 years from now, according to experts who spoke at a media briefing on malignant pleural mesothelioma. Many thousands of people at or near the disaster site had some exposure to asbestos, a causative agent of mesothelioma, said Stephen M. Levin, MD, medical director, Mount Sinai-Irving J. Selikoff Center for Occupational and Environmental Medicine.
Well over 20,000 persons involved in the rescue and recovery effort, he estimated, were exposed. Others fleeing or visiting the area were more fleetingly exposed. "The risk for most is relatively low," Dr. Levin said, "but not zero."
In one study, rats exposed to asbestos for as little as 1 day developed malignant mesothelioma. With longer exposure, the incidence rose, said Arthur L. Frank, MD, PhD, professor of occupational and environmental medicine, University of Texas Health Center at Tyler.
Human data, he added, corroborates that the disease can be induced by short workplace exposures. "When it comes to the cancer-causing effect, there’s no threshold," Dr. Frank said. "There is a risk at any dose level, but the likelihood of developing disease will obviously go up as the dose goes up."
Almost all Americans have some asbestos in their lungs, but the chance of developing asbestos-related malignant mesothelioma is 1 in 1 million for the general population, Dr. Levin said. For those with heavy exposure, such as construction workers, the risk rises to 1 in 10. "We know that it takes less exposure to asbestos to cause an asbestos-related cancer than it takes to cause scarring lung disease," he pointed out.
Predicting who will develop malignant mesothelioma is difficult, Dr. Frank said, because a variety of factors, including genetics, are probably involved. The consequences are dire because the disease is rarely detected at an early stage and is difficult to treat. "It’s almost uniformly fatal," Dr. Levin said.
Asbestos in the Towers