Nearly 4,000 New York City firefighters are being treated with steroid inhalants, and at least one is suffering from allergic alveolitis, a rare inflammation of the lung surface. Even people who spent only a few hours in the dust storm have suffered.

No one is yet speculating on the long-term prognosis. But in a random sample of 100 sick firefighters, 25 percent were found to have airway hyperreactivity, a strong indication they may develop asthma as a result of their exposure. “This is a major problem that no one is talking about,” says the fire department’s chief pulmonary physician. “We don’t know if [these conditions] will be permanent.”