Three years after the September 11 terrorist attacks on the Twin Towers, breathing problems plague nearly half of the rescue workers analyzed in a screening program, according to a report released by the Centers for Disease Control and Prevention.

Dr. Stephen Levin, lead investigator at Mount Sinai Hospital in Manhattan, found rescuers and Ground Zero cleanup workers are battling persistent sinusitis, asthma and a nagging cough, reports Newsday.

"From the beginning of the program in July of 2002," Levin told the newspaper, referring to the inception of the screening program he has overseen, "we have found high rates of upper respiratory problems, sinusitis laryngitis and higher rates of lower respiratory problems — asthma, bronchitis, chest tightness, coughing and wheezing."

The cough is so unique it was dubbed "World Trade Center Cough."

"We don't have an easy answer for the persistence" of the cough, said Levin, co-director of the World Trade Center Worker and Volunteer Medical Screening Program at Mount Sinai.

He attributed upper and lower respiratory problems to inhalation of pulverized concrete that burned and permanently scarred nasal, bronchial and lung tissue. Other destructive compounds included pulverized glass, acids and dust.

"Many of our patients tell us that since their World Trade Center experience, whenever they are exposed to vehicle exhaust, cigarette smoke or even cold air, they experience airway irritation," Levin said.

A separate report by the Government Accountability Office also found health issues. GAO investigators noted that 300 firefighters developed World Trade Center Cough. Most striking, the GAO found that the full impact of the health consequences remains unknown.