Researchers, among them Gisela Banauch, M.D., of Montefiore Medical Center in the Bronx, compared lung-function data compiled by the New York City Fire Department for 12,079 of its firefighters and emergency personnel for the 4 years before the attacks and 1 year after. All of those included in the study were directly exposed to toxins surrounding Ground Zero after the towers collapsed arriving either before the collapse or in the days immediately following.
The authors said more than 14 percent (1,660) of the rescue workers experienced early high-intensity exposure to the dust by arriving the morning of 9/11 and by being present during the collapse of the North and South Towers. Nearly 68 percent (8,185) had intermediate intensity exposure by arriving 2 days following the collapse. Nearly 16 percent (1.921) had low intensity exposure by arriving at the site on or after the third day.
"The percentage of FDNY rescue workers with lung function test measurements below the lower limit of normal increased by at least twofold within each exposure group from before to after 9/11," noted Banauch.
The investigators explained that rescue workers who had exposure to early and intermediate arrival-based periods had significantly more frequent and more severe respiratory symptoms than did the group that arrived later. In addition, researchers noted that exposure to pollutants at the World Trade Center have been implicated in problems such as World Trade Center cough and upper and lower airway inflammation with airway obstruction and bronchial hyperactivity.
According to Banauch, the initial lack of adequate respiratory protective equipment decreased any protective impact it would have been able to provide.
"In contrast to the pronounced influence of arrival time and work assignment on lung function, respiratory protective equipment had no appreciable effect on spirometric reduction after 9/11, she said.
"Important Occupational Lessons Learned"
John R. Balmes, M.D., of the University of California, San Francisco Lung Biology Center, noted in an editorial he wrote on the research that among the lessons learned is the need for medical surveillance for workers in jobs with high risk for exposure of toxins.
"While the tragedy of the World Trade Center collapse still sears the consciousness of those who value human life, some important lessons in occupational and environmental respiratory disease have been learned as a result of this disaster," he wrote.
According to Balmes, many responders have developed the World Trade Center cough, and their exposure to WTC dust appears to have caused accelerated decline in lung function, which could eventually lead to the development of chronic obstructive pulmonary disease.
Balmes also noted in the article that early and well-trained use of respiratory protective equipment could have prevented the workers from falling sick in the first place.
"Let us be better prepared for future disasters in many ways, including institution of plans to protect emergency responders from unnecessary occupational exposure to irritant dusts,' he wrote.