The data, drawn from the World Trade Center Health Registry, show that 3.6 percent of the 25,000 rescue and recovery workers enrolled in the registry report – a diverse group of firefighters police officers, medical workers, construction workers and volunteers – developed asthma after working at the site.
Rescue workers and responders from across the nation swarmed to the World Trade Center after the towers collapsed. Those who arrived at the disaster site on the day of the attacks – when the dust cloud was at its thickest – and stayed more than 90 days, reported the highest rate of new asthma cases: 7 percent.
Respirator Use Helped
Workers who wore respirators on Sept. 11 and Sept. 12 reported lower rates of newly diagnosed asthma (4 percent and 2.9 percent, respectively) than those who did not wear respirators ( 6.3 percent and 4.5 percent). Workers who went months without respiratory protection reported two to three times more asthma incidence than those who wore respirators from the outset. Though respirators proved to be protective, all worker groups, including those who reported wearing masks, had elevated levels of asthma.
In addition, the area where the workers were standing also affected their level of risk. Those who were caught in the dust cloud or worked on the debris pile reported asthma at higher rates (4.9 percent and 4.5 percent, respectively), presumably because they inhaled more dust.
“The dust from the World Trade Center collapse appears to have had significant respiratory health effects, at least for people who worked at the site,” said Dr. Thomas R. Frieden, New York City health commissioner. “These findings reflect the critical importance of getting appropriate respiratory protection to all workers as quickly as possible during a disaster, and making every effort to make sure workers wear them at all times.”
Study Has Limitations
The study's authors emphasized that one of the survey's drawbacks is that the registry is self-selecting, so it may have attracted more people who developed asthma than those who did not, and it may include people who said they developed asthma after 9/11 because they were not sure if they had it before.
This latest study, published in the journal Environmental Health Perspectives, supports a 2006 study, which determined that New York City firemen and emergency personnel exposed to dust from the collapse of the World Trade Center buildings experienced a decrease in lung function capability equal to 12 years of age-related decline. For more on this topic, read "Study: WTC Dust Cuts Lung Function Capability by 12 Years."
Later this month, the health department is scheduled to release a report on the mental health effects of Ground Zero based on the registry data.