Lung function still impaired by dust from World Trade Center

Many rescue workers who responded to the 2001 attack on the World Trade Center in New York continue to show breathing difficulties that haven’t improved in the years since the dust cleared, researchers report in the April 8 New England Journal of Medicine.

The effects go beyond what was first dubbed “World Trade Center cough,” although that symptom has lingered in some emergency workers, says study coauthor Thomas Aldrich, a pulmonologist at Montefiore Medical Center and Albert Einstein College of Medicine of Yeshiva University in New York City. Inhalation of the thick dust has caused bronchitis, asthma and symptoms of chronic obstructive pulmonary disease such as being short of breath, he says. Passersby have also shown increased asthma rates (SN: 8/29/09, p. 11).

To test lung function in rescue workers, Aldrich and his colleagues analyzed test results of 10,870 firefighters and 1,911 emergency medical service workers that had been recorded in 2000 or 2001 before the attack, and at least three follow-up breathing tests recorded between 2002 and 2008. The sample included 92 percent of all rescue workers who arrived at ground zero between September 11 and September 24.

Doctors assessed lung function by having each participant blow into a tube connected to a machine that measures the volume and speed of expelled air. About 5 percent of the general population would be expected to fall below the normal range for their age group and gender in such a test, Aldrich says. For nonsmoking firefighters, 3 percent fell below the cutoff before exposure to the dust at ground zero, but that rose to 18 percent in 2002 and has since stabilized at 13 percent of firefighters.

Among EMS nonsmokers, 12 percent fell below the normal range before the attack and 22 percent did in 2002, a percentage that has remained constant among this group. 

Former or current smokers among the rescue workers showed predictably poorer lung function.

Firefighters who arrived on the morning of 9/11 when the dust was densest were most likely to have diminished lung capacity. In all the measurements, scientists accounted for a natural decline in lung capacity due to aging in the years between 2000 and 2008.

Since there have been few biopsies of lung tissue in these workers, the precise nature of the lung disease is unclear. But inflammation probably plays a role, Aldrich says.

The plume at the scene “was a complex mixture of dust, cement and glass fibers,” says environmental scientist Paul Lioy of the Robert Wood Johnson Medical School in Piscataway, N.J., who was among the first scientists to take samples there.

And because it was a sudden, catastrophic event, he says, some protective supplies weren’t readily available. “In the first 24 hours, there weren’t many respirators there,” Lioy says. A 2004 study found that 19 percent of firefighters reported not using a respirator during the first two weeks at the site, whereas 50 percent reported using a respirator but only rarely.

In any case, Lioy says, rescue workers weren’t worried about breathing dust after they realized that no poisonous gas had been unleashed. “These people went in to save lives; they weren’t thinking about the dust,” he says.