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Ten years after the twin towers collapsed, firefighters, construction workers, and people who lived in lower Manhattan continue to face a number of health problems, due largely to exposure to airborne particles released following the attacks on September 11, 2001.
The disaster became an unprecedented public health emergency and several state and local agencies have been keeping tabs on tens of thousands of people in Lower Manhattan who were exposed to the dust cloud.
When the towers collapsed, they released a dust cloud made of 1.2 million pounds of concrete, gypsum, molten electronics, and asbestos particles, as well as burning jet fuel, and other materials, said William Rom, a pulmonologist at New York University Langone Medical Center and Bellevue Hospital, who has studied some of the health problems of the victims. For months after the attacks, the site smoldered, releasing a hot stew of toxic volatile chemicals and carcinogens. The dust cloud reached all of Lower Manhattan and even into Brooklyn.
As a result, hundreds of thousands of people—firefighters, rescue workers, construction workers, and residents—inhaled a huge amount of chemical-laced dust, said olfactory scientist Pamela Dalton of the Monell Chemical Senses Center, who has studied the nasal function of exposed individuals. “The exposure itself was unprecedented.”
Several different studies have noted increased rates of asthma, sinusitis, and acid reflux disease in exposed firefighters, rescue and recovery workers, and people living near Ground Zero. Rom and his colleagues analyzed the symptoms of 362 firefighters, most of whom were exposed to the site. By October 5, 2001, 80 percent of those present on the morning of the attack reported coughing, shortness of breath, chest pain, and wheezing. In the first year, lower airway lung function dropped significantly for the group, though it eventually stabilized at a lower level, he said.
The inhaled particles could have set off inflammation in the respiratory system, which likely played a large part in the symptoms people experienced, said Mayris Webber, the supervising epidemiologist for the World Trade Center Medical Monitoring and Treatment Program. “Many disorders occurring after 9/11—including asthma, bronchitis, sinusitis, and acid reflux—have been associated with chronic inflammation.”
More immediate respiratory problems stemmed from the dust cloud’s polychlorinated biphenyls, highly irritating organic compounds used in 1970’s electronics. Furthermore, because the pH of the material was so alkaline, similar to lye, the dust caused immediate shortness of breath and coughing as they got lodged in the small branches of the lungs, Rom said.
When Rom’s group looked at biopsies of the tissue, small particles can still be found deep in the lungs years later.
Mental Health Problems
Many people in NYC that fateful day were also burdened by post-traumatic stress disorder and depression. Several years later, 19 percent of the more than 70,000 people who entered the World Trade Center Registry had some symptoms of post-traumatic stress disorder, including flashbacks and trouble sleeping, compared to less than 4 percent of the overall population, said Sharon Perlman, an epidemiologist with the NYC Department of Mental Health and Hygiene who has studied the exposed populations.
Those who worked in rescue and recovery during the earliest and most intense parts of the tragedy were likelier to experience PTSD, as well as women, Hispanics, residents of the immediate area, and those who had lower levels of support from family and friends, said James Cone, a doctor and epidemiologist with the NYC Department of Mental Health and Hygiene who also studied these populations.
Many rescue and recovery workers also faced depression, anxiety, and substance abuse, Perlman added. And those with a mental health problem are also likelier to also have symptoms such as asthma or gastrointestinal reflux disease.
The dust cloud also wiped out the sense of smell for many workers. When Dalton and her colleagues exposed 102 WTC workers to a rose-water like scent, “some people could smell nothing,” she said, and virtually everyone had reduced sensitivity compared to similar workers who had never been exposed.
Even more troubling, 75 percent of the people couldn’t detect an irritant, something that normally caused burning and stinging in the nose. The culprit in this case, as in the lower airways, is likely the inflammation caused by particulates, which damages the cells that contain smell receptors.
Noses also contain metabolic enzymes that convert toxic chemicals into less dangerous byproducts, but chronic inflammation can wipe out that function. So worker with impaired noses may not only be less able to detect poisonous chemicals, they may also be more vulnerable to them, Dalton said.
Losing the sense of smell also subtly affects people’s experience of life, she added. “We don’t really think our sense of smell as adding that much to our lives. But when people do lose it, it’s like everything has become sort of pastel instead of highly saturated.”
One of the biggest lessons from the disaster is that consistent use of face masks can help reduce the health toll. Those who consistently and early wore disposable paper filters (like those used in hospitals), known as respirators, fared better than those who went without, Perlman said.
In the coming years, the health toll may only grow. Instead of seeing symptoms dissipate, “we’re seeing cumulative incidence rates continue to creep up over time,” said Matthew Mauer, a physician with the New York State Department of Health who is monitoring health in exposed state employees.
A study in the September 3 issue of The Lancet found a 19 percent uptick in cancer incidence 7 years after 9/11 among 9,853 firefighters who were exposed to the site. While it’s not clear that the cancer increase is directly caused by some exposure at Ground Zero, the link is plausible, said Webber, who was involved in the study. “Inflammation could lead to cancer because of the activities of leucocytes, including the production of proteins (cytokines and chemokines) that alter the behavior of target cells, stimulation of blood vessel growth (angiogenesis), and tissue remodeling.”
And that may just be the tip of the iceberg. Because cancer usually takes decades to develop, it’s possible that cancer rates are going to be even higher, Mauer said.
In addition, some of the respiratory problems could eventually worsen, with greater numbers of workers experiencing chronic obstructive pulmonary disease, a disease that often plagues longtime smokers, Mauer said. And as exposed populations get older, monitoring programs may start to see a higher mortality rate in the rescue workers, he added.
“We don’t know for sure what the long term implication is,” Mauer said. “That’s the million dollar question.”