Nearly five years ago, thousands of people rushed in to the site of the terrorist attack against the World Trade Center in New York City. As thousands of survivors and locals fled the burning and collapsing towers, a heroic effort was already under way to, first, save as many people as possible, then scour the ruins for survivors and bodies, and finally clean up the horrific mess.

Throughout most of this, the ruins smoldered, creating a long-term impact of this attack that few predicted at the time.

On September 14, 2001, I arrived in New York and breathed in lungfuls of the acrid stew of chemicals and ash. It made my nose tingle, and when I walked downtown to the disaster site, my eyes burned slightly, and I wished I had something to put over my mouth.

I was in Lower Manhattan for only a couple of days. Many workers labored there for weeks and months. Many of them have since come down with respiratory problems and other ailments possibly associated with a project that emphasized quick response and cleanup more than it did safety.

Now a Perspective column in the New England Journal of Medicine (NEJM) sums up some of the findings of the past five years about the dust and its aftermath. It cites studies that have measured the content of the air in the days and weeks following the attack, as well as studies that assess the health impact.

The composition of the air was mostly “coarse particles and pulverized glass fibers, asbestos, lead, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated furans and dioxins,” a toxic stew reported in great detail in a 2004 study in Environmental Health Perspectives. The dust was highly alkaline–pH 9/11.

Some of the materials were known or suspected carcinogens; others were nanoparticles of toxins that lodged in blood and cells. Most damaging were particles large and small that damaged airways and lungs. For instance, in one study, a group of firemen have 10 times the level of reduced lung function than would normally occur with age. Thousands of New Yorkers, from schoolchildren to police officers, have a persistent hacking known as the “World Trade Center cough.”

According to the NEJM article, many questions linger about this long-term collateral damage inflicted by the terrorists.

Still, there are some things we will never know for certain;indeed, we do not even know with any certainty the size of theexposed population. Continued tracking of the responders shouldprovide a clearer picture of the natural history of World TradeCenter cough syndrome and should guide selection of the mosteffective therapies. The registry will be informative regardingbroad questions of health, but although it includes more than71,000 registrants, analyses of follow-up data will not revealthe existence of relatively infrequent consequences unless theadditional risks are very high. The long-term risks of cancerwill be difficult to measure with any precision, although quantitativerisk-assessment approaches should prove useful for estimatingthe maximum potential burden of cancer. But even the full suiteof research efforts in progress may never provide the evidenceneeded to answer all the questions that will be raised aboutthe long-term health effects of the events of September 11.

Curiously, no one seems to have run genetic tests to gauge the susceptibility of victims to cancer and other maladies when exposed to environmental toxins. This science, called toxicogenomics (see my May 7 blog), is in its infancy, but it may already provide some clues into who will have the worst long-term effects. Someday, testing for genes that make one more or less susceptible to environmental toxins might help in the selection of who responds to disasters that involve ash and chemicals raining down.

Of course, genetic screening for job suitability is both a positive and a negative, since the same testing process could also be used to discriminate. But in the case of disasters such as the World Trade Center and Katrina, this might be a good use of this new science.

Articles cited:

Samet, Jonathan M., et. al., “The Legacy of World Trade Center Dust”, New England Journal of Medicine, Volume 356:2233-2236, May 31, 2007, Number 22

Landrigan, PJ, et. al., “Health and environmental consequences of the world trade center disaster”, Environmental Health Perspectives, 2004 May;112(6):731-9