You would think someone would have evidence like this. But after five and a half years of testing at ground zero, scientists still could not be absolutely certain about what was in the dust cloud that smoked out lower Manhattan on 9/11. Without an original sample from the initial plume, researchers and government agencies could offer only a calculated estimate. Now, with Esquire's discovery of a shirt and messenger bag coated with dust from the plume, we have an answer.
"That shirt was a godsend," says Thomas Cahill, a physics professor at UC Davis who has been studying the air at ground zero since the weeks immediately following the attack. "This is a preserved sample from five years ago that was light and fluffy and had not gotten humid or moist. It's as close as we're ever going to get to the stuff that was in the air for a person who was running in the street."
Cahill found that the dust preserved on the shirt and bag was significantly less toxic than samples he had previously tested, which were collected in the weeks following 9/11. Both sets of samples contained large amounts of gypsum and cement. (Gypsum is an innocuous mineral that dissolves in lung fluid and is often used as a food additive because of its high calcium content.) After testing both the particle size and properties of the Esquire dust using a Slotted 8 DRUM Impactor and UC Berkeley's synchrotron, Cahill concluded that in addition to the gypsum from drywall in the collapsed buildings, about one third of the sample consisted of alumino-silicates, natural minerals found in the earth's crust, and finely ground cement, which, while caustic--and the cause for the so-called World Trade Center cough--usually doesn't cause long-term health problems. In one significant way, however, the Esquire sample was different from samples recovered in September and October 2001: It contained ten to twenty times fewer toxic metals than the settled dust samples collected in the days following September 11 (Cahill hypothesizes that these toxic particles were not ground finely enough to float freely, like the gypsum and cement), and no ultrafine glass, metals, or sulfuric acid, which were found in abundance in the dust from the smoldering pile. (See "The Bag: A Breakdown")
Cahill believes the new sample is unique because it offers the first and, so far, only picture of the finest dust particles in the air at the time of the towers' collapse. Dust that size--about one one-hundredth the diameter of pollen--is the most likely to get lodged in the lungs and cause long-term health problems. It's also the hardest dust to catch and properly analyze. Unless those particles are captured while airborne--as they were by the bag worn by Eric Gillin, now editor of Esquire.com--they tend to fly away or get scattered on the ground.
While Cahill's initial findings sound like good news for the thousands of people caught in the overpowering dust cloud on that morning, they are not without caveats. First, the Esquire sample illustrates a single spot in the initial plume and does not necessarily reflect dust that later settled. Also, there's a big difference between the aerosolized dust created from the initial collapse of the towers and the aerosolized dust that rose from the smoldering pit in the hours, days, and weeks that followed while rescue and cleanup crews worked over the rubble. Filled with millions of pounds of burning computer parts, electrical cords, plastics, and gas, that dust contained high levels of noxious gas and particles that could, some say, cause long-term health problems, including cancer. "Stuff in the smolder pile was awful," says Cahill. "Brutal. It hits four of the five EPA factors for death from aerosols," the scale by which the government rates toxicity.
And even though materials taken from the Esquire sample don't appear to contain high levels of toxins, there's still room for caution, according to Paul Lioy, deputy director of the Environmental & Occupational Health Sciences Institute, whose analysis of 9/11 dust has been widely cited. Besides the caustic cement dust, Lioy theorizes the initial plume was likely laced with toxic gas from the more than twenty thousand gallons of jet fuel that were burning in the towers when they came down. "In the initial collapse, there's a lot of gas because of the fire," says Lioy. "The building is on fire. So the initial collapse, although presenting itself as mostly dust, would still have the dust and the gas. And those two things could have been synergistic. Nobody could protect themselves. You would have the dust on your body, but then you'd still be breathing the gas as you were walking around." Cahill, for his part, believes the jet fuel would have already burned away, but because the gases leave virtually no chemical fingerprint, we may never know how much was present in the plume and how toxic it was.
In addition, there are other, rarer long-term illnesses that could still affect those who were caught in the initial plume. While Cahill believes the very minimal traces of heavy metals and asbestos in the sample make the chance of developing WTC-dust-related cancer very small, nobody can ever know for sure.
In February 2002, five months after the attack, Felicia Dunn-Jones of Staten Island died of sarcoidosis, a rare dust-induced disease. Unlike most of the first responders who have contracted sarcoidosis and other dust-related diseases since that day, Dunn-Jones, a civil-rights lawyer who ran through the cloud as Gillin did, was exposed to the plume only immediately after the collapse. But it appears to have been long enough to take her life.
According to Dr. Alan M. Fein, a pulmonologist and expert on WTC-related diseases who testified at a hearing on Dunn-Jones's death conducted by the September 11 Victim Compensation Fund in 2004, her illness was likely triggered by a variety of factors--which would seem to suggest that anyone who was caught in the plume and made it this far should feel some relief. "My opinion is that it was the coming together of someone who had a genetic disposition--unable to handle some toxic material--with a sudden burst of this very high concentration of toxic material," Fein says.
When Dunn-Jones's family was granted $2.6 million from the compensation fund, she became the first civilian casualty of 9/11 dust. Yet five years after the collapse, her death appears to be the rare worst-case scenario. Cahill, who plans to publish a full report of his findings in a scientific journal later this year, says it shouldn't detract from the evidence, capped now by his new finding, that the most serious health threat posed by the initial plume was irritation and discomfort.
"Most of what we see are people who cough and spit," says Fein, referring to his patients who were caught in the dust cloud. "They have sinus problems. It's not life threatening. It's really more of a life-annoying process. My opinion is that the worst is over, but it would be due diligence to follow these people. You don't know what you don't know."