WEDNESDAY, May 30 (HealthDay News) -- It was a disaster that defied all imagination.
And now, more than five years after two jetliners plunged into New York City's twin towers on Sept. 11, 2001, there is much experts don't know and may never know about the health consequences of that unforgettable day.
"The real issue is the uncertainty of what we don't know," said Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York City. "And when you look at what we do know, the question arises as to whether we're looking at tip of the iceberg or the iceberg itself."
The disaster has been associated with a prolonged hacking known as "World Trade Center Cough" and with sarcoidosis, a disease that causes inflammation and scarring in the lungs.
Just this week, the New York City Chief Medical Examiner added the name of Felicia Dunn-Jones to the list of attack victims. Dunn-Jones, a 42-year-old attorney at the time of the attacks, died of sarcoidosis five months after the attacks. This marked the first time the city had officially linked a 9/11 death to the toxic plume.
According to a perspective piece in the May 31 issue of the New England Journal of Medicine, some responders have already received compensation and litigation is ongoing for thousands of people who allegedly fell ill after inhaling World Trade Center dust.
The article, by researchers at Johns Hopkins School of Public Health in Baltimore, outlined what is known and unknown about the medical fall-out of 9/11.
"We know that people were exposed to a very large, high-concentration cloud of dust which would be particles and gases in the air, especially on Day One right after the disaster," said Alison Geyh, co-author of the paper and an assistant professor of environmental health sciences at Johns Hopkins Bloomberg School of Public Health.
Scientists even have some insight into the composition of that dust, although this comes from an analyses of samples collected on the ground, which may or may not be the same as what was hovering in the air. Air was not sampled immediately after the disaster, for obvious reasons.
Generally, the range of contaminants in those samples was not surprising and included combustion-related carcinogens, building materials and some asbestos, a known carcinogen.
Samples collected the month after the disaster found high concentrations of particulate matter less than 2.5 micrometers in aerodynamic diameter. Size is a key component of risk, with smaller particles more able to penetrate the lungs. Samples that were taken from the sputum of firefighters who responded to the emergency showed gold, tin and titanium.
"It's the particles smaller than 2.5 micrometers that are inhaled and really get deep into the lungs," Horovitz explained. "When that happens, there are a bunch of consequences."
But there's more that experts just don't know.
"The big, big, big question is how concentrated was that mixture in the air on the day the buildings fell down," Geyh said. "It would be really helpful to us to know what the concentrations were that day but nothing was working, obviously, that day so we'll never know that. We will never exactly know what airborne concentrations were directly on the site across the entire time period people were there."
Researchers will also never know how many people were exposed. "We're never going to know how many people were exposed and that makes it difficult to quantify the extent of the potential health problems," Geyh said.
Nevertheless, the people who definitely were exposed need to be followed for the next decade or even two decades, Geyh said. "We need to follow them into the future to document what happens to their health," she said. "We're not saying that there is a problem or isn't a problem. We just need to make sure we know what is happening with these people and if we understand what is happening with this well-defined group, it will make it easier for other people who feel like they're having problems related to exposure."
Visit the World Trade Center Health Registry for more on the health consequences of 9/11.
SOURCES: Alison Geyh, Ph.D., assistant professor, environmental health sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore; Len Horovitz, M.D., pulmonary specialist, Lenox Hill Hospital, New York City; May 31, 2007, New England Journal of Medicine