6 Years Later, 9/11 Health Questi...(at the findings from the Selikoff center...),Health

The center's supporters -- including Stellman -- shot back that the Mount Sinai team's efforts were stymied early on by a lack of federal funding and the government's emphasis that worker health screening, not research, be the focus of their efforts at the site.

So, questions on the long-term health effects of those weeks of grueling work at Ground Zero remain unresolved and may never be resolved due to a paucity of data, the experts said.

"What we don't know certainly weighs much more heavily than what we do know," according to Horovitz.

One thing scientists do understand, he said, is that particles under 2.5 micrometers can lodge in the lungs' tiniest channels for years, potentially causing lung disease, atherosclerosis ("hardening of the arteries"), and even cancers.

Many of these illnesses may not show up for decades. "It is definitely far too early to know what's coming down the road for cancer, for example," Stellman said.

She believes it may never be certain whether Ground Zero exposure was carcinogenic. "Because, tragic and horrifying as [9/11] was, the population exposed may never be big enough [statistically] to actually give us a definite answer," Stellman explained.

The psychological consequences for workers are becoming increasingly clear, however. In another New York City health department report, released in August, researchers found that one in every eight responders and workers has come down with post-traumatic stress disorder (PTSD).

Risks for the troubling condition appear to correlate with the length of time workers spent at the Trade Center site, how soon they arrived after the disaster, and their level of training in dealing with traumatic events, the study
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