The results of the tests on firefighters were unique because researchers were able to look at their respiratory function tests from as far back as 1997. Routine lung tests had been carried out on the workers as part of standard medical screening.
"We were in a very unique position because these workers had had routine monitoring of their lung function before, and that's never happened before in a group this large," said Dr. Gisela Banauch of the Montefiore Medical Center in New York.
In the tests, rescuers who arrived on the scene of the World Trade Center collapse on Sept. 11, 2001 showed a significant reduction in the amount they could breathe out in one second, known as forced expiratory volume. They also displayed the most severe and frequent respiratory problems of any of the workers.
The ongoing study revealed that some of the workers still had breathing problems today. Some of the effects could be attributed to acute irritation of the airways, Banauch said, but some rescue workers were dealing with more long-term effects, according to smaller follow-up studies.
"My personal opinion is that when the towers collapsed, a lot of building materials were pulverized, so there was a lot of cement in the dust, which is very alkaline and which we know that causes burns."
While only 22 percent of the early arrivals reported wearing masks, 50 percent were using them by the third day. Researchers noted that no protective effect was found from mask use. Banauch said properly protecting firefighters from the dust would have been impossible.
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