Researchers from the Centers for Disease Control and Prevention, the New York City Fire Department and the Montefiore Medical Center (Bronx, NY) analyzed blood and urine samples obtained from 321 firefighters responding to the WTC fires and collapse, and a control group of 47 firefighters not present at the WTC. The analyzed the firefighters for exposure to 110 potentially fire-related chemicals.

Whether the firefighters were present during the collapse or arrived there one or more days later was a significant predictor variable for four of the 110 chemicals. Special Operations Command firefighters (i.e., Rescue, Squad and Marine units) were the most likely to have increased exposures.

"Firefighters and other rescue and recovery personnel may inhale gases or vapors released during a fire or collapse and may inhale and ingest particulates. Hand-to-mouth contamination, contamination inside masks, and dermal absorption also may be important factors affecting chemical absorption," the study authors write. "As expected, known products of combustion were present in greater amounts in exposed firefighters. Unanticipated increases in urinary antimony, serum heptachlorodibenzodioxin, and heptaochlorodibenzofuran also were associated with exposure. Although statistically significant elevations were found, their magnitude was not high enough to be of immediate clinical concern."

Not all elevated chemicals can be directly linked to the WTC disaster, however. Nor can the findings be applied to others in the area. "Although firefighters may have similar fire exposure backgrounds, those assigned to Special Operations Command more often respond to fires of greater intensity and have different job tasks, all of which may have lead to greater exposure to combustion products before and during the WTC disaster," according to the study. "Firefighter exposures during the WTC disaster were unique and extreme; our findings should not be generalized to other populations working or living near WTC."

Commenting on the study, Dr. Jim Burkhart, science editor for EHP, says, "It's encouraging that so few chemicals were found to be elevated out of the 110 studied. It's not clear if those that were elevated have potential for detrimental effect on these firefighters. Some are known toxicants that persist in the human body, however, so continuing to monitor these firefighters over the long-term would be helpful."

The lead author on the study was Philip Edelman of the CDC. Other authors were John Osterloh, James Pirkle, Sam P. Caudill, James Grainger, Robert Jones, Ben Blount, Antonia Calafat, Wayman Turner, Debra Feldman, Sherry Baron, Bruce Bernard, Boris D. Lushniak, Kerry Kelly and David Prezant. EHP is the journal of the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. The article will appear in print in the December issue of EHP. More information is available online at http://www.ehponline.org/docs/2003/6315/abstract.html.

Editor's note: Full copies of both reports are available by fax or e-mail (PDF format) to media at no charge. Go to www.ehponline.org/press, call 919-653-2582, or e-mail media@ehp.niehs.nih.gov.