THURSDAY, May 30, 2002 (HealthDayNews) -- On the day the last beam was pulled from the World Trade Center disaster site, the government released a new report saying searchers and cleanup crews at the site had not generally been breathing health-threatening levels of toxins.
Environmental tests that were taken at ground zero in the immediate weeks after the Sept. 11 attacks toppled the twin towers showed only traces of dangerous chemicals, including asbestos, heavy metals and other potential poisons.
Between Sept. 18 and Oct. 4, state and federal workplace safety officials found only two cases in which disaster workers were known to be inhaling perilously high amounts of poisons. One involved the potentially deadly gas carbon monoxide (CO), while the other involved the heavy metal cadmium, which can cause pneumonia and deadly lung damage.
Two other workers may have been exposed to dangerous levels of CO, but the samples weren't taken for long enough to be definitive, the researchers said.
In both of the confirmed cases, the workers were using either gas-powered tools or cutters that emit toxins, prompting the National Institute for Occupational Safety and Health (NIOSH) to recommend battery-operated devices instead. The agency also advised crews to work in areas with adequate ventilation if they were using the more hazardous equipment.
Kenneth Wallingford, an industrial hygienist at NIOSH in Cincinnati and a co-author of the report, said the researchers were surprised not to find more threatening exposures at the site.
"That was an unprecedented disaster, and you'd expect things out of the ordinary," Wallingford said.
NIOSH is a division of the Centers for Disease Control and Prevention, which released the study today.
As the fires from the collapsed buildings burned on in the days after Sept. 11, health officials worried that the air and dust around the site would be laden with toxins. A leading concern was asbestos, a known cancer-causing material used in fireproofing, and concrete, which contains crystalline silica, another potential carcinogen.
Researchers also tested for traces of heavy metals, such as mercury, lead and cadmium, as well as hydrogen sulfide from broken sewer lines, rancid food and rotting bodies, and various other compounds.
In all, scientists collected more than 1,100 air samples, as well as 33 samples of dust and debris in the area. They even rigged workers with devices that measured the air immediately surrounding them to get a sense of true occupational exposures.
One worker wielding an oxyacetylene cutting torch was exposed to levels of cadmium well above the government's safety threshold. And another using a gas-powered saw was breathing CO levels far higher than what's considered healthy.
But otherwise, the air quality at the disaster scene, while not exactly good, wasn't particularly damaging.
"Other than those two things we didn't really find any things that were above existing occupational standards or recommended standards," Wallingford said.
The Environmental Protection Agency conducted its own air quality samples of the disaster site and was especially concerned about the smoke plume and fires that rose from the rubble.
Like the NIOSH testing, the EPA also found few signs of harmful exposures. But Mary Mears, a spokeswoman for the agency's New York office, said there were enough spikes to recommend that workers wear personal protection equipment on the scene. As a result, the EPA distributed "tens of thousands" of respirators to crewmembers, Mears said.
Kelly McKinney, an official with the New York City Department of Health and a co-author of the study, said the findings were used at the time to protect workers at ground zero. McKinney said he had no information about whether the two workers overexposed to cadmium and CO, or the two potentially overexposed to CO, had developed any symptoms.
New York City set up the Lower Manhattan Air Quality Hotline to field complaints and concerns from residents. But a spokesman for the city's Office of Emergency Management said few people have been calling.
What To Do
To find out more about the air quality around the World Trade Center site, check out the Environmental Protection Agency. For more on occupational safety and health, visit the National Center for Occupational Safety and Health.
