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Assessing Risks

Sept 21, 2001 - WTC site.
Photo: Michael Rieger/FEMA News Photo

From an environmental perspective, probably the most difficult challenge confronting the agencies was identifying the substances in the dust and their potential health hazards.

“Determining which pollutants were out there in concentrations that were hazardous,” was at the top of EPA Region II’s list of challenges. That meant assessing the risks of exposures to pollutants it wasn’t required to monitor by law—such as dioxin, PCBs and dozens of other compounds—and for which health standards had not been set.


Of course, too, truly life threatening hazards awaited in the recovery effort. There were many hazardous materials, such as Freon tanks for the air conditioning units, stored in six underground levels of the WTC. If the fires reached these levels they might have triggered larger fires or toxic plumes. There were hazards amid the rubble because moving debris could open pockets of oxygen that could mix with combustible dust and vapors and cause other explosures.


So pinpointing sources of hazards were key.


Among the first agencies to help in this regard was EPA. But On-Scene Coordinator (OSC) Steve Touw, who had been to Hurricane Hugo and Floyd, as well as oils spills and overturned tank trucks, was unprepared for the scope and size of the environmental disaster at the 16-acre World Trade Center site. “The resources brought to bear were like nothing I’d ever seen,” he says.


Among other responsibilities, Touw was tasked with collecting hazardous materials, and so he had to determine where those might be by tracking hazardous waste permits on file—finding oil storage tanks in the basement, sources of perchloroethane from dry cleaning establishments, and so forth.


“We came cross several drums of cleaning chemicals at the former Vista Hotel,” Touw remembers, “and the excavators turned up a white vapor wafting up.” Suddenly, the site had to be evacuated, though, fortunately, says Touw, it only turned out to be casks of laundry detergent.