Report Says Twin Towers Left an Unprecedented Toxic Cloud

The air that hovered over New York in the months after the collapse of the twin towers contained an unprecedented combination of chemicals, scientists said Wednesday. As such, they said it may be impossible to forecast the long-term health impact.

The scientists, from a host of government and university laboratories, gathered Wednesday for the first time to compare findings about the dust, debris and polluted air in the aftermath of Sept. 11, in a conference at the annual meeting of the American Chemical Society.

The gases of toxic metals, acids and organics could penetrate deeply into the lungs of workers at ground zero, according to a study by scientists at UC Davis.

Lead study author Thomas Cahill, a professor of physics and engineering, said conditions would have been “brutal” for workers at ground zero without respirators and slightly less so for those in adjacent buildings.

“The debris pile acted like a chemical factory [that] cooked together the components and the buildings and their contents ... and gave off gases of toxic metals, acids and organics for at least six weeks,” Cahill said.

In the wake of a report that the White House pressured the Environmental Protection Agency into issuing premature statements that the air was safe, some New York leaders have called for an investigation.