Subsequent air testing revealed "a significant reduction in contaminants to levels well below state limits," Ms. Brown said.
Air testing, how it works and what it reveals or does not, has become part of the uneasy fabric of life in the areas around the disaster site.
Indoor air quality was delegated mostly to the city's Department of Health, which has done some indoor air testing, he said.
They said that under such a law, citizens' groups would not have been able to do the air testing that contradicted overly optimistic official air-quality reports after the destruction of the twin towers on Sept. 11, 2001.
He beat Mark "Spider Websterr fairly comfortably, and celebrated by jumping up and down and punching the air, testing not just the sturdiness of the stage but the very foundations of the Alexandra Palace.
Preparations for air testing are going on "because I shall not hesitate to order the tests if they are necessary to maintain the effective deterrent strength of the U.S.," the President told a press conference.
Air testing over one of the nation's biggest natural gas fields found two sites with extremely high levels of cancer-causing benzene and 19 more with elevated levels of the chemical, environmental regulators said.
Margie Feinberg, a spokeswoman for the Department of Education, said that PCBs are "persistent in our environment," and that air testing could not definitively connect PCBs to a specific source.
In addition to checking for biological agents, the soldiers, working with the Police Department, have also been monitoring for chemical agents and radiological contamination, supplementing open air testing done in several areas by the City Health Department and, under a new nationwide program, by the federal Homeland Security Department.
"There's little risk to the general public of any ongoing air pollution related to the World Trade Center," said Patrick L. Kinney, an associate professor of environmental health sciences at Columbia University, who has monitored air testing results and was briefed about Adelaide's findings.
While Skanska and other companies paid the subcontractor tens of millions of dollars, Environmental Energy Associates had no employees or equipment and did no work, according to the indictment, which said the subcontractor was hired to do concrete work, demolition, air testing, soil sampling and hazardous-gas monitoring.
