There are growing environmental concerns about the air quality around "ground zero" - the site of the collapsed World Trade Center. Some residents fear that the city's rush to return to normalcy came at the expense of people's health.

Health workers give breathing tests at this makeshift clinic, minutes from the ruins of the World Trade Center. Set up in a small trailer, they are examining workers without health insurance, who cleaned layers of dust strewn in office buildings from the collapsed Twin Towers.

An organizer of the clinic, Omar Henriquez, says many of the workers complain of health problems, such as what is being called the "World Trade Center cough."

"What we're finding is that a lot of people say they have symptoms, a dry cough, the bleeding noses, irregularities with the periods, pains in the chest, signs of asthma," Mr. Henriquez explains.

When the World Trade Center collapsed, it left about one million tons of debris, with traces of potential cancer-causing substances, such as asbestos, benzene, dioxins and PCBs. Some doctors say the greatest risk is for rescue workers who were directly exposed to the dust, sometimes without adequate protective gear.

Many still have a severe cough and have filed claims against the city. Recently, tests revealed elevated levels of mercury in the blood of four police officers at the site.

About 40,000 people live near "ground zero." Some, such as local politician Kathryn Freed, are concerned too.

"I have a hunch that they unfortunately probably should have evacuated most of us and kept most of us away for quite some time, and they obviously decided that they couldn't do that economically. But I'm afraid that we may find out, as we get older, that we are paying the cost of their rush to normalcy," she says.

The federal government's Environmental Protection Agency has conducted thousands of air quality tests in lower Manhattan since September 11. EPA spokeswoman, Mary Helen Cervantes, says the agency stands by its statements that according to its data, the area poses no long-term health risks.

"That does not mean that there is no risk. And we have stated as well very strongly since the very beginning that workers who work at the World Trade Center site need to take precautionary measures and wear precautionary gear that has been provided to them. [Also] people who are asthmatic or have other respiratory sensitivities need to take precautions," she says.

The EPA's ombudsman is looking into complaints about the way tests were conducted and the release of information to the public. Ms. Cervantes says many governmental agencies had overlapping responsibilities, and information was released as quickly as possible under the circumstances.

Still, some critics say that the government should have set up a so-called "superfund" to oversee a thorough and uniform cleanup of the area. A controversy recently erupted when private testing at a large apartment building near ground zero showed the presence of asbestos at 555 times above the suggested acceptable level.

Ms. Freed objects to the city's decision to allow landlords to run the cleanup of buildings dirtied by the collapsed towers.

"I think the city made a big mistake in the way they decided to do the clean up. Which was that they decided not to do the clean up. And in many cases I guarantee you, if you walk out in the street, you will find buildings that never, that never really cleaned up," she says.

Some residents also worry that open trucks carrying the wreckage from the Twin Towers are still spreading toxins.

Officials have assured parents that schools in the area have been thoroughly cleaned, but some parents still refuse to send their children to class so close to ground zero.