It is likely that those individuals who live and work in close vicinity to the site are at some increased risk

Dr Stephen Levin

Dr Stephen Levin, of the Mount Sinai School of Medicine in New York, spelled out the risk on Friday at an ACPM-convened meeting of health experts.

He said: "While the exact quantity of asbestos fibres emitted into the air immediately following the collapse of the World Trade Center remains unclear, it is likely that those individuals who live and work in close vicinity to the site are at some increased risk for the development of asbestos-related cancers, including malignant mesothelioma.

"Only after long-term follow-up and assessment of these individuals will we have a clearer picture of the true long-term health consequences."

Main risk

New Yorkers have legitimate health concerns about the potential risk

Dr Arthur Frank

The main risk factor for development of malignant mesothelioma is exposure to asbestos fibres.

The majority of people diagnosed with the disease have typically held jobs in which they inhaled asbestos over a prolonged period of time, such as construction workers, roofers, insulators and plumbers.

However, some individuals with more brief exposure to asbestos have developed mesothelioma - raising questions concerning the health consequences of asbestos exposure in the wake of 11 September.

Dr Arthur Frank, of the University of Texas, said: "While all of us are exposed to asbestos fibres to varying degrees throughout our lifetimes, New Yorkers have legitimate health concerns about the potential risk for development of asbestos-related cancer.

"We are now beginning to understand the subtleties of the connection between asbestos exposure and the potential for development of malignant mesothelioma."

Rare disease

The disease is a rare, and particularly deadly form of cancer that occurs in the linings of the lung or chest.

Numbers of cases in the US appear to be increasing.

World-wide approximately 10,000 people have the disease.

Long-term monitoring is essential given that malignant mesothelioma usually lies dormant for decades before symptoms appear.

Consequently, people are not diagnosed until long after their initial exposure to asbestos.

Symptoms of the disease may include chest pain, shortness of breath, difficulty swallowing, coughing, hoarseness, fever, sweating, fatigue and weight loss.

Current treatment options include surgery, chemotherapy, and radiation. However, average survival time is only one year.