Two preliminary studies have found that Ground-Zero recovery workers in New York may have little to fear concerning heavy metal and dangerous chemical compounds, but the threat of asbestos-based diseases is still very real.

The studies compiled by two New York research organisations were conducted with more than 10,000 firefighters, ironworkers and Manhattan residents. They are the initial results of major research looking into the effect of working with fumes and the cloud that surrounded the disaster area for weeks following the terrorist attacks

The piles of grey powder surrounding the site have been identified as asbestos dust, and authorities agree that the “cloud” around the site will have entered rescue workers’ respiratory tracts.

While site workers and nearby residents continue to suffer what is known as “WTC cough”, it may be another 20 years before they show asbestosis-linked symptoms.