A settlement of up to $657.5 million has been reached in the cases of thousands of rescue and cleanup workers at ground zero who sued the city over damages to their health, according to city officials and lawyers for the plaintiffs.
This settlement involved approximately 10,000 workers involved at the World Trade Center site. There was certainly a concern over possible asbestos and other hazardous dust/chemicals at this disaster site during rescue and clean-up operations.
You can read this New York Times article for more information.
