There were concerns about air quality from day one:
http://www.usatoday.com/news/nation/2002/02/07/usat-wtc-acov.htm
The Government must accept responsibility.
Found more links"
http://www.gothamgazette.com/rebuilding_nyc/topics/impact/health_risks.shtml
http://www.usatoday.com/news/nation/2002/02/07/usat-wtc-acov.htm
http://www.gothamgazette.com/rebuilding_nyc/topics/impact/health_risks.shtml