I know ISHN magazine is quoting reports by other sources (Report says government ignored health risks to Ground Zero cleanup workers), but I know for a fact that OSHA and EPA did extensive air sampling for air contaminants at Ground Zero of the World Trade Center after 9/11. Results of the sampling were posted in the OSHA and EPA web sites.
My former Area Director and several of my former OSHA co-workers were present at Ground Zero conducting the air sampling and providing respirators to the responders. The problem is that many responders, including firefighters, refused to wear the respirators.