It was feared that both workers and survivors of the World Trade Centre attack may be at risk from developing mesothelioma from exposure to asbestos. The ‘north tower’ (1st building to be constructed) contained tons of fireproofing material containing asbestos up to the 40th floor.
The following floors did not contain asbestos material as an impeding threat of a complete ban on the use of asbestos in building constructions in New York was implemented, hence subsequent floors contained substitute materials.
When the north tower collapsed health officials were concerned regarding the release of asbestos into the air and health advisors alerted emergency workers on site to wear protective clothing and change out of these and bag them up prior to leaving site.
Although health officials tested dust samples within the vicinity of the disaster within the first 24 hours and concluded that asbestos dust did not exceed safe limits, questions were still raised concerning the exposure from friable (crumbling) asbestos imbedded in the 1.5 million tons of debris during the 10 month clean up.
American College of Occupational and Environmental Medicine Study
The ‘American College of Occupational and Environmental Medicine’ compiled a study from air sampling over a three week period. Their results were based on the following risk assessment – type of asbestos, and duration of exposure
The type of asbestos dust in samples were ‘chrysotile’ which is believed to be less potent than ‘amosite’ or ‘crocidolite’, and the duration of airborne particles was relatively minimal, I.e. 26 days after the collapse – samples were found to be 500-fold lower in lower Manhattan than a chrysotile mining/mill community.
However – if the dust exposure had been crocidolite asbestos, then the risk for mesothelioma would have been 500-fold higher.