The initial dust cloud caused an enormously high concentration of airborne particulates, which was brief but unforgettable. Twentyfour hours later, the airborne concenfation of dust was markedly lower, but it remained uncertain as to the extent to
which asbestos exposures would be above background during the 10 months required to remove the 1.5 million tons of debris resulting from the collapse of the buildings.

This article will estimate the risk of developing lung cancer and mesothelioma from the asbestos exposure, including its uncertainty by asking the following questions: What were the asbestos fiber type(s) and concentration(s) in the air? When did the outside airborne asbestos levels post-9/11 return to the historical background levels for asbestos in NYC? What is the asbestos related cancer incidence likely to be as a consequence ofthese asbestos exposures?

The airborne asbestos monitoring undertaken by the US Environmental Protection Agency (EPA) after the attack was not based on health benchmarks or on acquiring data for a risk assessment. Little, if any, affention has been given to undertaking the type of air sampling necessary to perform a modem asbestos-related cancer risk assessment for 9/11.