What is the primary risk associated with asbestos in an air plenum?

The primary risk associated with asbestos in an air plenum is that it can be distributed over a large area. Air plenums are spaces used for air circulation in heating and cooling systems, and if asbestos is present in these areas, it can become airborne and spread throughout the building. This poses significant health risks to the occupants, as inhaling asbestos fibers can lead to severe respiratory problems, including asbestosis, lung cancer, and mesothelioma.

In contrast, while some options relate to immediate or localized effects of asbestos, they do not capture the broader risk of its dispersion through air circulation systems. The potential for widespread distribution increases the likelihood of exposure, making option B the most accurate representation of the significant hazard posed by asbestos in an air plenum.