Asbestos becomes a health hazard when it is:

Asbestos becomes a health hazard primarily when its fibers break down and become airborne, making them susceptible to inhalation. When asbestos-containing materials are disturbed or damaged, microscopic fibers can be released into the air. These fibers, if inhaled, can lead to severe respiratory issues and diseases, including asbestosis, lung cancer, and mesothelioma.

The other choices do not accurately convey the circumstances under which asbestos presents a danger. Painting over asbestos does not eliminate the risk; if the underlying material is subsequently disturbed, hazardous fibers can still be released. Wrapping asbestos in protective materials or storing it in a sealed container may help contain the fibers, but does not address the problem of existing asbestos that can deteriorate. Therefore, the correct answer emphasizes the critical health risk posed by airborne fibers, affirming the importance of proper handling and abatement of asbestos-containing materials.