What is mesothelioma?

Risk factors for malignant mesothelioma

Those indirectly at risk

Passive asbestos exposure

The widespread use of asbestos in the construction of public, commercial and residential buildings (especially in the 1970s) has exposed millions of adults and children to asbestos passively. Indeed, in 1982, it was estimated that there were more than 720,000 public buildings with asbestos in them. Older buildings may slowly release decaying asbestos into the air, but its removal is dangerous and must be done professionally.

Such passive exposure confers a much lesser risk of developing asbestos-related conditions than direct exposure -- with the exception of custodians and others responsible for maintenance. (Custodians may in fact become directly exposed when performing maintenance duties.) Nevertheless, in one analysis of mesothelioma deaths, five of the ten most commonly recorded occupations on the death certificates were not in industries associated with asbestos exposure. (It should be noted, though, that the death certificates do not record past work history.)

Another study reported that malignant mesothelioma occurred in 16 teachers from different parts of the United States, only 4 of whom had a history of exposure outside of school employment. One 1970s estimate is that 2-6 million school children and 100,000 to 300,000 teachers had been exposed to asbestos in schools.

Other cases of passive exposure include office workers (where asbestos was sprayed on ceilings) and those employed in hospitals.