What is mesothelioma?

Risk factors for malignant mesothelioma

Those directly at risk

The majority of malignant mesotheliomas occur in those people directly exposed to asbestos, either in its mining and transportation, the production of the many asbestos-containing products, or its uses in the construction and ship building industries. The list of those directly exposed includes:

• People involved in the mining and transportation of asbestos.
• Workers at plants manufacturing asbestos products.
• Users of asbestos products:
  • Brake mechanics. Brake shoes routinely contained asbestos, exposing brake mechanics to asbestos dust when repairing and replacing brake shoes. Four percent of products that still contain asbestos are 'friction products' (2003 data).
  • Boilermakers. Asbestos was routinely used in boilers, for its insulating properties.
  • Laggers/Insulators. Because of its heat resistance, asbestos was used to make insulating products for a variety of industrial uses, including coverings for furnaces, pipes and ovens.
  • Maintenance workers. Because of the widespread use of asbestos in buildings (wall board, insulation material, etc), maintenance workers are at risk of exposure.
  • Pipe fitters. The use of asbestos for gaskets and insulating pipes exposed pipe fitters to it.
  • Ship fitters and naval mechanics. The ship-building, -refitting and repair industries were a major source of asbestos exposure in World War II, insulating products being used for pipes, boilers and furnaces. In addition, naval mechanics were exposed.
  • Steel workers. As with boilers, asbestos was commonly used with other steel products such as steam pipes and ovens.

In addition to the direct exposure risks listed, malignant mesothelioma may develop indirectly in bystanders, in family members of workers or by passive exposure.