Asbestos

by

Ying Jiang, Ken Takahashi, Mehrnoosh Movahed

• LAST REVIEWED: 30 June 2014
• LAST MODIFIED: 30 June 2014
• DOI: 10.1093/obo/9780199756797-0123

Introduction

Asbestos is a naturally occurring mineral fiber that has historically been used in a wide range of industrial applications and consumer products. It emerged as a public health issue around the mid-20th century, when it became known that human asbestos exposure, mainly through the inhalation of its fine fibers, was capable of causing a range of diseases, including cancer. These diseases have been grouped together as asbestos-related diseases (ARD). As ARD primarily affect workers through occupational exposure, they can be considered a typical occupational disease. Due to the “inextinguishable” property of asbestos and its extensive use in various industries, this material is still ubiquitously present in society, where it may be found in products, buildings, and the environment. Moreover, there is no threshold to the carcinogenicity of asbestos, so there is no exposure level below which it can be considered safe. ARD have occurred among people exposed to much lower asbestos levels than those experienced by workers who directly handled the material; such lower-exposure-related ARD have been seen among individuals who work near contaminated sources (indirect occupational exposure), live with exposed workers (household exposure), and live near contaminated sources (residential exposures). As a consequence of the heavy burden of ARD, many industrialized countries have banned (officially as well as de facto) the use of asbestos. In stark contrast, many industrializing countries continue to use asbestos, perhaps because they have not yet solely shouldered the burden of ARD. Accordingly, various international organizations, spearheaded by the World Health Organization, have declared the need to eliminate ARD and have proposed that the best way to do this is to stop using all forms of asbestos. ARD have thus taken on the important dimension of a global public health problem.

Hazard and Risk Assessment

The World Health Organization (WHO), through the International Programme on Chemical Safety (IPCS), establishes the scientific basis for soundly managing chemicals and strengthening national capabilities and capacities for chemical safety. Through publication of the Environmental Health Criteria (EHC) documents, the World Health Organization implements chemical risk assessment within the IPCS. IPCS-EHC 53 on asbestos and other natural mineral fibers and IPCS-EHC 1998 on chrysotile asbestos (World Health Organization 1986 and World Health Organization 1998, respectively) synopsized the effects of these materials on animals, cells, and humans, and proposed areas for further research. In view of the time elapsed since publication, the earlier document should be viewed in a historical context. The International Agency for Research on Cancer (IARC) assesses carcinogenicity by convening working groups of multidisciplinary experts to review the available literature on specific themes. The most recent monograph IARC contains chapters on asbestos that include exposure data, cancer in humans and experimental animals, other relevant data and evaluation. The monograph concluded that “there is sufficient evidence” in humans and experimental animals “for the carcinogenicity of all forms of asbestos, that is chrysotile, crocidolite, amosite, tremolite, actinolite and anthophyllite” (p. 294). Castleman 2005 viewed asbestos from a medico-legal perspective.

• Castleman, Barry I. 2005. Asbestos: Medical and legal aspects. 5th ed. New York: Aspen.

  A definitive resource on the medico-legal aspects of asbestos. Issues related to prior and ongoing litigation are covered in depth, along with an extensive evaluation of the legal arguments put forth by the plaintiff and defense counsels. Also provides an international perspective on the political struggle over asbestos.

• International Agency for Research on Cancer. 2012. A review of human carcinogens part C: Arsenic, metals, fibres, and dusts. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans 100:219–309.

  DOI: 10.1016/S1470-2045%2809%2970134-2

  A comprehensive review of evidence for the carcinogenicity of asbestos, including an encyclopedic synopsis of hazard identification. This monograph reiterates sufficient human evidence for the carcinogenicity of the six asbestos types for lung cancer and mesothelioma, and adds laryngeal and ovarian cancer as asbestos-caused cancers. See also Epidemiology: General Issues.

• World Health Organization. 1986. International Programme on Chemical Safety: Environmental Health Criteria 53, Asbestos and Other Natural Mineral Fibres.

  Based on the collective view of an international group of experts, this compendium comprehensively describes the physical/chemical properties of asbestos and the available hazard information. Effects of asbestos and other natural mineral fibers on humans, animals, and cells are discussed, and recommendations for further research are made.

• World Health Organization. 1998. International Programme on Chemical Safety: Environmental Health Criteria 203, Chrysotile Asbestos.

  Based on the collective view of an international group of experts, this compendium comprehensively describes the physical/chemical properties of chrysotile asbestos and the available hazard information. Effects of chrysotile asbestos on humans, laboratory mammals, and cells are discussed, along with its environmental fate and effects on biota.