Asbestos Overview

What is asbestos?

Asbestos is a commercial term referring to a group of hydrated magnesium silicate minerals, sharing properties of flexibility, high tensile strength, and thermal (heat) and chemical resistance. The term asbestos comes from the Greek word meaning


“indestructible” or “unquenchable.” By convention, asbestos is divided into two mineralogical groups, amphibole and serpentine. The amphiboles include crocidolite (blue asbestos), amosite (brown asbestos), tremolite, anthophyllite and actinolite. Chrysotile (white asbestos) is the only variety in the serpentine group. Amphiboles are straight (needle-like), whereas serpentine asbestos is curvy (like a snake or serpent). Both the amphibole and serpentine minerals occur naturally as the asbestiform (fibrous) and non-asbestiform (massive) varieties.

These fibrous minerals have been used by humans for thousands of years. Because of its unique properties, asbestos has been used in fireproofing, insulation, heat retention, brake material, gaskets, joint compound, flooring, roofing materials and many other applications. In the late 19th century and into the 20th century, the use of asbestos became increasingly popular.

Most respirable particle of asbestos are extremely small, invisible to the naked eye. Fibers can be 1000s of times thinner than a single strand of human hair. As they become smaller and lighter, these asbestos fibers can become airborne and enter into the respiratory tract.

What diseases does asbestos cause?

Asbestos inhalation can produce a number of non-malignant diseases in humans. These include:

  1. Asbestosis (pulmonary interstitial fibrosis)
  2. Circumscribed pleural plaques
  3. Diffuse pleural thickening
  4. Pleural effusion (so-called Benign Asbestos Pleural Effusion or BAPE)
  5. Rounded atelectasis
  6. Asbestos corns

In addition, asbestos is a recognized human carcinogen and can increase the risk of developing certain malignancies, including:

  1. Lung cancer
  2. Malignant mesothelioma
  3. Laryngeal cancer
  4. Pharyngeal cancer
  5. Gastrointestinal cancer, including colorectal

Most asbestos-related diseases are dose-dependant, meaning the higher the dose, the higher the risk of disease. Most asbestos diseases occur decades after first exposure (i.e. a long “latency” period).

Some countries have banned the use of asbestos, whereas its use is widespread in some developing countries (like India and China). Asbestos-related litigation has been the most expensive and longest-running mass tort in US history, with hundreds of thousands of claims.

Where can I learn more?

National Institute for Occupational Safety and Health (NIOSH)- asbestos

American Cancer Society

Agency for Toxic Substances and Disease Registry (ATSDR)- ToxFAQs for asbestos

American Thoracic Society (ATS)- 2004 Official Statement on non-malignant asbestos disease