Serpentine and Amphibole Asbestos [A Subset of Elongated Mineral Particles (EMPs)]

Abstract

The term asbestos refers to two very different minerals, serpentine and amphibole, occurring in fibrous form with very different mineralogical properties. Unfortunately, the term “asbestos” has been used loosely when, in fact, it has always been appropriate to discuss them separately. This chapter focuses on the key essential differences which result in very different toxicological and epidemiological responses to the fibers from these two minerals. In particular, it is discussed how a fiber's potency dictates the health risk, how the fiber's mineralogy affects biopersistence in the lung, and how fiber length determines how the lung responds to this characteristic. The differential toxicology is presented, as well as the epidemiology of these fibrous minerals. The regulations in the United Stated are also discussed. It is now convenient to use the term asbestos to describe a subset of elongated mineral particles (EMPs). Although the term has been discussed with potential differing definitions depending on the authors' purpose from 1979 to 2023, a popular working definition for EMPs is any mineral particle with a minimum aspect ratio of 3:1. This chapter will focus on the asbestos subset.