Definitions of Asbestos

Asbestos has many definitions depending on the source and context.  Different groups define asbestos somewhat differently.  Most would agree that asbestos is a generic term that refers to fibrous forms of some naturally occurring silicate minerals with certain common physical properties including heat resistance, chemical stability, high tensile strength, low electrical conductivity and flexible fibers.

All groups recognize that three main types of asbestos, i.e. crocidolite, amosite and chrysotile were used commercially, asbestos can separate into very small fibers, these microscopic particles can become airborne and they can cause asbestos-related diseases when breathed into the lungs.

Industrial users and advocate groups have strong economic incentives to promote the benefits of asbestos and tend to emphasize the versatility, durability, and low cost of asbestos in their products.  Prior to strict regulations on its use, asbestos manufacturers and suppliers touted asbestos as the ideal material for home and industry, based on its combination of heat and fire resistance, strength and flexibility.  For this group, asbestos was the “magic mineral,” regardless of its toxic effect on people who breathed the fibers.

Primary care physicians and medical researchers are most interested in the health effects of asbestos in the human body.  They concentrate on how asbestos causes and relates to various diseases and conditions.  Determining the fiber type, size and length, source and duration of exposure, and amount of fibers present or absent in the patient is important to many medical studies.  The ability to cause disease is a requirement of any definition of asbestos for this group.

Geologists, mineralogists and other physical scientists identify asbestos according to well defined physical and chemical criteria used for all types of minerals.  This classification system includes precise measurements of the chemical composition; large scale and microscopic descriptions of grain size, color, hardness, habit and texture; chemical reactivity and crystal structure.  The geologic processes involved in their formation further define this group of minerals.  Some minerals which were not used commercially or shown to cause disease in people have been classified as asbestos or asbestiform.  This group considers asbestos to be a commercial name and not a mineralogical definition.

Regulatory agencies such as the Environmental Protection Agency (EPA), National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Administration (OSHA), Consumer Product Safety Commission (CPSC) and the Department of Health and Human Services Agency for Toxic Substances and Disease Registry (ATSDR) need to consider public policy, enforcement issues and legal ramifications when defining asbestos.  In certain circumstances, asbestos may be defined narrowly to cover a specific application or product.  In other cases the term may be used broadly, encompassing a range of materials and uses.  Anthophyllite, tremolite and actinolite are defined as asbestos or contaminants in asbestos containing material in most regulations.  Competing interests among members in this group leads to variations in the definition of asbestos.

The differences and inconsistencies in the definition of asbestos can cause confusion among members of the asbestos community.  Disagreement and debate over definitions can have significant impacts on public health, economic viability and legal proceedings.  It is important to recognize the intent of the author when reading any of the vast collection of asbestos-related literature available to the public.