The Natural Occurrence of Asbestos
The original appeal of asbestos is easy to understand: a mineral as fluffy as cotton yet as strong as steel. Often we associate naturalness with healthiness, but the occurrence of asbestos naturally in the air, water and soil does not make it any less unnatural once it enters our lungs, heart or gastrointestinal tract after being disturbed. Left alone, this mineral is harmless, so it’s important to limit your exposure or the exposure of your employees to naturally occurring asbestos or NOA.
NOA in Soil, Water & Air
NOA can be found in rocks and soil in its undisturbed state. Weathering processes can naturally disturb asbestos and release its fibers into the water and air. 1-25% or more of asbestos is generally found naturally within ultramafic rock near fault zones. Disturbing this rock in some way, either by crushing or breaking, releases asbestos fibers. Ultramafic rock does not as a rule contain asbestos; instead, it must be tested for the presence of NOA.
Types of Asbestos Minerals
NOA minerals are defined by their color, shape and applicable commercial uses. A complete list of such fibers is provided below.
● Crocidolite: This asbestos mineral is blue and is characterized by the ability to be reduced into smaller fibers than most other NOA fibers.
● Amosite: This brown asbestos mineral is used in ceiling tiles and various insulation products.
● Amphibole: These asbestos fibers are straight, a characteristic which is often considered more dangerous because it makes the fibers harder to expel from the body.
● Chrysotile: These asbestos fibers are white and are the most commonly used of all asbestos fibers in America.
● Serpentine: This asbestos mineral is curly.
● Tremolite/Anthophyllite/Actinolite: These asbestos minerals are regulated and are used in construction materials, though not in many consumer products.
● Winchite/Richterite: These minerals are unregulated and are referred to as asbestiform minerals, though they pose no less danger than regulated asbestos minerals.
Limiting NOA Exposure
The major strategies for limiting NOA exposure include excavating and disposing of NOA materials, limiting the dust generated by industrial activities, simply not disturbing NOA in the first place, and finally capping or covering NOA material. Which approach is used depends on many factors: the feasibility in terms of administrative and technical logistics, the weather and climate, the future and current land uses, the accessibility of the naturally occurring asbestos and the type of activity being performed in terms of how it disturbs NOA.
Asbestos occurs naturally in rocks and soil. When it is disturbed by weathering or human activities it can then be dispersed into the air and water. Given the various types of asbestos minerals, this can pose a serious threat. However, the knowledge of asbestos is wide-ranging and easily available from sources like the EPA. The strategies for limiting exposure to NOA are just as well-known, and as a result there is no excuse for spreading asbestos fibers other than a disregard for health over profitability.