While many people believe that asbestos is a man made product, the truth is that it occurs naturally in rocks around the world. In the United States, hot spots for asbestos deposits include California, the Rocky Mountains, and Central part of the country.
Though several specific minerals help make up the asbestos family, the majority can be found in three basic rock types – serpentinites, altered ultramafic rocks and mafic rocks. To a lesser degree, asbestos has also been known to be present in other rock types, such as alkalic intrusions, carbonatites, metamorphosed dolostones and metamorphosed iron formations. In all cases, asbestos forms when water, pressure and high temperatures combine in the presence of fractured or faulting rocks.
Asbestos fibers are released into the air due to weathering processes. Internal or external pressure exerted onto the rocks often cause asbestos-laden rock to break apart or become crushed. Over time, this leads to asbestos fibers depositing in the soil which overlays the asbestos-containing rock. In such cases, wind and human activities can easily create airborne asbestos hazards.
How To Limit Environmental Asbestos Exposure
A number of outdoor activities can place the general public at risk for exposure to naturally occurring asbestos. The majority of these activities pertain to working or playing in and around asbestos-laden soil. These include yard work, digging and driving, walking or biking over unpaved surfaces. During the course of such activities, dirt is stirred up and inhaled, which over time can lead to lung diseases such as mesothelioma.
A number of steps can be taken to minimize the potential for exposure to naturally occurring asbestos. In terms of outdoor yard work, home owners and gardeners are advised to cover asbestos-containing rock and soil with a thick layer of asbestos-free soil. If digging is required, then wetting the ground will serve to minimize the amount of dirt kicked into the air.
For outdoor enthusiasts and drivers, it is recommended that you stick to trails and roadways that are paved. If you must drive over asbestos-containing soil, then a slow speed will help reduce airborne particles. Children at play outside are suggested to stick to areas with ground coverings such as wood chips, sand, gravel, grass or mulch.
Tracking asbestos-laden dirt into the home is another hazard. This can be minimized by removing shoes before entering the home, keeping dirt and dust off of pets, using doormats and keeping windows and doors closed on windy days. When cleaning floors and other surfaces, a wet mop or rag is recommended. Vacuuming frequently with a vacuum that features a HEPA filter is also beneficial.
Limiting Naturally Occurring Asbestos Exposure To Workers
Beyond the miners who are tasked with extracting asbestos from rock, a number of other workers may be at risk for exposure to asbestos. The job fields that are most at risk to environmental asbestos exposure include construction workers, excavators, lumberjacks, gravel pit operators, farmers and landscapers. Basically, any professional that works in and around asbestos-laden soil is a potentially at risk for exposure.
Outdoor workers in California are at the highest risk for asbestos exposure. If you believe you or your employees may be working in an area that contains environmental asbestos, then it is recommended that you contact either the California Geological Survey (916-445-1825) or the El Dorado County Environmental Management Department (530-621-5300). Both of these agencies will help you follow Occupational Safety and Health Administration (OSHA) regulations to determine if asbestos is a health risk in your work area.
Based on the level of asbestos identified by OSHA, employees may be required to wear Personal Protective Equipment (PPE) such as respirators. Other steps that can be taken to reduce asbestos exposure to workers include:
- Using wet methods when working with soil and asbestos-containing products
- Avoiding the use of compressed air or leaf blowers for cleaning purposes
- Avoiding eating, drinking and smoking in dusty areas
- Limiting access of unnecessary visitors to the worksite
- Showering and washing hair before leaving the worksite
- Changing out of and leaving work clothes at the work site
For more information on limiting exposure to asbestos, please contact the Agency for Toxic Substances and Disease Registry (ATSDR) toll-free at 1-888-42-ATSDR.