GENERAL INFORMATION
Naturally occurring asbestos (NOA) may be found in at least 44 of California's 58 counties. Asbestos is the name for a group of naturally occurring silicate minerals. Exposure to asbestos may result in asbestos fibers being inhaled or ingested, which over time in some cases, may result in damage the lungs or membranes that cover the lungs, leading to illness or even death.
Naturally occurring asbestos, often found in serpentine rock formations, is present in several foothill areas of Placer County. When naturally occurring asbestos containing material is disturbed asbestos fibers may be released and become airborne, thereby creating a potential health hazard.
A copy of the brochure Asbestos-containing Rock and Soil: What California Homeowners Need to Know is available.
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FREQUENTLY ASKED QUESTIONS
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Where are NOA deposits, or rock formations that may contain NOA, located in Placer County?
Considering the findings of the U.S. Environmental Protection Agency (U.S. EPA) and the Agency for Toxic Substances and Diesease Registry (ATSDR) activity-based air monitoring in El Dorado Hills in El Dorado County, will similar monitoring be conducted by the District?
What is being done to minimize the disturbance of NOA deposits, or rock formations that may contain NOA, in Placer County?
What is asbestos exposure and why is asbestos exposure a concern?
What can I do to reduce my exposure and that of my family to NOA fibers?
Additional Information Resources
Where are NOA deposits, or rock formations that may contain NOA, located in Placer County?
NOA deposits are most often found in ultramafic rock formations. Often NOA is found in serpentine rock. Geologic maps prepared by the California Geologic Survey (formerly the California Division of Mines and Geology) show areas of higher probability for asbestos containing rock within the broad zone of faults that follows the low foothills and lay in a south-east to north-west band. The Placer County communities of Auburn, Colfax, Meadow Vista, and Foresthill are among those that are within this fault band. Generally, there are no areas of high probability of occurrence for NOA in Placer County that lay to the west of Folsom Lake nor to the south of Wise Road. That is, Roseville (and Granite Bay), Rocklin, Lincoln, Loomis, Penryn, and Newcastle lay within geologic areas that have a lower probability for the presence of NOA. There are some isolated areas of higher probability for the presence of NOA within the Tahoe National Forest.
The identification of locations in Placer County has been improved with the development of an enhanced 1:100,00 scale map by the California Geological Survey. This map denotes areas of Placer County that are more or less likely to contain NOA that is based on available soil and geologic studies, with some field verification. This map and report, also know as Special Report 190, is available at the California Geological Survey’s website. Information on how to purchase paper copies of the report and map is available at the following website.
The characterization of an area as having a lower overall probability of NOA presence means that although the likelihood is slight, in some instances NOA might be found within such an area. Similarly, a location in the area identified as being most likely to have NOA may not contain NOA
NOA deposits have been found in rock other than ultramafic and serpentine rock; for example NOA deposits have been found in metavolcanic rocks such as the Copper Hill Volcanics in the Folsom vicinity. Metavolcanic rock formations are prevalent to the northeast, north, and west of Auburn. Finally in areas of sedimentary of alluvial rock deposits, such as exist in western Placer County; it is possible that analytically detectible NOA may be found.
- An Enhanced map (1:100,000 scale) of areas likely to contain naturally occurring asbestos in Placer County. The report and map image is 3.7 MB in size and may take some time to download. This map was prepared by the California Geological Survey for the District as Special Report 190 which assessed the likelihood of the presence of NOA in various areas of Placer County.
- Detailed maps have been prepared showing the relative likelihood of the presence of naturally occurring asbestos. These maps are derived from the Enhanced Map prepared by the CGS. Because the scale is increased from the parent map, the area maps provide an increased ability to locate specific points while introducing some additional uncertainty.
- California Geological Survey's General Location Guide for Ultramafic Rocks in California - Areas More Likely to Contain Naturally Occurring Asbestos - Portable Document Format file, (2.2MB)
- Maps displaying ultramafic rock and other Placer County geologic formations at 1:250,000 scale:
- Geologic Map of the Sacramento Quadrangle, Map 1A, Sheet 1 of 4, available as part of a set of four sheets Order No. RGM 001A) from the California Geological Survey.
- Geologic Map of the Chico Quadrangle, Map 7A, Sheet 1 of 5, available as part of a set of five sheets (Order No. RGM 007A) from the California Geological Survey.
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Considering the findings of the U.S. Environmental Protection Agency (U.S. EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) activity-based air monitoring in El Dorado Hills in El Dorado County, will similar monitoring be conducted by the District?
For several reasons, the District does not believe that activity-based monitoring by the District is necessary at this time. Currently, the U.S. EPA has no plans to conduct any monitoring in Placer County.
The activity-based air monitoring conducted in El Dorado by U.S. EPA and ATSDR was intended to determine if activities (such as playing baseball, playing soccer, and jogging), and the incumbent disturbance of dust while performing the activities, increased exposure to asbestos fibers over background reference sampling. The area is known to have NOA containing materials and NOA deposits. The result from the sampling indicates that the disturbance of dust containing asbestos fibers will result in increased air concentrations of up to 43 times that of fiber counts for reference samples taken without activities occurring.
The U.S. EPA has stated that it is not currently possible to accurately assess the health risk for El Dorado Hills residents from the types of exposures that were observed in its study. Furthermore, the U.S. EPA has stated that a health assessment was not the purpose of the studies, but the results are of concern because of the potential for long-term development of asbestos-related diseases. The ATSDR's study was restricted to assessing the potential health risks based on activity-based sampling for NOA at the Oak Ridge High School, in El Dorado Hills. ATSDR has promised to evaluate community exposures, and recommended that it would be prudent for people who live in the community to take steps to minimize exposures, since presumably the community at-large may face similar exposures if NOA is present in the dust and soil of their homes.
Consideration of the findings of the U.S. EPA and ATSDR from the air sampling studies conducted in El Dorado Hills, has led the District to the following conclusion regarding the need for activity-based sampling. In areas where NOA is know to be present in the soil and in surrounding areas, activity-based sampling would likely indicate an increase in exposures due to dust and soil being disturbed. However, as there are no means to evaluate the increased health risk from such increased exposures, little would be gained by the performance of such sampling. It is simpler and more direct for the assumption to be made that asbestos fibers may be present in dust and soil in areas where NOA is know to be present or more likely to be found, and to direct efforts and available resources into reducing potential exposures to the fibers.
Air sampling conducted by the California Air Resources Board (CARB) in 1999 found low, but detectable, asbestos fiber concentrations at locations in Foresthill and Auburn. While paving of McKeon-Ponderosa Way, in Foresthill, has undoubtedly reduced dust disturbance, the results supports the District's reasonable conclusion that where NOA is found you are likely to find some asbestos fibers in the air. There is no level at which exposure to asbestos fibers is deemed to be free of risk. Since activities that disturb dust and soil that potentially contains NOA fibers will likely increase the concentration of fibers in the air, precautions should be taken to either minimize participation in the activity or to minimize dust disturbance for the activity, or both.
Information on the U.S. EPA Studies in El Dorado Hills
Information on the ATSDR's studies in El Dorado Hills see the Web Page for the El Dorado County Environmental Management Department.
Information on air monitoring for NOA in Placer County
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What is being done to minimize the disturbance of NOA deposits, or rock formations that may contain NOA, in Placer County?
The District believes that the best and most effective approach to minimizing and preventing impacts from naturally-occurring asbestos is a proactive program that to minimize and control soil disturbance and thereby limit the release into the air of fine particulate matter, including any asbestos fibers that may be present. This approach is one that is endorsed by the State Air Resources Board through the State's adoption of regulations that the District enforces to control and manage dust in areas where NOA may be present.
Since 1986 the District has had a control measure restricting the use of asbestos containing materials in road surfacing applications, one of the earliest adopted in the State, and far in advance of the State Air Resources Board adoption in 1990 of the Asbestos Air Toxic Control Measure for Asbestos-Containing Serpentine Asbestos (revised and re-titled in 2001 as the Asbestos Airborne Toxic Control Measure for Surfacing Applications).
Among other steps taken independently by the District is the adoption of a local dust control regulation in 2003 that is one of the most stringent in the state. This local regulation goes beyond the state's measures by providing standards for the control of sources of fugitive dust, including dust from construction activities, and is not limited in applicability to areas where NOA is found. In the identified areas of higher probability for the presence of NOA and where NOA, or rock potentially containing NOA, is known to be located, the District enforces the implementation of the State's Asbestos Airborne Toxic Control Measure for Construction, Grading, Quarrying, and Surface Mining Operations.
The District recognizes the fugitive dust rule nor the State's asbestos control measures are effective without dissemination the requirements to construction companies and enforcement. Beginning in fiscal year 2002-2003 the District enhanced its presence in the field by adding staff to conduct patrols throughout the County for dust violations and to visit construction sites. The District has advised all land use and public works departments of all Placer County jurisdictions of the requirements for NOA control in land development and construction, and has allied with willing jurisdictions to enforce the dust control and NOA control requirements. The District has also conducted out reach to construction firms operating in Placer County. Among the public out reach efforts has been the development of an informational brochure for homeowners and renters, and a contract with the California Geological Survey of the Department of Conservation to develop improved maps of potential naturally occurring asbestos areas in Placer County to aid the public in identifying these areas of concern. The District seeks to further educate the public and to partner with Placer County jurisdictions to more effectively manage both NOA and dust.
The District has also closely followed the identification of concerns about NOA in El Dorado County and the work conducted by U.S. EPA and ATSDR. This work is of interest because the findings in El Dorado County may translate to potential concerns in any similar area where NOA is located. Any concerns that are raised by the results from the U.S. EPA and ATSDR testing in El Dorado County will be evaluated to determine whether District programs should be modified or enhanced in light of the results. In addition the District will work closely with the California Air Resources Board, U.S. EPA, air districts, and other public entities to implement any future NOA control recommendations that arise are appropriate for our area, and to disseminate any new findings.
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Members of the public can aid the District in controlling dust, in general, by reporting any dust from construction sites and from other activities where soil is disturbed. In particular, it is of concern to the District if the dust crosses a property line or a public road, or if a plume of dust rises into the air. Contact the District at 530-745-2330. After hours or on weekends, a call to that number will be routed to the Placer County Sheriff's Dispatch Office, to notify District on-call staff. |
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What is asbestos exposure and why is asbestos exposure a concern?
Asbestos exposure primarily results from breathing in asbestos fibers, and less commonly from ingesting asbestos fibers. Asbestos is made up of fibers so small that you cannot see them. If rocks, soil, or products containing asbestos are disturbed, they can release asbestos fibers into the air. These fibers can be breathed into your lungs and could remain there for a lifetime. In some cases, the fibers might damage the lungs or membranes that cover the lungs, leading to illness or even death. Most people don't show any signs or symptoms of asbestos-related disease until 10 to 20 years or more after they were exposed.
Information about the Health Effects of Asbestos
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What can I do to reduce my exposure and that of my family to NOA fibers?
Because there is no level of asbestos exposure established that is deemed to be without risk, and because of a latency period of 10 to 20 years or more for any signs or symptoms of asbestos related disease to appear, precautions should be taken to minimize exposure to dust that potentially contains asbestos fibers.
The Agency for Toxic Substances and Disease Registry (ATSDR), part of the Department of Health and Human Services, has provided the following advice to limit your exposure to potentially asbestos fiber containing dust, if you live in an area where NOA has been disturbed and is likely to become airborne:
- Walk, run, hike, and bike only on paved trails.
- Play only in outdoor areas with a ground covering such as wood chips, mulch, sand, pea gravel, grass, asphalt, shredded rubber, or rubber mats.
- Pave over unpaved walkways, driveways, or roadways that may have asbestos-containing rock or soil.
- Cover asbestos-containing rock or soil in gardens and yards with asbestos-free soil or landscape covering.
- Pre-wet garden areas before digging or shoveling soil.
- Keep pets from carrying dust or dirt on their fur or feet into the home.
- Remove shoes before entering your home to prevent tracking in dirt.
- Use doormats to lower the amount of soil that is tracked into your home.
- Keep windows and doors closed on windy days and during nearby construction.
- Drive slowly over unpaved roads.
- Use a wet rag instead of a dry rag or duster to dust.
- Use a wet mop on non-carpeted floors.
- Use washable area rugs on your floors and wash rugs regularly.
- Vacuum your carpet often using a vacuum with a high efficiency HEPA (High Efficiency Particulate Air) filter.
Additional websites with information on asbestos include:
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