Naturally Occurring Asbestos

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 and in some cases, may result in damage to 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.

The brochure Asbestos-containing Rock and Soil: What California Homeowners Need to Know (PDF) is available for homeowners or renters who are concerned about naturally occurring asbestos.

Note: The Placer County Air Pollution Control District is not delegated for Asbestos NESHAP enforcement, and accordingly notices concerning asbestos in construction and demolition should be referred to the California Air Resources Board. Any questions regarding requirements for asbestos in construction materials should be made to the staff of the Air Resources Board or the staff of the U.S. Environmental Protection Agency.

Construction & Grading Requirements in NOA Areas

A Naturally-Occurring Asbestos Dust Mitigation Plan (ADMP) Guidance (PDF) has been developed to assist in the enforcement of the State’s Asbestos Airborne Toxic Control Measure for Construction, Grading, Quarrying, and Surface Mining Operations, and APCD Rule 228, Fugitive Dust requirements. The District requires that if an area to be disturbed is greater than one acre, and an owner/operator is subject to asbestos ATCM requirements, an Asbestos Dust Mitigation Plan must be submitted to the Air Pollution Control Officer (APCO). The Guidance uses the Enhanced Map by CGS and its derivatives to determine if an Asbestos Dust Mitigation Plan is required. 

Use of the ADMP Guidance Application form is encouraged as submission of an original plan will be subject to increased fees due to additional review time required in the approval process. For further information, view the Construction and Grading in NOA areas page.