Contaminants and Waste - Naturally Occurring Asbestos (NOA)
NOA includes several types of naturally occurring fibrous minerals found in serpentine and ultramafic rocks. Serpentine and ultramafic rocks are common in the Sierra foothills, Klamath mountains and coast ranges. NOA is known to occur in Caltrans Districts 1 through 6, 8 9 and 10. Asbestos is a known carcinogen and can be released from these rocks when they are broken and crushed or by weathering and erosion. When NOA is disturbed by construction, grading and other surface activities, asbestos fibers can become airborne. Such activities are regulated by the California Air Resources Board to reduce dust emissions during construction-related activities.
Policy
- Management of Naturally Occurring Asbestos (NOA) Deputy Directive DD-71 (PDF)
- Governor's Office of Planning and Research State Clearinghouse Memorandum Addressing Naturally Occurring Asbestos in CEQA Documents (PDF)
Guidance
- U.S. Environmental Protection Agency (US EPA) asbestos home page
- El Dorado County's asbestos page
- ARB Guidance to Working in NOA areas During Construction Activities (PDF)
Technical Information
- California Geological Survey NOA presentation (PDF)
- California Geological Survey (CGS) asbestos information
- What is Asbestos? (DTSC) (PDF)
- Office of Environmental Health Hazard Assessment (OEHHA) asbestos fact sheet
- Agency for Toxic Substances and Disease Registry (ATSDR) asbestos facts
- NOA in Placer County, California (PDF)