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Last Updated: Wednesday, January 17, 2018 3:08 PM

Naturally Occurring Asbestos (NOA) Information

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.

Naturally Occurring AsbestosNaturally Occurring AsbestosNaturally Occurring AsbestosNaturally Occurring Asbestos



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