Naturally Occurring Asbestos (NOA)

Naturally occurring asbestos includes a group of minerals commonly found in ultramafic and serpentine rock formations. Asbestos can also be found in rock near fault zones or in sediments derived from these rocks.

Ultramafic rock is made up of 90 percent or more of dark colored iron-magnesium-silcate minerals. Serpentine commonly occurs in metamorphic areas throughout the state.

Naturally occurring asbestos can be released when the rock is broken or crushed. This may happen when cars drive over unpaved roads or driveways surfaced with these rocks, or when land is graded.

Asbestos is also released naturally through weathering and erosion. Once released from rock, asbestos can become airborne. The primary pathway for human exposure to asbestos is through inhalation of dust particles containing asbestos. All forms of asbestos may cause serious health effects, including respiratory disease or cancer.