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Category Asbestos Analysis
Publish Date 10/27/2008
Author ben sublasky
Title CARB 435 & Asbestos Exposure
Introduction Asbestos Analysis - The Right Way

California (CA) Mesothelioma and Asbestos Exposure

Due to its geologic history and location, several types of asbestos occur naturally within California's state lines. The most common form is chrysotile asbestos (known as white asbestos), which accounts for roughly 95 percent of asbestos found in American buildings. Chrysotile asbestos forms in serpentine rock, a metamorphic rock that forms from pressure over time. Located at the convergence of two tectonic plates, California is rich in serpentine rock. California is so abundant in this metamorphic material that it named serpentine its state rock in 1965, and was actually the first state to designate a state rock. Serpentine rock and its parent substance, ultramafic rock, are found in great abundance along fault lines, the Sierra foothills, the Klamath Mountains, and the Coast Ranges of California.

Even though mankind has been aware of asbestos' health hazards since the time of the Greeks, it wasn't until 1990 that the California Air Resources Board (CARB) began to regulate the amount of asbestos in crushed serpentine and ultramafic rock used in surfacing applications (such as gravel on unpaved roads). With an original limit of asbestos contamination (in rock and soil for surfacing) set at 5 percent, the CARB revised the allowable limit to less than 0.25 percent in 1998. The board also added regulations regarding dust emissions from construction, grading, and surface mining in areas with serpentine and ultramafic rock. The California Environmental Protection Agency reports several sources of naturally occurring asbestos emissions, which include unpaved roads or driveways surfaced with ultramafic or serpentine rock, construction activity in ultramafic or serpentine rock deposits, or rock quarrying activities where ultramafic or serpentine rock is present. For the complete article please visit:   http://

What is CARB 435?
In the United States, asbestos has been frequently found in soil or vermiculite.  Within the soil, serpentine rock which are often a component of road material, parking lots, playground surfaces, waste piles and construction sites have been known to contain asbestos fibers which may often be released from serpentine rock formations. Vermiculite is commonly found in building materials that were formerly used for insulation purposes. Additionally, vermiculite was commonly used for potting soils and fertilizers. While utilized for many purposes, one of the most common uses was for a product commonly known as a 'popcorn ceiling'.  These fibers can be identified using modern microscopic techniques. The methodology utilized in the is known as the California Air Resources Board (CARB 435) method - this method requires the 'fine milling' of the sample to create a completely homogenous mixture. This maximizes the possibility of detection and increases the accuracy of quantification. The analysis can be performed via Polarized Light Microscopy (PLM) or Transmission Electron Microscopy (TEM). Both analyses utilize the widely recognized EPA/600/R-93/116 method. The differences between the two are, basically, sensitivity. The PLM method would use a 400 or 1000 point count while the TEM method would be used for a more definitive analysis with sensitivities down to 0.001% by weight.

Matrix Options

This method has many applications for several material types:

  • Soil - because soil is not homogeneous, the milling of these samples is a critical component of the analytical process so that a completely homogenous mixture can be analyzed, which is vital for obtaining the most accurate results possible.
  • Rock – when dealing with naturally occurring asbestos, as found frequently in serpentine rocks, the milling processes can give overall asbestos content of the rock submitted.
  • Vermiculite – often used as insulation in building attics, crawlspaces, and filler insulation, vermiculite often has natural asbestos fibers in varying quantities.
  • Bulk Material – sometimes bulk materials, such as spray applied ceiling material, floor tiles, cement or other building materials with may potentially contain asbestos fibers in uneven distribution.
For additional information about this method,please contact us at 1-888-455-3675, or go to the California Resources Board

About LA Testing:

LA Testing currently services 1,000 clients world-wide. Those clients include IAQ professionals, environmental consultants, abatement firms, restoration firms, environmental engineers, industrial hygienists, construction firms, engineering firms, remediation firms, contractors, mortgage companies, home inspectors, building inspection firms, carpet cleaners, duct cleaners, home owners, home builders, air conditioning contractors, roofing companies, health and safety professionals, hospitals, doctors, manufacturing firms, management firms, real estate firms, landlords, mortgage companies, attorneys, testing firms, laboratories, schools, universities, forensic consultants, health departments, fortune 500 firms and state, local and federal government agencies.

LA Testing currently operates in South Pasadena, CA providing  full analytical services, including environmental microbiology (mold, bacteria, legionella, coliforms, indoor allergens, mycotoxins, endotoxins), DNA based polymerase chain reaction (PCR), asbestos, lead, indoor air quality, industrial hygiene, environmental chemistry, materials, forensic, failure, and mechanical testing. In addition to laboratory services, the firm plans to provide free IAQ seminars,  free sampling workshops and training in the near future.

LA Testing currently holds accreditations with the American Industrial Hygiene Association (AIHA), the AIHA Environmental Microbiology Laboratory Accreditation Program (EMLAP), the AIHA Environmental Lead Laboratory Accreditation Program (ELLAP), the AIHA Industrial Hygiene Laboratory Accreditation Program (IHLAP), the National Voluntary Laboratory Accreditation Program (NVLAP), CA E-LAP and various other state, federal and private accrediting bodies. The lab is also successful participants in AIHA's Proficiency Analytical Testing (PAT), Environmental Lead Proficiency Analytical Testing (ELPAT), and the Environmental Mold Proficiency Analytical Testing (EMPAT) programs. LA Testing maintains a rigorous in-house QA/QC program to ensure that our clients are receiving the most accurate and legally defensible results possible.

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