This page last reviewed May 18, 2017
The California Air Resources Board announces the release of
the Implementation Guidance Document for Test Method 435 Field Sampling and
Laboratory Practices.
This guidance document is intended to be used in conjunction
with the regulation, Test Method 435, to assist laboratories, consultants,
local air pollution control districts, and other asbestos stakeholders in the
application and performance of M435.
Test
Method 435 (M435) (Cal.
Code Regs., tit. 17, § 94147), entitled "Determination of Asbestos Content of
Serpentine Aggregate," was recommended for adoption during hearings of the
Air Resources Board (ARB or Board) in April 1990, in support of the Asbestos
Airborne Toxic Control Measure (ATCM) for Surfacing Applications (Cal. Code
Regs., tit. 17, § 39106). This ATCM aims to reduce public exposure to
naturally occurring asbestos (NOA) by limiting the asbestos content of
surfacing materials. In 2001, the Board also recommended for adoption the
Asbestos
ATCM for Construction, Grading, Quarrying, and Surface Mining Operations (Cal.
Code Regs., tit. 17, § 39105) to minimize generating asbestos-containing dust
during those activities. This second
ATCM also references M435 as an approved test to measure the asbestos content
of bulk materials.
In response to stakeholders who were receiving variable M435
results from analyses of the same samples by different laboratories, ARB staff
conducted a M435 Interlaboratory Study (ILS).
The ILS identified variability in laboratory equipment and procedures
that can significantly affect the reported asbestos content of M435 rock and
soil samples. Following this, all
aspects of the test method were studied.
This non-regulatory guidance document consists of clarifications and
recommendations developed by ARB staff through years of method testing and
iterative consultations with many asbestos stakeholders during public
workshops, surveys, and presentations in scientific meetings. It is expected that using the guidelines in
this document during the collection, processing, and analysis of potential
asbestos-containing aggregate samples will result in more accurate and
repeatable M435 asbestos content measurements.
If you would like to subscribe to the list server for "Naturally-Occurring Asbestos" in order to be advised of changes to this area of the website, please visit the Naturally-Occurring Asbestos list serve homepage for instructions on how to subscribe.
For more information about the M435 revision activities, please contact Patrick Rainey at (916) 327-4756 or Rebecca Neumann at (916) 324-1145.