CALIFORNIA AIR RESOURCES BOARD
Auditorium, First Floor
400 "P" Street
April 12, 1990
90-3-1 Semi-Annual Report on the South Coast Plan ---
90-3-2 Public Hearing to Consider the Adoption of 001
a Regulation Establishing a Test Method for
the Determination of Asbestos Content of
90-3-3 Public Hearing to Consider the Adoption of 046
an Airborne Toxic Control Measure for Asbestos-
Containing Serpentine Rock in Surfacing
90-3-4 Consideration of an Appointment to the Research ---
ITEM NO.: 90-3-2
Public Hearing to Consider Adoption of a Regulation Establishing
a Test Method for the Determination of Asbestos Content of
The staff recommends that the Board adopt Section 94147, Title
17, California Code of Regulations, which incorporates by
reference Method 435, Determination of Asbestos Content of
The Board is authorized by Health and Safety Code Section
39607(d) to adopt procedures ("test methods") to determine
compliance with its nonvehicular (stationary source) emission
standards and those of the districts.
The ARB staff is proposing the adoption of method 435 -
Determination of Asbestos Content of Serpentine Aggregate. This
method can be used to determine the asbestos content in
serpentine aggregate in piles, on conveyor belts, or on surfaces
such as roads and parking lots. The sampling method is adapted
from a number of American Society for Testing Materials sampling
methods. A minimum of three grab samples are taken per 1000 tons
of serpentine aggregate. The grab samples can be obtained with a
shovel, insertion tube, hand trowel, augers, or automated
sampler. The grab samples are composited and crushed to no
larger than three-eighths of an inch. A one pint sample of the
composited material is further crushed with a Braun Mill to
produce a material of which the majority will be less than 200
mesh (Tyler equivalent).
The analytical method employs polarized light microscopy and a
particle counting technique. The number percent of asbestos
concentration is the percent asbestos fiber present in 400 random
chosen particles. Dispersion staining is used to determine
whether the fiber is asbestos.
The public was given an opportunity to provide comments and
suggestions on the proposed method at four workshops held on July
27, 1989, October 19, 1989, November 28, 1989, and January 30,
1990. Two working group meetings were held on December 15, 1989,
and January 5, 1990, to provide the staff with additional
Adoption of standardized test methods promotes uniformity and
quality assurance in testing activities. Standardized test
methods support and enhance such activities as compliance
determination and emission inventory.
SUMMARY OF IMPACTS OF PROPOSED BOARD ACTION
Significant issues and public comments raised at workshops have
been addressed by subsequent revisions to the proposed test
method. The staff believes that adoption of the proposed method
would not result in any significant adverse air quality,
environmental, or economic impacts.
In a separate rulemaking scheduled for April 12-13, 1990, the
Board plans to consider adoption of an airborne toxic control
measure for asbestos-containing serpentine rock in surfacing
applications. The proposed toxic control measure would, with
some exceptions, prohibit the sale and application of serpentine
material for surfacing applications where the serpentine material
is determined to have an asbestos content greater than one
percent as measured by Method 435. If the Board adopts the
proposed airborne toxic control measure, Health and Safety Code
Section 39666(d) requires districts to adopt the control measure
or one equally effective or more stringent.
ITEM NO.: 90-3-3
Public Hearing to Consider the Adoption of the Proposed Control
Measure for Asbestos-Containing Serpentine Rock in Surfacing
The staff recommends that the Board adopt a regulation
eliminating the sale and use of asbestos-containing serpentine as
surfacing material. The staff also recommends that the Board
direct the Executive Officer to issue a nonbinding advisory to
all schools, preschools, and day-care centers informing them of
the potential health hazards of having areas surfaced with
asbestos-containing serpentine rock.
In March 1986, the Air Resources Board identified asbestos as a
toxic air contaminant. The most common form of
naturally-occurring asbestos found in the state is chrysotile,
which is found predominantly in serpentine rock. Although many potential
sources of airborne asbestos fibers are currently regulated with
serpentine rock, which can be potential sources of airborne
asbestos, are not uniformly regulated. These sources include
surfaces covered with serpentine rock that are subjected to
physical disturbances, such as roads, parking lots, and
The staff, along with the air pollution control districts
represented on the Technical Review Group (TRG) Asbestos
Committee, believe that the use of serpentine as a surfacing
material can pose significant potential health risks to the
public. The staff report presents the staff's findings with
regard to the potential health benefits, cost impacts, and
environmental impacts of the proposed regulation.
Serpentine and Asbestos
In California, serpentine rock is sometimes used as a surfacing
material for unpaved areas (e.g., unpaved roads, playgrounds, and
parking lots). Serpentine is usually recognizable by its
characteristic pale green to greenish black color. Asbestos
fibers from asbestos-containing serpentine rock are released into
the ambient air by physical disturbances, such as vehicle travel
on unpaved roads.
The Regulation and the Advisory
The proposed regulation would substantially reduce asbestos
emissions from unpaved areas surfaced with asbestos-containing
serpentine (defined as serpentine with greater than one percent
asbestos) by eliminating its future use as a surfacing material,
suppliers would have to test the rock and report the asbestos
content to the buyer. Suppliers of serpentine would also be
required to inform buyers if the serpentine material they are
purchasing is illegal for use on surfaces (that is, if it
contains greater than one percent asbestos).
The proposed nonbinding advisory would inform schools,
pre-schools, and day-care centers of the potential health hazard
associated with having asbestos-containing serpentine rock on
playgrounds or other surface areas.
Potential Health Benefits
Implementation of the regulation would provide a reduction in
public exposure to asbestos near areas that would otherwise be
surfaced with asbestos-containing serpentine rock.
The available data indicate that high asbestos concentrations can
occur near serpentine roads with vehicle travel and when
serpentine rock is otherwise disturbed by human activities. The
estimated potential risks associated with these concentrations
are as high as hundreds of thousands of cancer cases per million
people exposed. (The best estimate of the potential risk is tens
of thousands per million).
By eliminating the future use of asbestos-containing serpentine
rock, existing serpentine surfaces would eventually be replaced
with other types of rock, such as limestone, river rick, or
serpentine rock that contains less than one percent asbestos.
The proposed regulation would prevent the addition of
asbestos-containing serpentine to existing roads during
maintenance and would, thus, result in a phase-out over time of the
serpentine rock now on roads.
The staff believes that areas surfaces with asbestos-containing
serpentine rock located at schools or day-care centers may expose
children to potentially harmful levels of asbestos. By
following our advisory, this preventive action would protect the
health of children.
Potential Cost Impacts
The proposed regulation would have a financial impact on
serpentine quarries, buyers of road surfacing material, and air
pollution control districts.
If serpentine quarries choose to market serpentine rock for
surfacing applications, they would incur costs due to testing for
asbestos, loss of market, and reduced demand for serpentine. The
costs due to testing are estimated to range from $100 to $230 for
each 1,000 tons of material tested (about a 4 percent increase in
the current price of serpentine material).
Buyers of road surfacing material would incur increased costs by
having to choose an alternative to serpentine rock for their
surfacing applications, or choosing to pave. The most likely
alternatives are more expensive, partly because of increased
transportation costs. The total costs of building a road with
either limestone or river rick are estimated to be about 25 to 35
percent higher than building an unpaved road with serpentine
material. The cost of building a paved road is about double the
cost of building an unpaved road.
Some air pollution control districts would incur costs due to
routine inspections of serpentine sellers and buyers, and
possible testing of serpentine rock that is offered for sale.
However, state law allows districts to charge permit fees that
cover the increased costs that districts would incur as a result
of this regulation. Any increase in expense for adding scrutiny
of records to a quarry inspection should be minor and it could be
recovered with fees.
Potential Environmental Impacts
The proposed regulation may result in significant adverse
environmental impacts in that a slight increase in vehicular
emissions may occur if alternative surfacing materials are
imported to the affected areas. However, we believe that the
regulations will result in significant reductions in asbestos
emissions, and an accompanying health benefit from reduced human
exposure to asbestos, and that this consideration overrides any
adverse environmental impact that may occur as a result of any
slight increase in vehicular emissions.
We know of no feasible mitigation measures or alternatives that
would substantially reduce vehicular emissions while at the same
time providing the overall health benefit realized by the
significant reductions described above. No adverse impacts on
water and land are expected.
Schools and day-care centers may choose to follow our nonbinding
advisory and remove serpentine rock from playgrounds and other
areas. Wetting the material during removal could mitigate any
asbestos emissions resulting from the removal. Asbestos-containing
serpentine, however, may be considered a hazardous
waste and removal could result in an additional burden to
landfills. Such impacts may not occur if serpentine material can
be reused as fill, road base, or in other nonsurfacing
applications to prevent such impacts.
The staff is aware of the potential economic and environmental
impacts of this regulation. The staff is also aware of the
uncertainties that exist in the data supporting this proposed
regulation. However, California law states that "while absolute
and undisputed scientific evidence may not be available to
determine the exact nature and extent of risk from toxic air
contaminants, it is necessary to take action to protect public
health". The staff believes this proposed regulation is
reasonable and will reduce public exposure to asbestos emissions
in areas where asbestos-containing serpentine rock is currently
used as a surfacing material.