EPA910-R-04-004
United States
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
Office of Environmental Assessment Investigation and Engineering Unit March 2004
Study of Asbestos
Contamination of Former
Vermiculite Northwest / W.R.
Grace Vermiculite Exfoliation
Facility
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Study of Asbestos Contamination of Former
Vermiculite Northwest / W.R. Grace
Vermiculite Exfoliation Facility
March 2004
Jed Januch and Keven McDermott
U.S. Environmental Protection Agency, Region 10
Office of Environmental Assessment
Investigation and Engineering Unit
Seattle, Washington
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Abstract
The Environmental Protection Agency (EPA) has determined that vermiculite ore mined at the former W.R. Grace
vermiculite mine in Libby, Montana, is contaminated with asbestos. Libby ore was processed at vermiculite exfoliation
plants across the country including one located in Spokane, Washington. EPA Region 10 conducted a three phase study at
the Spokane vermiculite exfoliation plant to determine if asbestos fibers in the soil at the site could become airborne when
the soil was disturbed. First, soil samples were taken from several locations within the site boundary and analyzed using
polarized light microscopy and X-ray diffraction. Analysis revealed that most of the asbestos in the soil is similar to the
amphibole asbestos that occurs in vermiculite from Libby, Montana.
In phase two, twelve soil specimens were collected from the site and eleven were agitated inside a laboratory enclosure
equipped with air monitoring equipment. Ten of the soil specimens contained asbestos that became airborne when the soil
was agitated. Filters used for collection of air samples were analyzed with a transmission electron microscope (TEM) and
were found to contain asbestos. The concentration of asbestos found in the air ranged from 0.051 fibers per cubic centimeter
(f/cc) to 10.713 f/cc.
During phase three, EPA staff collected eighteen air samples while performing property maintenance and excavation tasks
at two locations on-site. Personal monitors with air filters were placed in the workers breathing zone and stationary monitors
were placed near the work areas. Some filters were analyzed using phase contrast microscopy (PCM). Six of these samples
contained fibrous material measuring from 0.02 f/cc to 0.25 f/cc of air. Other samples were analyzed using TEM. Four of
these samples contained asbestos fiber concentrations ranging from 0.010 f/cc to 0.045 f/cc of air. Several asbestos fibers
were also detected in filters from stationary air monitors.
Analysis of air samples by TEM showed a majority of the fibers were amphiboles similar to those that occur in
vermiculite from Libby, Montana. Approximately 52% of the airborne asbestos fibers detected in both experiments had
aspect ratios of greater than or equal to 20:1 and approximately 15% of the fibers counted were greater than or equal to
20 jjm in average length.
This study clearly shows that asbestos in the soil at the former vermiculite exfoliation plant in Spokane can be released
into the air when the soil is actively disturbed. Because there is a clear pathway for asbestos to move from contaminated soil
to the air, individuals working on the site can be exposed to potentially hazardous levels of airborne asbestos fibers.
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Acknowledgements
Many people contributed to the quality of this study. We would like to thank our colleagues at EPA Region 10 including
Earl Liverman; Julie Wroble; Bruce Woods, Ph.D.; David Terpening; Marion "Doc" Thompson; Grechen Schmidt; and
Christopher Moffett.
We are grateful to those who provided analytical support: David Frank, PhD., EPA Region 10 for analyzing samples by x-
ray diffraction; Susan Davis, Washington State Department of Ecology, for analyzing our samples by polarized light
microscopy and phase contrast microscopy; and John Harris, MPH, and his staff at Lab/Cor, Inc., for analyzing our samples
by transmission electron microscopy.
We greatly appreciate the assistance of Aubrey Miller, MD, MPH, EPA Region 8 for his technical expertise and
willingness to review early drafts of our report.
We also wish to thank our external peer review team for the valuable comments and insights they provided: Jill Dyken,
Ph.D., P.E., Agency for Toxic Substances and Disease Registry; Mickey Gunter, Ph.D., University of Idaho; and James
Webber, Ph.D., School of Public Health, State University of New York at Albany.
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Table of Contents
Abstract i
Acknowledgments ii
Table of Contents iii
Introduction 1
Background 1
Regulation of Asbestos 1
Minerals Associated with Libby Vermiculite 1
Health Studies Involving Amphibole Asbestos 2
Vermiculite Processing 2
History of the Former Vermiculite Plant in Spokane 3
Property Description 3
Previous Investigations at Site 4
The OEA Study 5
Phase I - General Surveillance of Site 5
Sampling Methods 5
Analytical Methods 5
Polarized Light Microscopy 5
X-Ray Diffraction 6
Results of Analysis 6
Phase II - Air Monitoring in an Experimental Enclosure 6
Sampling Methods 6
Analytical Methods 8
Phase Contrast Microscopy (PCM) 8
Transmission Electron Microscopy (TEM) 8
Results of Analysis 8
Phase III - Task Based Monitoring On-Site 9
Sampling Methods 10
Analytical Methods 12
Results of Analysis 12
Fiber Morphology 13
Risk Analysis 14
Summary 14
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Introduction
The former vermiculite exfoliation plant in Spokane,
Washington, received vermiculite ore from Libby, Montana.
In 2000 and 2001 the EPA Region 10 Office of
Environmental Cleanup (ECL) confirmed the presence of
asbestos in the soil at this site. The following year
investigators with the EPA Region 10 Office of
Environmental Assessment (OEA) were asked to determine
whether asbestos present in the soil at the site could become
airborne when the soil was disturbed, posing a potential
exposure risk to people working on the site. The study also
attempted to further characterize the types of asbestos fibers
present.
The OEA study was conducted between May and October
2002 and consisted three phases:
Background
• general surveillance of the site and collection of soil
samples;
• air monitoring in a laboratory enclosure while soil
samples from the site were agitated;
• air monitoring on site while property maintenance and
excavation tasks were performed.
This report provides background information on Libby
vermiculite and health impacts from asbestos. These are
followed by the a description of the study, the analytical
results and a brief description of potential risk. The OEA
study was conducted under the authority of the
Comprehensive Environmental Response, Compensation
and Liability Act.
Regulation of Asbestos
The Environmental Protection Agency (EPA) and the
Occupational Safety and Health Administration (OSHA) are
the two primary federal agencies that have promulgated
regulations designed to reduce potential exposure to asbestos
in the environment and the workplace. These two agencies
share common definitions of asbestos, but differ on how
asbestos contamination is measured and what response
actions are required.
EPA and OSHA currently regulate only six forms of
asbestos: chrysotile, amosite, crocidolite, anthophyllite,
actinolite, and tremolite. All are members of the amphibole
group of minerals with the exception of chrysotile, which is
a member of the serpentine group of minerals.1 The EPA
regulates asbestos under the Clean Air Act (CAA), the
Toxic Substances Control Act (TSCA), and the
Comprehensive Environmental Response, Compensation
and Liability Act (CERCLA). For the purposes of this
report, the term asbestos will be used to describe fibrous
minerals, some of which are not specifically included in the
CAA or TSCA, but are subject to regulation under
CERCLA.
CERCLA and Chapter 40 of the Code of Federal
Regulations (CFR) allow EPA to abate, prevent, minimize,
stabilize, mitigate, or eliminate any release or threat of
release of hazardous substances or pollutants and
contaminants where such release results in a threat to public
health or welfare of the United States or the environment.
Among the criteria used to determine if a threat exists
include:
• actual or potential exposure to nearby populations from
hazardous substances or pollutants and contaminants;
• high levels of hazardous substances or pollutants or
contaminants in soils at or near the surface that may
migrate;
• weather conditions, such as wind, that may cause
hazardous substances or pollutants and contaminants to
migrate or be released; or
• other situations or factors that may pose threats to public
health or welfare of the United States or the environment.
Minerals Associated with Libby
Vermiculite
Studies of Libby vermiculite have shown the ore contains
varying quantities of amphibole minerals, which have
commonly been referred to as asbestos. A United States
Geological Survey (USGS) study identified several
amphiboles including winchite, richterite, tremolite,
magnesioriebeckite, magnesio-arfvedsonite, and possibly
edenite in Libby vermiculite. The most abundant of these
were winchite, richterite, and tremolite. The USGS also
determined the morphology of a majority of the amphiboles
in their study falls between prismatic crystals and
asbestiform fibers. All of the amphiboles observed, with the
possible exception of magnesioriebeckite, can occur in the
fibrous or asbestiform habit.2 Among the list of amphiboles
present in Libby vermiculite, only tremolite is included by
name in EPA's regulations.3
1 Deer, W.A., Howie, R.A., and Zussmcm, 1992, An Introduction to Rock Forming Minerals, Second Edition, pages 223-275 and 344-352,
Pearson Education Limited, Essex, England.
2 Meeker, G.P., Bern, A.D., Brownfield, I.K., Lowers, H.A., Sutley, S.J., Hoefen, T.M., and Vance, J.S., The Composition and Morphology
of Amphiboles from the Rainy Creek Complex, Near Libby, Montana. American Mineralogist, Volume 88, pages 1955-1969, 2003.
3 Title 40 Code of Federal Regulations, part 763. Asbestos means the asbestiform varieties of: Chrysotile; crocidolite; amosite;
anthophyllite; tremolite; and actinolite.
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Background
Health Studies Involving Amphibole
Asbestos
Asbestos is a Class A human carcinogen that commonly
enters the body through inhalation. Inhalation of airborne
asbestos fibers increases the risk of nonmalignant interstitial
and pleural lung disease, lung cancer, and mesothelioma.4
Several studies have implicated fibrous amphiboles, such as
those found in Libby vermiculite, in cases of asbestos-related
disease.
The National Institute of Occupational Health (NIOSH)
studies show former Libby mine workers had substantial
occupational exposure to asbestos. These studies
documented significantly increased rates of asbestosis and
lung cancer among former workers. Additional asbestos-
related disease was also reported among the household
members of former mine workers and by other Libby
residents who had no known direct connection with the
mining operation.5
EPA Region 8 has been engaged in a long-term site
investigation at the former W.R. Grace vermiculite mine in
Libby, MT. The investigation has generated new
information about asbestos contamination in the vermiculite
ore from that mine. EPA Region 8 has determined that an
imminent and substantial endangerment to public health
exists in Libby due to asbestos contamination.6
Health impacts of exposure to the asbestos contaminated
Libby vermiculite were identified by W.R. Grace as early as
1977. Internal correspondence from the W.R. Grace
Construction Products Division showed ex-employees at
Libby experienced lung cancer at a rate five times the
national average. This conclusion was based on an in-house
study conducted by W.R. Grace. The correspondence stated
"...we have experienced asbestosis in 41.5% of the workers
(with over 10 years' service) in Libby, as well as in 28% of
the workers (with over 10 years' service) exposed to Libby
ore in the expanding plants."7
Other facilities which processed Libby vermiculite ore are
reporting health impacts. A recently published case,
reported in the American Journal of Respiratory and Critical
Care Medicine, described the results of analyzing lung tissue
of a former employee at a vermiculite exfoliation plant in
California. The worker was exposed to the same fibrous
amphiboles as those found in Libby while working two
summers at the California exfoliation plant. This was the
worker's only identified exposure to asbestos during his
career. The worker died of asbestosis fifty years later.8
The American Journal of Industrial Medicine reported on
a case involving an individual who worked for the Air Force,
between 1970 and 1987, packing cans of paint for shipment
two or three hours per day. The cans were packed in boxes
which he filled with vermiculite. He did not wear a
respirator. He knew of no asbestos exposure in the
workplace or home environment. He has been diagnosed
with a probable case of asbestosis.9
A 2003 study of another non-regulated amphibole
implicated the amphibole fluoro-edenite in a cluster of
deaths from pleural mesothelioma.10 These studies provide
evidence that mineral forms of asbestos not specifically
regulated by EPA or OSHA can cause diseases such as
asbestosis, lung cancer and mesothelioma. The risk of
developing these diseases depends upon many factors,
including the chemistry and shape of the fiber, level of
exposure, duration of exposure, the individual's
physiological response to fiber exposure, and the smoking
history of the exposed individual.11
Vermiculite Processing
Vermiculite is produced from ore mined throughout the
world. Processed vermiculite has many desirable properties.
It is absorbent, light weight, and fire resistant and has
numerous uses. Historically, vermiculite has been used for a
variety of products including loose-fill insulation, as a carrier
for agricultural chemicals, and as an additive in potting
soils.12
The vermiculite ore from Libby was mined from an open
pit and beneficiated, crushed, sized, and sorted at the mine
site into vermiculite concentrate. The vermiculite
concentrate was shipped by rail to various exfoliation
facilities around the United States, including the facility
located in Spokane, Washington.
ATSDR, Toxicological Profile for Asbestos (updated), September 2001.
ATSDR, Asbestos, Year 2000 Medical Testing of Individuals Potentially Exposed to Asbestiform Minerals Associated with Vermiculite in
Libby, Montana, A Report to the Community. August 23, 2001.
Fibrous Amphibole Contamination in Soil and Dust at Multiple Locations in Libby Poses an Imminent and Substantial Endangerment to
Public Health, Christopher P. Weis, Ph. D. July 9, 2001.
W.R. Grace correspondence dated May 24, 1977.
Robert S. Wright, Jerrold L. Abraham, Philip Harber, Bryan Burnett, Peter Morris, and Phil West. Fatal Asbestosis 50 years after Brief
High Intensity Exposure in a Vermiculite Expansion Plant. American Journal of Respiratory Critical Care Medicine, Volume 165. Pp
1145-1148, 2002.
Pneumoconiosis in a Vermiculite End-Product User, Thomas Peter Howard, MD, US Veterans Administration, American Journal of
Industrial Medicine, Volume 44, pages 214-217, 2003.
Comba, P., Gianfagna, A., and Peoletti, L, Pleural mesothelioma Cases in Biancavilla are related to a New Fluoro-Edenite Fibrous
Amphibole. Archives of Environmental Health. Volume 58, Number 4, pages 229 -232. April 2003.
ATSDR, Asbestos, Year 2000 Medical Testing of Individuals Potentially Exposed to Asbestiform Minerals Associated with Vermiculite in
Libby, Montana, A Report to the Community. August 23, 2001.
Industrial Rocks and Minerals, 6th Edition, Society for Mining, Metallurgy, and Exploration, Inc. 1994.
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Background
Vermiculite products manufactured at the exfoliation
plant in Spokane, Washington, from ore mined in Libby,
Montana, were sold under the trade name Zonolite. In 2000,
EPA tested samples from a bag of Zonolite Chemical
Packaging Vermiculite and found it was contaminated with a
Figure 1.
Commercial Vermiculite
significant quantity of amphibole asbestos.13 While Zonolite
Chemical Packaging Vermiculite is no longer being
commercially produced, the product was still offered for sale
at two Seattle area stores that sell garden supplies.
History of the Former Vermiculite Plant in
Spokane
The Spokane Vermiculite facility was operated between
1951 and 1973 by two different companies, Vermiculite
Northwest, Inc. and later W.R. Grace and Company. Both
companies exfoliated Vermiculite at the facility, and
packaged and stored commercial Vermiculite products on
site. Records show up to 10,317 tons of Vermiculite were
processed at the site from January 1967 to October 1970.14
The Vermiculite concentrate that was shipped to the
Spokane site was off-loaded on the north side of the
warehouse building. The concentrate was shoveled into a
gas-fueled expansion furnace which heated the ore to
approximately 1000° Fahrenheit (F). Water between the
layered structure of the Vermiculite ore converted to steam
forcing the mineral itself to expand 6 to 30 times its original
thickness. This expansion process is called exfoliation or
popping. The exfoliated Vermiculite went through a cooling
chute and rock separator, after which it was put through a
cyclone device to remove dust before the product was
packaged.15 Dust from the Vermiculite manufacturing
process was generally swept off the floor, out the back door,
and onto the ground on the north side of the warehouse.16
After 1973, the site was occupied by the Wilburt Vault
Company, which manufactured concrete products such as
septic tanks and burial vaults. Spokane County acquired the
site in January 2000 to store heavy equipment.17
Property Description
The Spokane Vermiculite facility is approximately two
acres in size. It is located at 1318 N. Maple Street, Spokane,
WA. The legal description of the property is Parcel B,
portions of Block 23, 24 and 25 of the Chamberlains
Addition.18 It is bordered by Maple Street to the west,
Maxwell Avenue and an alley and private residences to the
north, Cedar Street to the east, and Sharp Avenue, an alley,
private residences, and Spokane County vehicle maintenance
shops to the south.
During the period of study, a portion of the former
warehouse stood on the southwest corner of the site. It has
since been removed. A concrete slab, located east of the
former warehouse, is where the Vermiculite expansion
furnace and Vermiculite concentrate storage were situated.19
Several metal buildings, a concrete bridge abutment which
used to connect with north Walnut Street, and a bluff,
approximately 25 - 35 feet in elevation, are located north of
the warehouse. Remnants of a railroad spur that serviced the
site are located approximately 85 feet north of the warehouse
running east to west.
U.S. Environmental Protection Agency (2000) Sampling and analysis of consumer garden products that contain Vermiculite. EPA 744-
R-00-010
U. S. Environmental Protection Agency, Region 8, review of 103 Vermiculite Northwest, Inc. invoices for the period 1/14/67 to 10/14/70.
Interview on February 19, 2000 with Milton McDaniel, former supervisor at the Vermiculite Northwest/ W.R. Grace Vermiculite
exfoliation plant.
Interview on May 22, 2002 with Tim Groh, former employee at the Vermiculite Northwest/ W.R. Grace Vermiculite exfoliation plant.
U.S. Environmental Protection Agency, Region 10, Office of Environmental Assessment Report on Vermiculite Expansion Facilities
Investigation, May 23, 2000.
Spokane County Tax Records
Interview on May 22, 2002 with Tim Groh, former employee at the Vermiculite Northwest/ W.R. Grace Vermiculite exfoliation plant.
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Figure2.
Map of Spokane
1318 N. Maple Street
Spokane, Washington Broadway
Previous Site Investigations
In 2000 and 2001, Ecology and Environment, Inc.
(E&E), the Region 10 Office of Environmental Cleanup
contractor, conducted two site visits that included sampling
and analysis. During the first site visit, eight samples were
taken. Analysis of the samples identified trace levels of
asbestos in several samples and one sample with a
concentration of 2% asbestos.20 During the second site visit,
twenty-seven samples were collected from various locations.
The analytical results showed trace levels in nine samples
and two samples with concentrations of 2% and 3%.21 The
results were considered in determining sample locations for
the OEA study.
20 Trip Report, TDD: 00-03-0012. Ecology and Environment, Inc.
21 Vermiculite Northwest Removal Site Evaluation Trip Report, Spokane, Washington, TDD:01-07-0014. Ecology and Environment, Inc.
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The PEA Study
The following sections of this report detail the sampling
techniques, analytical methods used in each phase of the
study and results of analysis. The sampling techniques were
developed by OEA and were detailed in a quality assurance
project plan (QAPP) approved by chemists in the EPA
Region 10 Quality Assurance and Data Unit. Modification
of sampling procedures described in the QAPP were
documented in the project notebook.
Phase I - General Surveillance of Site
EPA investigators reviewed available information and
analytical data on the Spokane site to determine where
samples should be taken. Once on site, accumulations of
what appeared to be loose vermiculite concentrate or waste
(stoner) rock were observed in the soil at several locations
on the north and east side of the warehouse. The material
observed was irregular platy mineral approximately 0.25 to
0.5 inches in diameter and black to dark grey in color.
Several white colored fragments of a fibrous mineral were
observed in the soils where the platy mineral was observed,
as shown in Figure 3. Most of the platy mineral and white
colored fragments were observed at depths between 7 and 14
inches below the soil surface. It was evident that the top
layers of soil north and east of the warehouse were fill
material. It also appeared that the dirt road surface east of
the warehouse had been maintained with a road grader.
Figure 3.
Weathered Vermiculite and Amphibole
In some areas under the fill material, OEA investigators
observed a fine light brown to grey colored layer of material
believed to be weathered ash from the 1980 eruption of
Mount Saint Helens. Beneath the ash layer, on the north side
of the warehouse, OEA investigators observed a layer of
suspected vermiculite concentrate or stoner rock at a depth
of approximately 14 inches.
Sampling Methods
On May 22 and 23, 2002, EPA investigators collected
thirteen bulk soil samples from the site for analysis by
polarized light microscopy (PLM). Most of the bulk
samples consisted of approximately four ounces of soil taken
from several locations where suspected vermiculite
concentrate or stoner rock was observed.22 Results of
analysis of samples collected during the previous site visits
by EPA contractors and other information provided during
interviews with former W.R. Grace employees familiar with
the site was also considered.
Three of the bulk soil samples were collected from under
the warehouse building, either through the floor boards or
through sections of a wall. Ten bulk soil samples were
collected from locations around the north and east side of the
warehouse, around the concrete bridge abutment, and across
the hillside northeast of the warehouse. The soil samples
were collected with pre-cleaned stainless steel spoons and
were placed in four ounce glass containers with Teflon® lids.
Analytical Methods
Two different analytical techniques were used in this
phase of the study. Analysis by PLM was used to determine
if asbestos fibers were present in the bulk samples. X-Ray
diffraction was used to more accurately determine the
composition of the white colored fibrous mineral that was
observed in the soils where suspected vermiculite
concentrate or stoner rock was observed.
Polarized Light Microscopy (PLM) Analysis
The Phase I soil samples were analyzed by PLM by the
Washington State Department of Ecology. The PLM
analysis was intended to aid in the identification of areas
where asbestos may be present. This analysis was not
intended to quantify the amounts of asbestos present.
The method used was the Standard Operating Procedure
for the Screening Analysis of Soil and Sediment Samples for
Asbestos Content SOP: EIA-INGASED2.SOP dated
1/11/99.23 The analysis involved placing aliquots of the soil
samples into a test tube, adding water, then agitating. The
contents of the test tube are poured through a 3-inch inside
diameter 60 mesh, 250 micron (|Jin) sieve and the material
left on the sieve is transferred to a plastic dish. Then the
samples were dried and viewed with a stereo microscope to
identify fiber bundles for analysis by PLM.
22 Waste material from the exfoliation process consisting of vermiculite ore that did not "pop ".
21 Method developed in Boston by Scott Clifford, a chemist with the Investigations and Analysis Unit, OEMS U.S. EPA Region I.
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The PEA Study
Fiber bundles were mounted in 1.605 refractive index oil
and analyzed using a Nikon Opti-phot Pol microscope at
200X magnification. Fibers observed were checked for
diagnostic optical properties such as angle of extinction, sign
of elongation, and refractive indices by central stop
dispersion staining.24
X-Ray Diffraction (XRD) Analysis
Several fiber bundles, suspected to be Libby amphibole,
were isolated from four bulk samples and washed with
deionized water. The fiber bundles were hand picked for
analysis by XRD with the aid of a stereo microscope. The
majority of the fiber bundles appeared white, but some also
appeared slightly green. When pressure was applied with
steel forceps, the fiber bundles fragmented into long rigid
fibers. Approximately one gram of fiber bundles was
isolated from bulk soil samples 3, 4, 5, and 10 and combined
into a clean glass vial and submitted for analysis.
XRD analysis was conducted by EPA staff at the
Manchester Laboratory. A sample was disaggregated and
lightly crushed under a hood using a mortar and pestle to
reduce the grain size. Isopropanol was used to prevent
modification of the crystal structure during crushing. An
XRD mount was prepared using an eyedropper to place the
isopropanol slurry with entrained specimen onto a quartz
plate and allowed to dry. The XRD mount was also
examined by optical microscopy.
Mineral identification was conducted using EPA Region
10 Method XRD-QL for Compound Identification by X-ray
Diffraction Analysis. Mineral identification was made by
comparison with reference samples and with the Powder
Diffraction File (PDF) maintained by the International
Centre for Diffraction Data (ICDD).25
Results of Analysis
Eleven of the thirteen samples collected during Phase I
were analyzed using PLM. Eight samples showed the
presence of one or more types of asbestos, both amphibole
and serpentine (chrysotile).
Fiber bundles, such as those shown in Figure 4, were
isolated from soil samples and analyzed by XRD. The
analysis of these fiber bundles revealed the diffraction
pattern was typical of minerals belonging to the amphibole
Figure 4.
Bundles of Fibrous Amphibole Viewed at 20x Isolated from Soil
Samples
group. The diffraction pattern was also compared to a
fibrous sample of Libby amphibole mineral and was found
to be similar. In addition to the amphiboles, a minor amount
of vermiculite and trace amounts of biotite, talc, and calcite
were detected in this sample.
Analysis of one health and safety sample obtained when
specimens were collected from under the warehouse
revealed an asbestos concentration of 0.024 f/cc of air.
Phase II - Air Monitoring in an
Experimental Enclosure
EPA investigators collected twelve larger specimens of
soil that were co-located with twelve of the four-ounce bulk
samples collected in Phase I. The larger Phase II specimens
were needed for tests conducted in a sealed enclosure at the
laboratory where air samples were taken.
Sampling Methods
Each specimen collected for Phase II consisted of
approximately 1 cubic foot of soil with as much of the
vegetation and larger stones removed as possible. The
specimens were identified as Soil(s) 1 through 12, in Table 1
below. Ten were collected on May 22 and 23, 2002, and
two were collected on July 16, 2002. Figure 5 shows the
locations where the specimens were collected.
24 Susan Davis, Microscopist, Washington State Department of Ecology
25 Memo dated 1/30/03 from Dr. DavidFrank, EPARegion 10 Risk Assessment and Evaluation Unit.
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The PEA Study
Table 1.
Phase II - the Dates Collected and Locations for
Soil Specimens 1-12.
Specimen
Number
Soil #1
Soil #2
Soil #3
Soil #4
Soil #5
Soil #6
Soil #7
Soil #8
Soil #9
Soil #10
Soil #11
Soil #12
Date
Collected
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
May 22 & 23, 2002
July 16, 2002
July 16, 2002
Location
under warehouse
under warehouse
east of warehouse
northeast of warehouse
east of warehouse
hillside west of bridge abutment
hillside east of bridge abutment
hillside east of bridge abutment
hillside east of bridge abutment
north of warehouse
top of bluff
railroad track bed
Each soil specimen was placed inside clean stainless steel
pans that were sealed closed for transport to the laboratory.
Due to rainy conditions during sampling, the soil specimens
were wet and not typical of the soil moisture content at this
site during most of the year. To reduce the moisture content
of the soil, the specimens were placed inside a drying oven
for a period of 8-12 hours at 60° centigrade (C). After
removal from the oven, they were allowed to cool for
approximately 12 hours.
After drying, each specimen of soil was tested separately
inside a sealed stainless steel Kewaunee Scientific
Equipment (KSE) glove box. The inside dimensions of the
glove box are approximately 4 feet long by 3 feet high with a
depth of 21 inches at the top and 27 inches at the bottom
(containing approximately 680 liters of air). The glove box
is equipped with a front glass viewing panel and fluorescent
lighting. The air inside the glove box was drawn through 25
millimeter (mm) air monitoring cassettes with 0.45 |Jm
mixed cellulose ester (MCE) filters. The cassettes were
suspended inside the center of the glove box, approximately
14 inches above the work area, and were connected to two
Figure 5
Phase I and II Sample Locations for Soils 1-12. Aerial Photograph Courtesy of Spokane County.
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The PEA Study
Allegro® A-100 Hi Volume sampling pumps with R-3603
Tygon® tubing. Replacement air was introduced into the
glove box during the sample pump operation by two sections
of R-3603 Tygon® tubing. Metal clamps were closed over
the tubing to keep air from escaping the glove box when the
pumps were not operating.
Each specimen of soil was agitated with a stainless steel
spoon for several minutes until airborne dust was visible.
Air samples were collected from inside the work area
approximately 1 hour after the soil was agitated. This
allowed time for larger particles in the air to settle. This was
done to reduce the risk of overloading the air monitoring
filters which would allow for TEM analysis by direct
transfer. Several of the air filters were observed under PCM
to roughly estimate the degree of filter loading. A duplicate
set of samples was collected using approximately the same
air flow and sampling duration as the samples which
appeared optimally loaded when viewed by PCM. The
duplicate samples were shipped to Lab/Cor, Inc., a contract
laboratory, for analysis by TEM.
Three types of air samples were taken for each specimen
of soil studied. A work area background sample was
collected by drawing air with a high volume pump through a
pair of filters for approximately 30 minutes at a flow rate of
2.5 to 3.5 liters per minute, prior to putting the soil into the
glove box. The samples collected during the soil agitation
were collected by drawing air through a pair of filters for
between 12 to 24 minutes at a flow rate of 2.5 to 3.5 liters
per minute.
Between sampling events, while the work area inside the
glove box was being cleaned, a health and safety sample was
collected outside the glove box through a filter connected to
a personal pump used by the investigator. The health and
safety samples were collected for approximately 30 minutes
with a high volume pump at a flow rate of 1.5 liters per
minute. Health and safety samples are used to determine
possible exposure to the staff using the glove box. The
glove box was cleaned with a high efficiency particle
arrestance (HEPA) vacuum and washed down with
deionized water and wiped dry with clean paper towels.
Samples taken during disturbance of the first specimen of
soil tested (Soil 1) were very time consuming to analyze due
to the large number of fibers that needed to be counted.
Based on the difficulty experienced with Soil 1, EPA
investigators decided not to collect air samples using Soil 2.
Analytical Methods
Phase Contrast Microscopy (PCM)
Phase II samples were screened at the Manchester
Environmental Laboratory (MEL) to determine appropriate
particulate loading of the air filters. The method used was
Asbestos by PCM NIOSH 7400.26
The filters were cut into wedges with a surgical steel
knife and placed, particulate side up, on clean glass
microscope slides. The slides were then placed into an
aluminum hot block and 250 micro liters (joL) of acetone
were injected into the inlet port of the hot block, collapsing
the filter wedges. Then 3-5 jjL of triacetin was placed on the
filter wedges to fix them to the slides and cover slips were
applied. The slides were viewed with a Nikon phase
contrast microscope (PCM) at 400X magnification. Fibers
were sized using a Walton-Beckett graticule as reference.
Only fibers greater than 5.0 jam with a length to width
(aspect) ratio27 of greater than 3:1 were counted.28 Fiber
density is reported by MEL in fibers per square millimeter
(f/mm2). This value has been converted to f/cc for this
report.29
Transmission Electron Microscopy (TEM)
Phase II air monitoring samples were analyzed by Lab/
Cor using the NIOSH 7402 method for Asbestos by TEM.30
In accordance with that analytical method, the sample filters
were collapsed in acetone, coated with a thin layer of carbon
at high vacuum, and placed on a 200 mesh copper TEM grid
and allowed to dissolve in acetone until cleared of filter
debris. The analysis was performed with a Philips 410 TEM
equipped with an ED AX PV9800 X-ray analyzer. The
samples were scanned at a magnification of approximately
990X using an accelerating voltage of 100 KV. The
magnification was increased to about 10,OOOX for structure
sizing. Fibers viewed using the NIOSH 7402 method are
counted if they are greater than 5.0 jam in length with an
aspect ratio greater than 3:1.31 Fiber density is reported as
f/cc.
Results of Analysis
The Phase II data demonstrates that the disturbed soil
emitted asbestos fibers under laboratory conditions.
However, air sampling within an experimental enclosure
may not be representative of real life exposures. This should
be considered when comparing the data to regulatory
standards.
26 Asbestos and other fibers by PCM Method 7400 NIOSH Manual of Analytical Methods, Fourth Edition, 8/15/94.
27 The 3:1 aspect ratio is also included in the EPA reference method published in 40 CFR Part 763.121 appendix A.
28 Susan Davis, Microscopist, Washington State Department of Ecology
29 Fibers/cc = f/mm2 x 385 mm2 divided by V (the average flow rate x sample duration) x 1000.
30 Asbestos by TEM Method 7402 NIOSH Manual of Analytical Methods, Fourth Edition, 8/15/94.
31 John Harris, Lab/Cor, Inc., Seattle, Washington
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The PEA Study
Analysis of air samples taken during disturbance of Soil 1
revealed the greatest variety and number of asbestos fibers.
The majority of fibers were serpentine (chrysotile) although
amphibole fibers were present as well. Chrysotile asbestos
may have been added to some of the insulation products
manufactured at this site.32 The total concentration of
asbestos fibers detected in duplicate samples was 10.461 f/cc
of air and 10.713 f/cc.
Figure 6.
Fibers from Soil 12 Observed with a PCM at 400x Magnification
Analysis of samples taken during disturbance of Soil 3, 4,
10, and 12 revealed a number of fibers consisting mostly of
amphibole asbestos. Total concentration of asbestos fibers
detected in duplicate samples taken during disturbance of
Soil 3 was 6.546 f/cc and 4.933 f/cc. Total concentration of
asbestos fibers detected in duplicate samples taken during
disturbance of Soil 4 was 4.818 f/cc and 5.624 f/cc. Total
concentration of asbestos fibers detected in duplicate
samples taken during disturbance of Soil 10 was 0.823 and
1.277 f/cc. The total concentration of asbestos fibers
detected in duplicate samples taken during disturbance of
Soil 12 was 1.526 f/cc and 2.186 f/cc.
Analysis of air samples taken during disturbance of Soils
5, 6, 7, and 11 revealed lower numbers of asbestos fibers.
Total concentration of asbestos fibers detected in duplicate
samples taken during disturbance of Soil 5 was 0.315 f/cc
and 0.205 f/cc. Total concentration of asbestos fibers
detected in duplicate samples taken during disturbance of
Soil 6 was 0.153 f/cc and 0.158 f/cc. Total concentration of
asbestos fibers detected in three samples taken during
disturbance of Soil 7 was 0.096 f/cc, 0.136 f/cc, and 0.051
f/cc. The total concentration of asbestos fibers detected in
duplicate samples taken during disturbance of Soil 11 was
0.262 f/cc and 0.238 f/cc.
Analysis of air samples taken during disturbance of Soil 8
revealed only one sample having numbers of asbestos fibers
detected at a concentration of 0.051 f/cc. Both samples
resulting from disturbance of Soil 9 revealed no asbestos
fibers detected. A summary of Phase II sampling and
analysis are included in Table 2 on page 10.
Figure 7.
Asbestos Fiber on Air Filter Derived from Soil 12 in Phase II
Viewed by TEM
021029-05
21/2
2660
23 x 0.85 (microns)
Winchite
Sample No:
Struc No:
Negative No:
Dimensions:
Identification:
1.0 micron
No asbestos fibers were detected in any of the work area
background samples or the health and safety samples
collected during Phase II of this study.
Phase III - Task Based Monitoring On-Site
Phase III was intended to determine if asbestos could
become airborne if workers on the site disturbed the soil.
Two locations were selected for field exercises.
The first location, designated location C, was on top of
the bluff on the north boundary of the site. This location was
recommended by the ECL On-Scene Coordinator because of
its close proximity to homes near the north side of the site.
The second location, designated location A/B, was between
the warehouse (Area A) and the rail bed (Area B). This
location was selected because results of analysis for samples
collected in Phase II indicated there was a significant
concentration of amphibole fibers in the soil. Figure 8 is an
aerial photograph showing the locations of Areas A, B, and
C as well as the stationary monitoring locations.
32 Interview on May 22, 2002 with Tim Groh, former employee at the Vermiculite Northwest/ W.R. Grace vermiculite exfoliation plant.
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The PEA Study
Table 2.
Phase II - Airborne fiber concentrations associated with soil disturbance under experimental conditions.
Description
Soil 1
Under Warehouse
GPS file Q052223a
SoilS
Concrete Pad
GPS file Q05315b
Soil 4
Area A
GPS file Q052223a
SoilS
East edge of Concrete Pad
GPSfileQ052316a
Soil 6
West of Concrete Bridge Abutment
GPSfileQ052318a
Soil?
Hillside
GPS file Q052318b
SoilS
Hillside
GPS file Q052320a
Soil 9
Hillside
GPS file Q052320b
Soil 10
Area A
GPSfileQ052315a
Soil 11
AreaC
GPS file Q082622b
Soil 12
AreaB
GPS file Q082622a
Sample Number
02244010
02244011
02264106
02264107
02244050
02244051
02244056
02244057
02324660
02324661
02284404
02284405
02284406
02324654
02324655
02274104
02274105
02274111
02274112
02294305
02294306
02314604
02314605
Sample collection
Duration (D), Air Volume (AV)
D= 15 min, AV=2964 cc/min
D= 15 min, AV= 3065 cc/min
D= 12 min, AV= 3034 cc/min
D= 12 min, AV= 3051 cc/min
D= 12 min, AV= 3003 cc/min
D= 12 min, AV= 3004 cc/min
D= 12 min, AV= 3032 cc/min
D= 12 min, AV = 3033 cc/min
D= 12 min, AV= 3123 cc/min
D= 12 min, AV= 3012 cc/min
D= 12 min, AV= 3310 cc/min
D= 12 min, AV= 3323 cc/min
D= 24 min, AV= 3164 cc/min
D= 12 min, AV= 3140 cc/min
D= 12min, AV= 3054 cc/min
D= 12 min, AV= 3159 cc/min
D= 12 min, AV= 3150 cc/min
D= 12 min, AV= 3096 cc/min
D= 12 min, AV= 3056 cc/min
D= 12 min, AV= 3051 cc/min
D= 12 min, AV= 3008 cc/min
D= 12 min, AV= 3132 cc/min
D= 12 min, AV= 3125 cc/min
Total Asbestiform
Minerals by 7402
TEMf/cc (Libby
amphiboles plus
amosite and
chrysotile)
10.461
10.713
6.546
4.933
4.818
5.624
0.315
0.205
0.153
0.158
0.096
0.136
0.075
0.051
ND*
ND
ND
0.823
1.277
0.262
0.238
1.525
2.186
* ND = None Detected
During the sampling period, the wind direction and
velocity fluctuated out of the north and west from 0-5 miles
per hour (estimated). It was also noted the surface layer of
soil at location C was somewhat dry but became more moist
below a depth of three to four inches. Similarly, the soil
below the gravel layer at location A/B was also moist.
Sampling Methods
On October 22 and 23, 2002, OEA investigators collected
air samples from the site as part of the on-site monitoring
phase of this study. Activities that disturbed the soil were
conducted at two locations while air samples were collected
with both stationary air monitors and personal air monitors.
A total of 32 samples was collected during Phase III. Of
these, 12 were personal air monitoring samples for TEM
analysis, 6 were personal air monitoring samples for PCM
analysis, 7 were area monitoring samples (6 analyzed by
TEM and 1 analyzed by PCM) and 7 samples were taken for
quality assurance background and blank samples. To allow
for some comparison of results between TEM and PCM
analytical techniques, 5 samples were analyzed using both
PCM and TEM.
At monitoring location C, investigators performed
property maintenance tasks such as mowing, shoveling,
raking, tilling, and leaf blowing. Two stationary monitoring
stations were set up, one the west side and another on the
east side of the location C.
10
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The PEA Study
Figure 8
Phase III Monitoring Areas A, B, and C. Aerial Photograph Courtesy of Spokane County.
•i
At monitoring location A/B, a trench was excavated from
east to west along the south side of the rail bed and two
trenches along the north side of the warehouse. The trenches
were excavated using a mid-size Kubota tractor equipped
with a back-hoe, shown in Figure 9. The trenches were
between 10 and 15 feet in length and approximately 2 to 3
feet in depth and approximately 1.5 and 2 feet wide. A leaf
blower was used to simulate wind during this activity, and
was also helpful in drying out damp soil.
The ambient air monitored at locations C and A/B was
drawn through 25 millimeter (mm) air monitoring cassettes
with 0.45 |Jin mixed cellulose ester (MCE) filters. The
cassettes were suspended approximately 4 feet above the
ground and were connected to Allegro® A-100 Hi Volume
sampling pumps with R-3603 Tygon® tubing. The pumps
were calibrated before and after the sampling using a
Gilibrator ® electronic micro processor controlled calibration
unit equipped with high flow cell capable of measuring 2 to
30 liters of air/minute.
Figure 9.
Task Based Monitoring in Phase III Excavation at Area A/B
11
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The PEA Study
One EPA worker operated the power equipment while
observers roamed inside the locations and around the
perimeter. The worker operating the power equipment wore
two personal Gilian HFS-513 air sampling pumps connected
with R-3603 Tygon® tubing to either 0.45 |Jm MCE filters
for TEM analysis or 0.8 m MCE filters for PCM analysis.
The observers wore a single Gilian HFS-513 air sampling
pump connected with R-3603 Tygon® tubing to a 0.45 |Jin
MCE filter for TEM analysis. The personal monitoring
pumps were calibrated before and after the sampling using a
Gilibrator ® electronic micro processor controlled calibration
unit equipped with a standard flow cell capable of measuring
20 cc to 6 liters of air per minutes.
Analytical Methods
Air filter samples collected during Phase III were
analyzed using PCM and TEM. The personal monitoring
samples collected during Phase III were analyzed by Lab/
Cor using the NIOSH 7402 method. Stationary monitoring
samples were analyzed using the ISO 10312 method for
direct identification of asbestos in airborne samples.33 This
analysis is similar to the NIOSH 7402 method. Generally
the fibers are counted if they are greater than 5.0 jam in
length with an aspect ratio greater than 5:1. The ISO 10312
method also allows for counting PCM equivalent fibers with
an aspect ratio of 3:1 or greater, which are longer than 5.0
jjm and with a diameter between 0.2 and 3.0 jam.34 Fiber
density is reported as f/cc.
Results of Analysis
Samples derived from personal monitors at Location C
were analyzed using either PCM, TEM, or both. Three
samples from Location C analyzed by PCM contained fibers
with concentrations ranging from 0.11 f/cc to 0.25 f/cc. Six
samples from Location C analyzed by TEM contained no
asbestos fibers. (See Table 3) Two air samples were
collected using area monitors in Location C. These monitors
were located at the east and west ends of the work area. Both
samples were analyzed by TEM. The east stationary monitor
contained one chrysotile fiber and three amphibole fibers.
The west stationary monitor contained one chrysotile fiber.
At location A/B three samples from the investigators'
personal monitors that were analyzed by TEM contained
Table 3.
Phase III - Personal Monitor Sample Analysis Results showing levels detected by PCM and TEM
(9 detects of 18 personal monitoring samples collected)
Description
Soil #11
Soil #11
Soil #11
Soil #12
Soil #12
Soil # 4, 10
Soil # 4, 10
Soil # 4, 10
Soil # 4, 10
Sample No.
02434357
02434363
02434366
02434370
02434372
02434375
02434376
02434377
02434379
Location
Area C on top of bluff
Area C on top of bluff
Area C on top of bluff
Area A/B - rail bed
Area A/B - rail bed
Area A/B - north of
warehouse
Area A/B - north of
warehouse
Area A/B - north of
warehouse
Area A/B - north of
warehouse
Activity
Observer
Equipment operator
- roto till
Equipment operator
- leaf blower
Observer
Equipment operator
- leaf blower
Observer
Observer
Equipment operator
- leaf blower
Observer
Equipment operator
- backhoe
Sample collection
- Duration (D)
- Air Volume (AV)
D= 60 minutes
AV= 1.5 liters/minute
D= 60 minutes
AV= 2.5 liters/minute
D= 60 minutes
AV= 2.3 liters/minute
D= 40 minutes
AV= 2.5 liters/minute
D= 40 minutes
AV= 2.2 liters/minute
D= 72 minutes
AV= 2.4 liters/minute
D= 71 minutes
AV= 1.5 liters/minute
D= 45 minutes
AV= 1.5 liters/minute
D= 72 minutes
AV= 2.4 liters/minute
PCM
fibers/cc
0.25
0.11
0.16
NA
0.02
NA
0.16
NA
0.04
7402 TEM
fibers/cc
NA
ND
ND
0.010
ND
0.033
0.045
ND
NA
ND = None Detected
NA = Not Analyzed
33 Ambient Air-Determination of Asbestos Fibres-Direct-Transfer Transmission Electron Microscopy Method. ISO 10312, First edition
1995-05-01.
34 John Harris, Lab/Cor, Inc., Seattle, Washington
12
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The PEA Study
amphibole fibers. The asbestos fiber concentrations ranged
from 0.01 f/cc to 0.045 f/cc. Three air samples from personal
monitors analyzed by PCM contained fibers with
concentrations ranging from 0.02 f/cc to 0.045 f/cc. The air
sample collected from the area A/B east stationary monitor
analyzed by TEM contained three amphibole fibers. A
summary of the Phase III analysis of personal monitor
samples is included in Table 3.
Phase III results demonstrate that if disturbed, soil at all
three locations will emit asbestos fibers. By performing
simulated property maintenance and excavation tasks,
investigators were able to release measurable amounts of
asbestos fibers that were captured in some of the area
monitors down wind of the activities or in some of the
personal monitors worn by EPA workers.
Figure 10.
Bundles of Fibrous Amphibole Viewed at 200x by PLM
Dispersion Staining Objective in 1.605 Refractive Index Liquid
Fiber Morphology
During the OEA study the majority of asbestos observed
appeared fibrous. Images captured using various microscopic
techniques (P.M., PCM, TEM, and stereo-microscope)
clearly show asbestos fibers and/or fiber bundles in several
samples. (See figures 2, 3, 4, 5, and 7) Approximately 52%
of the total asbestos fibers counted by TEM during Phase II
and III had an aspect ratio of 20:1. Approximately 15% of
the fibers counted were greater than or equal to 20 jam in
average length. The analytical methods used in this study
did not count fibers less than 5 jam in average length and less
than 0.2 jam in average width. It is important to note that
shorter thin fibers less than 5.0 jam in length may have
toxicological significance.
13
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Risk Analysis
Data from analysis of samples collected at this site during
Phases II and III were used by OEA to perform a risk
analysis for potential future on-site residents and workers.
This analysis does not address residents that currently live
adjacent to the site because no samples were collected from
their homes or yards.
Using standard conservative assumptions about inhalation
rates, exposure frequency and exposure duration, the data
suggest elevated risks to on-site workers or residents. The
physical characteristics (length and diameter) of the Libby
amphiboles identified in study samples analyzed likely
contribute to greater toxicological potency and therefore
greater risk than reflected in EPA's current inhalation unit
risk value.35
While the risk of exposure to Libby amphiboles from this
site may be minimized if the soil is left undisturbed, the
potential for risk of exposure would likely increase if
contaminated soil is disturbed enough to suspend asbestos
fibers in air through excavation or wind erosion.
Summary
The OEA study of the former vermiculite processing
facility in Spokane, Washington, revealed that asbestos in
the soil can become airborne if the soil is disturbed.
Even when the asbestos concentrations in the soil appear
very low by PLM, agitation of asbestos contaminated soil in
a laboratory enclosure resulted in a very high concentration
of airborne fibers.
During on-site excavation and property maintenance
activities, air monitoring revealed the concentration of
asbestos fibers at levels which suggest an elevated risk.
Therefore, the asbestos contaminated soil at this site may
pose a potential health hazard for workers involved in future
excavation and development of the property
35 Memo regarding Vermiculite Expansion Plant, Spokane, WA, Preliminary Risk Assessment, Julie Wroble, Toxicologist, U.S.
Environmental Protection Agency, Region 10, May 29, 2003.
14
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