AIRBORNE ASBESTOS CONCENTRATIONS
DURING BUFFING OF RESILIENT FLOOR
TILE
by
Environmental Quality Management, Inc.
Cincinnati, Ohio 45240
and
Environmental Health Service
New Jersey Department of Health
Trenton, New Jersey 08625
EPA Contract No. 68-D2-0058
Project Officer
Aaron R. Martin
Stationary Source Compliance Division
U.S. Environmental Protection Agency
Washington, D.C. 20460
and
Technical Project Officer
Alva Edwards
Water and Hazardous Waste Treatment Research Division
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
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DISCLAIMER
The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency under Contract 68-D2-0058 to Pacific
Environmental Services, Inc., and under Subcontract No. SSCD-92-01 to
Environmental Quality Management, Inc. It has been subjected to the Agency's peer
and administrative review, and it has been approved for publication as an EPA
document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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FOREWORD
Today's rapidly developing and changing technologies and industrial products
and practices frequently carry with them the increased generation of materials that, if
improperly dealt with, can threaten both public health and the environment. The U.S.
Environmental Protection Agency (EPA) is charged by Congress with protecting the
Nation's land, air, and water resources. Under a mandate of national environmental
laws, the Agency strives to formulate and implement actions leading to a compatible
balance between human activities and the ability of natural systems to support and
nurture life. These laws direct the EPA to perform research to define our
environmental problems, to measure the impacts, and to search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning,
implementing, and managing research, development, and demonstration programs to
provide an authoritative, defensible, engineering basis in support of the policies,
programs, and regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes, and Superfund-related
activities. This publication is one of the products of that research and provides a vital
communication link between the research and the user community.
This report provides information on airborne asbestos concentrations measured
during routine spray buffing of asbestos-containing resilient floor tile in New Jersey
schools.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
HI
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ABSTRACT
Although asbestos-containing resilient floor tiles are considered nonfriable, the
frictional forces exerted on the tile during routine maintenance operations can
generate asbestos-containing structures. A study was conducted to determine the
level of airborne asbestos concentrations during routine spray buffing of asbestos-
containing floor tiles at 17 schools in northern, central, and southern New Jersey.
Although the schools selected do not represent a statistical random sample, they do
represent a cross section of floor conditions and floor-care maintenance practices.
Increased airborne asbestos levels during spray buffing were measured at 12 of
the 17 schools. The increase was statistically significant at 7 of the 17 schools.
Overall, the mean relative increase in airborne asbestos concentrations during spray-
buffing with the high-speed machines (1000 to 1500 revolutions per minute) was
statistically significantly higher than that during buffing with low-speed machines (175
to 330 revolutions per minute). More than 99 percent of the asbestos structures
collected before and during spray buffing were chrysotile; less than 1 percent were
amphibole. Machine speed appeared to have a significant effect on the structure
morphology of the airborne asbestos structures generated during spray-buffing.
Results of the study indicate that spray-buffing can generate asbestos-containing
particles from the surface of asbestos-containing resilient floor tile. The estimated
8-hour time-weighted average (TWA) of total fiber concentrations (0.093 f/cm2
maximum) in the breathing zone of the machine operators (as determined by phase
contrast microscopy) did not exceed the OSHA action level of 0.1 f/cm3, 8-hour TWA.
Environmental Quality Management, Inc., submitted this document to the U.S.
Environmental Protection Agency's Office of Research and Development, Risk
Reduction Engineering Laboratory, in fulfillment of Contract No. 68-D2-0058. The
IV
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report covers the period of July to December 1992, and work was completed as of
December 31, 1992.
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CONTENTS
Disclaimer jj
Foreword iii
Abstract iv
Figures viii
Tables ix
Acknowledgments x
1. Introduction 1
Background 1
Objectives 2
2. Conclusions and Recommendations 3
Conclusions 3
Recommendations 4
3. Study Design and Methods ' 5
Sampling Strategy 5
Sampling Methods 6
Analytical Methods 8
Statistical Methods 9
4. Quality Assurance 11
Sample Chain of Custody 11
Sample Analyses 11
5. Results and Discussion 15
Study-Site Characteristics 15
Airborne Asbestos Concentrations Before and During
Spray-Buffing 20
Airborne Asbestos Concentrations Based on Frequency
of Spray-Buffing 29
Personal Breathing Zone Concentrations of Total Fibers 29
Paired TEM and PCM Analyses 31
Characterization of Bulk Floor Tile Surface 31
Characterization of Surficial Asbestos Structures 33
Morphology and Size Distributions of Asbestos Structures 33
Particulate Loading on Filters 40
References . 42
vi
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CONTENTS (continued)
Appendices
A Individual Airborne Asbestos Concentrations (Determined by TEM)
Before and During Buffing of Asbestos-Containing Resilient Floor Tile 43
B Distribution of Airborne Asbestos Structures Measured at Each School
(Percentages of Total Number of Asbestos Structures) 48
C Cumulative Size Distributions of Asbestos Structures Measured Before
and During Buffing at Each School (Cumulative Percentages) 52
D Size Distribution of Asbestos Structures in Air Samples Collected
Before and During Buffing of Asbestos-Containing Floor Tiles in
Each of the 28 Study Areas at 17 Sites 56
E Percent Occlusion of Grid Openings by Paniculate 86
vii
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FIGURES
Number Page
1 Average Airborne Asbestos Concentrations (Measured by TEM) Before
and During Buffing of Asbestos-Containing Resilient Floor Tile 26
2 Scanning Electron Micrograph of Bulk Floor Tile Surface from an
Area in Poor Condition 32
3 Scanning Electron Micrograph of a Bulk Floor Tile Surface from an
Area in Good Condition 34
4 Transmission Electron Micrograph of Tape Lift Sample Taken
Before Buffing 35
5 Airborne Matrix Observed in a Sample Collected During Buffing 38
VII!
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TABLES
Number , £§33.
1 Data Summary for Replicate Analyses 13
2 Data Summary for Duplicate Analyses 13
3 Characteristics of the Resilient Floor Tile at Each Study Site 16
4 Description of Resilient Floor Tile Maintenance Practices 18
5 Characteristics of Floor Buffing Equipment and Materials 21
6 Summary of Airborne Asbestos Concentrations Measured By TEM
Before and During Buffing of Floor Tile 24
7 Total Fiber Concentrations During Buffing of Resilient Floor Tile
(as Measured by PCM) 30
8 Paired PCM and TEM Analyses for Selected Samples 31
9 Overall Distribution of Asbestos Structures Measured Before and
During Buffing of Resilient Floor Tile (Percentages) • 36
10 Distribution of Asbestos Structures Measured Before and During
Low and High Speed Buffing of Resilient Floor Tile (Percentages) 37
11 Cumulative Size Distribution of Asbestos Structures Measured
Before and During Buffing of Resilient Floor Tile
(Cumulative Percentages) s 39
12 Size Distribution of Asbestos Structures Measured, Before and
During Low and High Speed Buffing (Percentages) 39
IX
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ACKNOWLEDGMENTS
This document was prepared for EPA's Office of Research and Development in
fulfillment of Contract No. 68-D2-0058. Aaron R. Martin served as the EPA Project
Officer, Thomas J. Powers served as the EPA Work Assignment Manager, and Alva
Edwards served as the EPA Technical Project Officer. Special appreciation is
extended to Patrick J. Clark of EPA's Risk Reduction Engineering Laboratory (RREL)
and to the staff of RREL's Transmission Electron Microscopy Laboratory for
conducting the analyses of the air samples. Review comments and suggestions
offered by Bruce A. Hollett, CIH, Kin F. Wong, Ph.D., and Robert M. Jordan, Ph.D. of
EPA are sincerely appreciated. Also greatly appreciated are the administrative efforts
of Roger C. Wilmoth of RREL
This document was written by John R. Kominsky and Ronald W. Freyberg of
Environmental Quality Management, Inc. (EQ) and James A. Brownlee, Donald R.
Gerber, Gary J. Centifonti, and Richard M. Ritota of the Environmental Health Service,
New Jersey Department of Health (EHS-NJDOH). The authors also acknowledge the
technical contributions of Edward Millerick, Cynthia Mitchell, and John Sharp of EHS-
NJDOH. The authors also acknowledge Kim A. Brackett, Ph.D. for preparation and
interpretation of the morphological data.
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SECTION 1
INTRODUCTION
Although no longer manufactured in the United States, asbestos-containing
resilient floor tiles are installed in residential dwellings, institutions, commercial and
public office buildings, and industrial facilities. The organic matrix in floor tiles may be
either asphalt or polyvinyl chloride, and their dimensions are either 9 in. by 9 in. or
12 in. by 12 in. The asbestos in nearly all floor tiles is chrysotile, which is dispersed
throughout the thickness of the tile. Although these floor tiles are considered
nonfriable, the frictional forces exerted on these materials during routine floor-care
maintenance operations can generate asbestos-containing particles.
Background
The principal types of maintenance performed routinely on resilient floor tiles
include spray buffing and dry burnishing, and wet scrubbing and stripping followed by
refinishing. The U.S. Environmental Protection Agency (EPA), school districts, and the
Resilient Floor Covering Institute have monitored airborne asbestos levels during wet
stripping of asbestos-containing floor tiles.1 ** These studies have shown elevated
levels of asbestos structures in the air during the stripping operation (based on
transmission electron microscopy), but the 8-hour time-weighted average (TWA)
concentrations (based on phase contrast microscopy) were below the Occupational
Safety and Health Administration (OSHA) permissible exposure limit and action level
of 0.2 and 0.1 fiber per cubic centimeter of air, respectively. If the action level is
exceeded, periodic personal air monitoring, employee training, and medical
surveillance are required (29 CFR 1910.1001). The results of the two analytical
techniques differ mostly because phase contrast microscopy (PCM) does not detect
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the smaller fibers (<5 u.m in length and <0.25 )im in width) as measured by
-•if' -'ftf - 'jp; •' !5j5.
transmission electron microscopy (TEM). Also, the OSHA methodology requires a
length to width ratio (aspect ratio) of 3:1 or greater whereas the TEM methodology has
an aspect ratio of 5:1 or greater. In response to concerns raised by school districts
and building managers regarding the release of asbestos structures during stripping
operations, the EPA issued interim guidance on appropriate procedures for the
stripping of asbestos-containing floor coverings.4
Little data are available for evaluating the extent of asbestos structures
released during other floor-care maintenance procedures, such as spray-buffing.2-3
Spray-buffing is the restorative maintenance of a previously polished floor by use of a
suitable floor-polishing machine immediately after the surface has been mist-sprayed
with an appropriate product whereby the wet application is buffed to dryness.5 The
levels of airborne asbestos structures released during spray-buffing could be higher
than those during wet stripping, especially if the floor has been poorly maintained (i.e.,
minimal wax layer), is worn, or is otherwise damaged. The Risk Reduction
Engineering Laboratory (RREL) of the U.S. EPA and the Environmental Health Service
(EHS) of the New Jersey Department of Health (NJDOH) conducted a study to
evaluate airborne asbestos concentrations during routine spray-buffing of asbestos- '
containing floor tile.
Objectives
The objectives of this study were as follows:
1. To determine the airborne asbestos concentrations during routine spray
buffing of asbestos-containing resilient floor tile in a cross section of
schools in northern, central, and southern New Jersey.
2. To compare the fiber concentrations measured by phase contrast
microscopy during routine spray-buffing of asbestos-containing floor tile
with the OSHA action level of 0.1 fiber per cubic centimeter of air,
8-hour TWA.
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
Conclusions
The following are the principal conclusions reached during the study:
0 Spray-buffing can cause asbestos structures to be generated from the
surface of asbestos-containing resilient floor tile. Increased airborne
asbestos concentrations during spray-buffing were measured at 12 of the
17 schools studied. The increase was statistically significant at seven of
these schools.
0 Overall, the mean relative increase in airborne asbestos concentrations
during spray-buffing with the high-speed machines (1000 to 1500 rpm)
was significantly higher than the relative increase during spray-buffing
with the low-speed machines (175 to 330 rpm). On average, airborne
asbestos concentrations were approximately five times higher during
than before spray-buffing with the high speed machines, whereas spray-
buffing with the low-speed machines showed a two-fold increase during
buffing than before.
0 Machine speed appears to have a significant effect on the structure
morphology of the airborne asbestos structures generated during spray-
buffing. The percentage of asbestos fibers observed during high-speed
buffing was approximately 2.5 times greater than that before buffing;
whereas, the percentage of asbestos fibers observed during low-speed
buffing was approximately 1.3 times greater. The percentage of
asbestos matrices measured during high-speed buffing were
approximately 1.2 times lower than before buffing; whereas the
percentage of asbestos matrices measured during low-speed buffing was
essentially unchanged (i.e., <0.4 percent lower).
0 The estimated 8-hour TWA of total fiber concentrations (0.093 f/cm3
maximum) in the breathing zone of the machine operators (as
determined by phase contrast microscopy) did not exceed the OSHA
action level of 0.1 f/cm3, 8-hour TWA.
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Recommendations ••
»».. •*- w- . n
Further research is recommended to study the effect of buffing methods on the
release of asbestos structures from the surface of asbestos-containing resilient floor
tiles. A study should be designed to evaluate the extent of asbestos release during
application of the two buffing methods (low-speed spray-buffing and high-speed dry-
buffing) on three levels of floor care (poor, intermediate, and good). The results of this
study would define the need for and nature of guidance for the buffing of asbestos-
containing resilient floor tiles.
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SECTION 3
STUDY DESIGN AND METHODS
This study was conducted at 17 schools in northern, central, and southern New
Jersey. The selected schools were distributed among eight school districts. Although
these schools do not represent a statistical random sample, they do represent a cross
section of floor conditions and floor-care maintenance operations.
Access to the schools was coordinated directly by the Environmental Health
Service of the New Jersey Department of Health (EHS-NJDOH). The EHS-NJDOH
collected bulk samples of all floor tiles, documented floor-care practices, floor
conditions, and characteristics of the floor-buffing equipment and materials in each
school, as well as other variables that might have an impact on the release of
asbestos structures.
In all of the schools, the existing custodial staff performed the floor-care
maintenance operations. The floors were prepared (i.e., dry and/or wet-mopped) and
spray-buffed in accordance with established practices and procedures at the
respective schools.
Sampling Strategy
The first study objective was to determine whether airborne asbestos
concentrations increase during the spray-buffing of floor tile. This was addressed by
collecting air samples before and during floor-buffing operations. A maximum of two
distinct areas were tested in each school studied. Immediately before buffing
operations began, three baseline, fixed-station, area air samples were collected in
each test area under normal building conditions (i.e., no intentional air disturbance
beyond that attributable to normal occupancy activity in the area). Three personal
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breathing-zone samples were collected during buffing operations for comparison with
•-t:. i. > f
the baseline samples. These samples also were taken under normal occupancy
conditions (i.e., no air disturbance beyond that attributable to the buffing itself). These
samples were collected in the breathing zone of the buffing machine operators so they
would be representative of airborne asbestos levels during spray-buffing operations.
The three baseline and three personal breathing zone samples were analyzed by
transmission electron microscopy (TEM).
The second study objective was to compare total fiber concentrations during
buffing operations with the OSHA action level of 0.1 fiber per cubic centimeter (f/cm3),
8-hour TWA (29 CFR 1910.1001). This was achieved by collecting one sample in the
breathing zone of the machine operator during the spray-buffing in each area. These
samples were collected in accordance with OSHA sampling protocols and analyzed by
phase-contrast microscopy (PCM).
Quality assurance/quality control (QA/QC) samples were also collected at each
school. These consisted of two field blanks (one open and one closed) at each
school. If a second test area was monitored at a school, two additional open field
blanks were collected.
Bulk samples of each type of floor tile present in each school were also
collected to confirm the percentage and type of asbestos in the floor tile.
Sampling Methods
Fixed-Station Area Air Samples
The baseline, fixed-station, area air samples were collected on open-face,
25-mm-diameter, 0.45-jim-pore-size, mixed cellulose ester (MCE) filters with a 5-jim-
pore-size MCE diffusing filter and a cellulose support pad contained in a three-piece
cassette. The filter cassettes were positioned on tripods approximately 5 feet above
the floor, with the filter face at a 45-degree angle toward the floor. The filter assembly
was attached to an electric-powered (110 VAC) 1/6-horsepower vacuum pump
operating at a flow rate of approximately 9 L/min. Air volumes ranged from 564 to
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916 L At the end of the sampling period, the filters were turned upright before being
disconnected from the vacuum pump. They were then stored in this position until they
were analyzed by TEM.
The sampling pumps were calibrated with a precision rotameter (Manostat
Model 36-546-215) both before and after sampling. Because the precision rotameter
is a secondary standard, it was calibrated with a primary airflow standard both before
and after-the study.
Personal Breathing Zone Air Samples
Three personal breathing zone air samples were collected on open-face, 25-
mm-diameter, 0.45-|im-pore-size MCE filters with a 5-jj.m-pore-size MCE diffusing filter
and a cellulose support pad contained in a three-piece cassette. These samples were
analyzed by TEM. A fourth personal breathing zone sample was collected on a 25-
mm-diameter, 0.8-}im-pore-size MCE filter, and a cellulose support pad contained in a
three-piece cassette with a 50-mm conductive extension cowl. The fourth persona!
breathing zone sample was collected in accordance with OSHA protocols and
analyzed by PCM.
The four filter cassettes were positioned in the breathing zone of the buffing
machine operator Each filter was attached to approximately 50 ft. of Tygon tubing
that was attached to an electric-powered (110 VAC) 1/6-horsepower vacuum pump
operating at a flow rate of approximately 9 L per minute. Air volumes ranged from
617 to 970 L. To achieve the target air volume of 600 liters in the time required to
spray-buff the test area, traditional battery-powered, personal sampling pumps could
not be used because of their limited airflow rates (approximately 2 L/min with the
0.45-|im-pore-size MCE filter).
Bulk Floor Tile Samples
Bulk samples were collected of each type of floor tile present in each school.
Each sample consisted of a 2-in. by 2-in. section of floor tile. A 2-in. by 2-in. template
was used to delineate the area on the floor tile. A hammer and wood chisel were
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Bulk Floor Tile Samples
The type and percentage of asbestos in the floor tile were determined by
polarized light microscopy (PLM) analysis in accordance with the EPA test method
"Interim Method for Determination of Asbestos in Bulk Insulation Samples" (EPA
600/M4-82-020). A confirmatory analysis was performed on floor tile from eight of the
17 schools. The samples were analyzed by TEM in accordance with Chatfield's
Method (SOP-1988-02, Revision No. 1: Analysis of Resilient Floor Tile). Portions of a
freshly fractured edge of the bulk samples were analyzed by scanning electron
microscopy (SEM) to examine the condition of the floor tile surface.
Statistical Methods
Descriptive statistics were calculated for each school and each area within a
school. These descriptive statistics included the sample size; arithmetic mean,
minimum, and maximum airborne asbestos concentrations; and the arithmetic
standard deviation. All estimated concentrations were based on the number of
asbestos structures counted. If no asbestos structures were counted in a sample, a
value of 0 s/cm3 was used as the measured concentration. Results of the quality
assurance samples were not included in the statistical analysis of the data.
A two-factor analysis of variance (ANOVA) was used to compare airborne
asbestos concentrations before and during floor buffing. Each school was considered
separately. The experimental factors in the ANOVA analysis were the sample period
(baseline, during) and area within a school (A or B). If only one area was studied at a
school, the analysis was reduced to a one-factor ANOVA, which is equivalent to a
Student's t-test.
The natural logarithm of each measured concentration was used in the ANOVA
analysis. This transformation was used to make variances more equal and to provide
data that are better approximated by a normal distribution. This is equivalent to
assuming that the data follow a lognormal distribution. If one or more samples
showed a measured concentration of 0 s/cm3 at a given school, the transformation
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used to remove the tile, which was then placed in a labeled Ziploc plastic bag. The
exact location of the sample was recorded on a plan drawing of the building.
Analytical Methods
Air Samples
The 0.45-jj.m-pore-size MCE filters were prepared and analyzed in accordance
with the nonmandatory TEM method specified in the Asbestos Hazard Emergency
Response Act (AHERA) Final Rule (October 30, 1987; 40 CFR Part 763). In addition,
the specific length and width of each structure were measured and recorded. A
sufficient number of grid openings were analyzed to ensure a sensitivity (the
concentration represented by the finding of a single structure) of no greater than 0.005
asbestos structure per cubic centimeter of air sampled, unless the degree of loading
made this impractical. Samples were analyzed according to AHERA nonmandatory
TEM counting rules except that some grid openings with greater than 25 percent
particulate matter were analyzed. AHERA specifies that grid openings covered with
greater than 25 percent particulate matter should not be analyzed. This exception to
the AHERA nonmandatory method was made because of the research nature of this
study to obtain additional information.
Each of the 0.8-n.m-pore-size MCE membrane filters was analyzed by phase
contrast microscopy (PCM). These samples were prepared and analyzed according to
the NIOSH 7400 protocol (Revision 3, June 5,1989, National Institute of Occupational
Safety and Health Manual of Analytical Methods). All fibers with a 3:1 (or greater)
length-to-width ratio were counted using the A counting rules. The analytical
sensitivity was approximately 0.01 f/cm3 of air sampled. Although the NIOSH 7400
protocol specifies to reject a graticulate field if an agglomerate covers approximately
one-sixth or more of the field, an exception to this rule was made on some heavily
loaded samples.
8
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ln(x + 0.002), where x is the measured airborne asbestos concentration, was applied
to each measurement before the ANOVA was performed. The constant 0.002 was
chosen to be smaller than the analytical sensitivity for these measurements and was
added to all values (baseline and during) at that school so the comparison would not
be biased. The log transformation was used only for the ANOVA tests; it was not
used for any other part of the data analysis (e.g., data graphs or descriptive statistics).
All statistical comparisons were performed at the 0.05 level of significance.
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SECTION 4
QUALITY ASSURANCE
Sample Chain of Custody
During the study, sample chain-of-custody procedures were an integral part of
both the sampling and analytical activities and were followed for all air and bulk
samples collected. The field custody procedures documented each sample from the
time of its collection until its receipt by the analytical laboratory. Internal laboratory
records then documented the custody of the sample through its final disposition.
Standard chain-of-custody procedures were used. Each sample was labeled
with a unique project identification number, which was recorded on a sample data
sheet along with such information as sampling date, location of the sampler,
starting/stopping rotameter readings, sampling flow rate, starting/stopping times, and
sampling conditions.
Sample Analysis
Specific quality assurance procedures outlined in the AHERA rule were used to
ensure the precision of the collection and analysis of air samples; these included filter
lot blanks, open and closed field blanks, and repeated sample analyses (replicate and
duplicate analyses).
Filter lot blanks, which are samples selected at random from the lot of filters
used in this study, were analyzed to determine background asbestos contamination on
the filters. Five percent (50 filters) of the total number of filters (2000 filters) from the
lot used in this research study were analyzed by the EPA-RREL TEM laboratory. The
filters were prepared and analyzed in accordance with the nonmandatory AHERA TEM
method. The TEM analysis of the 50 0.45-|im-pore-size MCE filters showed a
11
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background contamination level of Q asbestos structures per 10 grid openings on each
* sp • ... .'48 -•£
filter.
Open field blanks are filter cassettes that have been transported to the
sampling site, opened for a short time (<30 sec) without air having passed through the
filter, and then sent to the laboratory. Closed field blanks are filter cassettes that have
been transported to the sampling site and sent to the laboratory without being opened.
Two 0.45-u.m-pore-size MCE field blanks (one open and one closed) and two 0.8-{j.m-
pore-size MCE field blanks (one open and one closed) were collected at each school.
If a second test area was monitored at a school, two additional open field blanks were
collected (one 0.45-u.m-pore-size MCE and one 0.8-u.m-pore-size MCE). Ten grid
openings were examined on each filter. No asbestos structures were found on any of
the closed field blanks; three asbestos structures (33 s/mm2) were found on a
0.45-u.m-pore-size MCE open field blank at Site 3.
The reproducibility and precision of the TEM analyses were determined by an
evaluation of repeated analyses of randomly selected samples. Repeated analyses
included replicate analyses and duplicate analyses. A replicate analysis of 10
samples was performed to assess the uniformity of the distribution of asbestos
structures on a single grid preparation. A replicate analysis is a second analysis of
the same sample preparation performed by the same microscopist as the original
analysis. The microscopist uses the same grid preparation but counts different grid
openings from those originally read. Table 1 presents the results of the replicate
analyses.
A duplicate sample analysis of 4 samples was performed to assess the
reproducibility of the TEM analysis and to quantify any analytical variability resulting
from the filter preparation procedure. A duplicate analysis is the analysis of a second
TEM grid prepared from a different area of the sample filter but analyzed by the same
microscopist who performed the original analysis. Table 2 presents the results of the
duplicate analyses.
The coefficient of variation (CV) for the replicate and duplicate analyses was
estimated by assuming a lognormal distribution of the data on the original scale and
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TABLE 1. DATA SUMMARY FOR REPLICATE ANALYSES"
Original Analysis
Sample Number
02A-02D
04A-03B
06A-03D
07B-03B
09A-02D
11A-02B
12A-03D
13B-01D
16A-01D
17B-01B
Nb
1
0
14
3
2
4
9
45
0
13
s/cm3
0.05
0
0.065
0.014
0.009
0.020
0.043
0.225
0
0.065
Replicate Analysis
N
5
0
20
1
1
2
11
49
0
17
s/cm3
0.025
0
0.093
0.005
0.005
0.010
0.052
0.245
0
0.085
8 A replicate analysis is a second analysis of the same sample preparation
performed by the same microscopist.
b Number of asbestos structures.
TABLE 2. DATA SUMMARY FOR DUPLICATE ANALYSES8
Original Analysis
Sample Number
05A-03D
08B-01B
10A-03B
17B-03B
Nb
23
21
53
5
s/cm3
0.112
0.103
0.254
0.024
Duplicate Analysis
N
31
11
62
8
s/cm3
0.151
0.054
0.298
0.038
a A duplicate analysis is the analysis of a second TEM grid preparation
by the same microscopist.
b Number of asbestos structures.
13
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estimating the variance on the log scale. The variance was estimated by the mean
square error obtained from a one-factor ANOVA of the log-transformed data with the
sample identification number as the main factor. The CV associated with the replicate
analyses was 52 percent, and that associated with the duplicate analyses was 31
percent.
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SECTION 5
RESULTS AND DISCUSSION
Study-Site Characteristics
Resilient Floor Tile
Table 3 presents the characteristics of the 28 study sites representing 17
schools. The resilient flooring included mostly 9-in. by 9-in. tiles and some 12-in. by
12-in. tiles. Although the asbestos content of the tiles ranged from 1 to 38 percent,
the content of most of the tiles exceeded 10 percent. The areas that were spray-
buffed ranged from 727 to 3386 ft2; the average area was approximately 2150 ft2. Any
floor areas with damaged (e.g., broken) or missing tiles were isolated to prevent their
contact with the buffing machine.
Floor Care Maintenance Practices
Table 4 presents the wax-stripping and spray-buffing floor-care maintenance
practices at each of the schools. Sixteen of the 17 schools used a black pad for
stripping the floors, whereas EPA's interim procedure guidelines for the stripping of
resilient floor coverings recommend the use of the "least abrasive pad possible".4 The
schools wet-stripped and refmished the floors one to three times a year (during the
summer, winter, or spring breaks).
The floors were dry- and/or wet-mopped before they were spray-buffed. All of
the schools dry-mopped the floors, and nine of the schools both dry- and wet-mopped
the floors. The floors are typically spray-buffed once a year; however, some schools
spray-buffed the floors one to three times each week.
15
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TABLE 3. CHARACTERISTICS OF THE RESILIENT FLOOR TILE
AT EACH STUDf SITE
Site
1A
1B
2A
3A
3B
4A
5A
6A
6B
7A
7B
8A
SB
9A
10A
10B
11A
11B
12A
12B
13A
13B
14A
15A
16A
Area Buffed,
ft2
1480
1480
1697
1643
1643
1996
2171
2088
2088
2430
2430
1913
1614
1590
2731
3386
2700
3180
1630
3185
3230
2196
1829
2174
727
Location
Classrooms
Classrooms
Cafeteria
Classrooms
Classrooms
Cafeteria
Cafeteria
Hallway
Hallway
Classrooms
Classrooms
Hallway
Hallway
Hallway
Hallway
Hallway
Hallway
Hallway
Hallway
All-purpose room
Hallway
Hallway
All-purpose room
All-purpose room
Hallway
Tile Size,
in.
9x9
9x9
9x9
12x12
12x12
9x9
9x9
9x9
9x9
12x12
9x9
9x9
9x9
9x9
9x9
9x9
9x9
9x9,
12x12
9x9
9x9
9x9
9x9
9x9
9x9
12x12
% Asbestos
7
7
5-9
5-13
5-13
9-12
19-23
2-10
2- 10
11 -14
10-24
10-25
10-25
2-15
12
12
1.5-13
0.5-4
5-10
15
3-17
10-38
3-14
10-15
1 -3
(continued)
16
-------
TABLE 3 (continued)
Area Buffed, Tile Size,
Site ft2 Location m. % Asbestos
16B 908 Cafeteria 9x9 10-15
17A 2274 Classrooms 9x9 10-15
17B 1654 Classrooms 9x9 10-15
17
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Buffing Equipment and Materials
$%, '_3>' ^ -. . W^
Table 5 presents the characteristics of the buffing equipment (e.g., machine
speed) and materials (e.g., buffing pad color) used. Twelve of the schools used
buffing machines operating at 1000 to 1500 rpm and five used buffing machines
operating at 175 to 330 rpm. The speeds are based on information contained on the
machines nameplate or that provided by the manufacturer of the.machine. The
appropriate buffing pad (i.e., a white pad with high-speed machines and a red pad
with low-speed machines) was used at all of the schools except two. The two
exceptions were at School No. 1 where a red pad was used with a high-speed
machine, and at School No. 13 where a green pad (designed for heavy scrubbing and
light stripping applications) was used with a low-speed machine.
Airborne Asbestos Concentrations Before and During Spray-Buffing
Three samples were collected before and three during routine spray-buffing of
asbestos-containing floor tile in each area within a school. Table 6 presents the
descriptive statistics (i.e., mean, minimum, maximum, and standard deviation)
separately for each school/area combination and each sampling period (i.e., baseline
and during spray-buffing). (Individual airborne asbestos concentrations are presented
in Appendix A.) Figure 1 shows the average airborne asbestos concentrations at each
area before and during spray-buffing.
Increased airborne asbestos levels during spray-buffing were noted at 12 of the
17 schools. The increase was statistically significant at.seven of these schools (Nos.
1, 5, 6, 7, 12,14, and 17). Compared with baseline measurements taken before
buffing, airborne asbestos concentrations were qualitatively the same or lower during
buffing at the remaining five schools (Nos. 2, 4, 9, 10, and 16).
Overall, the mean relative increase in airborne asbestos concentrations during
spray-buffing with the high-speed machines (1000 to 1500 rpm) was significantly
higher (p=0.0326) than the relative increase during spray-buffing with the low-speed
machines (175 to 330 rpm). On average, airborne asbestos concentrations were
20
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approximately five times higher during spray-buffing than before spray-buffing with the
higher speed machines, whereas spray-buffing with the lower-speed machines showed
a two-fold increase during buffing than before.
Airborne Asbestos Concentrations Based on Frequency of Spray-Buffing
Table 4 presents the frequency at which spray-buffing is performed at each
school. Spray-buffing is routinely performed (one or more times weekly) at seven
schools, whereas spray-buffing is performed less frequently (once per month to once
per year) at the remaining ten schools. The mean airborne asbestos concentrations
measured before buffing at the schools in which spray-buffing is routinely performed
(0.035 s/cm3) was significantly greater (p=0.0004) than the mean baseline
concentration measured at schools in which spray-buffing is performed less frequently
(0.007 s/cm3).
Personal Breathing Zone Concentrations of Total Fibers
Table 7 presents total fiber concentrations in the machine operator's breathing
zone during spray buffing, as measured by PCM. The actual time spent buffing the
floors ranged from 64 to 97 minutes.
School maintenance workers do not typically spray-buff floors for a full 8-hour
work shift. According to school custodians at the five sites (Nos. 6A, 10A, 11 A, 13B,
and 16B) that showed measured levels above 0.1 f/crn3, the average time spent
buffing floors on a typical day ranges from 1..5 to 2.5 hours. Assuming that a
maintenance worker spends no more than 2.5 hours a day buffing the floor and has
no additional exposure to asbestos for the remainder of the day, the predicted 8-hour
time-weighted average (TWA) concentrations for all of these sites would be less than
the OSHA action level of 0.1 f/cm3, 8-hour TWA. The maximum estimated 8-hour
TWA exposure concentration (0.093 f/cm3, 8-hour TWA) was measured at Site 11 A.
On July 20, 1990, OSHA proposed to lower the permissible exposure limit to 0.1 f/cm3
(55 CFR 29722).
29
-------
TABLE 7. TOTAL FIBER CpNCENTRATIONS
DURING BUFFING OF RESILIENT FLOOR
TILE (AS MEASURED BY PCM)
Total Fiber Concentration,
Site f/cm3
1A
1B
2A
3A
3B
4A
5Aa
6A
6Ba
7A
7Ba
8Aa
8Ba
9A
10A
10B
11A
11B
12A
12B
13A
13B
14A
15A
16A
16B
17A
17B
0.033
0.034
0.078
0.077
0.076
0.024
-
0.130
-
0.048
-
.
•
0.030
0.133
0.061
0.295
0.065
0.067
0.070
0.085
0.220
0.042
0.076
0.080
0.104
0.027
0.055
Samples were all too heavily loaded with
paniculate to count.
30
-------
Paired TEM and PCM Analyses
Four of the personal breathing zone samples collected for PCM analysis were
also analyzed by TEM. Table 8 presents the concentrations associated with these
paired analyses. The PCM concentrations were higher than the corresponding TEM
concentrations in two of the four samples; the TEM concentrations were higher in the
other two samples. Typically, concentrations determined by TEM are consistently
higher than those determined by PCM, primarily because of the inability of PCM to
detect fibers less than 5 |im in length and less than 0.25 \im in width. Because PCM
analysis does not distinguish asbestos fibers from nonasbestos fibers and the TEM
concentrations are based solely on asbestos structures, finding higher levels with PCM
than with TEM is not unreasonable. This is especially true if the sample's environment
was fraught with settled paniculate and debris.
TABLE 8. PAIRED PCM AND TEM ANALYSES
FOR SELECTED SAMPLES
Concentration
Sample Number
06A-01D2
11A-01D2
13A-01D2
16A-01D2
PCM, f/cm3 TEM, s/cm3
0.130
0.295
0.085
0.080
0.277
0.178
0.262
0.005
Characterization of Bulk Floor Tile Surface
The bulk samples of floor tile collected at each site to confirm the presence and
approximate percentage of asbestos content were also analyzed by scanning
electronic microscopy (SEM). Portions of a freshly fractured edge of each bulk
sample were carbon coated and analyzed by SEM to examine the condition of the
floor tile surface and to confirm the asbestos content determined by PLM. Surface
conditions varied from extremely pitted with large numbers of asbestos bundles
exposed on the surface (Figure 2) to excellent (i.e., no pitting or exposed asbestos
31
-------
*-
32
-------
libers) condition (Figure 3). The wax coating on the surface of the floor tile could be
characterized as having a sponge-like or honeycomb appearance due to the presence
of circular pores of varying diameters (Figure 3). Energy dispersive x-ray analysis
(EDXA) of the bulk floor tile samples revealed a tile matrix characterized by a distinct
chlorine peak and the presence of titanium and other metallic elements commonly
used in the formulation of pigments.
Characterization of Surficial Asbestos Structures
Surface samples were collected from some of the floor tile before and after
spray-buffing by using a proprietary tape-lift sampling method developed by the R. J.
Lee Group, Inc., and analyzed by TEM. The tape-lift samples provide a record of the
surficial material which was easily removable from the floor tile prior to buffing. One
advantage of this sampling protocol is that no solvents are used which could dissolve
or otherwise alter the vinyl or asphalt floor tile matrix. Figure 4 illustrates a typical
tape-lift sample collected from floor tile before spray-buffing. The structures
resembled a web-like network of surface wax material similar to the surface seen in
the bulk samples analyzed by SEM. The edges of the pores are readily visible, and
the wax matrix between the pores contains large numbers of asbestos-containing
structures with sizes ranging from less than 1 u,m to several micrometers in length.
These networks often extended over several grid openings representing structures that
approached 0.2 to 0.5 mm in length. Paniculate structures embedded in the matrices
were analyzed by energy dispersive x-ray analysis. The majority of particles
containing asbestos displayed matrix materials similar to the bulk floor tile samples.
Some particles produced EDXA spectra containing large amounts of calcium and/or
calcium sulfate, probably due to either cementitious mortar or gypsum binders from a
non-tile source which had become entrapped in the wax.
Morphology and Size Distributions of Asbestos Structures
The TEM analysis of the 163 air samples collected before and during spray-
buffing yielded a total of 4598 asbestos structures, of which more than 99 percent
33
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were chrysotile and less than 1 percent were amphibole. This proportion of chrysotile
» ^fc %j|v" ' ^jSs* ' '****
and amphibole existed both before and during spray-buffing. The asbestos in nearly
all floor tiles is chrysotile. Table 9 summarizes the overall structure morphology
distribution separately for each sampling period. Overall, the asbestos structures were
primarily matrices (approximately 80 percent) and to a lesser extent, fibers, clusters,
and bundles. (Appendix B presents a summary of the structure morphology
distributions observed at each study site.)
TABLE 9. OVERALL DISTRIBUTION OF ASBESTOS STRUCTURES MEASURED
BEFORE AND DURING BUFFING OF RESILIENT FLOOR TILE
(PERCENTAGES)
Type of Asbestos
Sampling Period
Baseline
During Buffing
Chrysotile
99.8
99.7
Amphibole
0.2
0.3
Fibers
9.3
18.8
Structure
Bundles
2.1
1.6
Morphology
Clusters
4.2
2.5
Matrices
84.4
77.1
Table 10 presents the structure morphology distribution separately for each
machine speed and sampling period (i.e., baseline and during spray-buffing). The
structure morphology for asbestos structures observed before (i.e., baseline) low-
speed buffing was comparable to that observed during low-speed buffing. That is,
similar percentages of fibers, bundles, clusters, and matrices were observed both
before and during low-speed buffing. The structure morphologies for asbestos
structures observed during high-speed buffing, however, were distinctly different. The
morphologies for asbestos structures observed during high-speed buffing showed that
the percentage of asbestos fibers observed during high-speed buffing was
approximately 2.5 times greater than the percentage of fibers observed before buffing.
In contrast, the percentage of asbestos matrices were greater before high-speed
buffing than during buffing. One possible explanation for a decrease in the number of
asbestos matrices during buffing is that the high speed buffing pulverizes any
asbestos-containing particles lying on the surface of the floor and/or any particles
contained in the wax layer on the floor tile. This could also explain the increase in the
36
-------
percentage of asbestos fibers during high speed buffing. Another possible explanation
for the increase in the percentage of asbestos fibers during high-speed buffing could
be the abrasion of surficial fibers from the floor tile.
TABLE 10. DISTRIBUTION OF ASBESTOS STRUCTURES MEASURED
BEFORE AND DURING LOW AND HIGH SPEED BUFFING
OF RESILIENT FLOOR TILE
(PERCENTAGES)
Type of Asbestos
Machine
Speed
Low
High
Sampling
Period
Baseline
During Buffing
Baseline
During Buffing
Chrysotile
99.8
99.9
100
99.6
Amphibole
0.20
0.10
0
0.40
Fibers
8.9
12.3
10.2
25.5
Structure
Bundles
1.8
1.3
3.1
1.9
Morphology
Clusters
4.5
2.0
3.4
3.0
Matrices
84.8
84.4
83.4
69.6
Figure 5 illustrates a typical airborne asbestos-containing matrix observed
during buffing. In general, the airborne matrices had an appearance similar to the
bulk floor tile surface and the tape-lift samples, but much smaller in size. This
observation appears to support the possibility that the buffing activity caused a
mechanical shearing of the surface material and consequent release of the surface
material into the surrounding air.
Table 11 presents the overall cumulative size distributions of asbestos
structures in the air before and during spray-buffing. Overall, there does not appear to
be any significant difference in the cumulative size distributions before and during
buffing. Table 12 presents the overall structure size and fiber size distributions
separately for each machine speed and sampling period. Overall, less than 1 percent
of the asbestos fibers measured before and during were greater than 5 jim in length.
37
-------
*. ,ir.
38
-------
TABLE 11. CUMULATIVE SIZE DISTRIBUTION OF ASBESTOS STRUCTURES
MEASURED BEFORE AND DURING BUFFING OF RESILIENT FLOOR TILE
(CUMULATIVE PERCENTAGES)
Structure Length, urn
Sampling Period
Baseline
During Buffing
<1
34.7
40.2
<2
49.4
52.8
<3
59.3
61.3
5
32
34
29
23
Fiber
£1
84
80
70
94
length,
<5
100
100
97
100
urn
>5
0
0
3
0
Although Table 12 shows comparable structure morphologies before and during
low-speed buffing, the structure morphologies for high-speed buffing were different for
structures less than 1 ^im in length. Specifically, a larger percentage of the structures
observed during high-speed buffing were less than 1 p.m compared to structures
observed before high-speed buffing. The increased number of structures less than
1 jim in length could be due to (1) the pulverization of asbestos structures on the floor
surface and/or asbestos structures contained in the wax layer, and/or (2) the abrasion
of surficial fibers from the floor tile.
'Appendix C presents the cumulative size distributions measured at each study
site. Appendix D contains a series of particle graphs showing the structure lengths
and widths measured at each study site. Each particle graph contains a "PCM
39
-------
window" that delineates the area on the graph where structures would be large
enough to be detected by PCM.
Particulate Loading on Filters
Twenty of the 194 samples were heavily loaded with paniculate matter. Five of
the 28 personal breathing zone samples analyzed by PCM and three of the 166
samples analyzed by TEM were too heavily loaded to count. Four personal breathing
zone samples analyzed by PCM were counted despite having graticulate fields with
more than 1/6 of the field covered by particulate; eight of the personal breathing zone
samples analyzed by TEM were counted despite having grid openings with more than
25 percent of the opening covered by particulate matter. Excessive particulate loading
on filters results in overlapping structures that were likely individual structures in the
air, but are counted as single structures according to AHERA nonmandatory TEM
Method and NIOSH 7400 counting rules. Hence, on overloaded samples, the
resulting concentrations could actually be underestimating the true airborne asbestos
level.
The four personal breathing zone samples that were analyzed by PCM despite
having graticulate fields with slightly more than 1/6 of the field covered by particulate
showed total fiber concentrations ranging from 0.048 to 0.133 f/cm3. The
corresponding estimated 8-hour TWA concentrations ranged from 0.015 to 0.042
f/cm3. Although these concentrations are below the OSHA action level (0.1 f/cm3),
they should be considered the minimum exposure concentrations during spray-buffing
for these workers and an underestimation of the true levels.
The eight TEM samples having grid openings with more than 25 percent of the
opening covered by particulate matter were all samples collected during buffing. The
samples were collected at five different sites, all of which showed elevated airborne
asbestos concentrations during spray-buffing. Therefore, if the measured levels
underestimate the actual airborne concentrations during buffing at these sites, then the
relative magnitude of the increase may also be underestimated.
40
-------
Appendix E contains information on the degree of overloading for each of the
samples collected during this study. The percentage of particulate in each grid
opening is estimated for each of the samples.
41
-------
REFERENCES
1. U.S. Environmental Protection Agency. Monitoring of Asbestos Fiber Release
During Maintenance of Asbestos-Containing Floor Tile: A Case Study. Draft
Report. Office of Pollution Prevention and Toxics, Washington, D.C. January
1992.
2. Los Angeles Unified School District. Vinyl Asbestos Floor Study: Routine
Buffing and Stripping Operations in the Los Angeles Unified School District.
Environmental Health and Safety Branch, Los Angeles, CA. March 1990.
3 ENVIRON Corporation. Evaluation of Exposures to Airborne Fibers During
Maintenance of Asbestos Containing Resilient Floor Tiles Using Recommended
Work Practices. Report prepared for Resilient Floor Covering Institute and
Armstrong World Industries, Inc. September 10, 1990.
4 U.S. Environmental Protection Agency. Interim Guidelines for Maintenance of
Asbestos-Containing Floor Coverings. Office of Toxic Substances, Washington,
D.C. January 1990.
5 American Standard Testing Materials. Standard Definitions of Terms Relating
to Polishes and Related Materials. Standard D2825-69. Committee D-21 and
Subcommittee D21.91. Washington, D.C. November 7, 1984.
42
-------
APPENDIX A INDIVIDUAL AIRBORNE ASBESTOS CONCENTRATIONS
(DETERMINED BY TEM) BEFORE AND DURING BUFFING OF
ASBESTOS-CONTAINING RESILIENT FLOOR TILE
Site
Number
1A
1A
1A
1A
1A
1A
1B
1B
1B
1B
1B
1B
2A
2A
2A
2A
2A
2A
2A
3A
3A
3A
3A
3A
3A
3B
3B
3B
3B
3B
3B
4A
4A
4A
4A
4A
4A
Sample
Number
01A-01D
01A-02D
01A-03D
01A-01B
01A-02B
01A-03B
01B-01D
01B-02D
01B-03D
01B-01B
01B-02B
01B-03B
02A-01D
02A-02D
02A-02DR
02A-03D
02A-01B
02A-02B
02A-03B
03A-01D
03A-02D
03A-03D
03A-01B
03A-02B
03A-03B
03B-01D
03B-02D
03B-03D
03B-01B
03B-02B
03B-03B
04A-01D
04A-02D
04A-01B
04A-02B
04A-03B
04A-03BR
Sampling Period
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
Replicate of 02A-02D
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
Baseline
Baseline
Baseline
Replicate of 04A-03B
Concentration,
s/cm2
0.019
0.014
0.010
0.009
0.005
0
0.015
0.019
0.005
0
0
0.005
0
0.005
0.024
0.005
0
0.010
0.010
0.025
0.010
0
0.005
0
0
0.009
0
0
0
0
0
0
0
0
0
(continued)
43
-------
APPENDIX A (continued)
Site
Number
5A
5A
5A
5A
5A
5A
5A
6A
6A
6A
6A
6A
6A
6A
6B
6B
6B
6B
6B
6B
7A
7A
7A
7A
7A
7A
7B
7B
7B
7B
7B
7B
7B
8A
8A
8A
8 A
8A
Sample
Number
05A-01D
05A-02D
05A-03D
05A-03DD
05A-01B
05A-02B
05A-03B
06A-01D
06A-02D
06A-03D
06A-03DR
06A-01B
06A-02B
06A-03B
06B-01D
06B-02D
06B-03D
06B-01B
06B-02B
06B-03B
07A-01D
07A-02D
07A-03D
07A-01B
07A-02B
07A-03B
07B-01D
07B-02D
07B-03D
07B-01B
07B-02B
07B-03B
07B-03BR
08A-01D
08A-02D
08A-03D
08A-01B
08A-02B
Sampling Period
During Buffing
During Buffing
During Buffing
Duplicate Analysis of 05A-03D
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Replicate of 06A-03DR
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline ,
Baseline
Baseline
Replicate of 07B-03B
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Concentration,
s/cm2
0.088
0.123
0.112
0.151
0.014
0.010
0.005
0.124
0.302
0.065
0.093
0.076
0
0.015
0.291
0.137
0.189
0.018
0.015
0.053
0.161
0.179
0.097
0
0
0.010
0.400
0.379
0.464
0.005
0.005
0.014
0.005
0.030
0.030
0.015
0.005
0.010
(continued)
44
-------
APPENDIX A (continued)
Site
Number
8A
00
OD
8B
8B
8B
9A
9A
9A
9A
9A
9A
9A
10A
10A
10A
10A
10A
10A
10A
10B
10B
10B
10B
10B
10B
11A
11A
11A
11A
11A
11A
11B
11B
11B
11B
11B
11B
Sample
Number
08A-03B
08B-01 B
08B-01 BD
08B-02B
08B-03B
09A-01D
09A-02D
09A-02DR
09A-03D
09A-01B
09A-02B
09A-03B
10A-01D
10A-02D
10A-03D
10A-01B
10A-02B
10A-03B
10A-03BD
10B-01D
10B-02D
10B-03D
10B-01B
10B-02B
10B-03B
11A-01D
11A-03D
11A-01B
11A-02B
11A-02BR
11A-03B
11B-01D
11B-02D
11B-03D
11B-01B
11B-02B
11B-03B
Sampling Period
Baseline
Baseline
Duplicate Analysis of 08B-01 B
Baseline
Baseline
During Buffing
During Buffing
Replicate of 09A-02D
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
Duplicate Analysis of 10A-03B
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
Baseline
Baseline
Replicate of 11 A-02B
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
Concentration,
s/cm2
0.020
Oj f\fi
.103
0.054
0.020
0
0.009
0.005
0
0.020
0.010
0.094
0.033
0.076
0.005
0.254
0.297
0.035
0.029
0.034
0.030
0.040
Of\ A f*
.045
0.097
0.015
0.053
0.020
0.010
0.025
0.075
0.090
0.067
0.069
0.015
0.005
(continued)
45
-------
APPENDIX A (continued)
Site
Number
12A
12A
12A
12A
12A
12A
12A
12B
12B
12B
12B
12B
12B
13A
13A
13A
13A
13A
13A
13B
13B
13B
13B
13B
13B
13B
14A
14A
14A
14A
14A
14A
15A
15A
15A
15A
15A
15A
Sample
Number
12A-01D
12A-02D
12A-03D
12A-03DR
12A-01B
12A-02B
12A-03B
12B-01D
12B-02D
12B-03D
12B-01B
12B-02B
12B-03B
13A-01D
13A-02D
13A-03D
13A-01B
13A-02B
13A-03B
13B-01D
13B-01DR
13B-02D
13B-03D
13B-01B
13B-02B
13B-03B
14A-01D
14A-02D
14A-03D
14A-01B
14A-02B
14A-03B
15A-01D
15A-02D
15A-03D
15A-01B
15A-02B
15A-03B
Sampling Period
During Buffing
During Buffing
During Buffing
Replicate of 12A-03D
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
Replicate of 13B-01D
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
Concentration,
s/cm2
0.113
0.047
0.043
0.052
0.014
0.009
0.014
0.062
0.150
0.075
0.054
0.113
0.029
0.206
0.015
0.025
0.040
0
0.005
0.225
0.245
0.329
0.318
0.051
0.143
0.390
0.050
0.020
0.087
0.005
0.005
0.010
0.102
0.216
0.135
0.098
0.126
0.058
(continued)
46
-------
APPENDIX A (continued)
Site
Number
16A
16A
16A
16A
16A
16A
16A
16B
16B
16B
16B
16B
16B
17A
17A
17A
17A
17A
17A
17B
17B
17B
17B
17B
17B
17B
17B
Sample
Number
16A-01D
16A-01DR
16A-02D
16A-03D
16A-01B
16A-02B
16A-03B
16B-01D
16B-02D
16B-03D
16B-01B
16B-02B
16B-03B
17A-01D
17A-02D
17A-03D
17A-01B
17A-02B
17A-03B
17B-01D
17B-02D
17B-03D
17B-01B
17B-01BR
17B-02B
17B-03B
17B-03BD
Sampling Period
During Buffing
Replicate of 16A-01D
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Baseline
Baseline
During Buffing
During Buffing
During Buffing
Baseline
Replicate of 17B-01B
Baseline
Baseline
Duplicate Analysis of 17B-03B
Concentration,
s/cm2
0
0
0
0.004
0.005
0
0
0
0
0
0
0.005
0.005
0.059
0.052
0.057
0
0
0.005
0.119
0.035
0.189
0.065
0.085
0.061
0.024
0.038
47
-------
APPENDIX B. DISTRIBUTION OF AIRBOgNE ASBESTOS STRUCTURES
MEASURES AT EACft SCHOOL
(PERCENTAGES OF TOTAL NUMBER OF ASBESTOS STRUCTURES)
Type of Asbestos
Sample Type Chrysotile
Amphibole
Structure Morphology
Fibers Bundles
Clusters
Matrices
Site 1A
Baseline (N=7)
During Buffing (N=10)
100
100
0
0
14.3
80
0
0
0
0
85.7
20
Site 1B
Baseline (N=2)
During Buffing (N=8)
100
100
0
0
0
75
0
25
0
0
100
0
Site2A
Baseline (N=5)
During Buffing (N=2)
100
100
0
0
60
100
0
0
0
0
40
0
Site 3A
Baseline (N=2)
During Buffing (N=18)
100
100
0
0
0
22.2
0
0
0
27.8
100
50
Site 3B
Baseline (N=0)
During Buffing (N=2)
0
100
0
0
0
100
0
0
0
0
0
0
Site 4A
Baseline (N=0)
During Buffing (N=0)
0
0
0
0
0
0
0
0
0
0
0
0
Site 5A
Baseline (N=7)
During Buffing (N=245)
100
98.4
0
1.6
71.4
15.9
0
2.0
0
0.8
28.6
81.2
Srte 6A
Baseline (N=54)
During Buffing (N=291)
100
99.7
0
0.3
3.7
18.6
1.9
1
9.3
1
85.2
79.4
Site 6B
Baseline (N=59)
During Buffing (N=376)
100
99.5
0
0.5
8.5
12.8
0
3.5
0
2.7
91.5
81.1
(continued)
48
-------
APPENDIX B (continued)
Type of Asbestos
Sample Type
Chrysotile
Amphibole
Fibers
Structure
Bundles
Morphology
Clusters
Matrices
Site 7A
Baseline (N=3)
During Buffing (N-143)
-
Baseline (N=9)
During Buffing (N=430)
Baseline (N=1 3)
During Buffing (N=48)
100
100
100
100
100
97.9
0
0
Site7B
0
0
SiteSA
0
2.1
33.3
51
22.2
44
30.8
18.8
0
0
11.1
1.4
7.7
4.2
0
1.4
0
7.7
0
0
66.7
47.6
66.7
47
61.5
77.1
Site 8B
Baseline (N=59)
During Buffing*
98.3
1.7
15.3
3.4
18.6
62.7
Site 9A
Baseline (N=8)
During Buffing (N-4)
Baseline (N=1 16)
During Buffing (N-124)
100
100
100
100
0
0
Site 10A
0
0
50
25
12.1
5.6
12.5
0
6.0
1.6
0
0
3.4
0
37.5
75
78.4
92.7
Site 10B
Baseline (N=68) »
During Buffing (N=53)
100
100
0
0
4.4
9.4
1.5
1.9
2.9
0
91.2
88.7
Site 11 A
Baseline (N=48)
During Buff ing (N-1 11)
Baseline (N=51)
During Buffing (N=146)
100
100
100
100
0
0
Site 11B
0
0
2.1
6.3
5.9
8.2
2.1
0
0
0.7
12.5
0
7.8
3.4
83.3
93.7
86.3
87.7
(continued)
49
-------
APPENDIX B (continued)
Type of Asbestos
Sample Type
Chrysotile
Amphibole
Fibers
Structure
Bundles
Morphology
Clusters
Matrices
Site 12A
Baseline (N=25)
During Buffing (N=149)
100
100
0
0
4.0
7.4
8.0
2
0
4.0
88.0
86.6
Site 12B
Baseline (N=102)
During Buffing (N=183)
100
100
0
0
11.8
5.5
0
1.6
4.9
4.9
83.3
88
Site 13A
Baseline (N=32)
During Buffing (N=165)
100
99.4
0
0.6
0
7.3
3.1
0.6
3.1
0
93.7
92.1
Site 13B
Baseline (N=273)
During Buffing (N=425)
99.6
100
0.4
0
7.3
14.8
1.1
1.6
1.5
0.5'
90.1
83.1
Site 14A
Baseline (N=20)
During Buffing (N=74)
100
100
0
0
0
18.9
0
0
0
2.7
100
78.4
Site 15A
Baseline (N=132)
During Buffing (N=205)
100
100
0
0
4.5
20.5
3.0
1.5
5.3
2.9
87.1
75.1
Site 16A
Baseline (N=1)
During Buffing (N=3)
100
100
0
0
100
0
0
0
0
0
0
100
Site 16B
Baseline (N=4)
During Buffing (N=0)
100
0
0
0
0
0
0
0
0
0
100
0
Site 17A
Baseline (N=3)
During Buffing (N=70)
100
100
0
0
0
20
0
0
0
0
100
80
(continued)
50
-------
APPENDIX B (continued)
Type of Asbestos Structure Morphology
Sample Type Chrysolite Amphibole Fibers Bundles Clusters Matrices
Site 17B
Baseline (N=64) 100 0 17.2 0 0 82.8
During Buffing (N=146) 100 0 9.6 0.7 0 89.7
" The samples collected during spray-buffing were too heavily loaded with paniculate to count.
51
-------
APPENDIX C CUMULATIVE SIZE DISTRIBUTIONS OF ASBESTOS STRUCTURES
MEASURED BEFORE AND DURING BllFFING AT EACH SCHOOL
(CUMULATIVE PERCENTAGES)
Structure Length, urn
Sample Type
£1
<2
<3
-------
APPENDIX C (continued)
Structure Length, urn
Sample Type
<1
<2 <3
<4
<5
<10
SiteTB
Baseline (N=9)
During Buffing (N=430)
44.4
69.5
44.4 55.6
80.7 86
88.9
88.6
88.9
90.5
100
96.7
SiteSA
Baseline (N=13)
During Buffing (N=48)
38.5
25
53.8 61 .5
35.4 37.5
61.5
39.6
69.2
50
92.3
66.7
Site 8B
Baseline (N=59)
During Buffing*
44.1
52.5 64.4
67.8
79.7
98.3
StteSA
Baseline (N=8)
During Buffing (N=4)
Baseline (N=116)
During Buffing (N=124)
75
0
33.8
26.6
75 75
25 50
Site 10A
60.3 69.8
46.8 55.6
75
75
77.6
63.7
87.5
75
87.9
76.6
100
100
98.3
93.5
Site 10B
Baseline (N=68)
During Buffing (N=53)
30.9
26.4
52.9 69.1
50.9 67.9
76.5
69.8
82.4
75.5
98.5
92.5
Site 11 A
Baseline (N=48)
During Buffing (N=111)
Baseline (N=51)
During Buffing (N=146)
37.5
22.5
31.4
28.8
52.1 68.7
31.5 48.6
Site 11B
51 60.8
41.1 54.8
70.8
55.9
70.6
60.3
85.4
68.5
74.5
66.4
97.9
85.6
94.1
85.6
(continued)
53
-------
APPENDIX C (continued)
Structure Length, um
Sample Type
<1
<2 <3
<4
<5
£10
Site 12A
Baseline (N=25)
During Buffing (N=149)
16
23.5
36 56
32.9 46.3
56
51.7
64
59.1
96
86.6
Site 12B
Baseline (N=102)
During Buffing (N=183)
34.3
23.5
54.9 57.8
36.6 48.1
60.8
57.4
66.7
63.4
89.2
85.8
Site 13A
Baseline (N=32)
During Buffing (N=165)
18.8
28.5
34.4 37.5
44.8 48.5
43.7
52.7
46.9
57.6
78.1
84.8
Site 13B
Baseline (N=273)
During Buffing (N=425)
36.3
36
44.3 50.2
45.9 51.3
54.6
54.6
57.9
58.6
79.1
80.2
Site 14A
Baseline (N=20)
During Buffing (N=74)
15
28.4
40 65 ,
55.4 64.9
75
70.3
80
73.0
100
82.4
Site 15A
Baseline (N=132)
During Buffing (N=205)
33.3
35.6
47.7 58.3
54.1 64.9
64.4
69.8
74.2
76.6
88.6
88.8
Site 16A
Baseline (N=1)
During Buffing (N=3)
100
33.3
100 100
33.3 33.3
100
33.3
100
33.3
100
100
Site 168
Baseline (N=4)
During Buffing (N=0)
50
0
50 75
0 0
100
0
100
0
100
0
Site 17A
Baseline (N=3)
During Buffing (N=70)
0
54.3
0 100
64.3 70
100
75.7
100
81.4
100
94.3
(continued) 54
-------
APPENDIX C (continued)
Structure Length, u.m
Sample Type ^1
<2 <3
<4
<5
S10
Site 17B
Baseline (N=64) 37.5
During Buffing (N=146) 37.7
51 .6 60.9
54.1 66.4
64.1
73.3
64.1
78.1
85.9
93.2
11 The samples collected during spray buffing were too heavily loaded with paniculate to count.
55
-------
APPENDIX D
SIZE DISTRIBUTION OF ASBESTOS STRUCTURES IN
AIR SAMPLES COLLECTED BEFORE AND DURING
BUFFING OF ASBESTOS-CONTAINING FLOOR
TILES IN EACH OF THE 28 STUDY
AREAS AT 17 SITES
56
-------
The figures contained in this appendix illustrate the size of the asbestos structures
measured by TEM on the samples collected before and during spray-buffing. Structure lengths
and widths are illustrated for each study site in Figures D-l through D-28. Each figure contains
a "PCM window" (see below) which delineates the area on the graph where structures would be
large enough to be detected by PCM (i.e., structures greater than 5 pm in length and greater than
0.25 pm in width). The PCM window also shows structures with length-to-width aspect ratios
of 3 to 1 and 5 to 1. These aspect ratios relate to the A and B counting rules in NIOSH Method
7400.
PCM Window
(5 tan in length, 0.25 pm in width)
57
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85
-------
APPENDIX E
PERCENT OCCLUSION OF GRID OPENINGS BY PARTICIPATE
86
-------
TABLE E-1. DEGREE OF OVERLOADING ON SAMPLES ANALYZED BY TEM
Field Sample ID
01A-01B
01A-02B
01A-03B
I 01A-01D
01A-02D
I 01A-03D
I 01B-01B
01 B-02B
01B-03B
01B-01D
101 B-02D
01 B-03D
02A-01B
02A-02B
02A-03B
02A-01D
02A-02D
I02A-03D
03A-01B
03A-02B
03A-03B
03A-01D
03A-02D
03A-03D
03B-01B
Lab ID Number
92C-002-01
92C-002-02
92G-002-03
92C-002-04
92C-002-05
92C-002-06
92C-002-09
92C-002-10
92C-002-1 1
92C-002-12
92C-002-13
92C-002-14
92C-002-16
92C-002-17
92C-002-18
92C-002-19
92C-002-20
92C-002-21
92C-002-24
92C-002-25
92C-002-26
92C-002-27
92C-002-28
92C-002-29
92C-002-32
% Paniculate/grid
5-10
1-5
<1
1-5
1-5
1-5
1-5
1-5
1-5
1-5
5
5
1-5
1-5
1-5
5-10
5-10
5-10
<1
1-5
<1
1-5
1-5
1-5
1-5
(continued)
87
-------
TABLE E-1 (contiuned)
Field Sample ID
03B-02B
03B-03B
03B-01D
03B-02D
03B-03D
04A-01 B
04A-02B
04A-03B
04A-01 D
04A-02D
05A-01B
05A-02B
05A-03B
05A-01D
05A-02D
05A-03D
06A-01B
06A-02B
06A-03B
06A-01D
06A-02D
06A-03D
06B-01B
06B-02B
06B-03B
Lab ID Number
92C-002-33
92C-002-34
92C-002-35
92C-002-36
92C-002-37
92C-002-39
92C-002-40
92C-002-41
92C-002-42
92C-002-43
92C-002-47
92C-002-48
92C-002-49
92C-002-50
92C-002-51
92C-002-52
92C-002-55
92C-002-56
92C-002-57
92C-002-58
92C-002-59
92C-002-60
92C-002-63
92C-002-64
92C-002-65
% Particu late/grid
1-5
1
1-5
1-5
1-5
1
1
1-5
1-5
1-5
1-5
1-5
1-5
40-50
25-35
15-20
10-15
<1
1-5
10-15
10-15
10-15
1
1-5
5-10
(continued)
88
-------
TABLE E-1 (contiuned)
Field Sample ID
I 06B-01D
| 06B-02D
I —
| 06B-03D
I 07A-01B
07A-02B
I 07A-03B
07A-01D
07A-02D
j 07A-03D
07B-01B
I 07B-02B
I 07B-03B
I 07B-01D
| 07B-02D
07B-03D
08A-01B
08A-02B
08A-03B
08A-01D
08A-02D
08A-03D
08B-01B
08B-02B ,
08B-03B
J 08B-01D
Lab ID Number
92C-002-66
92C-002-67
92C-002-68
92C-002-70
92C-002-71
92C-002-72
92C-002-73
92C-002-74
92C-002-75
92C-002-78
92C-002-79
92C-002-80
92C-002-81
92C-002-82
92C-002-83
92D-001-01
92D-001-02
92D-001-03
92D-001-04
92D-001-05
92D-001-06
92D-001-09
92D-001-10
92D-001-11
92D-001-12
% Particulate/grid
15-20
20-40
15-20
1
1
1
5
2-5
2-5
1
1
1
15-20
15-20
20-25
1-5
1-5
1-5
30-40
15-20
10-20
5
2-5
5
50-60
(continued)
89
-------
TABLE E-1 (contiuned)
f
Field Sample ID
08B-02D
08B-03D
09A-01B
09A-02B
09A-03B
09A-01D
09A-02D
09A-03D
10A-01B
10A-02B
10A-03B
10A-01D
10A-02D
10A-03D
10B-01B
10B-02B
10B-03B
10B-01D
10B-02D
10B-03D
11A-01B
11A-02B
11A-03B
11A-01D
11A-03D
Lab ID Number
92D-001-13
92D-001-14
92D-001-16
92D-001-17
92D-001-18
92D-001-19
92D-001-20
92D-001-21
92D-001-24
92D-001-25
' 92D-001-26
92D-001-27
92D-001-28
92D-001-29
92D-001-32
92D-002-33
92D-001-34
92D-001-35
92D-001-36
92D-001-37
92D-001-39
92D-001-40
92D-001-41
92D-001-42
92D-001-44
% Particu late/grid
15-20
50-65
1-5
1-5
1-5
2-5
2-5
5
1
2-5
2-5
5
5
5
1
2-5
2-5
2-5
1
2-5
1-3
1
1
5
5-10
(continued)
90
-------
TABLE E-1 (contiuned)
—
Field Sample ID
========= =J=
11B-01B
11B-02B
11B-03B
I 11B-01D
11B-02D
L_
| 1 1 B-03D
12A-01B
12A-02B
12A-03B
12A-01D
•
12A-02D
L —
12A-03D
I 12B-01B
I 12B-02B
| —
I 12B-03B
|| 12B-01D
I 12B-02D
I ' 12B-03D
13A-01B
—
13A-02B
—
13A-03B
13A-01D
I 13A-02D
| 13A-03D
j 13B-01B
Lab ID Number
"•"
92D-001-47
92D-001-48
92D-001-49
92D-001-50
92D-001-51
92D-001-52
92D-001-54
92D-001-55
92D-001-56
92D-001-57
92D-001-58
92D-001-59
92D-001-62
92D-001-63
92D-001-64
92D-002-65
92D-001-66
92D-001-67
92D-001-69
92D-001-70
92D-001-71
92D-001-72
92D-001-73
92D-001-74
92D-001-77
% Particulate/grid I
' '"'•""• —_._. .!..-.. I . ... M, !,..,._ ...I.I 1
1-3
1
1
5-10
1-3
1-3
1
1
10-15
5
5-10
1-3
2-5
1-3
5
10
5
1-3
1 I
1 I
5-10 I
2-5 I
2-5 |
1-3 |
(continued)
91
-------
TABLE E-1 (contiuned)
Field Sample ID
13B-02B
13B-03B
I 13B-01D
13B-02D
I 13B-03D
I 14A-01B
I 14A-02B
14A-03B
\ 14A-01D
I 14A-02D
I 14A-03D
15A-01B
15A-02B
J 15A-03B
15A-01D
I 15A-02D
15A-03D
16A-01B
| 16A-02B
I 16A-03B
I 16A-01D
16A-02D
I 16A-03D
| 16B-01B
J 16B-02B
Lab ID Number
92D-001-78
92D-001-79
92D-001-80
92D-001-81
92D-001-82
92D-002-01
92D-002-02
92D-002-Q3
92D-002-04
92D-002-05
92D-002-06
92D-002-09
92D-002-10
92D-002-11
92D-002-12
92D-002-13
92D-002-14
92D-002-17
92D-002-18
92D-002-19
92D-002-20
92D-002-21
92D-002-22
92D-002-25
92D-002-26
% Particu late/grid
3-5
3-5
10-15
10-15
25
1
1
1
5-10
5-10
5
3
3-5
1-3
, 5-10
5-10
5-10
1
1-3
1-3
1
1-3
1-3
1-3
3-5
(continued)
92
-------
TABLE E-1 (contiuned)
Field Sample ID
16B-03B
16B-01D
16B-02D
16B-03D
17A-01B
17A-02B
17A-03B
17A-01D
17A-02D
17A-03D
17B-01B
17B-02B
17B-03B
17B-01D
17B-02D
17B-03D
Lab ID Number
92D-002-27
92D-002-28
92D-002-29
92D-002-30
92D-002-32
92D-002-33
92D-002-34
92D-002-35
92D-002-36
92D-002-37
92D-002-40
92D-002-41
92D-002-42
92D-002-43
92D-002-44
92D-002-45
% Particulate/grid
1
3-4
3-4
3
1
1
1
1
1
1
3-4
3
1
3-4
1-3
3-4
93
-------
TABLE E-2. DEGREE OF OVERLOlDINGfON SAMPLES ANALYZED BY PCM
Field Sample ID
| 01A-01D2
| 01B-01D2
02A-01D2
I 03A-01D2
I 03B-01D2
I 04A-01D2
I 05A-01D2
I 06A-01D2
06B-01D2
07A-01D2
07B-01 D2
08A-01D2
I 08B-01D2
09A-01D2
10A-01D2
10B-01D2
11A-01D2
11B-01D2
12A-01D2
12B-01D2
13A-01D2
' 13B-01D2
14A-01D2
15A-01D2
J 16A-01D2
Lab ID Number
92D-001-84
92D-001-87
92D-001-89
92D-001-92
92D-001-95
92D-001-97
92D-001-100
92D-001-103
92D-001-106
92D-001-108
92D-001-111
92D-001-113
92D-001-116
92D-001-118
92D-001-121
92D-001-124
92D-001-126
92D-001-129
92D-Q01-131
92D-002-47
92D-002-49
92D-002-52
92D-002-54
92D-002-57
92D-002-60
% Particulate/grid
NA
10-15
10-15
5-10
10-15
5-7
25-30
10-15
30-35
15-20
20-25
50-60
70-80
2-5
15-20
10-15
8-10
10-15
10-20
20-25
10-15
5-10
3-5
3-5
3-5
(continued)
94
-------
TABLE E-2 (continued)
Field Sample ID
16B-01D2
17A-01D2
17B-01D2
Lab ID Number
92D-002-63
92D-002-65
92D-002-68
% Particulate/grid
3-5
2-4
3-5
95
------- |