United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-86/070 Jan 1987
&EPA Project Summary
Assessment of Assay Methods
for Evaluating Asbestos
Abatement Technology at the
Corvallis Environmental
Research Laboratory
Mark A. Karaffa, Robert S. Amick, Ann Crone, and Charles Zimmer
Two analytical methods and two
sampling techniques were evaluated
for their effectiveness in a project to re-
move air-entrainable asbestos from the
Corvallis Environmental Research Lab-
oratory in Corvallis, Oregon. The two
analytical methods were phase con-
trast microscopy (PCM) and transmis-
sion electron microscopy (TEM). The
sampling techniques included a static
(nonaggressive) method and an aggres-
sive one using a blower.
Air sampling was conducted at an
EPA office building that had undergone
an amosite asbestos abatement pro-
gram. The aggressive sampling tech-
nique revealed that air-entrainable as-
bestos remained in work areas after
completion of abatement actions. Re-
sults also confirm that under similar
sampling conditions, TEM analysis de-
tects more fibers than PCM because of
the former's better resolving capability.
Because PCM does not discriminate be-
tween asbestos and other fibers and
cannot resolve fibers thinner than
about 0.2 ixm, this method may not ac-
curately reflect the true hazard poten-
tial.
TEM coupled with aggressive sam-
pling should be recommended as the
analytical method of choice for final
post-abatement clearance testing.
This Project Summary was devel-
oped by EPA's Water Engineering Re-
search Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Background
The Technical Assistance Program of
the Office of Pesticides and Toxic Sub-
stances of the U.S. Environmental Pro-
tection Agency (EPA) provides guidance
and information on the identification of
asbestos-containing materials in build-
ings and on the correction of potential
asbestos hazards. Four EPA Guidance
Documents contain much of the exist-
ing technical information about as-
bestos in nonindustrial settings.1"4
These documents describe how to es-
tablish an asbestos identification and
control program, provide background
information and direction to school offi-
cials and building owners on exposure
assessment, and give instruction on
how to develop and implement an as-
bestos abatement program. The most
recent asbestos guidance from EPA not
only emphasizes recent experience and
new information on asbestos control
but also introduces and discusses crite-
ria for developing an appropriate as-
bestos control plan.
Considerable scientific uncertainty
still surrounds the effectiveness of
specific abatement actions in reducing
the risk of exposure to airborne as-
bestos. One critical concern among
those responsible for asbestos abate-
-------
ment is how clean the contractor leaves
a building (or building area) after re-
moving the asbestos material or after
completing work that could have dis-
turbed an asbestos-containing material
(e.g., encapsulation, enclosure, or spe-
cial maintenance operations). The two
criteria recommended by the EPA guid-
ance (1983)3 that was in effect at the out-
set of this study were visual inspection
of the worksite and air monitoring after
completion of the project. Visual inspec-
tion should detect incomplete removal,
damage caused by abatement activity,
and (most important) the presence of
debris or dust left by inadequate
cleanup of the work area. Air monitor-
ing by the membrane filter collection
technique and phase-contrast micro-
scopic (PCM) analysis are recom-
mended to supplement the visual in-
spection and to determine whether
elevated levels of airborne fibers gener-
ated during the removal process have
been sufficiently reduced. This currently
recommended optical microscopic
technique is one of two methods speci-
fied by the National Institute for Occu-
pational Safety and Health (NIOSH) to
determine airborne fiber concentra-
tions; it is used by the Occupational
Safety and Health Administration
(OSHA) to measure total airborne fibers
in occupational environments.
The EPA-recommended air-
monitoring methodology for determin-
ing abatement completion (NIOSH
Method No. P&CAM 239) was as fol-
lows:
Air sampling should begin after
the project has been completed
and all surfaces in the abatement
site have been cleaned, preferably
within 48 hours after abatement
work is finished. A minimum of
three air monitors per worksite
and at least one per room is rec-
ommended. Air is drawn through
a membrane filter for about 8
hours at a flow rate of approxi-
mately 2 L/min. A total air volume
of approximately 1,000 liters col-
lected at the specified flow rate
should be sampled. After the sam-
pling, a section of the filter is
mounted on a microscope slide
and treated to form a transparent,
optically homogeneous gel. The
fibers are sized and counted by
using a phase-contrast micro-
scope at 400 to 450X magnifica-
tion. For counting purposes, a
fiber is defined as a particle with a
physical dimension longer than 5
micrometers and a length-to-
diameter ratio of 3 to 1 or greater.3
This method is intended to give an in-
dex of the airborne concentration of
fibers of specified dimensions in an at-
mosphere known or suspected to con-
tain asbestos; it is not designed to count
fibers less than 5 jxm long or to differen-
tiate asbestos fibers from other fibrous
particulates.
The most significant limitation of the
PCM method compared with transmis-
sion electron microscopy (TEM) and
scanning electron microscopy (SEM) is
that PCM ts limited in the detection of
fine particles (i.e., those with submicron
diameters or lengths less than 5 (jum)
that may be toxicologically significant.
For example, in glove-box tests of simu-
lated industrial mechanical operations
on asbestos-containing products
(drilling, sawing, and sanding), the PCM
method counted fewer than 1 percent of
the fibers counted by TEM.5 Although
conditions of this glove box study were
obviously different from asbestos
abatement activities, some concern ex-
isted about the relative merits and capa-
bilities of the different analytical meth-
ods used to determine representative
fiber concentrations. Another study es-
timated that small asbestos fibers (i.e.,
fibers less than 0.2-jxm wide and 5-|xm
long that are not detected by the PCM
method) were present at 50 to 100 times
the concentration of the larger, optically
visible fibers.6
Study Objective
The objective of this research project
was to identify and quantify the air-
borne amosite asbestos fibers present
in building atmospheres after an as-
bestos remedial activity was completed
and the building was reoccupied. The
project focused on the adequacy of
EPA's previously recommended PCM
method of analysis and static sample
collection technique. The PCM method
was compared with TEM methods, and
the feasibility of an alternative aggres-
sive sampling technique was investi-
gated. The results of this study estab-
lished the advantages and limitations of
applying PCM and TEM analytical meth-
ods, both separately and in conjunction
with an aggressive sampling technique,
to the evaluation of air quality following
asbestos abatement.
Reliable methods of air sampling and
analysis permit the use of monitoring
results to be included in evaluating the
efficacy of asbestos abatement meth-
ods and in developing better technical
guidance for abatement contractors,
building owners, and other parties di-
rectly responsible for remedial asbestos
programs. Active or recently completed
abatement sites were selected for moni-
toring because they provided an excel-
lent opportunity to collect real-world
data, and because the monitoring tasks
could be arranged with minimum lead
time and coordination.
The conditions in a work area while
the final air samples are collected can
greatly influence the results of a posta
batement assessment. After an abate
ment action, the air is usually sampled
under static conditionsthat is while
the area is sealed off, before ventilation
is restored, and after at least a 24-hour
settling period following the final wet
cleaning. Consequently, this monitoring
technique may fail to detect residual
fibers that have settled on horizontal
surfaces or that were missed by the
cleaning.
Residual asbestos fibers constitute a
potential exposure hazard because they
could be reentrained later, when the air
in the area is agitated by personnel traf
fie, air flow from ventilation systems,
and custodial activities. Thus, for more
accurate characterization of postabate-
ment fiber concentrations, the work
area should experience appreciable air
movement to simulate actual use condi
tions during air monitoring.
The introduction of air turbulence into
the work area during the collection of
stationary air samples is termed
"aggressive sampling." This method
entails the creation of air movement by
the use of blowers, fans, brooms, or
compressed air streams to entrain any
particulate matter that may be present.
The advantages of the aggressive sam-
pling technique over the static (or
nonaggressive) sampling are that the
former reflects worst-case conditions
and that the testing requires a relatively
short period. The disadvantages are
that this technique is not readily stand-
ardized or reproducible, nor does it re-
flect normal exposure levels to occu-
pants. As with the static sampling
method, no criteria have been estab-
lished to define an acceptable or safe
level of fibers in a nonoccupational en-
vironment. The research on fiber con-
centration levels using the PCM and
TEM methods is continuing so that the
before-, during-, and after-abatement
criteria can be developed within the
next 2 years.
-------
Project Description
Site Selection
Air monitoring was conducted at two
selected sites from which friable as-
bestos building materials had been re-
moved: Site 1, Columbus East High
School, Columbus, Indiana; and Site 2,
the EPA Environmental Research Labo-
ratory in Corvallis, Oregon.
This report describes only the results
of the air monitoring survey conducted
at Site 2. The monitoring data from Site
1 and the significance of these data are
the subject of a separate report (Assess-
ment of Assay Methods for Evaluating
Asbestos Abatement Technology:
Columbus East High School, Columbus,
Indiana, EPA/600/2-86/053). These se-
lected sites met the following criteria:
The abatement plan involved the re-
moval of friable, spray-applied,
asbestos-containing material.
The contractors carried out the work
area preparation, removal, and de-
contamination in accordance with
EPA-recommended specifications
and requirements.1
Multiple work areas containing ho-
mogeneous asbestos material were
available for monitoring.
The building owner and abatement
contractor agreed to cooperate with
EPA and to provide access to se-
lected areas of the building.
Building Description
The Corvallis Environmental Re-
search Laboratory (CERL) is housed in a
two-story, reinforced-concrete structure
built in 1966. The building contains a
total gross area of approximately 465
m2 (45,000 ft2). A single-pass heating,
ventilating, and air conditioning (HVAC)
system supplies the occupied building
areas with 100 percent outside air. The
outside air enters through intakes on
the roof, is tempered by heating or chill-
ing coils, and is distributed by a closed-
duct system to ceiling-mounted dif-
fusers in all rooms and laboratories. Air
flows through louvers in the bottom of
interior doors and passes into the hall-
ways (which serve as air plenums to the
outside), or it is exhausted through lab-
oratory fume hoods.
Asbestos-containing Materials
Asbestos-containing insulation had
been spray-applied and tamped on to
the concrete ceiling (beams and deck) of
four rooms (Rooms 146, 155, 157, and
159) and the penthouse in the main
CERL facility and on beams in the boiler
room (Room 163). The large air intakes
located under the building, which sup-
ply ventilating air to the boiler and
chiller room, were also lined with as-
bestos. The insulation material on the
ceilings of Rooms 155, 157, and 159 and
in the air ducts had been removed in
1984 during a controlled abatement
program. The asbestos-containing insu-
lation in Room 146 (deionizer room), the
boiler room, and the penthouse was still
in place.
Samples collected from Room 146
and the penthouse were analyzed by
polarized light microscopy and disper-
sion staining. The results indicated 80
percent amosite asbestos in each of the
two bulk samples analyzed. At the time
of the survey, the remaining insulation
material was characterized as highly fri-
able, loosely packed, and showing
some signs of deterioration (loose,
hanging pieces were visible).
Methods and Procedures
The sampling procedures and analyti-
cal methods are outlined briefly here.
They are described fully in the full re-
port and in the project summary for Site
1 (Assessment of Assay Methods for
Evaluating Asbestos Abatement Tech-
nology: Columbus East High School,
Columbus, Indiana, EPA/600/2-86/053).
Abatement Program
The asbestos-containing insulation in
Rooms 155, 157, and 159 and in the air
intakes was removed between May 21
and July 2, 1984. The abatement plan
and schedule prepared by the contrac-
tor and submitted to CERL were re-
viewed and approved by EPA before
work was begun. The work plan was in
accordance with the then-current EPA
guidelines and EPA and OSHA asbestos
regulations for asbestos removal and
decontamination. On completion of the
abatement effort, CERL personnel sur-
veyed the work performed by the abate-
ment contractor, performed additional
cleaning of the work areas, and made
arrangements for the painting of all ceil-
ing surfaces from which the asbestos
insulation had been removed.
According to CERL accounts, each
work area was isolated from the rest of
the building by temporary barriers. Ven-
tilation ducts and openings to the out-
side or to adjacent rooms were sealed.
Walls and floors were covered with
plastic sheeting. Fully protected abate-
ment workers first wetted the insulation
with amended water and then scraped it
off. The asbestos-containing debris was
placed in scalable plastic bags and dis-
posed of at a local EPA-approved sani-
tary landfill. Each work area was
cleaned three times, and a settling pe-
riod of 24 hours was allowed between
cleanings. The ceiling surfaces were
painted to bond any residual fibers not
removed by the scraping, brushing, and
wet-cleaning.
Monitoring Approach
The sampling strategy for this study
was to collect representative samples
for PCM and TEM analysis from
(1) rooms where friable asbestos-
containing insulation had been re
moved, (2) rooms that were never
treated with asbestos-containing mate-
rials, and (3) outdoors. Samples for sub-
sequent PCM and TEM analyses were
collected from two or three representa-
tive locations in each room approxi-
mately 6 weeks after completion of all
abatement activities. Two of the three
monitored rooms from which asbestos
insulation had been removed had been
reoccupied. (Room 159 was vacant at
the time of the survey.) Both static and
aggressive sampling techniques were
used in each room. The static sampling
was conducted first during regular
working hours while the facility was oc-
cupied. The aggressive sampling was
conducted on a Saturday when the sam-
pling areas were unoccupied. Filter
holders containing either 0.8-^m Mil-
lipore* mixed-cellulose ester (PCM) or
0.4-p.m Nuclepore polycarbonate filters
(TEM) were positioned 1.3 to 1.5 m (4 to
5 ft) above the floor at arbitrary loca-
tions. Battery-powered sampling
pumps were used to draw air through
the filters. The constant-flow pumps
were calibrated to 2.5 L/min and were
operated for 8 hour per test. Samples
were collected concurrently at outdoor
locations during each monitoring pe-
riod.
On completion of each monitoring
survey, samples were submitted to the
appropriate laboratory for preparation
and analysis. The Nuclepore filters were
carbon-coated before they were trans-
ported to the laboratory for TEM analy-
sis.
Overview of Air Sampling
Strategy
Samples designated for PCM and
TEM analysis were collected with both
*Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
-------
static and aggressive methods in six dif-
ferent rooms. Samples were also col-
lected in the surrounding environment
outside the building. The areas sampled
included three rooms that had been
treated previously with asbestos insula-
tion and have since been abated and
rooms that have never been treated
with asbestos. Representative samples
for PCM and TEM analysis were col-
lected approximately 6 weeks after all
abatement activities had been com-
pleted. Outdoor air samples were col-
lected concurrently with indoor sam-
ples on the roof of the building or at
ground level in the open field west of
the main building.
Side-by-side samples (one for PCM,
one for TEM) were collected in each
room under static and aggressive sam-
pling conditions. The number of sam-
ples per room was not specified by the
study design, but three of each type of
sample were collected within each
room. The static sampling was per-
formed first during regular working
hours with the building occupied and
the HVAC system operating. The ag-
gressive sampling was performed on a
Saturday while the sampling areas were
unoccupied and the HVAC system was
not operating. Placement of the sam-
pling equipment within each work area
was the same during both static and ag-
gressive sampling.
Results
Air Monitoring Results
Table 1 presents a detailed listing of
the results of PCM and TEM analysis of
samples collected under aggressive and
static sampling conditions after abate-
ment. With one exception, all concen-
trations of asbestos fibers and total
structures under aggressive sampling
conditions were higher than the corre-
sponding measurements made under
static sampling conditions. The excep-
tion involved two samples with differ-
ences that were considered negligible
because they were below the limit of
reliable quantitation for the analytical
method.
Comparisons of PCM and TEM analy-
ses of samples collected under static
and aggressive sampling conditions are
presented graphically in Figure 1, which
is based on the data results presented in
Table 1.
Statistical Comparisons
Statistical Method of Analysis
The Mann-Whitney test was used to
determine whether the observed differ-
ences in analytical methods and sam-
pling conditions were statistically sig-
nificant.7 Use of the Mann-Whitney test
required no prior assumption regarding
the nature of the underlying probability
distribution function of measurements
of asbestos fiber concentrations.
Analytical Methods
Tables 2 and 3 compare the geometric
averages of fiber concentrations deter-
mined by PCM and TEM analyses under
static and aggressive sampling condi-
tions. Table 4 summarizes these results.
Based on the application of the Mann-
Whitney test and the assumption that
the fiber/volume concentrations are
comparable, the difference between
PCM and TEM results is statistically sig-
nificant (i.e., p < 0.03) for samples col-
lected outdoors and indoors in abated
areas under static conditions. The dif-
ference between PCM and TEM results
from indoor sampling of nonasbestos
areas was also statistically significant
(p<0.10) under static sampling condi-
tions; however, this conclusion was
based on a small sample size (n = 3).
The ratios of TEM/PCM concentrations
for static sampling were 3.0 for ambient
samples, 3.3 for indoor abated-area
samples, and 7.5 for indoor nonas-
bestos-area samples. The difference be-
tween PCM and TEM results is not
statistically significant (i.e., p > 0.005)
for indoor samples from both abated
and nonasbestos areas under aggres-
sive sampling conditions. For aggres-
sive sampling in abated areas, the ratio
of TEM/PCM was 1.8. For aggressive
sampling in nonasbestos areas, the
ratio of TEM/PCM was 1.9.
Sampling Conditions
Table 2 also compares static and ag-
gressive sampling conditions for PCM
and TEM analyses in both abated and
nonasbestos areas. The difference be-
tween the geometric average fiber con-
centrations under static and aggressive
sampling conditions was statistically
significant (i.e., p < 0.002) for both PCM
and TEM in abated areas. For PCM
analyses, the ratio of aggressive to
static fiber concentrations was 7.0; for
TEM analyses, the ratio was 3.7. For
sampling conducted in nonasbestos
areas, the difference between the geo-
metric average fiber concentrations
under static and aggressive sampling
conditions was statistically significant
for PCM analyses (i.e., p < 0.002) but
not statistically significant for TEM
analyses (i.e., p > 0.04). For nonas-
bestos areas, the ratio of aggressive to
static fiber concentrations for PCM
analyses was 8.0; for TEM analyses, the
ratio was 2.0.
Comparison of Indoor Abated
Samples and Ambient Samples
Also included in Tables 2, 3, and 4 are
the PCM and TEM analyses of samples
collected in the ambient atmosphere
and in indoor abated areas.
The difference between asbestos con-
centrations measured under aggressive
sampling conditions in indoor abated
areas and those measured in ambient
samples was statistically significant
(p < 0.02). The ratio of asbestos concen-
trations measured by TEM under ag-
gressive sampling conditions in indoor
abated areas to ambient TEM concen
trations was 6.2.
Comparison of Indoor Nonas-
bestos Samples and Ambient
Samples
For samples analyzed by PCM, the ge-
ometric mean asbestos concentration
for indoor samples collected statically
in nonasbestos areas was below the de-
tection limit of the analytical method, as
were the ambient PCM samples. Conse-
quently, no meaningful comparisons
can be made. For PCM samples col-
lected aggressively, the geometric
mean concentration was 0.016 x 106
fibers/m3 compared with lower than
0.002 x 106 fibers/m3 for ambient sam-
ples, a ratio of 16.0 (if a concentration of
0.001 x 106 fibers/m3 for ambient sam
pies is assumed). This observed differ
ence was statistically significant
(p>0.01). One nonasbestos area
(Room 152, the instrumentation laboira
tory) was extremely dusty, so the ag-
gressive sampling procedure entrained
large quantities of house dust that had
accumulated on shelf and cabinet tops
over many years. This fact accounted
for the relatively high PCM fiber counts.
For TEM samples collected inside
nonasbestos areas under static condi
tions, the geometric mean asbestos
fiber concentration was 0.015 x 106
fibers/m3 compared with 0.006 x 106
fibers/m3 for TEM ambient samples, a
ratio of 2.5. This observed difference
-------
T
T
i i
H.II.IIIIII....I Nonasbastos Areas
Aggressive TEM
nun
Hum Nonasbestos Areas
Aggressive PCM
MM..,.....,,..,,.., Nonasbestos Areas
Nonaggressive PCM
[muni Nonasbestos Areas
Nonaggressive TEM
IM.MI
III,,,,Mill Abated Areas
Aggressive TEM
<
1MIHBIMI Abated Areas
Aggressive PCM
(l Abated Areas
Nonaggressive TEM
iiiiini Abated Areas
Nonaggressive PCM
±
PCM
l_
MM........ AbJ*nt
TEM
J L
Range
J L
i i i i
_L
25% 75%
Percentiles
J L
.001
.002 .003 .004 .005 .007 .010
.020 .030 .040 .050 .070 .100
106 Fibers/m3
200 .300 .400 .500 .700 1.00
2.00
Figure 1. Comparison of airborne fiber concentrations for PCM and TEM under static (nonaggressive) and aggressive conditions.
was not statistically significant (i.e.,
p>0.10), nor was it significant under
aggressive sampling conditions (i.e.,
p > 0.10), where the ratio was 5.0. Be-
cause the comparisons of fiber concen-
trations for TEM samples in nonas-
bestos areas and ambient samples are
based on very small sample sizes (n = 3
and n = 2, respectively), the observed
differences are not statistically signifi-
cant at a probability level of >0.05.
Comparison of Samples From
Indoor Abated and
Nonasbestos Areas
For all PCM samples (aggressive and
static), the observed differences in fiber
concentrations in indoor abated and
nonasbestos areas were not statistically
significant (p > 0.08 for static conditions
and p > 0.05 for aggressive conditions).
For PCM samples collected under static
conditions, the ratio of fiber concentra-
tions in abated areas to nonasbestos
areas was 3.0 (a concentration of
0.001 x 106 fibers/m3). For PCM sam-
ples collected under aggressive condi-
tions, the ratio was 1.3.
For all samples analyzed by TEM, the
difference between abated and nonas-
bestos areas was also not statistically
significant (p -0.10 for static condi-
tions). For TEM samples collected under
static conditions, the ratio of asbestos
fiber concentrations in abated to nonas-
bestos areas was 0.7. Under aggressive
conditions, this ratio was 1.3 for as-
bestos structures, and 1.2 for asbestos
fiber concentrations.
Conclusions
The following conclusions resulted
from this study:
1. The aggressive sampling tech-
nique used in this problem-
definition study revealed that air-
entrainable asbestos fibers were
present in previously abated areas.
TEM analysis of aggressive sam-
ples from building areas that were
never treated with asbestos insula-
tion also revealed detectable levels
of asbestos fibers.
Regardless of the analytical
method used, the fiber concentra-
tions measured under aggressive
sampling conditions were signifi-
cantly higher than those measured
under static conditions. The ratios
of aggressive to static PCM fiber
concentrations in abated and
nonasbestos areas were 7.0 and
8.0, respectively. By TEM analysis,
these ratios were 3.7 and 2.0.
The study results clearly demon-
strate that under similar sampling
conditions, TEM analysis identifies
more fibers than PCM. The ratio of
TEM/PCM fiber concentrations for
static sampling was 3.0 for ambi
ent samples, 7.5 for indoor nonas
bestos areas, and 3.3 for indoor
abated samples. The ratios for ag-
gressive sampling in indoor areas
were about 2 to 1.
Asbestos concentrations deter-
mined by TEM in abated areas with
-------
Table 1. Results of PCM and TEM Analysis
Nonaggressive
Aggressive
PCM
Sampling Location
Abated areas
Room 155
Room 157
Room 159
Nonasbestos areas
Room 173
Room 152
Room 205
Outdoors (ambient)
Ground
Roof
Blanks
Sample
Number
COR-02
COR-03
COR-01
COR-04
COR-05
COR-06
COR-08
COR-07
COR-09
COR-13
COR-14
COR- 10
COR-16
COR- 19
COR- 11
COR- 17
COR-21
COR-44
COR-43
COR-18
COR-42
COR-45
COR-47
COR-48
COR-49
106 Fibers/m3
0.007 1
0.002*
< 0.002*
0.008*
0.006*
0.01*
<0.002#
-------
aggressive sampling were signifi-
cantly (6.2) times higher than am-
bient TEM concentrations. The
TEM concentrations under aggres-
sive conditions in the nonasbestos
areas were 5 times higherthan am-
bient TEM concentrations, but this
difference was not statistically sig-
nificant.
Recommendations
Although time-consuming and ex-
pensive, TEM should be recommended
as the analytical method of choice for
measuring airborne asbestos fiber con-
centrations for final clearance testing of
work areas after asbestos abatement.
After a standardized TEM protocol and
an aggressive sampling procedure are
incorporated into asbestos guidelines, a
criterion should be established to define
an acceptable asbestos fiber concentra-
tion in building areas after asbestos
abatement. Continued research should
focus on the development of a quicker,
less expensive method for monitoring
buildings after asbestos abatement and
on more efficient abatement practices.
References
1. U.S. Environmental Protection
Agency. Asbestos-Containing Mate-
rials in School Buildings: A Guidance
Document, Part 1. Office of Toxic
Substances, Washington, D.C.
20460. March 1979.
2. Sawyer, R.N., and D.M. Spooner.
Asbestos Containing Materials in
School Buildings: A Guidance Docu-
ment, Part 2. Office of Toxic Sub-
stances, U.S. Environmental Protec-
tion Agency, Washington, D.C.
20460. March 1979.
3. U.S. Environmental Protection
Agency. Guidance for Controlling
Friable Asbestos-Containing Materi-
als in Buildings. EPA/560/5-83-002,
Office of Toxic Substances, Wash-
ington, D.C 20460. March 1983.
4. U.S. Environmental Protection
Agency. Guidance for Controlling
Asbestos-Containing Materials in
Buildings. EPA/560/5-85-024, Office
of Toxic Substances, Washington,
D.C. 20460. June 1985.
5. Falgout, D. Environmental Release of
Asbestos From Commercial Product
Shaping. EPA/600/2-85/044,
Engineering-Science, Fairfax, Vir-
ginia. August 1985.
6. Chatfield, E.J. Measurement of As-
bestos Fibre Concentrations in Ambi-
ent Atmospheres. Study No. 10, On-
tario Research Foundation. 1983.
7. Mosteller, F , and R.E.K. Rourke.
Sturdy Statistics: Nonparametrics
and Order Statistics, Addison
Wesley, Reading, Massachusetts.
1973.
The full report was submitted in fulfill-
ment of Contract No. 68-03-3197 by PEI
Associates, Inc., under the sponsorship
of the U.S. Environmental Protection
Agency.
Table 3. Comparison of Sampling Results by Sample Location*
Sample Location Comparisons
Samples Included
in Comparison
PCM-Static
PCM-Aggressive
TEM-Static
TEM-Aggressive
Indoor Abated/
Indoor Nonasbestos
3.0
1.3
0.7 (0.7) +
1.2 (1.3)t
Indoor Abated
Outdoors
3.0
3.5
1.7(1.7)'
6.2 (6.7)*
Indoor
Nonasbestos/
Outdoors
1.0
16.0
2.5 (2.5) r
5.0 (5.2)'
*AII quantities are ratios of the geometric mean fiber concentrations. For PCM samples, fiber
concentrations include all fibers greater than 5 (xm in length; for TEM samples, fiber concen-
trations include all asbestos fibers.
* Ratio of geometric mean concentrations of asbestos structures.
Table 4. Summary Comparison of PCM and TEM Analyses of Air Samples Collected During Static and Agressive Conditions*
Nonasbestos Areas Abated Areas
Analytical Technique
PCM, fibers (>5\i.m)'m3
TEM, asbestos fibers/m3
TEM, asbestos structures/m3
Outdoor (Ambient)
BDLf
6,000§
6,000§
Static
Aggressive
Static
Aggressive
BDL
15,000
15,000
BLRQ*
(16,000)
30,000
31,000
BLRQ
(3,000)
10,000
10,000
BLRQ
(21,000)
37,000
40,000
*AII values are geometric means.
*BDL = Below detection limit ( = 1,136 fibers/m3).
*BLRQ = Below limit of reliable quantitation (^22,720 fibers/m-').
^Geometric mean based on two sample values. One sample value was below the detection limit for TEM analysis ( 5,688 asbestos fibers
structures/m 3).
-------
Mark A. Karaffa, Robert S. Amick, Ann Crone, and Charles Zimmer are with
PEI Associates, Inc., Cincinnati, OH45246-0100
William C. Cain is the EPA Project Officer (see below).
The complete report, entitled "Assessment of Assay Methods for Evaluating
Asbestos Abatement Technology at the Corvallis Environmental Research
Laboratory," (Order No. PB 87-110 961 /AS, Cost $13.95, subject to change)
will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-86/070
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