United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-93/152 September 1993
Project Summary
Airborne Asbestos
Concentrations Three Years After
Abatement in Seventeen
Schools
John R. Kominsky, Ronald W. Freyberg, James A. Brownlee,
Donald R Gerber, Gary J. Centifonti, and Kim A. Brackett
From 1988 through 1991, the U.S.
Environmental Protection Agency's
(EPA) Risk Reduction Engineering
Laboratory (RREL) and the New Jersey
Department of Health's (NJDOH) Envi-
ronmental Health Service (EHS) con-
ducted air monitoring in 17 schools in
New Jersey to determine the effective-
ness of their asbestos control pro-
grams. In 1988, a study was conducted
to document Asbestos Hazard Emer-
gency Response Act final clearance
concentrations of asbestos at these 17
schools. The findings of this study
prompted a followup study in 1990 to
determine the airborne asbestos con-
centrations 2 yr after the abatement
efforts in these schools. Although the
data from the 1990 study provided in-
formation regarding airborne asbestos
levels during simulated occupancy con-
ditions 2 yr after abatement, whether
these data were representative of lev-
els during actual occupancy was
equivocal. Another followup study was
conducted in May 1991 to determine
the airborne asbestos concentrations
in these 17 schools during actual oc-
cupied conditions. Eight of the sites
showed airborne asbestos levels above
the AHERA criteria of 70 s/mm2.
Reentrainment of residual asbestos-
containing debris from the 1988 abate-
ment or operations and maintenance
(O&M) activities may have contributed
to the elevated airborne asbestos con-
centrations measured during the May
1991 study.
This Project Summary was developed
by EPA's Risk Reduction Engineering
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
T'ne ultimate goal of every asbestos
abatement project is to eliminate or re-
duce, to the extent possible, the actual or
potential hazard presented by airborne as-
bestos structures. From 1988 through
1991, the EPA's RREL and NJDOH's EHS
conducted a series of studies to deter-
mine the effectiveness of asbestos control
programs in 17 schools in New Jersey.
The 1988 study documented Asbestos
Hazard Emergency Response Act
(AHERA) clearance air-sampling practices
and final clearance concentrations of air-
borne asbestos at 20 abatement projects
in 17 New Jersey schools. The results of
the study prompted a followup study in
1990 (Phase II) to determine the airborne
asbestos concentrations in these 17
schools 2 yr after abatement. Although
the data from the 1990 study provided
information regarding airborne asbestos
levels under simulated occupancy condi-
tions, whether the data were representa-
tive of conditions during actual occupancy
remained equivocal.
Therefore, an additional followup study
was conducted in May 1991 (Phase III) to
determine the airborne asbestos levels dur-
ing actual occupied conditions 3 yr after
abatement in these same schools. The 17
schools were not a statistical random
sample; their selection was based largely
on availability. Furthermore, because the
Printed on Recycled Paper
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17 schools were likely to differ in their
abatement history and status with respect
to the presence of asbestos-containing
material, a site-by-site evaluation was per-
formed. No consideration was given to
combining data across all sites to reach a
general conclusion.
Objectives
The objectives of the Phase III study
were: (1) to determine the airborne asbes-
tos levels measured under occupied con-
ditions in 17 schools that underwent abate-
ment in 1988, (2) to determine whether
the airborne asbestos levels measured un-
der occupied conditions in 1991 were sig-
nificantly different from those measured
outdoors, (3) to determine whether the
airborne asbestos concentrations mea-
sured in 1991 were significantly different
from the AH ERA clearance concentrations
measured in 1988, and (4) to determine
whether the airborne asbestos concentra-
tions measured under occupied conditions
in 1991 were significantly different from
those measured under simulated occu-
pancy conditions in 1990.
Study Sites
The study summarized here was con-
ducted at the same 17 schools involved in
the 1988 EPA-RREL/NJDOH-EHS study,
which documented AHERA air monitoring
practices and final clearance concentra-
tions of airborne asbestos, and in the 1990
EPA-RREL/NJDOH-EHS study, which
measured airborne asbestos concentra-
tions 2 yr after abatement.
The 17 schools involved 20 abatement
sites. Access to each school was coordi-
nated directly by NJDOH-EHS. Area air-
borne asbestos concentrations were mea-
sured at each site in the same three ar-
eas as in the previous studies: (1) the
previously abated area, (2) the perimeter
area (outside the abated area but inside
the building), and (3) outdoors. The actual
abatement and perimeter areas could not
be separated because the containment
barriers present during the 1988 abate-
ment had been removed. Also recognized
was the fact that, in the interim since
1988, other sources (e.g., routine mainte-
nance of asbestos-containing resilient floor
tile or other O&M activities) may have
contributed to the current concentrations
of airborne asbestos.
Air Sampling Strategy
Phase III-May 1991
At each site, five area air samples and
three quality assurance samples (one
closed and two open field blanks) were
collected at approximately the same loca-
tions as those collected during the 1988
and 1990 studies. The samples were col-
lected during school hours, 8:00 am to
3:00 pm. Because certain sampling situa-
tions (e.g., inside a classroom) could not
tolerate noise from an electrically pow-
ered sampling pump, the pumps were
placed in special acoustical cases de-
signed to attenuate the noise of the sam-
pling pump to a sound pressure level of
<40 dB (RE 20 N/m2) at a distance of 3 ft.
A noise level of 40 dB is rated as "quiet"
for private offices and conference rooms.
Phase III Followup - Summer 1991
Followup air sampling in the previously
abated work area and in the perimeter
area was conducted during unoccupied
conditions in accordance with a modified
aggressive sampling protocol designed to
simulate normal building activity. The pro-
tocol involved sweeping only the floors
with the exhaust of a 1 -hp leaf blower at a
rate of 5 min/1,000 ft2 of floor space. One
stationary fan (18-in. diameter, axial flow)
per 10,000 ft3 was positioned with the air
directed toward the ceiling to maintain air
movement during sampling.
Phase Ilia - Early August 1991
Followup air monitoring was conducted
in August 1991 at 10 of the 20 sites (Sites
B, D-H, K, M ,N, and Q). Sites B, D-G, K,
and M were selected because the aver-
age airborne asbestos concentration in
the previously abated area and/or perim-
eter area exceeded 0.02 asbestos struc-
ture per cubic centimeter (s/cm3). Sites N
and Q were also monitored because these
sites were in the same schools as sites K
and B, respectively, which had levels ex-
ceeding 0.02 s/cm3. Site H was monitored
because replicate analyses of selected
samples at this site showed average as-
bestos levels above 0.02 s/cm3. This value
(0.02 s/cm3) is derived from the AHERA
40 CFR 763 initial screening criteria of 70
s/mm2. At each of the 10 sites, 5 area air
samples and 3 quality assurance samples
were collected in the same three areas as
the samples collected during occupied con-
ditions in May 1991.
Phase Illb - Late August 1991
Based on the results of the Phase Ilia
monitoring, four schools (Sites F, G, H,
and M) were required to conduct response
actions (i.e., cleaning) in the previously
abated area and/or perimeter area to re-
duce residual airborne asbestos contami-
nation. After these response actions, ad-
ditional area air samples were collected.
At each of the four schools, five area air
samples and three quality assurance
samples were collected in the same areas
as were the Phase III and Phase Ilia
samples (no outdoor samples were col-
lected at Site M).
Phase Illc - September 1991
Airborne asbestos concentrations at Site
M were still elevated after the Phase Illb
monitoring. Therefore, the previously
abated area and the perimeter area re-
sponse actions were again conducted, and
five additional samples and one closed
and two open field blanks were collected
in these areas.
Site Documentation
For each of the 17 schools monitored in
May 1991, the NJDOH-EHS documented
the history of the abatement activities be-
tween 1988 and 1991 and the O&M ac-
tivities on any remaining asbestos-con-
taining building material (ACBM) in the
previously abated area and perimeter area.
This information was obtained from abate-
ment notices required under the New Jer-
sey Administrative Codes (N.J.A.C. 8:60-
7 and N.J.A.C. 12:120-7), AHERA Asbes-
tos Management Plans, and information
provided by the designated person and/or
school officials who were interviewed.
NJDOH Visual Inspection
After conducting the followup air moni-
toring at the eight schools, which involved
10 sites, in August 1991 (Phase Ilia), a
certified AHERA building inspector from
NJDOH-EHS visually inspected each of
these schools. Before conducting the in-
spection, the inspector reviewed each
school's Asbestos Management Plan. The
review included (1) recording the material
category (e.g., thermal system insulation),
amount of material (e.g., linear feet), and
condition of material (e.g., damaged ther-
mal system insulation) for the ACBM re-
maining in the previously abated area and
perimeter area; (2) recording completed
response actions (including O&M); and
(3) recording any renovations that had
occurred.
Sampling Methods
Fixed-Station Area Air Samples
Air samples were collected on open-
face, 25-mm-diameter, 0.45-u,m-pore-size,
mixed cellulose ester (MCE) membrane
filters with a 5-(o.m-pore-size, MCE, backup
diffusing filter and cellulose support pad
contained in a three-piece cassette. The
filter cassettes were positioned approxi-
mately 5 ft above the floor on tripods, with
the filter face at approximately a 45-de-
gree angle toward the floor. The filter as-
sembly was attached to a 1/6-hp electri-
cally powered vacuum pump operating at
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a flow rate of approximately 9 L/min. Air
volumes ranged from 943 to 2536 L. At
the end of the sampling period, the filters
were turned upright before being discon-
nected from the vacuum pump; they were
then stored in this position. The sampling
pumps were calibrated with a calibrated
precision rotameter both immediately be-
fore and after sampling.
Bulk Samples
Bulk samples of suspect ACBM (e.g.,
thermal system insulation, fireproofing, and
resilient floor tile) or debris were collected
by the NJDOH inspector for laboratory
analysis to determine the asbestos con-
tent. The samples were collected by ei-
ther a standard coring tool or the collec-
tion of debris. Both types of samples were
placed in labeled containers.
Analytical Methods
Air Samples
The MCE filters were prepared and ana-
lyzed in accordance with the nonmandatory
transmission electron microscopy (TEM)
method, as described in the AHERA final
rule (40 CFR 763). A sufficient number of
grid openings were analyzed for each
sample to ensure a sensitivity (the con-
centration represented by a single struc-
ture) of no greater than 0.005 s/cm3 of air
sampled. In addition to the requirements
of the nonmandatory TEM method, the
specific length and width of each structure
were measured and recorded. The
samples were prepared and analyzed by
EPA's TEM laboratory in Cincinnati, OH.
Bulk Samples
The type and percentage of asbestos in
the bulk samples were determined by po-
larized light microscopy and X-ray diffrac-
tion. The samples were prepared and ana-
lyzed in accordance with the "Interim
Method for Determination of Asbestos in
Bulk Insulation Samples" (EPA 600/M4-
82-020). The samples were prepared and
analyzed by the NJDOH's Public Health
and Environmental Laboratories in Tren-
ton, NJ.
Statistical Methods
Airborne asbestos concentrations mea-
sured in each of the three sampling loca-
tions were characterized by the use of
descriptive statistics. Because the 20 sites
were likely to differ in their abatement
history and status with respect to the pres-
ence of asbestos-containing material, each
site was considered separately. The de-
scriptive statistics included the arithmetic
mean, minimum and maximum concentra-
tions, and sample size.
A single-factor analysis of variance
(ANOVA) was used to examine differences
between concentrations measured in the
previously abated work area, perimeter
area, and outdoors for each site. A single-
factor ANOVA analysis was also used to
compare airborne asbestos concentrations
measured in 1988, 1990, and 1991 for
each sampling location. All statistical com-
parisons were performed at the 0.05 level
of significance.
Quality Assurance
Specific quality assurance procedures
outlined in the AHERA rule were used to
ensure the precision of the collection and
analysis of air samples, including filter lot
blanks, open and closed field blanks, and
repeated sample analyses.
Site Descriptions
Post-1988 abatement occurred at 1 of
the 20 sites (Site O) in the previously
abated area and at 4 of the 20 sites (Sites
A, D, L, and N) in the perimeter area. At
15 sites, ACBM is still present in the pre-
viously abated areas; at all of the sites,
ACBM is still present in the perimeter ar-
eas.
Airborne Asbestos Levels During
Occupied Conditions In May 1991
Table 1 presents the mean, minimum,
and maximum airborne asbestos concen-
trations measured at each of the 20 sites
in the 17 schools. Figure 1 illustrates the
average airborne asbestos concentrations
in the previously abated and perimeter
areas. Eight of the 20 sites showed levels
above the AHERA initial screening crite-
rion of 70 s/mm2 (40 CFR 763) and above
0.02 s/cm3 (NJDOH clearance criterion).
Comparison of Previously Abated
Area With Outdoors
At 6 of the 20 sites (Sites B, E, F, G, K,
and Q), mean airborne asbestos concen-
trations in the previously abated area were
significantly higher than were those out-
doors. Mean concentrations in the previ-
ously abated area were at least one order
of magnitude (i.e., 10 times) greater than
were the mean concentrations outdoors.
At all of the other 14 sites, the difference
between mean levels in the previously
abated areas and outdoors was not statis-
tically significant.
Comparison of Perimeter Area
With Outdoors
At 4 of the 20 sites (Sites B, F, N, and
Q), mean airborne asbestos concentra-
tions in the perimeter area were signifi-
cantly higher (at least one order of magni-
tude) than were those outdoors. At the
remaining 16 sites, the difference between
mean levels in the perimeter areas and
the outdoors was not statistically signifi-
cant.
Comparison of Previously Abated
Area With the Perimeter Area
At 3 of the 20 sites (Sites E, G, and K),
mean airborne asbestos concentrations in
the previously abated area were signifi-
cantly greater than were those in the pe-
rimeter area. Mean concentrations in the
previously abated area were approximately
4 times greater than were those in the
perimeter area at Site E, approximately 5
times greater at Site G, and approximately
14 times greater at Site K. At all of the
other 17 sites, the difference between
mean concentrations in the previously
abated area and the perimeter areas was
not statistically significant.
Overall Structure Morphology and
Length Distributions
The TEM analysis of 100 samples col-
lected during occupied conditions in the
previously abated area, 94 samples col-
lected in the perimeter area, and 85
samples collected outdoors yielded a total
of 601 asbestos structures, 99.7% of which
were chrysotile asbestos and 0.3% were
amphibole. Overall, the asbestos struc-
tures were primarily fibers (66%), and to a
lesser extent, matrices, bundles, and clus-
ters.
Overall, 1.5% of the measured asbes-
tos structures were greater than 5 u,m in
length; most of the structures (92%) were
less than 2 |o.m in length.
Phase III Follow-up Air Monitoring-
August1991
Followup air monitoring was conducted
by EPA-RREL/NJDOH-EHS in August
1991 at 10 of the 20 sites (B, D-H, K, M,
N, and Q). These sampling results indi-
cate that four sites (F, G, H, and M)
showed average levels exceeding 0.02 s/
cm3 in both the previously abated area
and the perimeter areas. Based on the
results at these four sites, NJDOH-EHS
required response action at each of the
four schools. Three of the four schools
employed licensed asbestos-abatement
contractors and one used in-house, trained
staff to conduct response actions to re-
duce the levels of airborne asbestos.
After the response actions at these four
schools, EPA-RREL/NJDOH-EHS con-
ducted followup air monitoring to deter-
mine the residual levels of airborne as-
bestos. Based on these sampling results,
NJDOH-EHS determined that further ac-
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Table 1. Airborne Asbestos Concentrations* Measured During Periods of Occupancy at Seventeen Schools in May 1991
Previously abated area
Site
A
B
C
D
E
F
G
H
I
J
K
L
O
P
Q"
R
S
T
Mean
Minimum
Maximum
0.001
0.027
0.005
0.020
0.037
0.043
0.027
0.004
0.004
0.003
0.041
0.006
0.023
0.004
0.005
0.004
0.009
0.005
0.001
0.001
0
0.01
0
0.003
0.011
0.032
0.011
0
0
0
0.014
0
0
0.003
0
0
C
0
0
0
0.003
0.055
0.012
0.059
0.069
0.066
0.037
0.014
0.007
0.011
0.097
0.016
0.056
0.009
0.022
0.011
0.018
0.010
0.004
0.007
Mean
0.003
0.012
0.001
0.004
0.010
0.036
0.005
0.005
0.005
0
0.003
0.003
0.004
0.015*
0
0.001
0.012
0.001
0.003
0.001
Perimeter area
Minimum
0
0004
0
0
0
0.010
0
0
0
0
0
0
0
0
0
0
0.004
0
0
0
Outdoors
Maximum
0.008
0.024
0.003
0.009
0.029
0.058
0.011
0.011
0.011
0
0.007
0.006
0.007
0.046
0
0.004
0.024
0.004
0.011
0.004
Mean
0.003
0.001
0.003
0.004
0.003
0.001
0.001
0.003
0.005
0.001
0
0
0.003
0
0.001
0
0.001
0.004
0.001
0
Minimum
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Maximum
0.005
0.004
0.007
0.012
0.007
0.002
0.004
0.006
0.020
0.004
0
0
0.007
0
0.003
0
0.004
0.012
0.004
0
'Asbestos concentration, s/cm3 (N=5)
' Outdoor samples are the same as those collected at Site C (i.e., Site M was the second abatement project at this site).
' Outdoor samples are the same as those collected at Site K (i. e., Site M was the second abatement project at this site).
" Perimeter and outdoor samples are the same as those collected at Site 3 (i.e., Site Q was the second abatement project at this school).
tion was required at Site M. Further re-
sponse actions were performed at this
school, and NJDOH-EHS collected addi-
tional samples. The final results showed
an average concentration of 0.005 s/cm3
in the previously abated area and 0 s/cm3
in the perimeter area; therefore, no further
action was required at this school.
NJDOH Visual Inspections
Asbestos-containing debris (including
fireproofing, thermal system insulation, ceil-
ing tile, and plaster dust) was present at
all of the 10 sites. The sources of the
debris were the 1988 abatement, abate-
ments that occurred after 1988, and/or
O&M activities.
Six sites (B, E, F, K, H, and Q) con-
tained at least one ACBM not identified in
the original AHERA inspection; i.e., the
original AHERA inspection did not record
the presence of this material in the Man-
agement Plan for the school. The previ-
ously unidentified materials included ven-
tilation duct insulation and TSI. (These
data were provided to the school officials,
and the schools have reportedly corrected
their Management Plans accordingly.)
At one site (Site F), the Management
Plan was in error regarding the identifica-
tion and location of asbestos-containing
material (ACM). The Management Plan
indicated the presence of spray-on mate-
rials. No spray-on materials were present;
however, TSI was found. (These data were
provided tc the school officials, and the
school has reportedly corrected its Man-
agement Plan accordingly.)
Post-Abatement (1988) versus
Simulated Occupancy (1990)
Previously Abated Area
On average, concentrations measured
during simulated occupancy (1990) in the
previously abated area were significantly
less than were the post-abatement con-
centrations (1988) at 11 of the 20 sites
(Sites C, D, F, H, J-N, Q, and T). At the
remaining nine sites, no significant differ-
ences were noted.
Perimeter Area
On average, concentrations measured
during simulated occupancy (1990) in the
perimeter area were significantly less than
were the post-abatement concentrations
(1988) at 5 of the 20 sites (Sites D, H, L,
P, and T). At only one of the sites was the
mean concentration significantly greater
during simulated occupancy than during
post abatement (Site R). At the remaining
14 sites, no significant differences were
noted.
Outdoors
On average, concentrations measured
outdoors in 1990 were significantly less
than were concentrations measured in
1988 at 2 of the 20 sites (Sites D and N).
At only one site was the mean outdoor
concentration greater in 1990 than in 1988
(Site R). At the remaining 17 sites, no
significant differences were noted.
Post-Abatement (1988) versus
Occupied Conditions (1991)
Previously Abated Area
On average, concentrations measured
in the previously abated area during occu-
pied conditions (1991) were significantly
less than were the post-abatement con-
centrations (1988) at 8 of the 20 sites
(Sites C, D, H, L-N, Q, and T). At two
sites (Sites E and G), mean concentra-
tions of airborne asbestos were signifi-
cantly higher in the previously abated area
during occupied conditions in 1991 than
they were post-abatement in 1988. At the
remaining 10 sites, no significant differ-
ences were noted.
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Perimeter Area
On average, concentrations measured
in the perimeter area during occupied con-
ditions (1991) were significantly less than
were the post-abatement concentrations
(1988) at 5 of the 20 sites (Sites D, H, L,
P, and T). At only one of the sites (Site F)
was the mean concentration significantly
greater during occupied conditions than
they were post abatement in 1988. At the
remaining 14 sites, no significant differ-
ences were noted.
Outdoors
On average, concentrations measured
outdoors in 1991 were significantly less
than were concentrations measured in
1988 at 2 of the 20 sites (Sites D and N).
The mean outdoor concentration was
greater in 1991 than in 1988 at two sites
(Sites A and E). At the remaining 16 sites,
no significant differences were noted.
Simulated Occupancy (1990)
versus Occupied Conditions
(1991)
Previously Abated Area
On average, concentrations measured
in the previously abated area during occu-
pied conditions (1991) were significantly
greater than were those measured during
simulated occupancy (1990) at 7 of the 20
sites (Sites D-G, K, M, and R). At the
remaining 13 sites, no significant differ-
ences were noted.
Perimeter Area
On average, concentrations measured
during occupied conditions (1991) were
significantly greater than were those mea-
sured in the perimeter area during simu-
lated occupancy (1990) at only 1 of the 20
sites (Site F). Conversely, on average,
Site R showed significantly greater con-
centrations during simulated occupancy
than during actual occupied conditions. At
the remaining 12 sites, no significant dif-
ferences were noted.
Outdoors
Mean outdoor concentrations of airborne
asbestos measured in 1991 were signifi-
cantly greater than were concentrations
measured in 1990 at 2 of the 20 sites
(Sites A and E). At the remaining 16 sites,
no significant differences were noted.
Conclusions
Seven of the 20 sites (5 of the 17
schools) sampled under occupied condi-
tions in 1991 showed significantly higher
airborne asbestos concentrations in the
previously abated area and/or the perim-
eter area than did those existing outdoors.
Differences in mean concentrations be-
tween those measured inside the schools
and those existing outdoors were not sta-
tistically significant at the other 13 sites.
Eight of the 20 sites showed average
airborne asbestos concentrations above
the AHERA initial screening criterion of 70
s/mm2. Visual inspections conducted by
the NJDOH indicated that reentrainment
of residua! asbestos-containing debris from
the 1988 abatement or from O&M activi-
ties may have contributed to the elevated
asbestos concentrations measured in
these schools.
At the 10 sites where followup air moni-
toring was conducted in 1991, visual in-
spections conducted by the NJDOH-EHS
showed that 6 sites had at least one ACM
that was not identified in the Asbestos
Management Plan. At one of these six
sites, the Asbestos Management Plan was
in error regarding the identification, loca-
tion, and condition of ACM.
Three of the 20 sites showed signifi-
cantly higner airborne asbestos concen-
trations in the previously abated area and/
or the perimeter area in 1991 than did
those measured in 1988. Conversely, 9 of
the 20 sites showed significantly lower
airborne asbestos concentrations in the
previously abated area and/or perimeter
areas in 1991 than those measured in
1988. Differences between mean concen-
trations measured in 1988 and 1991 at
the other eight sites were not statistically
significant.
The mean airborne asbestos concen-
trations measured in the previously abated
area and/or the perimeter area at 7 of the
20 sites during occupied conditions in 1991
were significantly greater than were those
measured under simulated occupancy con-
ditions in 1990. Conversely, one site
showed significantly lower concentrations
during occupied conditions than during
simulated occupancy. Differences in mean
concentrations measured in 1990 and
1991 at the other 12 sites were not statis-
tically significant.
Recommendations
Followup air monitoring should be con-
ducted at these schools to determine if
elevated post-abatement airborne concen-
trations of asbestos is continuing. The
followup air monitoring should be coupled
with detailed visual inspections to deter-
mine the sources of the asbestos and to
identify appropriate remedial measures.
The results of the followup study will pro-
vide information regarding the long-term
effectiveness of asbestos control pro-
grams. This information may assist EPA
in evaluating the need for issuance of
guidance on asbestos management prac-
tices.
The full report was submitted in partial
fulfillment of Contract No. 68-D2-0058,
Work Assignment No. 1-18, by Environ-
mental Quality Management, Inc. under
subcontract to Pacific Environmental Ser-
vices, Herndon, Virginia 22070. This work
was conducted under the sponsorship of
the U.S. Environmental Protection Agency.
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I
I
0.05
0.04
0.03
0.02
0.01
o
§
O
0.05
0.04
0.03
0.02
0.07
Previously abated area
A BCDEFGHIJ KLMNOPQRST
A BCDEFGHIJ KLMNOPQRST
0.05
_ 0.04
0.03
0.02
o.or
., 0.05
0.04
0.03
0.02
'. 0.01
-> o
Figure 1. Average airborne asbestos concentrations (s/cm3) in the previously abated area (top) and perimeter area (bottom) measured during occupied
conditions in May 1991.
ŁU.S. GOVCtNMENT PRINTING OFFICE: 1993 - 7SO-07I/800JM
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J.R. Kominsky and R.W. Freyberg are with the Environmental Quality Manage-
ment, Inc., Cincinnati, OH 45240; J.A. Brownlee, D.R. Gerber, and G.A.
Centifonti are with the New Jersey Department of Health, Environmental
Health Service, Trenton, NJ 08625; Kim A. Bracken is with the International
Technology Corporation, Cincinnati, OH 45246
Thomas J. Powers is the EPA Technical Project Officer (see below)
The complete report, entitled "Airborne Asbestos Concentrations Three Years
After Abatement in Seventeen Schools," (Order No. PB93-218501AS;
Cost: $27.00, 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:
Risk Reduction Engineering 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
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-93/152
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