United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-93/143 October 1993
i&EPA Project Summary
Fluorescent Tracer
Evaluation of Protective
Clothing Performance
Richard A. Fenske
Field studies evaluating chemical pro-
tective clothing (CPC), which is often
employed as a primary control option
to reduce occupational exposures dur-
ing pesticide applications, are limited.
This study, supported by the U.S. Envi-
ronmental Protection Agency (EPA),
was designed to evaluate several pro-
tective garments and to determine the
ability of specific CPC components to
reduce worker exposure. The studies,
conducted in central Florida during cit-
rus applications of Ethion 4 Miscible™,
examined cotton workshirts and
workpants, cotton/polyester (C/P) cov-
eralls, SMS coveralls, and Sontara cov-
eralls. CPC performance was evaluated
by fluorescent tracers and video imag-
ing analysis and by the patch tech-
nique. Nonwoven coveralls allowed sig-
nificantly greater exposure than did tra-
ditionally woven garments primarily
because of design factors (e.g., large
sleeve openings). Fabric penetration
occurred with high frequency for all
test garments, and none can be con-
sidered chemically resistant under
these field conditions. Improved cover-
all garments would, however, provide
only a small further reduction in expo-
sure. Faceshields would reduce the ex-
posure approximately three times more
than would improved coveralls. Expo-
sure pathways that would probably be
undetected or inaccurately quantified
by the patch technique were measured
by fluorescent tracers and imaging
analysis. The patch technique, however,
was far more sensitive in detecting fab-
ric penetration. Workers conducting
airblast applications would be better
protected by closed cab systems or
any other technology that places a well-
defined barrier between the worker and
the pesticide spray. Personal protec-
tive equipment (PPE) requirements
should consider the potential for heat
stress, and conditions under which PPE
is not to be used should be defined
and enforced to reduce the risk of ill-
ness related to heat stress. Protective
garments designed and marketed for
use by pesticide applicators should be
field tested to determine performance,
and users should be provided with ac-
curate information regarding the chemi-
cal resistance of such garments.
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
CPC is often employed as a primary
control option to reduce occupational ex-
posure during pesticide applications. CPC
has traditionally been evaluated in two
phases: laboratory and field performance
testing. Although laboratory testing can
provide information about pesticide pen-
etration through fabric, field testing under
realistic exposure conditions is needed to
determine the overall efficiency of reduced
penetration. Design factors that enhance
or reduce exposure are evident only dur-
ing field use of the clothing.
Field methods to evaluate CPC perfor-
mance are limited. The patch technique,
which places collection pads above and
Printed on Recycled Paper
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beneath clothing to estimate garment pen-
etration, can produce highly variable mea-
surements since pesticide exposure dur-
ing applications is, in most cases, not
uniform. Exposure may also occur by path-
ways that the patch technique was not
intended to detect; e.g., deposits through
openings in garments or by cross-con-
tamination. The use of fluorescent tracers
and video imaging analysis provides an
opportunity to conduct realistic field per-
formance evaluation of CPC. This tech-
nique allows visualization of exposure pat-
terns on the skin and quantitative esti-
mates of pesticide deposition.
The primary objective of this study was
to evaluate the performance of CPC un-
der realistic pesticide application condi-
tions. Specific aims were to (1) identify
dermal exposure pathways, (2) compare
dermal exposures of workers wearing test
garments to those of workers wearing tra-
ditional protective clothing, (3) determine
the scientific validity and feasibility of em-
ploying the fluorescent tracer technique
as an evaluation method, and (4) deter-
mine the ability of specific CPC compo-
nents to reduce total worker exposure.
The overall study was divided into two
components: the Protective Clothing Per-
formance Study, designed to address aims
one through three, and the Total Expo-
sure Distribution Study, designed to ad-
dress the fourth aim.
Methods
Field studies occurred in central Florida
during citrus applications of Ethion 4
Miscible™ [EPA Reg. No. 279-1254].
Ethion 4 Miscible™ is a liquid concentrate
formulation containing 4 Ib active ingredi-
ent (Al)/gal and is 46.5% Al by weight.
The active ingredient is the organophos-
phorus insecticide, ethion [0,0,0',0'-tetra-
ethyl S,S'-methylene bisphosphoro-
dithioate]. All applicators were adult males
who applied pesticides as part of their
normal work duties.
Four garment types were selected for
evaluation in the Protective Clothing Per-
formance Study: two were traditional gar-
ments used in agriculture and two were
made from nonwoven fabrics selected by
EPA investigators. Fabric characteristics
were as follows:
• Cotton workshirt + workpants (woven,
untreated): 100% cotton twill material;
twill woven construction;
• C/P coverall (woven, untreated): a
65% cotton/35% polyester twill
material; twill woven construction;
• SMS coverall (nonwoven, treated): 100%
polypropylene composite material with
three-layered construction; thermally
pointbonded laminate of spunbonded,
mett bbwn, spunbonded fabric;
• Sontara coverall (nonwoven, treated):
50% polyester, 50% wood pulp
material with both pointbonded and
spunbonded construction; spunlaced
composite.
Eight replicate exposures of each gar-
ment were proposed based on previous
studies that indicated statistical differences
in garment performance with a similar
sample size. Each applicator in the study
wore each of the garments at least once
to minimize potential confounding result-
ing from personal application procedures.
Equipment type, tank size, and amount of
fluorescent tracer applied per tank were
controlled for all applications in Year 01.
Uncontrolled variables included number of
tanks applied, application time, and indi-
vidual work practices. Each applicator was
given a black, cotton T-shirt, chemical-
resistant gloves, and one of the protective
garments to wear. Mixers were not moni-
tored during this study.
Participants in the Total Exposure Dis-
tribution Study conducted replicate appli-
cations of ethion under normal field condi-
tions. Two protective coveralls (cotton and
Sontara) were assigned to applicators on
a random basis. In one-half of the repli-
cate applications, protective gloves also
assigned on a random basis were worn.
All applicators wore plastic face shields.
Fabric characteristics were as follows:
• Cotton coverall (woven): a 100%
cotton denim material; twill woven
construction; untreated;
• Sontara coverall (nonwoven, treated);
described above.
Twelve replicate tests of each garment
were conducted, with each participant
wearing each type of garment four times.
The Ethion 4 Miscible™ formulation was
applied throughout the study according to
label instructions. Natural oil and other
agricultural chemicals (e.g., copper,
Benlate™, Kocide)™ were frequently added
to the spray mixture. In some cases, no
ethion was included in the spray mix. All
applicators used airblast sprayers with 500-
gal tanks pulled by open-air tractors with
a top canopy for shade. Each worker was
monitored during application of four 500-
gal tanks. A commercially available fluo-
rescent whitening agent, Calcofluor RWP
(4-methyl-7-diethylaminocoumarin), was
employed as a tracer of pesticide residue
deposition. Tracer concentration in the
spray mix was constant throughout the
studies (300 gm per 500 gal H2O; 160 ppm).
Protective Clothing
Performance Study Sampling
Pre- and post-exposure video images
were made of each subject's hands, head,
neck, forearms, upperarms, upper torso,
and lower torso. All images were acquired
using a second generation video imaging
analysis system. Fluorescent tracer depo-
sition patterns were also evaluated quali-
tatively by visual observations and scor-
ing. Dermal patches were attached above
and below the protective garment on the
thighs to estimate protective clothing pen-
etration. Images were analyzed with the
customized C-language software pro-
grams, VITAE-MAP and VITAE-CALC.
Post-exposure images were outlined to
isolate the body region of interest and
then were superimposed onto the pre-
exposure images. Histograms (grey level
frequency distributions) of these images
were then subtracted, and the net fluores-
cence was transformed to tracer mass by
means of a standard curve. The data for
the standard curve was developed in the
laboratory by spotting known amounts of
the tracer on human skin. Patches were
cold-solvent extracted and analyzed for
ethion by electron capture gas chroma-
tography. The same extracts were ana-
lyzed for the tracer by spectrofluorometry.
Total Exposure Distribution
Study Sampling
The traditional patch technique recom-
mended for applicator exposure assess-
ment was employed with minor modifica-
tions. Twenty alpha cellulose patches were
positioned on each worker. A pair of
patches (one on the outer garment and
one inner patch on the skin) were at-
tached to the upper legs (4), lower legs
(4), upper arms (4), and lower arms (4),
chest (2), and back (2). After a worker
was suited in a protective garment, both
hands were washed with ethanol by plac-
ing the hand in a plastic bag containing
250 ml ethanol; wrapping the mouth of
the bag tightly around the wrist; relaxing
the hand; and having a staff member shake
the hand in the solution for 30 sec. This
procedure was repeated twice for each
hand. After the worker finished spraying
his tanks, this handwash procedure was
repeated. All workers' hands were washed
regardless of whether they worked bare-
handed or wore gloves. All workers' wore
faceshields that extended from forehead
to chin. When the worker returned from
spraying, field staff removed his faceshield
and wiped the entire face of the shield
with an ethanol-moistened gauze pad.
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Results
Protective Clothing
Performance
Thirty-three applications of insecticide
involving six workers were monitored; the
Sontara garment was worn in nine appli-
cations and each of the other three gar-
ments were worn in eight applications.
Tracer concentration was maintained at
300 g/tank for all applications, but ethion
concentration varied substantially. The to-
tal amount of tracer and ethion Al applied
ranged from 0.4 to 1.2 and 0 to 10.9 kg,
respectively. Fluorescent tracer exposure
measurements produced by video imag-
ing analysis were normalized to reflect a
standard application of four tanks and ex-
pressed as an hourly rate. In all cases,
tracer exposure beneath protective cloth-
ing was greatest for the forearms. Mean
forearm exposure was lowest for the
workshirt (34 jig/hr), and exposure was
lower for the C/P coverall than for either
of the nonwoven coveralls 64 ja.g/hr for C/
P coveralls compared with 87 and 93 jig/
hr for SMS and Sontara garments, re-
spectively). A similar exposure pattern ob-
served for the upper arms was not evident
for the torso. Variability within each gar-
ment group was high for all body regions,
with coefficients of variation ranging from
89% to 260%. Neither parametric (ANOVA)
nor nonparametric (Kruskal-Wallis) tests
among garment types yielded significant
differences.
A substantial amount of the variability
observed across garment types was be-
lieved to be due to differences in garment
challenge; i.e., the amount of fluorescent
tracer reaching the outside of the gar-
ments and the exposed skin surfaces.
Head exposure provides an indication of
the tracer challenge that each worker re-
ceived during application, since none of
the workers wore PPE for this region.
Exposure data for the forearms, upper
arms and torso were therefore normalized
by the average head exposure (96.7 jig/
hr) for the entire study group as follows: a
challenge adjustment factor was calcu-
lated by dividing the group mean head
exposure by each individual's head expo-
sure; each individual's forearm, upper arm
and torso exposure values were then mul-
tiplied by this adjustment factor to pro-
duce normalized exposure data for these
body regions. If differences in individual
challenge are contributing to the variabil-
ity observed within garment groups, then
this adjustment should reduce within-group
variability and allow a more direct assess-
ment of the effect of garment type on
exposure to protected regions. The ad-
justment decreased the coefficient of varia-
tion (CV) in 10 of 12 cases, with the range
of CVs reduced from 89% to 260% to
64% to 192% (Table 1).
The pattern of exposure between wo-
ven and nonwoven garments remained
similar to that observed in the original
data set, but the pattern within nonwoven
garments was altered such that the SMS
garment exhibited higher adjusted expo-
sure than did the Sontara garment for all
body regions. Statistical analysis of the
challenge-adjusted data by the Kruskal-
Wallis test indicated the following: forearm
exposure was significantly higher for the
SMS garment than for the other three
garments; forearm exposure was also sig-
nificantly higher for the Sontara garment
than for the woven garments; upper arm
exposure was significantly higher for the
Sontara garment than for the two woven
garments; upper arm exposure was prob-
ably higher for the SMS garment than for
the workshirt and woven coveralls, but
differences were not statistically signifi-
cant at this sample size; no significant
differences in torso exposure were ob-
served. The detection of high levels of
tracer on the forearms for the nonwoven
garments suggests that dermal exposure
occurred by spray entering through the
sleeve opening. The detection of relatively
high levels of tracer on the upper arms for
the Sontara garment suggests that both
fabric penetration and deposition through
the sleeve opening contributed to expo-
sure.
Scores based on visual observations
following application corresponded well to
the imaging analysis results (Figure 1).
Torso exposure was not significantly dif-
ferent across the garment types (ANOVA:
p<.05), but both upper arm and forearm
exposures were different. Visual scoring
indicated even more pronounced differ-
ences between the woven and nonwoven
garments for the arms and for the fore-
arms in particular, It was also apparent
during visual observation that arm expo-
sure decreased with increasing distance
from the wrist and that most torso expo-
sure occurred at or near the neck. These
observations suggest that in the majority
of cases the tracer was being deposited
on skin by movement under the garment
rather than through fabric (Figure 2).
Ethbn exposure (Table 2) was estimated
by multiplying the fluorescent tracer expo-
sure data by the average ratio of ethion
and tracer deposited on outer patch sam-
plers on the upper region of the body
(chest, shoulder, and head). Since work-
ers applied widely varying amounts of
ethion, average ethion/tracer ratios were
calculated for applications with 5 pints
Ethion 4 Miscible™ per 500-gal tank and
12 pt/500 gal tank. These ratios averaged
8.90 ± 4.4 and 21.34 ± -8.4 for the 5 pt
and 12 pt/tank concentrations, respectively.
Despite a broad range of ratio values within
each group (4 to 19 and 9 to 35, respec-
tively), the proportion of the average ra-
tios was virtually identical to the 2.4 pro-
portion of pt/tank (12pt/5pt).
Percent penetration of ethion through
protective clothing was calculated dividing
the inner patch sampler value by the outer
patch sampler value and multiplying by
100. In Year 01, garment breakthrough
occurred in all of the 23 applications for
which complete data were available. Mean
penetration values for the four garments
were quite similar, ranging from 4.7% -
7.2%, and did not differ significantly. In
Year 02, ethion penetration at the legs
was greater for the cotton coveralls than
for the Sontara coveralls (2.7 versus 0.8;
KW: p<.02). The same pattern was ob-
served for the chest, but this was not
statistically significant because of the high
variability within each garment type (5.4
versus 1.4; KW: p=.17). Ethion penetra-
tion of the Sontara garment was much
lower in Year 02 than in Year 01 (0.8%
versus 6.3% penetration at the legs). Com-
paring the woven coverall garments across
the years indicated that the 100% cotton
coveralls performed more effectively than
did the C/P coveralls (2.7% versus 4.7%
penetration at the legs).
Total Exposure Distribution
Study
Twenty-four applications were moni-
tored: 12 in which the cotton coverall was
worn and 12 in which the Sontara coverall
was worn. All exposure data are expressed
as hourly rates (ng/hr) based on a mea-
sured application rate of 17 min/tank. Hand
exposure without gloves averaged 13,812
(ig/hr, and ranged from 2000 to 23,000
|ig/hr. When nitrile gloves were worn, ex-
posure decreased nearly eightfold to 1,762
(xg/hr, with a range of 193 to 9,370 |tig/hr
(ANOVA: p<.0001). Clearly, use of gloves
substantially reduced, but did not elimi-
nate, hand exposure. Face and head ex-
posures were calculated by extrapolating
the average of four torso patch samplers
to the relevant surface areas (650 cm2 for
face, 1180 cm2 for head). This calculation
yielded an average face exposure value
of 965 ng/hr and an average head expo-
sure value of 1,752 u,g/hr.
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Table 1. Challenge-Adjusted Fluorescent Tracer Exposure by Garment Type* (\ig/hr)
Forearms Upper Arms Torso
UcUIIIUIH
Type
Workshirt
C/P coveralls
SMS
Sontara
Mean
46.2 A+
56.3 A+
388. 9 B+
109.8 c*
CV(%)
64
108
89
71
Mean
1.7D+
4.1°+
107.8
19.8 £+
CV(%)
Mean
CV(%)
149
192
138
82
30.9
24.5
82.0
39.9
97
70
154
131
* These values have been normalized by group mean head exposure.
+*-£ Values within columns with different letters are significantly different (Kruskal-Wallis; p<.05).
1
(0
I
Forearms
Upper Arms
D Torso
4 -
2-
Workshirt
C/P coverall
SMS
Sontara
Garment Type
Figure 1. Qualitative evaluation of fluorescent tracer exposure for four test garments by body region.
Inner patch samplers were categorized
as either (1) quantifiable (>0.84 |ig/
sample), (2) trace (0.24-0.84 u,g/sample),
or (3) unexposed (<0.24 jig/sample). In
the majority of cases, garment break-
through occurred for the body regions pro-
tected by coveralls (Table 3). For cotton
coveralls, 34% of the inner patch sam-
plers had quantifiable ethion and an addi-
tional 29% had trace levels, resulting in a
breakthrough frequency of 63%. For the
Sontara coveralls, 26% of the inner patch
samplers had quantifiable ethion and an
additional 43% had trace levels, resulting
in a breakthrough frequency of 69%. Ex-
posure to regions beneath protective gar-
ments was calculated by multiplying the
inner patch sampler deposition rate by the
appropriate standard surface area. Only
quantifiable ethion and trace values were
used, with trace values being assigned
one-half the limit of detection (007 ^g/
cm2); unexposed samples were assigned
values of zero. Total exposure to these
regions was then determined for each
worker, and average "protected body" ex-
posure was determined (protected body is
defined here as all regions beneath cov-
eralls).
The distributional characteristics of ex-
posure are important in that they indicate
the effectiveness of specific interventions
for reducing exposure and provide data
for recommending additional interventions.
Numerous applicator exposure studies
have reported the distribution of dermal
exposure across body regions, but most
often these studies have lacked specificity
concerning methods of calculations, use
of PPE, and underlying assumptions. Fur-
thermore, traditional sampling techniques
may have underestimated exposure be-
neath protective clothing because of depo-
sition through garment openings, as docu-
mented here. As a result, generalizations
sometimes cited concerning exposure dis-
tribution may be inaccurate. Based on the
data collected in this study, a series of
exposure scenarios has been developed
to identify the role of PPE in exposure
reduction. These data are believed to be
representative of airblast applicator expo-
sure in citrus orchards, and they may be
representative of orchard airblast expo-
sure in general. They are not, however,
applicable to other types of pesticide ap-
plications (e.g., groundboom, backpack),
nor do they reflect exposure patterns of
pesticide mixers or mixer/applicators.
Label requirements for Ethion 4
Miscible™ require that a worker wear the
following PPE during application: (1) pro-
tective suit of one or two pieces covering
all parts of the body except the head,
hands and feet; (2) chemical resistant
gloves and shoes; (3) National Institute
for Occupational Safety and Health or
Manufacture's Safety Association approved
respirator. In practice, these requirements
are not followed consistently during sum-
mer spraying of citrus in Central Florida.
Indeed, there is substantial evidence to
suggest that such requirements place an
undue burden on workers and may con-
tribute to physiological conditions related
to heat stress. It is not uncommon for
workers applying under high temperature
and high humidity conditions to forego the
use of a respirator and to alter protective
suits in a manner that allows greater air
circulation to the body.
The realities of actual field use of PPE
prompted the following scenarios to as-
sess the role of specific PPE combina-
tions in reducing dermal exposure. Expo-
sure estimates generated by these sce-
narios are given in (Table 4). Since this
study did not measure exposure to the
feet, the use of chemical resistant shoes
or boots is not discussed; exposure to this
body region is assumed to be zero in
subsequent calculations. Unfortunately,
one PPE option—chemical resistant hoods
—was not investigated in this study. Hoods
would appear to provide substantial pro-
tection for all portions of the head except
the face; however, no published studies
are available to demonstrate the effect of
hoods on head exposure.
SCENARIO 1: The unprotected worker.
This scenario assumes that workers use
virtually no PPE or that PPE is used in a
manner that provides little protection. Thus,
the hands, face and protected body re-
gions (regions beneath coveralls) are con-
sidered unprotected. Deposition rates mea-
sured on the outside of coveralls have
been used to estimate exposure to the
protected body regions.
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Figure 2. Fluorescent tracer exposure beneath the sleeves of the nonwoven garments was common
on the forearms and extended above the elbow in many cases.
SCENARIO 2: Cotton or Sontara Cov-
eralls only. Use of a protective coverall is
added to Scenario 1. Hand and head esti-
mates remain unchanged. This scenario
assesses the effect of the coveralls used
in this study but assumes that the worker
does not follow label requirements regard-
ing gloves.
SCENARIO 3: Cotton or Sontara Cov-
eralls + Gloves. Use of chemical resistant
gloves has been added to Scenario 2.
Head and protected body estimates re-
main unchanged. This scenario assesses
the effect of chemical resistant gloves on
hand exposure and is consistent with la-
bel requirements.
SCENARIO 4: Cotton or Sontara Cov-
eralls + Gloves + Faceshield. Use of a
faceshield has been added to Scenario 3.
Hand and protected body estimates re-
main unchanged. This scenario assesses
the effect of the faceshield when a worker
is following label requirements.
SCENARIO 5: Chemical Resistant Cov-
eralls + Gloves. Chemical resistant cover-
alls (100% effective) have been substi-
tuted for the cotton or Sontara coveralls
used in the study, and the faceshield has
been removed. Head exposure is that used
in Scenarios 1 through 3. Hand exposure
remains unchanged from Scenario 4. This
scenario assesses the effect of a truly
chemical resistant coverall on total expo-
sure when a worker is wearing label-re-
quired protective clothing. (It should be
noted that no field studies to date have
documented that commercially available
coveralls perform in this manner during
airblast applications.)
SCENARIO 6: Chemical Resistant Cov-
eralls + Gloves + Faceshield. Faceshields
have been added to the PPE in Scenario
5 to create a scenario in which all PPE
options are combined.
Dermal exposure to the unprotected
worker (S-1) was primarily to the protected
body regions (73%), with hand exposure
contributing nearly 24% of total exposure.
The use of cotton or Sontara coveralls (S-
2) reduced total dermal exposure by 73%,
and exposure to unprotected hands be-
came the primary contributor to total der-
mal exposure (87%). Thus, coveralls play
the most important role of any PPE in
reducing exposure during citrus airblast
applications. Adding chemical resistant
gloves (S-3) further reduced dermal expo-
sure to 94% of that received by the unpro-
tected worker when exposure is compared
with workers wearing coveralls. The use
of gloves reduced total dermal exposure
by 76%. Under this scenario the contribu-
tions of protected hands and unprotected
head were equal, accounting for more than
90% of total dermal exposure. The addi-
tion of faceshields (S-4) produced further,
but slight, decreases in exposure (to 95%
compared with the unprotected worker; to
81% compared with workers with cover-
alls), and hands again became the pre-
dominant source of exposure. When com-
pared with Scenario 3, however, in which
workers followed label requirements, ex-
posure was reduced by 21%.
In light of the partial failure of the cover-
alls evaluated in this study to prevent ex-
posure, it seems reasonable to ask
whether improved coveralls would provide
substantially greater protection. If 100%
effective coveralls had been worn with
gloves (S-5), only a slight decrease in
exposure (to 94% compared to the unpro-
tected worker; to 78% compared to work-
ers with coveralls; only 6% compared to
coveralls + gloves) would have occurred,
with remaining dermal exposure distrib-
uted equally between the protected hands
and unprotected head. Thus, use of
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Table 2. Ethion Exposure Estimates from Imaging Analysis for Protected Body Reg,
'ions (\ig/hr)*
Body Region
Forearm
Workshirt
C/P Coveralls
SMS
Sontara
Upper Arm
Workshirt
C/P Coveralls
SMS
Sontara
Torso
Workshirt
C/P Coveralls
SMS
Sontara
No.
of
Tests
8
8
8
9
8
8
8
9
8
8
8
9
5 Pints Insecticide
Mean
300.8
573.2
771.6
825.9
12.5
109.5
159.3
191.4
175.3
331.1
195.8
262.6
Range
18
18
36
80
1
1
1
9
o
18
9
0
- 650
- 1513
- 1905
-3222
fip
O£
- 819
- 890
- 854
- 7in
/ wl/
- 1495
- 1130
- 1237
12 Pints Insecticide
Mean Range
721.3
1374.3
1850.2
1980.4
29.9
262.5
382.0
458.8
420.4
793.8
469.5
629.5
43
43
86
192
0
0
0
21
0
0
21
0
- 1558
- 3628
- 4567
- 7725
- 149
- 1963
- 2134
- 2049
- 1750
- 1963
- 27104
- 29669
-&7s^^
ay^H^auun raw (o.yu ror i> pt/500 gal: 21.34 for 12 pt/500 gal).
Table 3. Chemical Protective Clothing Breakthrough Frequency by Garment
Total Quantifiable*
percent Ethion Percent
Garment
Patches Ethion Percent Ethion °+T*
Cotton
coverall
Sontara !
coverall
114
96
39
25
342
26.0
33
41
28.9
42.7
72
66
63.2
68.8
'Quantifiable = > 28 pgfal; > 0.84 \ng/sample
' Trace = < 28 pgjil and >8 pg^l; 0.24 - 0.84 ^/sample
^Frequency of quantifiable + trace breakthrough
One subject excluded due to very high deposition rates.
faceshields would provide greater expo-
sure reduction under these conditions than
would further efforts to provide truly chemi-
cal resistant coveralls. By implication use
of hoods would also be likely to provide
more protection than improved coveralls
The final scenario (S-6) indicates use of
faceshields and improved coveralls would
reduce exposure by 27% when compared
with the label-required PPE used in this
study.
Discussion
These studies have demonstrated that
coverall garments similar to those used
routinely by pesticide applicators did not
provide the levels of protection expected.
No significant improvement in protection
occurred when nonwoven garments were
substituted for traditional woven garments.
Indeed the nonwoven garments suffered
from the most serious flaws in design and
provided little, if any, increased resistance
to chemical penetration. The use of fluo-
rescent tracers and imaging analysis
clearly documented substantial exposure
to the arms of workers wearing garments
with large sleeve openings. When this de-
sign failure was rectified, little exposure
could be detected on the protected body
It appears that the strength of the tracer/
imaging analysis lies in measuring expo-
sures occurring under, rather than through,
garments and in detecting exposures that
otherwise would have been undocumented
by the patch technique. The use of patches
Table 4. Dermal Exposure Reduction by Personal Protective Equipment (PPE)
PPE Scenario
Percent
Scenario 1
Exposure
versus
Scenario 2
1 Unprotected Worker*
2 Cotton or Sontara>
coveralls only
3 Cotton or Sontara
coveralls + Gloves
4 Cotton or Sontara
coveralls + Gloves
+ Faceshields
5 Chem-Resistant
coveralls * + Gloves
6 Chem-Resistant
coveralls + Gloves
+ Faceshield
0
72.7
93.5
94.9
93.9
95.3
Reduction
Scenario 3
—
Total Dermal
Exposure
fag/hr)
57,974
15,806
Percent Total Exposure
Hands Head
23.8 3,0
87.4 u.i
Body
73.2
1.5
76.2
81.2
77.8
82.7
20.8
6.4
27.3
3,756
2,974
3,514
2,732
46.9
59.2
50.1
64.5
46.6
32.6
49.9
35.5
6.4
8.2
Deposition to outside of coveralls + hand + head exposure (torso patch estimate)
Depos^on beneath coveralls (mean of cotton and Sontara) + hanc™head exposure
* Gloves reduced exposure from 13,182 to 1 762 ug/hr. exposure.
* Assumes faceshield protects 44.7% of head
' Assumes chemical-resistant coveralls replace cotton or Sontara and provide 100% protection.
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to detect fabric penetration was far more
sensitive than was tracer/imaging analy-
sis. Low levels of tracer on skin were
difficult to quantify by imaging, whereas
chemical analysis of patch extracts de-
tected <10 ng/cm2. The techniques thus
served complementary functions in docu-
menting the limitations of chemical protec-
tive clothing performance.
Analysis of exposure distribution re-
vealed that further improvements in pro-
tective coveralls would do little to reduce
total dermal exposure of applicators un-
der the field conditions tested. Proper use
of such personal protective equipment as
gloves and faceshields could reduce ex-
posure more than chemically resistant cov-
eralls. It should be noted that hand expo-
sure may have been even higher than the
values reported here. Recent studies in
our laboratory indicated that only about
30% of the organophosphorus insecticide,
chlorpyrifos, in a liquid formulation, was
removed from hands by the ethanol
handwash procedure used in this study.
Further efforts should be directed at es-
tablishing accurate hand exposure assess-
ments methods.
The findings of this study are consistent
with those of an earlier study of protective
clothing performance during airblast appli-
cations. The most important finding of the
earlier study concerned the role of CPC in
exacerbating heat stress; this was con-
firmed by our observations. Use of such
garments during high temperature, high
humidity conditions places an excessive
and potentially dangerous burden on work-
ers. Label requirements for CPC must be
qualified by limits on environmental pa-
rameters related to heat stress to strike a
proper balance between protection and
comfort.
Conclusions
Exposure beneath CPC occurred due
to both design failures and fabric penetra-
tion. None of the test garments can be
considered chemically resistant under the
field conditions evaluated in this study.
Properly designed garments (woven or
nonwoven) such as those evaluated in
this study provide a substantial reduction
in exposure when compared with a theo-
retical "unprotected" worker, but improve-
ment in the chemical resistance of cover-
all garments will reduce further exposure
only a small amount. Faceshields could
provide approximately three more times
the exposure reduction than would result
from improved coverall garments. The
hands, even when protected by chemical
resistant gloves, contribute a substantial
proportion of total dermal exposure, as
does the unprotected face/head region.
The use of fluorescent tracers and video
imaging analysis allows measurement of
exposure that occurs by pathways that
the patch technique would be unlikely to
detect or inaccurately quantify (e.g., expo-
sure through openings in garments). The
patch technique was far more sensitive in
detecting fabric penetration. The tech-
niques appear to play complementary roles
in documenting the performance of CPC
under realistic field conditions.
Recommendations
Dermal and respiratory exposures un-
der the work conditions studied are rela-
tively high for pesticide applicators. Work-
ers conducting airblast applications would
be better protected by closed cab sys-
tems or any other technology that places
a well-defined barrier between the worker
and the pesticide spray. PPE requirements
should consider the potential for heat
stress and should be designed to strike a
balance between protection and comfort.
Conditions under which PPE is not to be
used should be defined and enforced to
reduce the risk of illness related to heat
stress. Implementation of PPE require-
ments or recommendations should include
procedures whereby employers and work-
ers receive appropriate and ongoing edu-
cation and training regarding PPE use.
Important factors to be considered in de-
veloping PPE requirements or recommen-
dations include:
• Woven or nonwoven coveralls similar
to those tested in this study provide
substantial protection to most of the
body; improvements in the chemical
resistance of such garments will
probably not reduce total dermal
exposure significantly;
• The hands, even when chemical
resistant gloves are worn, contribute
a substantial proportion of total dermal
exposure under the use conditions
studied. Further reduction in hand
exposure will be achieved only by
more effective employer and worker
education and training;
• The unprotected head represents a
substantial proportion of total dermal
exposure;
• Use of a hood covering the back of
the neck and most of the head would
reduce exposure significantly and
addition of a faceshield would further
reduce exposure;
• Protective garments designed and
marketed for use by pesticide
applicators should be field tested to
determine performance. Traditional
laboratory tests (e.g., permeability
testing) cannot characterize effects of
garment design and appear to be
inadequate measures of potential
chemical breakthrough.
• Users should be provided with
accurate information regarding
garments designed and marketed for
pesticide handlers. Claims regarding
the ability of garments to protect
workers should be accurate. In
particular, garments should not be
referred to as "chemical resistant" or
"liquid proof" unless these qualities
have been demonstrated under
realistic field use conditions.
The full report was submitted in fulfill-
ment of EPA Cooperative Agreement No.
CR-814919 by Rutgers University under
the sponsorship of the U.S. Environmen-
tal Protection Agency.
.a. GOVERNMENT PRINTING OFFICE: 19*3 - 7SO-07I/H0087
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Richard A. Fenske is now with the University of Washington, Seattle WA 98195
Carolyn Esposito is the EPA Project Officer (see below).
The complete report, entitled "Fluorescent Tracer Evaluation of Protective
Clothing Performance," (OrderNo. PB94-100 146/AS; Cost $19 50 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
Edison, NJ 08837
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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