United States
Environmental Protection
Agency
Risk Reduction Engineering Laboratory
Office of Research and Development
Cincinnati, OH 45268
Research and Development
EPA/600/S2-90/023
Aug. 1990
Project Summary
Pesticide Spray Penetration
and Thermal Comfort of
Protective Apparel for
Pesticide Applicators
J. O. DeJonge and E. Easter
The skin of those who work with and
around pesticides receives some mea-
sure of protection with the use of pro-
tective apparel. This research is aimed
at ultimately providing recommendations
for types of protective apparel for pest-
icide applicators for dermal exposure
protection and thermal comfort.
A laboratory spray system was devel-
oped and validated that delivers a
controlled amount of pesticide solution
to fabric samples so the amount of
pesticide penetrating the fabric can be
evaluated. To ensure consistency in
procedure and comparability of results,
standard laboratory conditions of 70°C
and 65% relative humidity were recom-
mended.
The initial penetration evaluation of
fabrics currently used by agricultural
workers determined that fabrics of
different construction and fiber content
provided varying degrees of protection.
Fabric characteristics of thickness, air
permeability, weight, finish, and fiber
content may be valuable indicators of
fabric penetration performance. Further
isolation of fabric characteristics variable
was necessary to clarify the confounding
variables; therefore, woven fabrics of
varying thicknesses and weight were
evaluated. When thickness remained the
same, pesticide penetration could be
attributed to weight; i.e., as fabric weight
increased, pesticide penetration de-
creased. At present, workers exposed to
pesticides must be cautioned against
wearing clothing with a fabric weight
below 250 g/m* (7.37 oz/yd*). When
nonwoven fabrics were evaluated, sev-
eral alternatives to the most commonly
used woven fabric were found to provide
equally good protection.
Applying higher levels of pressure arid
contamination increased pesticide pene-
tration; these are recommended to
evaluate fabric performance for a worst-
case scenario. Seams and zippers in a
garment may increase the potential for
pesticide penetration. Three physical
measurements rated woven fabrics to
determine their heat stress relief scores;
those with the highest rating provided
comfort nearly equal to that of chambray.
Of the nonwoven fabrics evaluated, the
combination of polyester and wood pulp
showed the most promise as comfortable
protective apparel.
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
The use of toxic chemicals in agricul-
ture presents a major source of potential
health risks. Previous research has
shown that the main route of pesticide
exposure is through the skin rather than
through the respiratory system. Therefore,
using protective apparel as a barrier
provides some measure of protection for
those who work with and around pesti-
cides. To date, research on apparel as a
-------
protective barrier has identified some
fabrics that allow minimal or no penetra-
tion of pesticide particulates. The
research in this area has been conducted
on isolated pesticides and fabrics; little
consideration was given to variables in
the pesticide formulation and fabric
characteristics that may affect penetra-
tion. A systematic approach to defining
the variables in both pesticides and
fabrics is needed to prepare for the
extensive testing required for a predictive
model for pesticide penetration through
fabrics.
The specific objectives below contrib-
ute to the data needed for a predictive
model and to screening fabrics to assure
thermal comfort
1. Penetration test method;
2. Pesticide penetration through fabrics;
3. Thermal comfort assessment.
Penetration Test Method
Three methods are commonly used to
evaluate a fabric as a barrier against
pesticide penetration: field studies, drop
methods, and laboratory spray systems.
Field studies use actual field conditions
and monitor the amount of pesticide that
penetrates the garment or fabric. The
penetrating pesticide is collected on
gauze pads that are later analyzed. Field
studies are invaluable In ascertaining the
acceptability of a garment, but they can
be costly and time consuming. In addition,
controlling variables that may influence
penetration Is difficult
The drop method uses a pipette to apply
a known amount of pesticide to the fabric.
A controlled amount of pesticide is
applied in a reproducible manner. This
method, hpweve'r, more closely simulates
mixing, cleaning up, and spill situations
than it does application situations.
The third method of exposing fabrics
to pesticide solutions is a laboratory spray
system. Spray systems too large or too
limited were refined and expanded into
the spray system developed in this project
(Figure 1). ,
The equipment was designed so the
spraying operation could be observed,
the operator protected, the pesticide
concentration and liquid flow rate con-
trolled, and the liquid sprayed uniformly.
Several different methods were used to
ensure consistent and accurate spray
application to each test specimen loca-
tion: spray coverage uniformity, consis-
tency in the amount of liquid delivered,
the effect of pressure on droplet size, and
the effect of separation distance between
the nozzle and the test specimen.
This chamber can be used under a fume
hood to minimize exposure. Standard
textile laboratory conditions of 70° F and
65% RH are suggested for penetration
laboratory work. Consistent standard
laboratory conditions ensure comparabil-
ity of results with other areas of textile
research.
Pesticide Penetration Through
Fabrics
In this part of our investigation, we
explored the effect of fabric character-
istics as barriers against pesticide pene-
tration. Eight characteristics were mea-
sured for each of 12 different fabrics. Four
pesticides representing two chemical
classes were used.
Fabric characteristics that have shown
some influence on penetration in the past,
or theoretically could influence transmis-
sion, were chosen for this study: fiber
content, fabric construction, surface
treatment, yarn count, weight, thickness,
air permeability, spray rating, and surface
tension.
The fabrics were chosen to represent
those readily available to agricultural and
experimental workers. Three of the
fabrics—denim, chambray, and work-
weight twill—are commonly found in
ready-to-wear a pparel and easily access-
ible to the agricultural worker.
Because previous studies have shown
that water repellent finishes increase
protection against penetration, a com-
mercial water repellent finish (7% Zepel
D*, 10% Noran F, and 4% Mykon NRW-
3) was applied to these fabrics. Fabrics
received two dips and two nips (textile
finishing measurements) under 20 psi
pressure and were then cured for 3 min
at 110°C. This resulted in a wet pickup
of approximately 90% for denim and
chambray and approximately 46% for the
work-weight twill fabric. Both treated and
untreated samples were evaluated.
Four of the nonwoven fabrics examined
are currently available in specially
designed protective clothing for pesticide
*Mention of trade names or commercial products
does not constitute endorsement or recommendation
for use.
Fabric Sample Holders
Plexiglass Slide Panels
Figure t. Illustration of spray chamber.
-------
applicators. These include Tyvek®,
polyethylene-coated Tyvek®, Saranex-
coated Tyvek®, and Gore Tex®. Two other
nonwoven fabrics were tested—experi-
mental fabrics treated with repellent
finishes that have the potential to be used
for protective clothing.
The 15.2 cm square sample exposed
to pesticide spray was a four-layer
assembly consisting of the test fabric, a
collector layer, foil, and foil backing.
In the spray chamber, the fabric spec-
imens were exposed to a 12% concen-
tration of the pesticide. After exposure, the
fabrics were allowed to dry for 1 hr. A
7.62 X 2.54 cm strip was removed, and
the pesticide was extracted from the test
fabric and collector layer. With the use
of gas chromatography analysis tech-
niques, the extract was analyzed and the
amount of pesticide that penetrated the
top layer of fabric as found on the collector
layer was determined (Table 1).
An Analysis of Variance determined that
fabrics provided varying degrees of
protection against pesticide penetration.
With the use of Duncan's multiple range
test, the fabrics were grouped according
to the amount of pesticide that penetrated
to the collection layer, with D being the
best and A the worst.
The chambray fabrics, both treated and
untreated, were in Groups A and B for
all pesticides—those providing poor or
below average protection against pesti-
cide penetration. These fabrics were the
least thick of the woven fabrics tested and
were of plain weave construction. Fabrics
in the group providing the most protection
(Group D) for all pesticides were the two
coated Tyvek® fabrics. Denim and twill
fabrics were also in this group for three
of the four pesticides. They were the two
thickest fabrics tested, and both are of twill
construction, indicating these character-
istics play an important role in preventing
pesticide penetration through fabrics.
Effect of Fabric Weight and
Thickness
Laboratory evaluation of fabrics has
determined that both measurable and
categorical variables, e.g., fabric con-
struction, of fabric characteristics may
influence penetration. The initial pesticide
penetration results found nonwoven
fabrics provide the best protection. Woven
fabrics of heavy cut twill construction,
including denim, also performed well. The
extremes of woven fabrics, light-weight
work shirt to heavy-weight denim, were
evaluated. As expected, the heavy-weight
fabrics performed better than didthe light-
weight ones. The question arose as to
how heavy a woven fabric w*as needed
to provide protection comparable to the
nonwoven fabrics.
Woven Fabrics
The purpose of this portion of our study
was to evaluate the effect of fabric weight
and thickness of woven fabrics on
pesticide penetration. Fabrics of 100%
cotton or 50/50% cotton/polyester were
characterized (Figure 2).
Three pesticides were evaluated: ethion
(46.5% active ingredient), chlorobenzilate
(45.5% active ingredient), and Dicofol
(42% active ingredient). The fabrics are
incorporated into the previously de-
scribed multi-layer fabric assembly. The
fluorocarbon finish did not statistically
affect the ability of a fabric to provide
protection for pesticide penetration.
The study results indicated that the
fabric characteristic of weight was highly
correlated with penetration. As weight
decreased, pesticide penetration
increased (Figure 3). The results of this
study were that if thickness remains the
same, penetration is attributed to fabric
weight; as fabric weight increased,
pesticide penetration decreased. This
study begins to isolate the weight at which
adequate protection could be provided.
The findings show that a fabric weighing
less than 250 g/m2 (7.37 oz/yd2) could
be vulnerable to greater amounts of
penetration.
At present, pesticides applicators and
agricultural workers must be cautioned
about wearing medium- to light-weight
woven clothing or wearing clothing that
has been reduced from its initial weight
by washing and wearing until it has
reached this medium-weight category of
below 250 g/m2 (7.37 oz/yd2).
Nonwoven Fabrics
The most widely used fabrics in cur-
rently available protective clothing are
nonwoven, and most of this clothing is
made of Tyvek®. In previous studies, this
fabric has proven to be an effective barrier
to pesticide penetration, especially when
Tyvek® has been coated with either a
Saranex® or a polyethylene coating.
Table 1. Amount of Pesticide Penetration fog/cm*): Initial Study
Code
W25
W26
W23
W24
W21
W22
N1
N2a
N2b
N13
N16A
N16B
Fabric
Denim
Denim-FI
Chambray
Chambray-FI
Twill
Twill-FI
Tyvek®
Tyvek®PE
Tyvek® -Sar
Gore Tex®
Ex.1
Ex.2
Captan
Group*
(5)0.0141;
(4)0.021
(5)0.045
(4)0.064
(5)0.007
(3)0.021
(5)0.246
(5)ND
(5)ND
(4)0.060
(4)0.007
(4)0.078
C
C
A
B
C
B-C
B
D
D
B-C
C
B
Dicofol
Group
(5)ND$
(5)ND
(5)0.234
(5)0.162
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(4)0.084
D
D
A
B
D
D
D
D
D
D
D
C
Ethion
Group
(5)ND
(5)ND
(4)0.040
(5)0.068
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(5)ND
(5)0.012
D
D
B
A
D
D
D
D
D
D
D
C
Methyl
Parathion
Group
(5)ND
(5)ND
(4)0.047
(4)0.033
(5)ND
(5)ND
(5)0.018
(5)ND
(5)ND
(5)ND
(5)0.017
(5)0.055
D
D
A-B
B-C
D
C-D
D
D
D
D
A
: Group—Duncan's Multiple Range Grouping
t (#)—number of fabric replications
$ ND—nondetectable
-------
mil
Average
40 -r
35 ..
30 -•
25 --
20 • •
g/m2
Average
15 -
10
W1 W3 W5 W7
W9 W11 W13 W15W16W23W25
Thickness
Weight
Flguro 2. Woven fabrics compared by weight and thickness.
Fabric
J
Thermal comfort field tests conducted on
Tyvek® have shown it to be very uncom-
fortable in temperatures greater than
29°C. Alternative nonwoven fabrics are
marketed with claims of upgrading pro-
tection with improved thermal comfort
Tyvek® was shown to provide barrier
qualities for the pesticides used in this
part of the study. However, there are
alternative fabrics that offer equally good
protection (Table 2). These include SMS
(spunbonded-meltblown-spunbonded),
Sontara, and experimental fabrics at the
University of Tennessee.
Effects of External Pressure and
Contamination Level
In laboratory spray studies to this point,
fabrics were held fixed in a horizontal plan
perpendicular to the spray nozzle; the
fabrics were "passive," without stress or
movement during the contamination
procedure. In field conditions, worker
motions, such as bending, stretching, or
leaning against solid objects, may result
in fabric stresses that could affect
pesticide penetration. Such effects should
be evaluated, if possible, in laboratory
spray testing. |
For this part of the study, four nonwoven
fabrics (Sontara, Finished Sontara, SMS,
and Finished SMS) were evaluated with
the use of two pesticides (Dicofol and
Terrazole® in ap.12% solution). The spray
chamber device was used to contaminate
the fabric samples. Similar four-layer
fabric assemblies were subjected to one,
two, or three passes of the spray solution
to achieve different levels of contamina-
tion. One set of fabrics was sprayed, dried,
and extracted without application of
external pressiire. A second set of fabrics
was sprayed, and within 15 sec, a 16 Ib
weight on a 91.6-cm square glass plate
was placed at the center of the test fabric
assembly. Thus, the nominal pressure
level was 1 psK The weight was removed
after 1 hr, and assembly was dried for 1
hr before the fabric layers were extracted
and analyzed.
Air tests showed that applying external
pressure and higher levels of contami-
nation increased pesticide penetration
through fabrics. External pressure was
shown to increase penetration by one or
two orders of magnitude. Such pressure
could easily occur when a worker leans
against the tractor cab or rests his arm
upon his leg. Clearly, when evaluating
fabrics for protective apparel, the fabric's
resistance to penetration by pressure
should be taken into consideration.
Research has also shown that in the
case of pressure penetration, repellency
treatments may be counter-productive.
These finishes may seal off the fibers as
a reservoir to store pesticide. When
pesticide solution is on the fabric and
pressure is applied to the fabric, the
pesticide must either pass into the fibers
or pass through the fabric. This is not to
suggest that repellent finishes are not vital
-------
Pesticide
Amount
Penetrated
(/jg/cm2)
0.500 T
0.400 • •
0.300 • •
0.200 . .
0.700 •
0.000
Chlorobenzilate
BH Dicofol
C3 Ethion
IV
5
W
9
W
11
W
13
W W W W
15 16 23 25
Figure 3. Comparison pesticide penetration.
Fabric
for the protection of spray applicators-
such finishes may allow protective gar-
ments to be constructed from natural
fibers that are more comfortable to the
wearer. We do suggest that the role of
absorbency and internal fiber storage of
pesticide as well as fabric surface energy
must be considered in the manufacturing
of the next generation of protective
clothing for pesticide spray applicators.
Effect of Seams and Closures on
Pesticide Penetration
Researchers have evaluated semi-
disposable jackets or jacket and trouser
for use during spraying at very high
temperatures. Although the garments
provided protection, some leaked around
the seams. As the shoulder seams
became stretched (one of the areas of
high pesticide deposition) leaks devel-
oped either through the seam or through
the elongated stitch openings. Re-
searchers recommended additional work
for evaluating and developing seams. In
this portion of our study, we evaluated
Table 2. Amount of Pesticide Penetration
Code
N1/
A/2/
N3/
N4/
A/7/
A/75/
A/76/l/
N16B/
A/77
A/78
W23
W25
Fabric
Tyvek®
Tyvek®
Sontara
Sontara
SMS
UTEx*
UTEx*
UTEx*
Duraguard®
Duraguard®
Chambray
Denim
Cnloroben
Group
(5)NDt
(5)ND
(5)ND
(5)ND
(5)ND
<5)ND
(5)ND
(5)ND
(5).208
(5).174
(5).059
(5)ND
zilate
*
C
C
C
c
c
c
c
c
A
A
B
C
Dicofol
Group*
(5)ND C
(5)ND C
(5)ND C
(5)ND- B
(5)ND C
(5)ND C
(5)ND C
(5)ND C
(5).068 A
(5).076 A
(5)ND C
(5)ND C
Ethion
Group*
(5)ND D
(5)ND D
(5).011 C
(5).019 C
(5)ND D
(5)ND D
(5)ND D
(5).088 C
(5).121 A
(5).074 B
(5).043 B
(5)ND D
: Group—Duncan's Multiple Range Grouping
tND—nondetectable
seams and closures to identify those
providing the best barrier to pesticides.
With the use of the pesticide Dicofol,
fabrics without seams were examined
with the spray chamber protocol to
provide comparison for evaluating the
effect of seams on pesticide penetration.
One fabric (SMS) allowed penetration.
Twenty seamed fabrics received the same
spray treatment; 14 of the 20 seamed
samples allowed penetration. The analy-
sis showed no significant differences
-------
among the seams. The conclusion was
there are no significant differences
between seams.
To evaluate zippers, Tyvek® was used
in all zipper constructions to eliminate
woven fabric effect The pesticide used
was Dicofol. Five different zipper con-
structions (a centered, a lapped tradi-
tional, a lapped experimental, an open-
face nylon, and an open-face metal type)
and 16 replications of these zipper
constructions were evaluated (85
samples).
Twenty-two percent of the zipper
samples allowed penetration. The lapped
traditional zipper was shown to provide
more protection than other zipper con-
structions. Because seams and zipper
construction have been shown to alter
pesticide penetration through fabrics,
seams and the type and placement of
zippers should be taken into considera-
tion when developing protective clothing.
Pesticide Penetration into
Fibers and Fabrics
The purpose of this phase of research
was to obtain more information about the
location of pesticides in fibers and fabrics.
We used Fourier transform infrared
photoacoustic spectroscopy (FTIR/PAS)
to allow us to directly determine the
location of pesticide in the fibers and
fabrics.
Three fabrics were evaluated: a 100%
cotton twill, an identical 100% cotton twill
treated with a fluorocarbon finish, and an
experimental SMS polypropylene compo-
site nonwoven fabric. The fluorocarbon
finish applied to the cotton twill was a
Corpel® finish from DuPont The two
pesticides, Terrazole® and Dicofol, were
applied to the fabrics. Fabric contamina-
tion was achieved either by pipetting
undiluted pesticide onto the fabric face
or by spraying dilute pesticide onto the
fabric face using the spray chamber. X-
ray photoelectron spectroscopy (XPS)
was performed on 1 cm X 1 cm squares
cut from near the center of each fabric
after placing the square on a slightly
larger square of aluminum foil and folding
the foil around the edges of the fabric to
secure loose fibers. FTIR/PAS was
performed either by using a 0.5 cm X 0.5
cm square cut from near the center of
each contaminated fabric after securing
the fabric in aluminum foil similar to the
samples prepared for XPS analysis or by
using a powder made by grinding a
contaminated fabric in a Wiley mill.
Both pesticides were readily absorbed
by cotton fibers. This suggests that a layer
of cotton fibers in protective apparel could
possibly provide dermal protection
through a mechanism involving absorp-
tion of pesticide into the fiber interior. The
findings suggestfthat, although the struc-
ture of the cotton fabric examined in this
work allowed both pesticides to penetrate
through the whole fabric thickness, cotton
fibers in another fabric structure could
provide effective dermal protection
against these two pesticides by contain-
ing pesticides through absorption. How-
ever, a fabric structure different from the
one examined in this work is required to
achieve protection since both pesticides
penetrated the fabrics. A suitable fabric
structure might involve a noncotton layer
that did not allow liquids to penetrate the
fabrics so that the pesticide remains on
the outer fabric surface and is absorbed
by the fibers.
The fluorocarbon finish had a complex
effect on pesticide surface deposition.
The fluorocarbbn finish did not eliminate
penetration of either pesticide through the
fabrics. However, unlike Dicofol, Terra-
zole® did not remain on the outermost
fabric surface but was absorbed deeper
into the fabric structure.
The SMS fabrjc exhibited mixed behav-
ior in limiting pesticide penetration
through the fabric. That is, penetration
was greatly limited for one but not for the
other pesticide. ^MS fibers also exhibited
mixed behavior^ in pesticide absorption.
This suggests that SMS has some poten-
tial to provide dermal protection, but
combinations of SMS with some other
textiles in a composite are indicated.
Thermal Comfort Assessment
The development of protective apparel
for pesticide applicators has long been
hampered by [the often contradictory
requirements jof providing adequate
protection against pesticide penetration
and still allowing thermal comfort in
conditions of high temperature and
humidity. As pesticide penetration work
continues to identify acceptable fabrics,
attention must be paid to the thermal
characteristics of these fabrics so that the
fabrics that provide relative comfort in
heat stress can be recommended. If this
is not done, the agricultural workers may
avoid wearing^ the available protective
apparel.
A battery of comfort-related physical
tests was used to assess which fabrics
provided comfort nearly equal to that of
cotton chambray during summertime
pesticide application work. Three phys-
ical measurements for heat, air-transport,
and moisture were gathered on the
fabrics: thermal transmittance (U-values),
wind penetration potential (WPP), and the
clothing radiant temperature (CLORT).
The combination of the three laboratory
tests provided eatings of the evaluated
fabrics (Table 8). The normalized total
scores ranged from 4.7 to 11.6. Those
fabrics with the highest overall heat stress
relief scores (HSRS)—those providing
comfort nearly equal to that of cotton
chambray—included both woven and
nonwoven fabrics. The woven plain
weave fabric, which was lighter in weight
and thickness than chambray, was shown
to have the highest HSRS. The thickest
and heaviest twill fabrics had the lowest
HSRS ratings. Fiber content did not
appear to influence the comfort as both
100% cotton and 50/50% cotton polyester
were included in this lowest HSRS group.
Two nonwoven fabrics made of a com-
bination of polyester and wood pulp
(Sontara) had excellent HSRS ratings and
showed great promise as comfortable
protective apparel. SMS, Gore Tex®, and
unfinished Tyvek® all had ratings similar
to that of denim.
These tests indicate weight and thick-
ness of woven fabrics influence thermal
performance. In nonwoven fabrics,
adding a natural fiber such as wood pulp
appeared to be the only factor to increase
the HSRS.
Conclusions
The research performed under this
cooperative agreement involves develop-
ing and validating a laboratory spray
method to test fabric penetration of pest-
icides, collecting data on spray penetra-
tion of pesticides through protective
apparel fabrics, and evaluating the
relationship between protective apparel
fabric characteristics and thermal com-
fort. The following conclusions may be
drawn:
1. A reproducible penetration test method
applied controlled pesticide sprays to
flat fabric swatches and measured the
resulting penetration. This method can
be used to screen fabrics for their
ability to protect a pesticide applica-
tor's covered skin from pesticide spray.
2. A database of laboratory spray pene-
tration data and fabric characteristics
was created for 18 woven fabrics and
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Table 3. Heat Stress Relief Score Rankings
Rank Code
Fabric
Normalized Score
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
W9
W23
N5
A/3
W5
W3
W11
W25
A/7
W21
N11
W22
N1
N13
A/9
W15
W7
W1
W13
W16
W14
Print Cloth
Chambray
New Sontara
Sontara
Broadcloth
Broadcloth
Twill
Denim
SMS
Twill
SMS
Twill
Tyvek®
Gore Tex®
SMS®
Twill
Duck
Poplin
Twill
Twill
Twill
11.6
10.0
9.6
9.4
8.4
7.8
7.6
7.3
7.0
6.6
6.6
6.4
5.9
5.6
5.5
5.3
5.3
5.2
4.8
4.8
4.7
10 nonwoven fabrics. Each woven
fabric was characterized according to
thickness, weight, air permeability, yarn
count, and surface energy. Each
nonwoven fabric was characterized
according to fiber content and finish.
a. The weight of woven fabrics most
influenced their penetration resist-
ance; as weight decreased, pene-
tration increased.
b. Nonwoven fabrics having a film
finish were most resistant to pest-
icide spray penetration.
3. Clothing of woven fabrics weighing
less than 250 g/m2 is much less
resistant to pesticide spray than is
clothing of heavier fabrics. Heavier
fabrics, however, will not necessarily
provide adequate protection.
4. The application of external pressure
and higher levels of contamination
increased pesticide penetration of the
fabric.
5. Seams and zippers in a garment .may
increase the potential for pesticide
penetration.
6. Pesticides were readily absorbed into
cotton fibers. This suggests that a layer
of cotton fibers in protective apparel
could possibly provide dermal protec-
tion through a mechanism involving
absorption of pesticide into the fiber
interior.
7. The fact that the nonwoven composite
fabric SMS retains the greatest amount
of pesticide on the interior of the fabric
structure suggests that a new gener-
ation of composite fabrics may help
provide increased pesticide protection.
8. Thermal comfort of fabrics was ranked
from tests to measure heat, moisture,
and air transport.
a. For the nonwoven fabrics, weight
and thickness are inversely related
to estimated thermal comfort.
b. For the nonwoven fabrics, including
a natural fiber, such as wood pulp,
increased the estimated thermal
comfort of the fabric.
Recommendations
1. The spray chamber test method devel-
oped in this project should be used to
screen fabrics for pesticide penetration
performance before field evaluations.
2. The spray chamber test method should
be evaluated for adoption as a stand-
ard American Society for Testing and
Materials test method.
3. To ensure statistically valid relative
comparisons of data, denim, chambray,
Tyvek®, and SMS should be included
in each successive experimental
design.
4. The laboratory pesticide spray pene-
tration database should be expanded
by adding penetration data and fabric
characteristics from laboratory and
field evaluations of fabrics with novel
materials or construction characteris-
tics.
5. Agricultural workers exposed to pest-
icide sprays should be cautioned
against wearing clothing of woven
fabrics lighter than 250 g/m2 (7.37 oz/
yd2). Clothing may be either purchased
with this weight or may decrease to
this weight through use over time (e.g.,
old denim jeans).
6. Before concluding that fabrics above
250 g/m2 will offer good spray pene-
tration resistance, fabrics over 250 g/
m2 should be tested to evaluate the
effect of movement of the body during
wear, pesticide buildup on fabrics, and
additional spray conditions.
7. Effective worst-case evaluation should
include the application of pressure to
the exposed fabric.
8. Seams in protective apparel should be
used in moderation to limit additional
pesticide exposure.
9. In areas of maximum pesticide adsorp-
tion (scrotum), the lapped, traditional
zipper rather than the commonly used
open and centered zipper should be
used in protective apparel.
The full report was submitted in fulfill-
ment of Cooperative Agreement No.
812486-01-0 by The University of Ten-
nessee under the sponsorship of the U.S.
Environmental Protection Agency.
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Jacquelyn O. DeJonge is with The University of Tennessee, Knoxville, TN 37996-
1900; and Elizabeth Easter is with the University of Kentucky, Lexington, KY
40506.
S. Krlshnamurthy is the EPA Project Officer (see below). ;
The complete report, entitled "Pesticide Spray Penetratiorf and Thermal Comfort
of Protective Apparel for Pesticide Applicators" (Order No. PB 90-226 820/
AS; Cost: $23.00, 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—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-90/023
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