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Ronald C. Jester
University of Delaware Cooperative Extension
Hands
and fingers are subject to an army of hazards on the farm. This
fact sheet reviews the hazards associated with exposure to chemicals.
Generally, exposure means contact through the skin or respiratory
system, and ingestion. Research reveals that at least 80% of
total body exposure to farm chemicals is to the hands.
Once
exposed, the person could be adversely like developing skin
dermatitis or a burn from a corrosive chemical. Chemical can
also be absorbed through the skin and into the body, causing
a reaction that can lead to acute poisoning. General symptoms
often associated with mild exposure to farm chemicals include
headache, fatigue, dizziness, loss of appetite, stomach cramps,
and diarrhea. Severe exposure to highly toxic compounds can
lead to loss of coordination, seizures, and unconsciousness.
When
working with agricultural and other chemicals, no single glove
will protect your hands completely. Gloves made from polymers
and other materials have their strengths and weaknesses in
terms of preventing resistance and physical properties like
resistance to tearing and abrasion. Since no protect-all polymer
exists, selecting the right glove for the job is imperative
to your safety.
The
selection of the proper chemical-resistant glove begins with
an evaluation of the job application. Factors that influence
this selection are:
- the
type of chemicals to be handled (or used)
- frequency
and duration of chemical contact
- nature
of contact (total immersion or splash only)
- concentration
of chemicals
- temperature
of chemicals
- abrasion/resistance
requirements
- puncture-,
snag-, tear-, and cut-resistance requirements
- length
to be protected (hand only, forearm, arm)
- dexterity
requirements
- grip
requirements (dry grip, wet grip, oily)
- cuff
edge (safety cuff, knit wrist, or gauntlet)
- color
requirements (to show contamination)
- thermal
protection (for example, when handling anhydrous ammonia)
- size
and comfort requirements
- price
The
type of chemical being used is the key factor for choosing
of what material the glove should be made. When possible use
the farm chemical as the basis for the selection. With emulsifiable
concentrates, volatile solvents (like toluene and xylene)
and nonvolatile solvents (like alkylated napthalenes and petroleum
oil) correct glove selection is critical. Some of the more
common glove materials are:
- butyl
- a synthetic rubber with good resistance to weathering
and a wide variety of chemicals
- rubber
- a highly flexible and conforming material made from a
liquid tapped from rubber plants
- neoprene
- a synthetic rubber having chemical and wear-resistance
properties superior to those of natural rubber
- nitrile
- a copolymer available in a wide range of acrylonitrile
(propane nitrile) content; chemical resistance and stiffness
increase with higher acrylonitrile content
- polyethylene
- a fairly chemical-resistant material used as a freestanding
film or a fabric coating
- polyvinyl
alcohol - a water-soluble polymer that exhibits exceptional
resistance to many organic solvents that rapidly permeate
most rubbers
- polyvinyl
chloride - a stiff polymer that is made softer and more
suitable for protective clothing applications by the addition
of plasticizers
- polyurethane
- an abrasion-resistant rubber that is either coated into
fabrics or formed into gloves or boots
- Server
Shield - a registered trademark of North Hand Protection,
it is highly chemical-resistant to many different class
of chemicals
- Viton®
- a registered trademark of DuPont, it is a highly chemical-resistant
but expensive synthetic elastomer
For
a given thickness, the type of polymer selected has the greatest
influence on the level of chemical protection. For a given
polymer an increase in thickness will result in a higher level
of protection. A rule of thumb is that double the thickness
will quadruple the breakthrough time.
The
manufacturing process of glove making may result in slight
variations in performance. The user is warned to exercise
care and to check the glove regularly for breakthrough and
diminished physical performance.
Physical
performance may be a more critical factor in some cases than
chemical resistance. If a job application involves handling
heavy, rough, or sharp objects then the glove must have high
resistance to abrasion, cuts, snags, etc. A hole in a glove
can provide much greater chemical exposure potential than
molecular permeation.
The
thicker the glove material the greater the chemical resistance.
But thick gloves can impair grip, dexterity, and safety. Consider
sensitivity and the ability to grip as very important factors.
The
proper glove design and fit contribute to comfort, productivity,
and safety. Curved-finger glove design fits the natural hand
contour for working comfort. Gloves that are too small bind
and cause undue hand fatigue. However, gloves that are too
large are uncomfortable, hard to work in and can be dangerous
if they get caught in moving machinery.
Use
the following steps in selecting the proper gloves when handling
farm chemicals:
- Refer
to manufacturer's Chemical Resistance Guide and Physical
Performance Chart and select the glove type with the highest
rating for the chemical and physical conditions. Also refer
to the chemical label and the Material Safety Data Sheet
(MSDS), which may recommend a specific glove type. One company
writes "The information contained in these guides is advisory
only. The purchaser must determine, by testing the product's
suitability for use with the specific chemical."
- Select
unsupported gloves for extra dexterity and sense of touch.
An unlined glove is recommended to minimize exposure from
contamination.
- Select
a palm finish to provide the grip needed for the job-smooth,
dipped, or embossed.
- Choose
the glove length by the depth to which the arm will be immersed
and by allowing for protection against chemical splash (see
Figure 1).
- Select
thin-gauge gloves for jobs demanding sensitive touch and
high flexibility. If greater protection or durability is
wanted, choose a heavy-duty style.
- Choose
the glove size or im that will assure optimum wear, dexterity,
working ease, comfort, and employee satisfaction.
Chemical
resistance and physical performance charts are not included
in this fact sheet because of the variance in manufacturers'
recommendations. A good example is white gasoline. One manufacturer
rated neoprene as an excellent glove for this, while another
could not recommend it because of a high permeation rate.
it is up to you to consult charts from specific glove manufacturers
to make a safe decision.
The
fact that little or no test data is available as yet for agricultural
chemicals makes the selection from vendor literature for such
application, at best, a difficult and uncertain task. Selecting
a glove from a retailer or vendor catalog should be only the
starting point. Further evaluation by the user is needed if
chemical resistance is an issue.
Always
inspect your gloves before using them. Of principal concern
are cuts, tears and punctures. Discoloration or stiffness may
indicate non-uniformities in the rubber or plastic or chemical
attack resulting from previous use.
Visual
inspection should be done every time you use the gloves to
detect pinholes or other defects. One way to accomplish this
is when they are still wet after having been washed, fill
the glove with water and tightly roll the gauntlet toward
the fingers and examine for leaks. Dispose of gloves that
have been damaged or show signs of chemical degradation.
Proper
handling of chemicals requires your wearing the gloves on
the inside of your shirt sleeves. The exception is when you
are working overhead and when your hands are in an upward
position. In that case, put your shirt sleeves inside the
gloves and turn up the cuff of the glove to catch any material
that may run down your arm.
It is
extremely important to avoid secondary exposure to the chemical
after application. Before removing the gloves, thoroughly
wash gloves with soap and water, or a detergent and water,
and then rinse with a lot of running water. The gloves may
now be removed. As the gloves dry in a decontaminated area,
thoroughly wash your hands with soap and water. Make this
a strict practice after every chemical application. Place
dry gloves in a sealed plastic bag or other container, and
store away Erom possible contamination.
Glove
decontamination and reuse are controversial and unresolved issues.
Often, surface contamination can be removed by scrubbing with
soap and water; at other times, as in the case of emulsifiable
concentrates, it may be practically impossible. The solvents
in many emulsifable concentrates prompt this concern. Volatile
solvents such as toluene and xylene, readily penetrate many
polymers and the nonvolatile solvents, such as alkylated napthalenes
and petroleum oil, are very difficult to remove from the glove
material.
Once
absorbed, some chemicals will continue to diffuse through
the material toward the inside EVEN AFTER the surface has
been DECONTAMINATED. For highly resistant chemical gloves,
the amount reaching the inside may be insignificant. But for
moderately performing materials, significant amounts of chemicals
reach the inside. This may not occur during use, but while
the glove is stored overnight. The next morning, when the
applicator dons the glove, he may be putting his hand into
direct con act with a hazardous chemical. In addition to the
chemical resistance of the glove material, the amount of chemical
that reaches the surface can be affected by the duration of
exposure, duration of storage, the surface area exposed, and
temperature.
The
decision to reuse the gloves requires consideration of these
factors as well as the toxicity of the chemical(s). In fact,
unless extreme care is exercised to ensure decontamination,
the reuse of chemical gloves that have been contaminated with
a toxic chemical is not advisable. For this reason, the disposal
of gloves on a regular and frequent basis is advisable.
Farmers
and pesticide applicators need to exercise extreme care in the
selection, care, and reuse of chemical-resistant gloves. Understanding
selection criteria, glove limitations, and proper care, and
adhering to safe handling procedures can eliminate most accidental
exposures.
Don't
ever believe that a glove can solve all problems when handling
toxic chemicals. The fact is no "impermeable" plastic or rubber
material exists and no one material serves as a barrier to
all chemicals.
YOU
are the key to hand safety and protection from chemicals.
You must determine suitability based on your own performance
requirements. Remember-your safety and health are in your
hands.
- Breakthrough
Time - The time which elapses between initial contact
of a chemical with the outside surface of a protective material
and when the chemical can be detected at the surface of
the material.
- Co-polymer
- A long chain molecule synthesized by reaction of more
than one monomer species with each other. Copolymers often
have cost and/or performance advantages over polymers.
- Degradation
- A reduction in one of physical properties of a glove or
protective clothing.
- Penetration
- The movement of chemicals through zippers, stitched seams
or imperfections (e.g., pinholes) in a protective clothing
material.
- Permeation
- Process by which a chemical can pass a protective film
without going through pores, or other visible openings (eg.,
what happens to air in an inflated balloon after several
hours -- same principle).
- Polymer
- A substance formed by the union of small molecules of
the same kind (monomers).
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and Reproduction Information: Information in NASD does not represent
NIOSH policy. Information included in NASD appears by permission
of the author and/or copyright holder. More
NASD Review: 04/2002
This document
is
SF-1
,
University of Delaware Cooperative Extension, Newark, Delaware.
Publication date: March 1991.
Ronald
C. Jester, Extension Safety Specialist, University of Delaware
Cooperative Extension, Newark, Delaware.
Commercial
companies or products are mentioned in this publication solely
for the purpose of providing specific information. Mention
of a company or product does not constitute a guarantee or
warranty of products by the Agricultural Experiment Station
or Delaware Cooperative Extension or an endorsement over products
of other companies not mentioned.
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