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INTRODUCTION
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.
SELECTION
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
- VitonĀ®
- 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 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.
USE AND CARE
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 from possible contamination.
REUSE QUESTION
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 contact 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.
SUMMARY
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.
DEFINITIONS
- 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).
This paper appears in the eLCOSH website with the permission of the author
and/or copyright holder and may not be reproduced without their consent. eLCOSH is an
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information provided on this web site, nor for its use or misuse.
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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