Howard
J. Doss and William McLeod
Michigan State University Extension
Michigan
farmers frequently work in areas laden with dust, molds and
toxic gases that can damage their respiratory systems. Without
proper protection, these farmers run the risk of developing
a chronic illness that can rob them of their ability to work
and enjoy life. In certain situations, such as in recently
filled silos or in manure pits, even a brief exposure to the
toxic gases can kill the unsuspecting farmer.
Matching
the respiratory protective device with the situation is as
important as selecting the right tool for the job. No farmer
would attempt an engine overhaul with an adjustable wrench
and pliers, so don:t count on a red bandanna tied around your
mouth and nose to protect you when the situation requires
a self-contained breathing apparatus similar to those worn
by firefighters.
These
types of dust respirator masks are designed to filter nuisance
dust and mold spores. Certain types of disposable dust masks
contain activated charcoal that remove some troublesome livestock
odors, organic vapors, mists that do not contain harmful vapors,
welding fumes and paint spray particles. A less expensive type
of mask, a particle mask, is only good for filtering out common
nuisance dusts, but provides no protection from molds. None
of these types of masks are capable of removing ammonia gas
or pesticide vapors.
The
cost of these types of masks ranges from less than 25 cents
to $6 each. There are disposable respirators available for
pesticides, anhydrous ammonia, and livestock ammonia available
in the $20 price range. These masks do not provide protection
from fumigants.
Farmers
can ensure that they are getting a respirator that will provide
the required protection by reading the label which explains
what type of particulates or vapors the masks are capable
or removing.
Available
in half-mask or full facepiece models, cartridge respirators
are capable of providing the farmer protection from a wide-range
of agricultural respiratory hazards. The full facepiece models
provide eye protection when there is a risk of chemical burning
or liquid splashing into the eyes.
Available in prices ranging from $30 to $100, cartridge-type
respirators are capable of providing protection from anhydrous
and livestock ammonia, pesticides (but not fumigants), disinfectants,
dusts, molds, welding fumes, and acid and organic vapors.
Farmers
need to be aware that the cartridge respirator system is designed
to filter out particulates and certain odors, they are not
an air supply for oxygen deficient areas such as in sealed
silos and manure pits, or in silos where silo gas is suspected.
Air-purifying
helmets are available for farmers who are seeking respiratory
protection from dusts, pesticides and anhydrous ammonia. The
helmet also provides protection for the entire head (see Figure
1). These air-pressurized helmets are equipped with a visor
and a drawstring collar to eliminate contaminated air from entering
under the helmet. A battery driven air pump filters incoming
air and pressurizes the entire helmet.
Helmets
are equipped with a rechargeable battery pack that can be
plugged into the tractor:s electrical system for extended
wear. The battery pack provides air flow for up to four hours
so the farmer can leave the tractor to load or repair equipment.
The
cost of an air-purifying helmet is about $700. Cartridge filters,
which last about 100 hours and cost $30 to $45 per set, are
available for pesticide and ammonia applications. The helmet
does not provide oxygen to the wearer, it only filters out
certain gases and particulates. The unit is not to be used
in oxygen deficient areas such as sealed silos and manure
pits, nor should it be used when applying fumigants.
The
self-contained breathing apparatus (SCBA) is a farmer:s only
protection when working with fumigants, or in manure pits, sealed
silos and other areas where oxygen is limited or where toxic
gases are suspected (see Figure 2). This type of unit, similar
to that worn by firefighters, provides the farmer with breathable
air for about 30 minutes.
The cost of the unit is about $1,600 and weighs about 45 pounds.
The user also needs to be instructed in proper use of the
unit.
There
are two basic types of elements for purifying air, mechanical
filters and chemical cartridges. Both are frequently used in
combination, with the filter element first screening out particulates
and the chemical cartridge filtering gases and vapors.
Chemical
Cartridge Elements
Chemical
cartridges are filled with a specially treated activated carbon
that has a high absorption capacity to certain gases and vapors.
As gases and vapors pass through the element they become trapped
on the carbon element, stopping them from entering the mask.
The absorption capacity of the cartridge is limited, so the
wearer should replace the cartridge when any taste, odor or
irritation is noticed.
Mechanical
Filter Elements
The mechanical
filter protects the wearer from dusts and mists by trapping
the particulates in the fibrous material of the mask. They become
more efficient as the mask is worn, but the filter element must
be replaced as it becomes more difficult to breath through.
Beards
and the physical size of the individual:s face may make fitting
a respirator difficult or impossible. Beards interfere with
the seal of mask-type respirators and half and full-face respirators.
Farmers with facial hair should consider an air-purifying helmet,
which can accommodate most beards.
Banana
oil ampules are available to test the fit of a respirator
before entering an area with contaminated air. To test for
proper fit, crush the ampules after installing the respirator,
if any odor is detected then adjustments must be made to the
respirator or new cartridges are needed.
Check
with your physician prior to using any respirator or self contained
breathing apparatus to be sure any pre-existing medical condition(s)
would not be further irritated by using a respirator or other
air-purifying device.
Disclaimer
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
Michigan
State University, Agricultural Engineering Department.
Howard
J. Doss, Agricultural Safety Specialist; and William McLeod,
Agricultural Engineering, Michigan State University Extension,
East Lansing, Michigan 48862. 5/93. Funded by the National
Institute of Occupational Safety and Health - #UO5/CC-4506052-02.
This
information is for educational purposes only. Reference to
commercial products or trade names does not imply endorsement
by the MSU Extension or bias against those not mentioned.
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