Southeastern U.S. Vegetable Crop Handbook - 2021 - 138

RESPIRATORY PROTECTIVE DEVICES FOR
PESTICIDES
For many toxic chemicals, the respiratory (breathing) system
is the quickest and most direct route of entry into the circulatory
system. From the blood capillaries of the lungs, these toxic substances
are rapidly transported throughout the body.
Respiratory protective devices vary in design, use, and protective
capability. In selecting a respiratory protective device, the user
must first consider the degree of hazard associated with breathing
the toxic substance, and then understand the specific uses and limitations
of the available equipment. Select a respirator that is designed
for the intended use, and always follow the manufacturer's
instructions concerning the use and maintenance of that particular
respirator. Different respirators may be needed for application of
different chemicals or groups of chemicals. Select only equipment
approved by the National Institute of Occupational Safety and
Health (NIOSH). The NIOSH approval numbers begin with the
letters TC. NOTE: The label will specify which respirator is needed
for that particular pesticide.
TYPES OF RESPIRATORS
Respiratory protective devices can be categorized into three
classes: air-purifying, supplied-air, and self-contained. Because
most pesticide contaminants can be removed from the atmosphere
by air-purifying devices, we will look at these in greatest detail.
Air-purifying devices include chemical cartridge respirators,
mechanical filters, gas masks (also referred to as canister filter respirators),
and battery powered respirators. They can be used only
in atmospheres containing sufficient oxygen to sustain life.
* Chemical cartridge respirators provide respiratory protection
against certain gases and vapors in concentrations not greater
than 0.1% by volume, provided that this concentration
does not exceed an amount that is immediately dangerous to
life and health. They are for use only when exposure to high
continual concentrations of pesticide is unlikely, such as
when mixing pesticides outdoors. They are available either
as halfmasks, covering only the nose and mouth, or as fullfacepiece
respirators for both respiratory and eye protection.
* Mechanical filter respirators (dust masks) provide respiratory
protection against particulate matter such as mists, metal
fumes, and nonvolatile dusts. They are available either as
disposable or reusable halfmasks that cover the nose and
mouth, or as reusable full-facepieces. Dust masks should
never be used when mixing or applying liquids because
splashed or spilled liquids, or pesticide vapors can be absorbed
by the mask.
* Many respiratory protective devices are combinations of
chemical cartridge and mechanical filter (prefilter) respirators.
These can provide respiratory protection against both
gases and particulate matter.
* Full-face piece respirators provide respiratory protection
against particulate matter, and/or against certain specific
gases and vapors, provided that their concentration does not
exceed an amount that is immediately dangerous to life and
health. Gas masks, like full-facepieces, cover the eyes, nose,
and mouth, but will last longer than cartridges when continu138
ously
exposed to some pesticides. A gas mask will not, however,
provide protection when the air supply is low. A special
respirator with a self-contained air supply should be worn in
these situations.
* Battery powered air-purifying respirators equipped with pesticide
filters/cartridges are also effective in filtering out pesticide
particles and vapors. They are available as halfmasks,
full-face masks, hoods, and protective helmets, and are
connected by a breathing hose to a battery powered filtration
system. This type of filtration system has the additional advantage
of cooling the person wearing it. But, like other air
purifying devices, this system does not supply oxygen and
must be worn only when the oxygen supply is not limited.
Chemical cartridge respirators protect against light concentrations
of certain organic vapors. However, no single type of cartridge
is able to remove all kinds of chemical vapors. A different
type of chemical cartridge (or canister) must be used for different
contaminants. For example, cartridges and canisters that protect
against certain organic vapors differ chemically from those that
protect against ammonia gases. Be sure that the cartridge or canister
is approved for the pesticide you intend to use. Cartridge respirators
are not recommended for use against chemicals that possess
poor warning properties. Thus, the user's senses (smell, taste,
irritation) must be able to detect the substance at a safe level if cartridge
respirators are to be used correctly.
The effective life of a respirator cartridge or canister depends
on the conditions associated with its use-such as the type and
concentration of the contaminants, the user's breathing rate, and
the humidity. Cartridge longevity is dependent on its gas and vapor
adsorption capacity. When the chemical cartridge becomes saturated,
a contaminant can pass through the cartridge, usually allowing
the user to smell it. At this point, the cartridge must be changed
immediately. There are times when the mechanical prefilter also
needs to be changed. A prefilter should be replaced whenever the
respirator user feels that breathing is becoming difficult. Dispose
of all spent cartridges to avoid their being used inadvertently by
another applicator who is unaware of their contaminated condition.
Chemical cartridge respirators cannot provide protection
against extremely toxic gases such as hydrogen cyanide, methyl
bromide, or other fumigants. Masks with a self-contained air supply
are necessary for these purposes.
USE AND CARE OF RESPIRATORS
Respirators are worn as needed for protection when handling
certain pesticides. The use of respirators is now regulated requiring
a health screening prior to their use by a health professional.
This is due in part to the Fumigant re-registration decisions by
EPA. These prerequisites are outlined in the OSHA Respiratory
Protection Act. Prior to using a respirator, read and understand the
instructions on the cartridge or canister and all supplemental information
about its proper use and care. Be sure the filter is approved
for protection against the pesticide intended to be used. Respirators
labeled only for protection against particulates must not be
used for gases and vapors. Similarly, respirators labeled only for
protection against gases and vapors should not be used for particulates.
Remember, cartridges and filters do not supply oxygen. Do
2021 Vegetable Crop Handbook for Southeastern United States
Southeastern U.S. Vegetable Crop Handbook - 2021

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