Many pesticide applicators do not use respirators correctly, and some don’t use them at all. The respiratory tract (lungs and other parts of the breathing system) is much more absorbent of pesticides than the skin. Even if the pesticide label does not require a respirator, an applicator should wear one if working in an enclosed area, and the pesticide label has a precautionary statement like “do not breathe vapor or spray mist” or “harmful or fatal if inhaled.” Applicators should also use respirators if they will be exposed for a long time to pesticides near the breathing zone.

Types Of Respirators
There are two basic types of respirators. The first is air purifying, which means that it removes contaminants from the air around the applicator. The second is air supplying, which supplies the applicator with clean air from an independent source.

For most situations, air-purifying respirators will provide enough protection. This type is most commonly used. However, it will not offer protection from fumigants, from extremely high concentrations of vapor, or when oxygen is low. Air-purifying respirators remove contaminants by filtering out dusts, mists, and particles, but can also remove gases and vapors. Some do one, and others do both. The product label will tell you which you need.

Air-purifying respirators come in three basic styles. The first includes dust/mist masks that filter out dusts, mists, and particles. They are shaped to cover the nose and mouth. The second consists of a mask with one or more cartridges. The third consists of a mask with one or two canisters containing air-purifying materials.

Cartridges may contain either dust/mist-filtering or vapor-removing material. A prefilter must be used with the vapor-removing cartridge to remove dusts, mists, and other particles before the air passes through the vapor-removing cartridge. Some vapor-removing cartridges have an attached prefilter. Generally, separate prefilters are preferred for use with pesticides because they often need to be replaced before the vapor-removing cartridge is used up.

Some cartridge-type respirators are one-piece units with cartridges permanently attached to the face piece. After use, the entire unit is discarded. Others are two-piece units with removable cartridges and a body that can be cleaned and reused. The dust/mist-filtering or vapor-removing cartridges and the prefilters can be replaced when they lose their effectiveness.

Canisters contain both dust/mist-filtering and vapor-removing material, and they contain more air-purifying material than cartridges. They last much longer and may protect better in situations where the concentration of gas or vapor in the air is high, but they are usually heavier and more uncomfortable to wear. Canister-type respirators are often called gas masks. They usually have the canister connected directly to the face piece or are worn on a belt and connected to the face piece by a flexible hose. They are designed to be cleaned and reused, and the canisters can be replaced.

Pick Proper Equipment
Select dust/mist-filtering masks and cartridges that are approved by the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) because others are not as protective and are not acceptable. Pesticide handlers must wear dust/mist-filtering masks or cartridges with NIOSH/MSHA approval number prefix TC-21C. Use a dust/mist mask that is held in place by two straps. Styles with one strap are not approved by NIOSH and MSHA, because they do not keep the respirator adequately sealed against the face.

NIOSH rates vapor-removing devices for the types of gases and vapors they will remove and requires that an organic-vapor-removing material and a pesticide prefilter be used. Applicators and handlers must use either a cartridge approved for organic vapor removal plus a prefilter approved for pesticides (NIOSH/MSHA approval number for both is TC 23C) or a canister approved for pesticides (NIOSH/MSHA approval number prefix is 14G).

How Long They Last
Materials that remove vapor gradually lose their ability to hold more gases and vapors. Their useful life can vary greatly depending on the amount of particles in the air, the concentration of vapor being filtered, the amount of absorbent material they contain, the breathing rate of the wearer, the temperature and humidity, and the length of time they have been stored before use and between uses.

An odor, taste, irritation, or dizziness is a signal that an applicator is no longer being protected. Some materials have a “service life indicator” to indicate when the material is nearly used up. The instructions on some other materials specify when to replace them, based on a specific number of hours of use. If there are no instructions about replacement, change the cartridge or canister after about eight hours of use.

How They Work
Air-purifying respirators draw air through the filters and vapor-removing materials in one of two ways. Ordinary air-purifying respirators depend on the wearer’s lung power to draw air through the purifying material with each breath. Powered air-purifying respirators assist the wearer by pulling the air through mechanically. Dust/mist masks and most cartridge and canister respirators are non-powered air-purifying respirators.
Powered air-purifying respirators should not be confused with air-supplying respirators, because they do not supply clean air. The air is cleaned by cartridges or canisters, as it is with other air-purifying respirators. Powered air-purifying respirators are available as lightweight backpacks, or they may be mounted on or in application equipment where the power is supplied by the vehicle’s electrical systems.

Air-supplying respirators are needed to work for extended periods in oxygen-deficient areas or where the pesticide concentrations in the air are particularly high. They have their own air supply and do not use surrounding air. They can be self-contained, airline-supplied, or contained with an encapsulating suit. The pesticide label will indicate if one is required.

Using respirators and using them correctly is necessary to protect the respiratory system. Applicators should always follow the pesticide label and respirator manufacturer’s instructions. Also, make sure that the respirator is in good working order and do a fit check to make sure all seals are tight.

Gary Brinen is an Alachua County Extension agent in Gainesville, FL.