Applicators and their employees using pesticides and uses that fall under Worker Protection Standards (WPS) must follow OSHA respirator requirements when a respirator is listed under the required Personal Protective Equipment (PPE). Respirators are required when it is determined that inhalation exposure to a pesticide is potentially hazardous. Unfortunately, the requirements listed on some pesticide labels are both highly technical and confusing. But following pesticide label requirements is the law. This article summarizes these requirements and clarifies some of the language on pesticide labels.
Some organic producers have been surprised that some organic pesticides may require the use of a respirator, particularly pesticides that are protein based. When this is the case, a respirator meeting the requirements listed on the pesticide label must be used; users must fit-test for that particular respirator each year and have a medical clearance to wear a respirator as often as required by their doctor. The revised WPS includes specific requirements for respirators when using pesticide products under the Agricultural Use Requirements that requires the use of a respirator. This revision requires all those who are required to use a respirator to have a medical evaluation and annual fit-tests for each type of respirator as required by pesticide products they use.
Pesticide labels requiring the use of respirators specify the minimum type of protection needed. This is based on the inhalation risk of the product, the site where it is used, and activity involved. Respirators have a National Institute for Occupational Safety and Health (NIOSH) certification code identifying which specific standards they meet. Under WPS, respirators must be approved by NIOSH. Simple dust masks, such as the one-strap dust mask, are not approved by NIOSH and not suitable nor approved for use with pesticides, even granular or dust formulations.
Types of Respirators Table 1 lists the categories and their corresponding codes for air-purifying and air-supplying respirators. These codes are used in the Personal Protective Equipment (PPE) section of the label to describe respirator requirements.
Table 1. NIOSH Respirator Codes and Descriptions
Air-filtering Respirators
TC-14G Gas masks with canister
TC-21C Powered air-supply particulate respirators with N,R, or P classified filters
TC-23C Air-purifying respirator (APR) with chemical cartridge or powered air-purifying respirator (PAPR) with chemical cartridge and particulate filter
TC-84A Non-powered particulate respirators with N,R, or P classified filtersNon-powered combination chemical cartridge/particulate respirators with N, R, or P filters
Air Supplying Respirators
TC-13F Self-contained breathing apparatus (SCBA) for entry or escape, demand or pressure-demand, respirator face piece is connected to portable breathable air in cylinders carried on the back of the wearer
TC-19C Supplied air respirators (SAR), the respirator face piece is connected to a "fixed" air source (not designed to be carried by the wearer)
Air-purifying Respirators
Air-purifying are among the most commonly used respirators with pesticide handling and have canisters, cartridges, or filters to remove contaminants from the air. They use negative pressure produced when we inhale to pull air through the filter. Powered air-purifying respirators have a battery-operated blower to move the air through the purifying elements and create positive pressure under the mask.
Particulate Filter Respirators
Of the organic approved pesticides that require a respirator, this is the most common type needed. Particulate filter respirators are appropriate when loading and applying granular or dust-formulated pesticides. Do not use a particulate filter respirators for applying liquid pesticides as these do not provide protection from organic vapors. If you can begin to smell or taste the chemical, the mask no longer fits properly; or if breathing becomes difficult, the filter is no longer effective and needs to be replaced. Masks must be replaced when they reach the service life listed by the manufacturer.
There are several categories for particulate filters based on their resistance to oil. Some pesticides contain oil byproducts, so this is an important requirement. The classification 'N' means the particulate filter is not resistant to oil; 'R' is resistant to oil for up to 8 hours; and 'P' is oil-proof. Particulate respirators are also rated for their efficiency to remove particles 0.3 microns in size. These efficiencies are 95%, 99%, and 99.97% (100%). The 95% filters should be appropriate for most pesticides as most spray particles are larger than 2 microns. As an example, the particulate filter 'R95' would be 95% efficient in removing particles at least 0.3 microns in size and is resistant to oil, but not oil-proof. Many people are familiar with N95s used to limit the spread of the Corona virus; this is just one level of particulate filter.
There are several types of particulate filters, including face-piece respirators, half-mask, and full-face respirators. The face-piece respirators are usually made of a cloth-like material and have two straps to adjust the fit. The half and full-face respirators are meant to be reused many times and have filters that can be snapped into place and replaced as needed. They can be used with particulate filters, chemical cartridges, or combination particulate filters and chemical cartridges.
Chemical Cartridge Respirators
Figure 2. Chemical Cartridge respirators use color codes on the filters to designate the types of vapors they reduce.
These respirators have different types of cartridges to remove different materials from the air. Cartridges are color-coded corresponding to the types of materials they protect against (Table 2). Some pesticides require respirators that protect against organic vapors as many pesticides are organic compounds in that they consist of carbon molecules. This should not be confused with 'organic agriculture.' Chemical cartridges are meant to protect against light concentrations typical of outdoor applications or when applying pesticides diluted with water. Some pesticide labels may require both particulate and organic vapor filtering; in that instance, a pink pre-filter for dust in combination with one of the organic vapor cartridges would be needed.
Do not wear a chemical cartridge respirator in an area considered immediately dangerous to life or health. This is an area where dangerous gases can build up, creating a deadly atmosphere that can kill in seconds. Examples are a manure pit or silo with gases; a chemical cartridge respirator will not provide adequate protection in these situations.
Table 2. Some of the Color Codes for Chemical Filtering Cartridges
Color Provides Protection Against
White Acid gases
Black Organic vapors
Yellow Acid gasses and organic vapors
Green Ammonia gas
Pink Dusts and welding fumes
Brown Acid gases, organic vapors and ammonia gases
Powered-air Purifying Respirator (PADR)
This uses a battery-powered fan to push air through the purifying element and may be suitable for particulate dusts, chemical mists, and vapors, depending on the particulate filters and chemical cartridges used. Since this is a positive pressure respirator, the advantage is that if there is a small leak, purified air is pushed out of the respirator rather than contaminated air pulled in. This may be better for people not healthy enough to wear a restrictive air mask.
Fit-testing for Respirators
Tight-fitting of respirators is required for particulate-filter masks, half-masks, and full-face mask respirators. Anyone can conduct a fit-test, but the fit-test must meet the OSHA respirator fit-testing standards (29 CFR 1910.134). Most regional health centers in Kentucky will conduct respirator fit-tests.
Fit-testing helps to reduce inhalation exposure. If the seal around the mask leaks, contaminated air is pulled in and inhaled. Facial hair interferes with the seal and is not permitted with these masks. With WPS, a fit-test must be performed for any tight-fitting respirator at least every 12 months. But before fit-testing, you must have a medical clearance. People with some medical conditions may be at a serious health risk if they work while wearing a respirator. Your employer or the owner/operator keeps a copy of the medical determination (not a copy of the confidential medical evaluation) for three years, stating whether you are medically able to use the respirator. The fit-test ensures that the respirator is properly sized and shaped for the wearer to prevent pesticide exposure. It is to be conducted at least annually by someone properly trained. Your employer or the owner/operator will keep records that fit-testing and training were conducted annually, as well as fit-test results, for three years.
Read all documentation provided with your respirator. It explains how to properly assemble, fit, clean, maintain, and store the respirator.
This article was adapted from: J. Hygnstrom, C. Ogg, and C. Alberts. Respirators for Handling Pesticides. EC3021. University of Nebraska Extension, Lincoln, NE.
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