The use of respiratory protective devices in farming operations is gaining more acceptance each year. As farmers become more aware of the danger dust particles, toxic gases, chemical vapors, and fumes can do to their health, using such devices makes good sense. The federal OSHA law, too, has spurred agricultural employers to provide respiratory protection for their employees.

Respiratory Hazards
There are two basic types of respiratory hazards a farmer finds himself confronted with--(1) working in atmospheres with impure air or, in other words, contaminated air and (2) working in oxygen deficient atmospheres.

Examples of contaminated atmospheres would be in fumigated grain bins, barn lofts with moldy hay, fields during tillage operations, and treated orchards to name just a few. Areas where a farmer would find oxygen deficient atmospheres would be in silos, high moisture grain storage, and manure pits. Some areas, like silos and manure pits, may contain both types of respiratory hazards.

Air contaminants may be visible or invisible. Those that you can see, like smoke or dust, are normally called particulates and those that you cannot see are normally called gas or vapor contaminants.

The "air" that we breathe contains about 21 percent oxygen. But in a confined space such as a silo or manure pit, the air sometimes becomes abnormal. What happens is that other toxic gases that may form in these spaces "displace" or "use up" available oxygen. Thus, you have an oxygen-deficient atmosphere. Insufficient oxygen concentrations cause harmful effects of mental processes, bodily functions, and coordination. At real low concentrations of oxygen, a person can collapse almost instantaneously and death can follow in a few minutes.

Respiratory Types
It follows then that the various types of respirators can be grouped into two groups--air-purifying and air-supplying. The air purifying respirators do just what their name implies--purifies the contaminated air that you breathe so that it is clean before it reaches your lungs. Since you are breathing the air around you, it must contain the proper amount of oxygen. This means that you couldn't use an air-purifying respirator in oxygen-deficient atmospheres.

Supplied-air respirators, on the other hand, are dependent on supplying air known to be pure and containing the 21 percent oxygen. This can be done by stationary air compressors utilizing air hoses and face masks or by wearing what is normally called a "self-contained breathing apparatus" (SCBA). A self-contained breathing apparatus is nothing more than the small air tank outfit scuba divers wear.

The mechanical filter respirator is the simplest type of air-purifying respirator. It consists of a soft rubber face piece with a mechanical filter which fits over the mouth and nose. The filter is made of fibrous materials and traps harmful particulates as the wearer breathes in. The filter can be changed or cleaned easily.

The "dust mask," which may be the type of respirator most farmers are familiar with, is a low cost version of the mechanical filter respirator. It is designed to be thrown away when dirty. Mechanical filter respirators are useless against toxic gases or vapors, but are excellent against dust, chaff, and molds.

Chemical cartridge respirators are what's needed to protect against toxic gases, vapors, and fumes. They work on about the same principle as the mechanical filter respirator, but utilize an absorbent material such as activated charcoal to purify the air of harmful gases and vapors as you breathe in. The filters are changeable so that the respirator can be used in different contaminated atmospheres. It is vital for a farmer to recognize that chemical cartridge respirators have limitations as to the amount of contaminate they can absorb, and that if the wrong type of chemical filtering agent is used in a contaminated area, the respirator is useless. Chemical cartridge respirators are not intended to be used where gases are extremely toxic, even in small concentrations such as manure gas. For these more toxic concentrations, gas masks are required.

Gas masks are similar to chemical cartridge respirators with the difference being the worker wears a "canister" on his back, chest, or beneath the chin, containing the chemical filtering agent. The canister is hooked to the face piece by an air hose.

Again, it is important to remember that gas masks, chemical cartridge respirators, and mechanical filter respirators are not to be worn in oxygen-deficient atmospheres.

Flow Chart
Knowing and understanding all types of respiratory hazards and protective devices a farmer might need can indeed be confusing. Organizing the information in a flow chart may help in remembering what type of respirator can be used for the different hazards.

RESPIRATORY HAZARD TYPE RESPIRATOR TYPE FARM WORK

Contaminated Air          Mechanical Filter           Haying, harvesting,
                          Chemical Cartridge          tillage, applying
                          Gas Mask                    lime, pesticides,
                                                      fumigation

Oxygen Deficient          Self Contained Breath-      Silos, manure pits
                           ing Apparatus              fumigation
                          Stationary Air Supply

Note: Some atmospheres can be so highly contaminated even gas masks have very limited value. In these instances, use an air supplying type respirator to ensure you breathe non-hazardous air.

Respirators can be obtained from a variety of sources, although any one source may not have all types. Farm supply stores, chemical suppliers, and local hardware stores may be the best source for the farmer. If they don't have the proper respirator on hand, they can most likely order it for you. Other sources would be large industrial safety equipment companies and mail order firms.

The cost of respirators varies considerably depending on the type needed. Mechanical filter respirators can be bought for under $10 while SCBA units can run up to a few hundred dollars. This is quite a range and you would be wise to shop around and see what's available in your area. Don't wait until someone dies or comes up with a nagging, life-long respiratory ailment to buy respiratory protection. The time to spend money for your health is NOW--while it will still do some good!

Keywords: ACCIDENT, AG-ENGINEERING, AGRICULTURAL-ENGINEERING, BREATHING,

          ENGINEERING, FARM, GAS, HAZARD, HEALTH, MURPHY-DENNIS,
          PERSONAL-PROTECTIVE-EQUIPMENT, PROTECTION, REFERENCE, RESPIRATION,
          SAFETY, TOXIC

.תתתתתתתתתתתתתתתתתתתתThe National Dairy Database (1992)תתתתתתתתתתתתתתתתתתתת .תתתתתתתתתתתתתתתתתתתתתתתתתת\NDB\OCCSAFE\TEXT2\93תתתתתתתתתתתתתתתתתתתתתתתתתתת

%f TITLE;AGRICULTURAL RESPIRATORY PROTECTIVE DEVICES %f COLLECTION;FARM AND OPERATOR SAFETY
%f ORIGIN;Pennsylvania
%f DATE_INCLUDED;June 1992