Agricultural Dust – Health Effects

Agricultural dust poses a huge health risk to workers and residents on farms.  What can be done about it?
Exposures and health effects from inorganic agricultural dusts.
M Schenker
Article from – NCIB – EHP – Environmental Health Perspectives –
“Most studies of respiratory disease from dust exposure in the agricultural workplace have focused on allergic diseases caused by inorganic dusts, specifically occupational asthma and hypersensitivity pneumonitis. Exposures to inorganic (mineral) dusts among farmers and farm workers may be substantial. Such exposures are most frequent in dry-climate farming regions. In such locations farming activities that perturb the soil (e.g., plowing, tilling) commonly result in exposures to farm operators of 1-5 mg/m(3) respirable dust and >= 20 mg/m(3) total dust. The composition of inorganic dust in agriculture generally reflects the soil composition. Crystalline silica may represent up to 20% of particles, and silicates represent up to 80%. These very high concentrations of inorganic dust are likely to explain some of the increase in chronic bronchitis reported in many studies of farmers. Pulmonary fibrosis (mixed dust pneumoconiosis) has been reported in agricultural workers, and dust samples from the lungs in these cases reflect the composition of agricultural soils, strongly suggesting an etiologic role for inorganic agricultural dusts. However, the prevalence and clinical severity of these cases are unknown, and many exposures are to mixed organic and inorganic dusts. Epidemiologic studies of farmers in diverse geographic settings also have observed an increase in chronic obstructive pulmonary disease morbidity and mortality. It is plausible that agricultural exposure to inorganic dusts is causally associated with chronic bronchitis, interstitial fibrosis, and chronic obstructive pulmonary disease, but the independent contribution of mineral dusts beyond the effects of organic dusts remains to be determined.”
Full text – Please follow the link for the full article.
“Agricultural dust exposure was recognized in the 16th century as a cause of respiratory disease (1), and dust exposure has continued to be a major source of respiratory morbidity and mortality among agricultural workers (2).
In general, agricultural dusts may be divided into those of organic and inorganic origin.
Organic dusts originate from plant and animal sources and are commonly the source of allergic diseases such as asthma. Inorganic dusts originate predominantly from the soil, and tend to result in nonallergic reactions in the lung. This article addresses diseases caused by exposure to inorganic dusts in the
agricultural workplace. It covers sources and composition of inorganic agricultural dusts, exposures to agricultural workers, diseases associated with inorganic dust exposure, and directions for future research.
While the respiratory effects of agricultural organic dusts have been recognized for centuries, there has been little recognition of the effects of inorganic dusts exposure in agriculture. Recent research, particularly in areas of dry-climate farming, has identified a range of adverse respiratory outcomes due predominantly to inorganic dust exposures.
It is important to note that dust exposures in the agricultural workplace are commonly to mixtures of organic and inorganic dusts, and it is not always possible (or valid) to attribute observed health effects to one component or the other, particularly on the basis of epidemiologic studies. I have described health effects resulting from exposure to the predominant dust component causing the observed effect.
Conclusions are generally based on the known effects of inorganic dusts in other occupational settings or on clinical or toxicologic studies. Nevertheless, it is recognized that organic dusts may be a contributing factor to some of these health outcomes and in some cases may be the predominant cause.
Inorganic Dust Sources and Composition
Silicates are the predominant inorganic fraction of most soils. They are classified on the basis of how extensively silica is polymerized. The degree of polymerization will in turn determine the resistance to chemical weathering. Respirable quartz also is found in soil dust, although weathering and chemical
reactions may make it less fibrogenic than freshly fractured quartz in other occupations such as quarrying and sandblasting (3). The inorganic fraction of soils from very arid locations may be dominated by calcium carbonate and more soluble salts rather than by silicates. Soils in warm humid climates may have a greater proportion of oxides and hydroxides of iron and aluminum. Clays in agricultural soils have a large surface area and charge and can potentially carry organic materials and pesticides. Little is known about the frequency or nature of such adsorbed exposures (4).”
Agricultural dust
Article from –  NASD
Lungs Need Protection from Farm Dust
Authors – Schwab, Charles V.; Zeimet, Denis; Miller, Laura
“Protective equipment is important when farmers work with pesticides and toxic products. Protective equipment is equally important when farmers work in dusty conditions common to most farms.
Exposure to grain dust, molds, pollen, animal dander, soil dust, welding fumes, and diesel exhaust can lead to serious respiratory problems. Although they are less toxic than some chemicals, dusts are suspended in the air and can easily enter the lungs and cause damage.
Dust in the lungs has both immediate and long-term effects. It can cause additional physical stress for the person, resulting in fatigue or shortness of breath. Long-term exposure to dust can be accompanied by congestion, coughing or wheezing, sensitivity to dust, and frequent respiratory infections such as colds, bronchitis, and pneumonia. Over time, exposure to dust can result in serious respiratory illnesses, such as farmer’s lung, asthma, emphysema, chronic bronchitis, and other irreversible, incurable ailments.
The National Safety Council reported that 300 workers on large farms were incapacitated due to respiratory conditions in 1990, about one-third caused by dust.
To avoid immediate and long-term respiratory problems, farmers are encouraged to wear protective equipment, such as a respirator, whenever they work in dusty conditions. Respirators may be a good choice if workers are:
congested or have breathing problems;
generally bothered by dust, or
concerned about the amount of foreign particles that get into the body.
This publication offers information about respirators used to protect lungs from farm dust. Chemicals such as pesticides, anhydrous ammonia, cleaning solvents, and disinfectants also require the use of protective equipment. Check pesticide applicator training manuals or discuss details with professionals.
Respirators can be one of two types: those that purify existing air, and those that supply air from a tank or other source.
Air-supplied respirators, such as the self-contained breathing apparatus (SCBA) used by firefighters, rarely are used in farming activities. They are relatively expensive and wearers must be trained.
Many dusty conditions on the farm can be improved with the use of an air-purifying respirator. This device fits over the nose and mouth and uses a filter or cartridge to mechanically remove dust particles from the air as the wearer breathes. An air-purifying respirator provides protection from dust and mists.
There are many styles of respirators on today’s market, however, not all are recommended for farming activities. Whether you’re selecting a new respirator or evaluating an existing respirator, always consider several factors.
Testing and approval: All respirators used in farming activities should be approved by the National Institute of Occupational Safety and Health (NIOSH). NIOSH-approved respirators have been tested and meet special federal standards.
Proper use: Many problems result from using an inappropriate respirator. For example, dust masks will not reduce chemical vapors. A respirator approved for use with chemicals may not filter dust.
Always use a respirator appropriate for the task. The specific contaminant for which the respirator is approved will be written on the cartridge filter or instructions with the respirator.
Proper rating: As part of the testing process, a respirator is assigned a “protection factor,” or PF rating, which indicates how well the respirator can perform its job. For farming activities, always use a respirator with a PF rating of 10 or above.
Proper size and fit: The respirator must form a good seal with the wearer’s face so that the respirator can function properly. Dust that slips through a poor seal goes directly to the lungs.
Respirators are available in various sizes and designs to fit most faces. Eyeglasses, clothing, and facial hair such as beards or sideburns, can interfere with the seal. All respirators must be “fit tested” by safety professionals, using smoke, saccharin, or banana oil while the device is being worn.
Cost: Respirators can be either disposable or non-disposable. Disposable respirators are inexpensive and can be discarded when dirty or when the job is finished, but they can be relatively expensive if protection is required on a regular basis. A better choice is a durable respirator that can be washed and stored after each use.
The wearer’s physical condition: The wearer of an air-purifying respirator must be in good physical condition. Since air is drawn through a filtering mechanism, breathing becomes more difficult, and can cause stress for people with medical problems, such as heart conditions or respiratory ailments. Always get a physician’s approval to wear a respirator.
No respirator can solve all air quality problems. Wearing a respirator incorrectly is as dangerous as not wearing a respirator at all. People have a false sense of security when wearing a faulty respirator or one that is inappropriate for the task.
Respirators should not be worn when concentrations of dust are in the explosive range. In this situation, you may protect your lungs from dust but you’re exposing yourself to other dangers. A general rule is that if it’s too dusty to see your hand at arm’s length, the environment is dusty enough to be explosive.
Another dangerous situation occurs when air-purifying respirators are used in toxic environments. Since air-purifying respirators do not provide oxygen, the air in the working environment must have at least 19.5 percent oxygen. Death can occur in a limited oxygen environment.
Respirators that filter dust cannot protect wearers in toxic chemical environments, such as manure pits, silos, or sludge tanks. Wearing a respirator equipped with a dust filter in these conditions can be fatal.
The use of respirators in day-to-day farm operations may be a new practice for many operators. However, respirators can reduce exposure to farm dust and may prevent serious respiratory problems.
How Much Do You Know?
How many farm workers in the United States suffer from serious respiratory illnesses each year?
less than 30
at least 300
more than 1,000
People who work in agriculture develop immunities to dusty conditions over time. True or false? Wearing a respirator, even if it does not fit correctly, is better than wearing none at all. True or false?
Most people cannot tell when a respirator fits properly. True or false?
Most respirators used in farming activities supply fresh oxygen. True or false?
A respirator with a chemical cartridge is appropriate to use when
cultivating in the wind.
removing the chemical for which it has been rated.
cleaning a hog confinement building.
See answers at the end of this document.
What Can You Do?
You can reduce your exposure to farm dust with these guidelines:
Make a list of jobs where you might need a respirator.
Determine proper respirator for the job. Check the label or with a professional if you have questions.
Compare the cost of disposable and non-disposable respirators.
Ask a professional to fit-test your respirator.
Routinely clean and inspect all non-disposable respirators. Discard disposable ones when dirty.”
Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

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