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| AGRICULTURAL STRUCTURES AND RESPIRATORY HAZARDS
I. INTRODUCTION Frequently, an agricultural respiratory problem is associated with the design, use, or type of product stored in a particular type of agricultural building. Therefore, an understanding of certain agricultural structures and associated diseases can be helpful when diagnosing and attempting to prevent respiratory diseases. This is especially true of grain and silage storage structures, as demonstrated by the following case example. A cattle feeder was moving high moisture corn from a silo to feed his cattle when the flow from the unloader stopped because the corn was bridging and not unloading properly. He entered the silo to knock the corn down. After working for a few minutes, he suddenly collapsed. The older of his two sons, who was working outside the silo, noticed his father's condition and climbed in to help him. He also collapsed. The younger son ran to the house to get his mother. She phoned the local emergency rescue team, which came immediately and brought a self-contained breathing apparatus. Wearing this respirator, one of the trained rescuers entered the silo and dragged the two men out. The father and son were taken to the hospital. After observing the patients for a few hours, during which they appeared to recover, the physician released them. The physician diagnosed their condition as silo filler's disease. The men's recovery was rapid and complete. In fact, the two men had suffered from oxygen deficiency rather than silo filler's disease. They had entered an airtight silo which is designed to store silage or high moisture grain. When placed in these silos, plant products continue metabolism until most of the oxygen is used up and the material is preserved. If the physician's diagnosis of silo filler's disease had been correct, the patients should have been monitored closely for 48 hours and followed for six weeks because of the possibility of delayed onset of pulmonary edema or bronchiolitis obliterans. Silo-filler's disease, a chemical pneumonitis caused by inhalation of oxides of nitrogen, occurs in nonairtight silos recently filled with silage. Knowledge of silo structure and function, combined with a few pertinent questions from the physician, could have assured correct diagnosis. The following sections describe agricultural structures, their functions, and work activities that are specifically associated with major respiratory health problems. Exposure to a causative agent occurs most commonly in the structures listed, but can occur elsewhere. Reading of the text will be greatly aided by reference to Table 1, which summarizes information on activities and resulting respiratory problems and lists other units in this series where specific hazards are discussed. Hazards not discussed elsewhere in the series, such as suffocation in grain bins, asphyxiation in airtight silos, and carbon monoxide poisoning, are described in greatest depth in this unit. Suggestions for preventing these respiratory problems are given. Farmers are known for good common sense; prevention, in general, relies on understanding the hazards involved, and then using common sense to avoid a hazardous environment or prevent its creation. Table 1 AGRICULTURAL STRUCTURES AND RESPIRATORY PROBLEMS FEED GRAIN, SILAGE, AND COMMODITY STORAGE AND HANDLING BUILDINGS Corn cribs
Agricultural Activities:
Moving and shelling corn out of crib; cleaning out
crib
Major Resulting Respiratory Problems:
Asthmatic attack
Bronchitis
Acute inflammatory response
Airways obstruction
Increased airways reactivity
TODS [Toxic organic dust syndrome] (rare)
Hypersensitivity pneumonitis (rare)
Causation of Respiratory Problems:
Grain dust, including bacterial and fungal spores
and by-products
For Discussion See:
Unit 2 (spoiled grain)
Unit 3 (grain dusts)
Grain bins
Agricultural Activities:
a) Moving grain out of storage, cleaning out
moldy residual grain
b) Entering bin that is being emptied
c) Improper application of fumigants; entering a
recently fumigated structure
Major Resulting Respiratory Problems:
a) Asthmatic attack
TODS
Bronchitis
Acute inflammatory response
Airways obstruction
Increased airways reactivity
Hypersensitivity pneumonitis (rare)
b) Suffocation
c) Irritation
Laryngeal edema
Bronchospasm
Pulmonary edema
Respiratory depression
Causation of Respiratory Problems:
a) Grain dust, including bacterial and fungal
spores and by-products
b) Grain entrapment
c) Fumigants
For Discussion See:
a) Unit 2 (spoiled grain)
Unit 3 (grain dusts)
c) Unit 6
Grain elevators and feed mills
Agricultural Activities:
a) Loading or unloading grain, cleaning grain
bins, grinding and mixing feed
b) Improper application of fumigants; entering a
recently fumigated structure
Major Resulting Respiratory Problems:
a) TODS
Bronchitis
Acute inflammatory response
Airways obstruction
Increased airways reactivity
Chronic obstructive pulmonary disease
Occupational asthma
Hypersensitivity pneumonitis (rare)
b) Irritation
Laryngeal edema
Bronchospasm
Pulmonary edema
Respiratory depression
Causation of Respiratory Problems:
a) Grain dust, including bacterial and fungal
spores and by-products
b) Fumigants
For Discussion See:
a) Unit 2 (spoiled grain)
Unit 3 (grain dusts)
b) Unit 6
Airtight silos
Agricultural Activities:
Entering silo filled with silage or high moisture
grain
Major Resulting Respiratory Problems:
Asphyxiation
Causation of Respiratory Problems:
Anoxia
Upright, nonairtight silos
Agricultural Activities:
a) Entering silo within 2 weeks of filling with
silage
b) Throwing off top layers of moldy silage
Major Resulting Respiratory Problems:
a) Sudden death, pulmonary edema, delayed
reaction with bronchiolitis obliterans ("silo
filler's disease")
b) TODS
Hypersensitivity pneumonitis
Causation of Respiratory Problems:
a) Oxides of nitrogen (silo gas)
b) Bacteria, fungi, and their by-products
For Discussion See:
a) Unit 5
b) Unit 2
Fruit and root storage buildings
Agricultural Activities:
Operating machinery or working in buildings with
improperly working heaters
Major Resulting Respiratory Problems:
Carbon monoxide poisoning
Causation of Respiratory Problems:
CO
LIVESTOCK AND POULTRY HOUSING OR PROCESSING Confinement houses: swine and poultry
Agricultural Activities:
Working inside building
Major Resulting Respiratory Problems:
TODS
Allergic rhinitis
Bronchitis
Acute inflammatory response
Airways obstruction
Increased airways reactivity
Chronic obstructive pulmonary disease
Occupational asthma
Causation of Respiratory Problems:
Organic dusts (from animals, their feed and their
wastes), and gases
For Discussion See:
Unit 4
Confinement houses and manure storage pits (swine, sheep, veal
calf, dairy or beef cattle with liquid manure system)
Agricultural Activities:
Entering building during manure pit agitation;
entering manure pit
Major Resulting Respiratory Problems:
Pulmonary edema, possibly respiratory arrest and
death
Causation of Respiratory Problems:
H2S
For Discussion See:
Unit 4
Confinement houses: poultry
Agricultural Activities:
a) Administering aerosol vaccines; working inside
building during disease outbreak
b) Working with diseased animals
Major Resulting Respiratory Problems:
a) Newcastle disease
b) Ornithosis [turkeys only] (rare)
Causation of Respiratory Problems:
a) Infection with Newcastle disease virus
b) Infection with Chlamydia psittaci
For Discussion See:
Unit 7
Sheep and dairy cattle housing
Agricultural Activities:
Cleaning buildings, especially those where animals
are born; assisting during birth process
Major Resulting Respiratory Problems:
Q fever
Causation of Respiratory Problems:
Infection with Coxiella burnetii
For Discussion See:
Unit 7
Conventional chicken coops (or other structures where wild
birds have roosted)
Agricultural Activities:
a) Cleaning or razing houses not in use for
several years
b) Working with infected poultry
Major Resulting Respiratory Problems:
a) Histoplasmosis
b) Newcastle disease (rare)
Causation of Respiratory Problems:
a) Infection with Histoplasma capsulatum
b) Infection with Newcastle disease virus
For Discussion See:
Unit 7
Turkey processing plants
Agricultural Activities:
Slaughter operations
Major Resulting Respiratory Problems:
Ornithosis
Causation of Respiratory Problems:
Infection with Clamydia psittaci
For Discussion See:
Unit 7
Cattle, sheep, or goat slaughterhouses
Agricultural Activities:
Slaughter operations
Major Resulting Respiratory Problems:
Q fever (rare)
Causation of Respiratory Problems:
Infection with Coxiella burnetii
For Discussion See:
Unit 7
EQUIPMENT AND SUPPLY BUILDINGS ON FARMS Machine shops, garages, machine storage buildings
Agricultural Activities:
a) Running gasoline or diesel fuel powered
engines, when buildings are not adequately
ventilated heating buildings with heaters that
are not working correctly
b) Welding galvanized iron
Major Resulting Respiratory Problems:
a) Carbon monoxide poisoning
b) Metal fume fever
Causation of Respiratory Problems:
a) CO
b) Zinc oxide
BARNS Barns
Agricultural Activities:
Moving or feeding hay, grain: grinding and mixing
feed; caring for animals
Major Resulting Respiratory Problems:
a) TODS
Allergic rhinitis
Bronchitis
Acute inflammatory response
Airways obstruction
Increased airways reactivity
Chronic obstructive pulmonary disease
Occupational asthma
Hypersensitivity pneumonitis
b) Q fever
c) Histoplasmosis
Causation of Respiratory Problems:
a) Hay dust
Grain dust
Bacteria, fungi, and their by-products in
moldy fodder
Dusts from animals, their feed, their wastes
b) Infection with Coxiella ournetii
c) Infection with Histoplasma capsulatum
For Discussion See:
a) Unit 2 (spoiled hay, grain)
Unit 3 (grain dusts)
Unit 4 (livestock confinement)
b) Unit 7 (infectious diseases)
c) Unit 7 (infectious diseases)
II. FEED GRAIN, SILAGE, AND COMMODITY STORAGE AND HANDLING BUILDINGS Here, more than elsewhere, respiratory problems are closely linked to specific structures and activities. Although a few problems such as silo filler's disease are widely known, others are not and misdiagnosis is common. If a physician has an understanding of the buildings and associated farming activities, a thorough occupational history can remedy this situation. Corn cribs Corn cribs are narrow wooden buildings used for storage of ear corn (corn not yet removed from the cob). Spaces between the boards of the crib sides allow circulating air to ventilate and dry the grain. Even though most corn in the United States is now shelled in the field with combines, many corn cribs remain and provide inexpensive storage for farmers who still pick some ear corn. Mold may appear during longterm storage. When shelling corn out of cribs or cleaning out cribs, clouds of dust (including plant particles, insect parts, mites, rodent fecal material, inorganic particles, and when corn has spoiled bacteria, fungi, their spores, and metabolic products) may be inhaled causing an attack of asthma, bronchitis, an acute inflammatory response, airways obstruction, increased airways reactivlty, and possibly the toxic organic dust syndrome (TODS). TODS is known to result from exposure both to dusts from grain that has not become moldy and to microorganisms and dusts from spoiled grain. Hypersensitivity pneumonitis also could be induced by exposure to spoiled corn. Both TODS and hypersensitivity pneumonitis are possible but probably uncommon responses to corn crib dusts, since corn cribs are more open and better ventilated than many farm structures. Grain bins Grain bins are used to dry and store shelled corn, oats, beans, rye, barley, and wheat. Typically, grain bins are cylindrical galvanized steel structures placed on a cement slab. The floor is concrete or steel with very small slots to allow ventilation from underneath (a drying floor). Grain is put into the bin by augering it up and into an opening in the roof. Grain is augered out from the floor surface or through a hole in the middle of the bin floor, with gravity keeping the grain flowing into the hole. From here, augers carry the grain to a truck, wagon, or automated feeding system. Bins cannot be emptied completely with an auger. To empty the last several feet of grain, the grain must be hand shoveled. During this operation, large quantities of aerosolized grain dusts, microorganisms and their by-products, and other particles may be inhaled, potentially causing an attack of asthma, bronchitis, an acute inflammatory response, airways obstruction, increased airvays reactivity, TODS, and possibly hypersensitivity pneumonitis. Grain truckers also may inhale these dusts while helping a farmer empty the bin or while leveling grain that is filling the truck. Respirators should be used during these tasks. When bins are fairly full, grain that is being removed from a bin forms a strong down-sucking motion. A vortex of moving grain formed from the grain's exit point, at the bottom of the bin, to the grain surface can suck any person in the bin downward, until eventually the person's head is covered and suffocation occurs. Once trapped in moving grain, even a strong person cannot remove himself or herself. Removal by others is difficult because of pressure and friction of the grain; grain removed from around the victim quickly flows back to entrap the victim once again. If a victim is submerged, rescuers should start the aeration fan but refrain from using the drier or unloading auger, or opening the gravity flow gate. Instead, large openings should be cut uniformly around the base of the bin to allow the grain to flow out, away from the victim. When the victim's head is exposed, or when a victim is only partially submerged, a shield (such as a 55-gallon drum with both ends removed) can be placed around the victim. Then the remaining grain can be removed through the uniformly spaced openings or by scooping grain from inside the shielded area. If possible, a lifeline should be attached to the victim and secured to the top of the bin. This should be used only to prevent further sinking while grain is being removed from around the victim. Anyone entering the bin to assist in rescue should wear a body harness and safety rope secured to two outside rescuers. The only prevention of grain bin suffocation is to assure that no one, under any circumstances, enters a grain bin while grain is being withdrawn. Farmers occasionally apply fumigants to grains in long-term storage. These highly toxic pesticides, if inhaled, can cause respiratory tract irritation, laryngeal edema, bronchospasm, pulmonary edema, and respiratory depression. Grain elevators and feed mills These enterprises are commonly found in grain producing and livestock raising areas. Elevator operators either store grain for producers, or they purchase grain which they dry, store, and grind for feed or which they ship to larger terminals. Farms and ranches that raise or feed out large numbers of livestock may also have extensive grain handling facilities, including a system of bins, tanks, and hoppers for grain and feed. Both elevators and feed mills have a series of bins and tanks for grain and feed storage. They are tightly closed to prevent infestation and spoilage, but grain is continuously being moved in and out of storage. Elevators and mills also have large wooden or steel buildings for storage to bagged feed, seed, pesticides, and other products. Since grain elevator and feed mill workers are exposed to grain dusts regularly over an extended time period, chronic as well as acute responses may be elicited. Clouds of dust are especially prominent whenever moving or grinding the grain. Acute and chronic responses to these dusts range from an acute inflammatory response of the respiratory tract and eyes and dermatitis to TODS, occupational asthma, bronchitis, airways obstruction, increased airways reactivity, chronic obstructive pulmonary disease, and rarely hypersensitivity pneumonitis. High concentrations of dusts are explosive, and have caused numerous deaths in elevator explosions. Fumigants, routinely applied to grain stored in elevators, can be extremely toxic or lethal when inhaled. Respiratory responses include respiratory tract irritation, laryngeal edema, bronchospasm, pulmonary edema, and respiratory depression. Airtight silos Called "oxygen-limiting structures" by their manufacturers, airtight silos are made of glass fused to steel or concrete-stave with epoxy lining. They can be tightly closed to limit the entrance of air. In these completely automated silos, internal air pressure is regulated by valves or by large vinyl bags, complex mechanisms that may need repair or maintenance. Silage or high moisture corn is blown into the silo at the top and removed from the bottom with an auger. Because these bottom unloaders often need repair, top unloaders are now available for conversion. Silage consists of the whole, chopped plant (alfalfa, clover, mixed grasses and legumes, corn, sorghum, oats, wheat, or milo) harvested at a high moisture stage. High moisture shelled corn is also sometimes stored in airtight silos. Silage is fed mainly to dairy cows and to feeder cattle, although alfalfa haylage also may be fed to sheep. Silage is harvested during the summer or early fall and fed out all year long. High moisture corn is fed to feeder cattle or swine, and may be used year round. When placed in airtight silos, plant materials continue aerobic cellular respiration until a low oxygen, high carbon dioxide atmosphere develops, in which metabolic processes are halted and plant material is preserved. This atmosphere implies oxygen deficiency and potential asphyxiation for anyone who enters. Even though the manufacturers of these silos instruct customers to call them for repair problems, farmers have entered to correct problems, or in situations such as the case study in the introduction to this unit. As long as feed stuffs remain in the structure, airtight silos should not be entered under any circumstances without use of a selfcontained breathing apparatus. Nonairtight silos These conventional (concrete stave, brick, metal, or wooden) silos are used to store the same kinds of chopped plant material as are airtight silos, and occasionally are used to store grain. Use of nonairtight silos much predates the newer airtight ones, and thus there is a much greater diversity of design among nonairtight silos. However, they all open only at the top, a feature that distinguishes these from airtight silos. Nonairtight silos have filling and unloading systems ranging from manually operated to automated. The farmer loads silage by blowing it in the top and unloads silage by shoveling it out by hand or by using a mechanical top unloader. In either case, the farmer will need to enter the silo to remove the top, spoiled layer of silage before beginning to feed out silage. When freshly chopped plant material is placed in these silos, natural processes can result in formation of oxides of nitrogen from nitrates in the plant material. Anyone who enters a silo to level silage when these gases are present may inhale enough to cause sudden death, pulmonary edema, or bronchiolitis obliterans, reactions commonly called silo filler's disease. The danger period extends for two weeks after filling. Mold grows in the top layer of silage, which is exposed to the air. Farmers shoveling this spoiled silage out the silo door are exposed to clouds of dust containing large concentrations of bacteria, fungi, and their metabolic products, which in this situation commonly cause TODS. Less commonly, these dust clouds can induce hypersensitivity pneumonitis. Even when a respiratory illness is traced to a nonairtight silo, cases of hypersensitivity pneumonitis or TODS may be incorrectly diagnosed as silo filler's disease because of greater awareness of this disease. Because of differences in treating these diseases, and the crucial need for follow-up of silo filler's disease victims, correct diagnosis is important and is aided by taking an occupational history. Key points to remember are that silo filler's disease usually occurs in summer or early fall, just after harvest and filling of silos. TODS and hypersensitivity pneumonitis usually occur in winter or spring, after mold has had a chance to grow and when silage is being fed out to cattle. These diseases can be separated from the third silorelated insult to the respiratory system, asphyxiation, by the type of silo involved: asphyxiation is associated with airtight silos, while the other responses are associated with nonairtight silos. Differentiation of TODS and hypersensitivity pneumonitis is described in Unit 3. Fruit and root storage buildings Located throughout the United States are buildings used for storage of root crops such as potatoes, and fruits such as apples and bananas. These buildings are usually large enough for a forklift truck to drive through and are often large enough for a tractor and wagon or large straight truck to enter. The buildings are tightly closed since a controlled environment must be maintained. Most of the fruit storage buildings are refrigerated. Facilities storing apples and pears may also have controlled atmosphere storage with oxygen content lowered and carbon dioxide content raised. Fruit and root crop storage buildings are usually entered periodically to remove part of the stored product. Since these buildings are often tightly sealed, accumulation of carbon monoxide from motor vehicles, forklifts, and improperly functioning or poorly vented space heaters can occur fairly rapidly. This results in carbon monoxide poisoning, or carboxyhemoglobinemia, causing headache and dizziness at lower CO concentrations and asphyxiation at higher CO concentrations. Prevention depends on adequate ventilation of buildings whenever vehicles are in operation and on maintaining heaters in proper working order. Machinery operated in these buildings may be operated by battery-powered rather than internal combustion engines, eliminating the problem. III. LIVESTOCK AND POULTRY HOUSING AND PROCESSING Confinement houses Confinement housing differs from conventional housing in that large concentrations of animals are housed in tightly constructed buildings for much or all of their lives. All of the animals' needs must be supplied within the building. The structure must include a ventilation system for control of heat and humidity, a system for watering the livestock, a system for feeding the livestock, and a system for handling animal wastes. Even in the most automated confinement facilities, many person-hours are needed to insure that all systems are working properly. Much time is spent monitoring the condition of the animals as well as working directly with them (with farrowing sows, for example). The ventilation system in confinement houses is often inadequate, especially in winter, to cope with the tremendous concentration of dusts and gases generated by the animals, their feed, and their wastes. Thus, workers in confinement buildings, especially those housing swine or poultry, may experience any of a complex set of acute and chronic respiratory reactions to these dusts and gases, including TODS, allergic rhinitis, bronchitis, an acute inflammatory response, airways obstruction, increased airways reactivity, and asthma; chronic obstructive pulmonary disease may prove to be a problem in future years. A second hazard is associated with liquid manure storage pits underneath or next to confinement structures housing swine, and sometimes housing sheep, veal calves, or beef or dairy cattle. Animal wastes, which are held in pits for months, suddenly release high concentrations of hydrogen sulfide (H2S) when they are agitated while being emptied. These gases may rise into confinement houses that are above the pits causing sudden pulmonary edema and possibly respiratory arrest and death. This also may happen to workers who descend into pits for a variety of reasons: to repair pumps, retrieve animals or tools, clean solids from the pit, install a new pit ventilation system, and the like. With their high concentrations of animals, confinement houses offer excellent opportunities for worker exposure to any infectious disease agent that may be present. Workers in swine confinement buildings may be exposed to the swine influenza virus, which typically causes subclinical or very mild, transient illness in humans (See Unit7 ). Poultry confinement workers may be exposed to the Newcastle disease virus particularly when spraying live attenuated vaccines onto poultry flocks, but also potentially when working with infected birds or performing a diagnostic post-mortem. Working with diseased turkeys could potentially result in ornithosis, although cases in humans are not contracted commonly in this setting. Sheep and dairy cattle housing Dairy barns or other conventional buildings sheltering cattle or sheep may be used to confine these animals while they give birth. Farmers typically assist with the birth or clean out the straw bedding after a birth, and thus may come in contact with the rickettsia Coxiella burnetii, which causes Q fever. Bovine TB is a potential human health hazard of persons working with stabled dairy cattle, but this disease is rare in the United States today because of the eradication program that has dramatically reduced infection among cattle (See Unit 7). Conventional chicken coops Conventional chicken coops are much today, having been largely replaced by confinement structures. These unused buildings may harbor the fungus Histoplasma capsulatum, which grows in soils richly fertilized by bird droppings. Inhalation of fungal spores, released into the air when these houses are cleaned or razed, causes histoplasmosis. Working in chicken coops with diseased birds could expose workers to Newcastle disease virus, although cases of this illness are uncommon. Turkey processing plants Workers in plants where turkeys are slaughtered and processed, especially workers eviscerating birds, may inhale chlamydial organisms that cause ornithosis, an infectious disease ranging from influenza-like infection to acute fulminating pneumonia. Cattle, sheep, and goat slaughterhouses Workers in these operations could, uncommonly, contract Q fever from infected animals. IV. EQUIPMENT AND SUPPLY BUILDINGS ON FARMS Machine shops, garages, machine storage buildings Since farmers are occupied from spring through fall with the cycle of crop raising, they use the winter season to do the bulk of their machinery repair and maintenance work. This usually means working inside closed garages, machine shops, machine storage buildings, or any other available structure. Running gasoline or diesel fuel engines indoors can result in carbon monoxide poisoning when the buildings are closed to prevent heat loss, and when heaters are not working correctly. Carboxyhemoglobinemia is manifest as headache and dizziness at lower concentrations; asphyxiation may occur at higher concentrations. Adequate ventilation of buildings is necessary at all times. Several farm shop work practices tend to increase a farmer's chances for accident or illness. Farmers do much of their own repair and maintenance work and are often self-taught in the use of tools and materials. Their work place is not supervised (as it would be in industry) so they have no one to remind them of safety precautions. Welding is one of those tasks often done in a "temporary" or makeshift shop--that is, in a less-than-ideal location, perhaps during winter in an unheated or poorly heated shed that is inadequately ventilated. Welding galvanized iron (which contains zinc) produces zinc oxide fumes that, when inhaled, cause the syndrome metal fume fever, which begins 4 to 12 hours following exposure. The exposed person first notices a sweet or metallic taste in the mouth, followed by throat dryness or irritation. Later symptoms include cough and shortness of breath, general malaise, weakness, fatigue, and muscle and joint pains. Leukocyte count and serum LDH may be elevated. Fever and shaking chills then develop, followed by profuse sweating. Resolution occurs in 24 to 48 hours. Metal fume fever can be prevented through adequate ventilation indoors, completing welding operations out-of-doors, or use of a dust and fume respirator. V. BARNS Barns are multipurpose farm structures. They may be used to store straw and hay, to mix or grind feed, as farm shops, or especially in winter to house livestock. Respiratory problems associated with any of these activities may therefore occur in barns as well as in other more specialized structures. Dairy barns are the most common type of barn now in use. Any activity associated with milking and caring for dairy cattle can be done in the typical multistoried dairy barn. These large, noncompartmentalized buildings allow for easy transport of the many types of aerosolized particles present. A variety of dusts can be aerosolized from the hay and grain often stored here and from animals housed and fed in the barn. Hay, straw, or loose grain can be stored in lofts. Plant particles can be released whenever these materials are moved or fed to animals. If grain or hay has spoiled, shoveling the grain or breaking open moldy bales releases clouds of dusts containing bacterial and fungal spores and metabolic products. On the barn's ground floor there may be cow stanchions or a milking parlor, free stalls, holding and sorting pens, an area with feeding bunks, box stalls for calving, calves, or other cow isolation, and areas for storing, mixing, and grinding feed. The complex mixture of organic dusts inhaled during these activities can result in a variety of acute and chronic respiratory responses: TODS, allergic rhinitis, bronchitis, an acute inflammatory response, airways obstruction, increased airways reactivity, potentially chronic obstructive pulmonary disease, occupational asthma, and hypersensitivity pneumonitis (breaking open moldy hay bales is the classical exposure for farmer's lung). A number of infectious diseases could be transmitted to humans from animals housed in barns. If sheep or cattle give birth here, Q fever could be contracted while assisting in the birth or from contact with infected placentas, reproductive discharges, or contaminated bedding. Bovine TB would have been a health hazard in past years, but is rare today because this illness has been nearly eradicated in the developed world. Old barns where chickens or wild birds have roosted are ideal sites for proliferation of the fungus causing histoplasmosis Newer steel dairy buildings contain the same types of areas as older barns, except that they are single-storied buildings with hay or straw storage on the ground floor. Persons can experience the same respiratory responses listed above in these newer buildings. u תתתתתתתתתתתתתתתתתתתתThe National Dairy Database (1992)תתתתתתתתתתתתתתתתתתתת תתתתתתתתתתתתתתתתתתתתת\NDB\OCCSAFE\TEXT2\OF200400.TXTתתתתתתתתתתתתתתתתתתתתתת %f TITLE;AGRICULTURAL STRUCTURES AND RESPIRATORY HAZARDS %f COLLECTION;FARM
AND OPERATOR SAFETY |
