During the latter half of the twentieth century, the number and stocking density of poultry raised in confinement increased tremendously. A major reason for increases was improved economic efficiency, with more birds being served by the building structure and the ventilation, heating, feeding, watering, and waste management systems. Also, environmental control systems were developed that could provide productive interior conditions for the large number of birds to be housed in one building. In addition, improvements in preventive veterinary medicine reduced the risk of losses to diseases.

The production of commercial poultry can result in some undesirable environmental side effects such as elevated levels of odor and dust, which are often associated with poor management. The air quality within poultry buildings should and can be managed to protect the health of both the poultry facility workers and the poultry they care for. Humans working and birds living in poorly managed and inadequately ventilated poultry housing can have respiratory ailments aggravated by exposure to such environments. Although noise levels are not usually high in a poultry house, hearing protection when working around noisy equipment may be warranted. Workers in poultry buildings may also be exposed to mechanical or electrical hazards. Very few poultry diseases can be transmitted to humans, but situations where transmission is possible should be avoided.

Poultry facility workers who spend the most time in the buildings and therefore experience the greatest amount of exposure are at greatest risk. These include poultry caretakers, farm managers, and flock supervisors. Another category of workers at risk include poultry catchers, who harvest the birds for transportation to processing plants.

Hazards in Poultry Buildings

Respiratory Hazards
Certain contaminants can exist in the interior air of a poultry house, particularly if ventilation is inadequate. Ammonia is the most prevalent noxious gas found in poultry house environments. Dusts found inside the poultry house are similar to other agricultural dusts and consist of molds, bacteria, insect parts, pollen, grains, mineral ash, animal fluid, dander, and excreta. If proper environments are not maintained in the poultry house or if workers do not wear protective respiratory devices when appropriate, their health can be jeopardized. Individuals with immunodeficiencies are particularly vulnerable to these environmental stresses. Health problems resulting from respiratory exposure to these contaminants may be chronic (lasting a long time or recurring), or acute (severe but short in duration). Acute problems are often recognizable since they may be dramatic, but chronic problems may be mistaken for or be aggravated by other health conditions such as the flu, allergies, or cough and bronchitis due to smoking.

Studies of the health of poultry facility workers in the United States and the United Kingdom have shown that the primary adverse health effects due to respiratory exposures were breathlessness, chest tightness, and airway inflammation, often manifested as bronchitis. Workers who smoke and those who have worked with poultry for more than 5 years are at greatest risk for such ailments. Although smoking can aggravate or cause respiratory problems, not all poultry workers with respiratory symptoms and reduced lung function are smokers. Such respiratory problems may be caused by poor air quality due to poor ventilation management since exposure to toxic gases and dust can irritate the mucus membranes. Also, chronic exposure to low levels of toxic gases may lead to airway inflamma- tion and a decrease in pulmonary function.

Other respiratory problems that can occur in poultry workers include allergic reactions, asthma, and hypersensitivity pneumonitis. An ailment known as organic dust toxic syndrome (ODTS) has occurred in workers exposed to dust in swine operations and grain handling and storage facilities. Thus it may occur in poultry facility workers who work in very dusty houses without respiratory protection. ODTS is characterized by flu-like symptoms such as headaches, muscle aches, and malaise occurring 2 to 6 hours after exposure.

Poultry catchers, who harvest birds for transportation to processing plants, are especially susceptible to poor air quality. They work in poultry buildings daily, their activities contribute to dust generation by the birds, and their physical exertion can lead to increased inhalation of contaminants in the absence of proper respiratory protection. Studies of poultry catchers in the United States have shown that they are exposed to higher levels of dust and endotoxin than poultry producers, and often experience chronic cough, phlegm, and wheezing. As with producers these symptoms occur most often among catchers who have worked with poultry for a long time (over 5 years). Since reduction of exposure to airborne contaminants is necessary to avoid such problems, ventilation management and respiratory protection are very important. Poultry facility workers who must exert themselves physically in the buildings should utilize respiratory protection that facilitates exhalation (such as masks with exhalation valves).

Noise Hazards
Hearing protection devices should be worn by workers exposed to excessive noise levels. While noise hazards are more prevalent in swine housing than poultry houses, significant noise levels can be generated by some fans and other equipment in poultry buildings. Chronic exposure to high levels of noise without protective devices may lead to permanent hearing loss.

Noise intensity is measured in decibels (db). An increase of 10 dB means the sound level is increased 10 times. A soft whisper is about 30 dB. An "A" indicated after dB refers to the type of filter used in devices for measuring noise levels; this filter approximates the human ear. The federal government (OSHA) limits noise exposure to an average of 90 dB over an eight hour work shift, since the duration of exposure to noise levels affects the amount of hearing damage or psychological effects which occur. Table 1 lists effects of noise exposure on humans. Table 2 give permissible noise exposures as specified by OSHA.

Noise in poultry housing arises from the birds as well as the machinery in the buildings, such as fans, feeding equipment, cages, and feeder chains and augers. The sound level from the combination of noises may reach 100 dB (depending on the type of fans and other equipment and how close the worker is to the equipment), in which case workers should wear protective devices to protect hearing.

Table 1. The Effect of Different Noise Levels on Humans.
 

Source: J. E. Gay, Institute of Agricultural Medicine and Occupational Health, University of lowa.

Table 2. Permissible Noise Exposures.
 

Source: J. E. Gay, Institute of Agricultural Medicine and Occupational Health, University of lowa.

The first evidence of noise-induced hearing loss is difficulty hearing high pitched sounds. Noise levels may be too loud when:

• the ears ring or buzz after exposure to noise
• a temporary muffling of speech or other noise is experienced
• the ability to tell music tones apart is lost
• understanding normal conversation is difficult.

Other Hazards
Other safety and health hazards for agricultural enterprises, including poultry produc- tion, include mechanical, electrical, chemical, and fire hazards, and heat and cold stress. Often these potential hazards become a higher risk when workers compromise safety precautions by taking guards from equipment or disregard safety policies. It is therefore imperative that workers are well trained, follow safety policies, and are encouraged to recognize and rectify potentially dangerous situations.

Machinery such as feeding equipment or fans must be equipped with safety guards, which should always be replaced after servicing. Improperly guarded or handled chains, sprockets, winches, belts and pulleys may act as pinch points. If a person's extremity happens to encounter such a pinch point, lacerations (cuts), avulsions (tearing off of tissue), or crushing injuries may occur. North Carolina Cooperative Extension Service publication AG-481-2, entitled Agricultural Machinery and Your Health and Safety, provides details on mechanical hazards and their prevention and management.

Electrical hazards arise when electrical equipment is not properly grounded or is not corrosion resistant, or when insulation around electrical wires is in poor repair. In such cases, electrocutions or nonfatal electrical shocks may occur. Fires may also develop from damaged electrical wires. In addition, lockout systems for breaker boxes should be used while servicing electrical equipment to prevent machinery from being turned on accidentally.

Chemical hazards arise when workers are exposed to chemical products such as fuels, pesticides, or cleaning agents. Spilling such chemicals on the skin can result in poisoning, irritation, or allergic reactions. Certain chemicals are rapidly absorbed through the skin and may cause systemic poisoning. Wearing gloves and protective clothing will decrease exposure to these agents.

Working in extremely hot or cold weather also constitutes a health hazard. Frequent work breaks and fluid replacement are needed in hot weather to prevent heat exhaustion. Adequate dry clothing, including gloves, are needed in cold weather to prevent frostbite.

Prevention and Management

The health and safety hazards identified above for poultry facility workers can be avoided or minimized by following certain procedures or using appropriate equipment. For example, each worker should have the basic personal protective equipment (PPE) needed for the job to be performed. The appropriate PPE will vary according to the job at hand. They include respiratory protection, hearing protection, safety glasses, gloves, clothing, shoes, and headgear.

Respiratory Hazards
Problems due to respiratory exposure to airborne contaminants can obviously be avoided if the air quality is kept sufficiently high. However, ventilation, air cleaning and other sanitation measures have in many cases been incapable of completely removing contaminants or have been too expensive for producers to install or utilize. As a result, the single most effective means of controlling respiratory hazards in poultry buildings is use of respiratory protection, devices-that is respirators or dust masks-by people in the buildings.

Respiratory protective devices vary in design, application, and protective capabilities. Selection depends on the amount of exposure, the substances involved, and the fit of the device. Only respiratory protection devices approved by the National Institute for Occupational Safety and Health (NIOSH) or the Mine Safety and Health Administration (MSHA) should be considered.

Fit is extremely important where respiratory equipment is concerned. Any respirator or mask should have two strong straps and a tight seal with no gaps. Respirators should never be modified and should always be NIOSH or MSHA approved. Manufacturers' instructions should be read carefully before the use of any respiratory protection.

Type of Masks

1. Disposable Dust and Mist Masks
These masks are made of filter material shaped to fit with two straps holding the mask to the wearer's head. These may not provide the best protection for all agricultural situations, but when used properly they can be sufficient for most agricultural jobs. They are the least expensive type of respiratory protection. Note that the cheapest form of disposable mask, often termed a comfort mask, can reduce exposure to some dust but is not ap- proved for toxic particles and is not approved by NIOSH or MSHA. Some disposable masks have valves to make exhaling easier, which are particularly helpful for workers undergoing physical exertion in the buildings. Disposable dust and mist masks cost $1 to $4 and last about a day.

2. Reusable Dust and Mist Masks
These masks operate like disposable masks but the filters are replaceable. They are ideal for workers who often require respiratory protection, and they can last from a few months to a few years. Some reusable masks also have an exhalation valve. Reusable masks cost $15 to $25 and the filters, which last about a week, cost $1 to $2.

3. Chemical Cartridge Respirators
These masks contain chemical cartridges composed of charcoal or another substance that absorbs gases and vapors. A particulate prefilter may be attached to the cartridge so the respirator can protect workers from both dusts and gases. These can also last from a few months to a few years. They cost $25 to $100 and cartridges cost about $5 a pair.

4. Powered Air-Purifying Respirators
These respirators blow filtered air invo a faceplece. They are cooler because of the air flow over the head and face. Beards, sideburns, and different sized faces do not hinder the fit. They are the most expensive type of respirator ($250-$700) but they will last for years. Note that these are the only respirators that will also provide protection for the eyes; they may be needed if a worker has sensitive eyes or the air quality is extremely poor.

Controlling Exposure
Besides the use of NIOSH/MSHA approved respiratory protection, limiting the duration of exposure of workers to house environments may prevent the development of respiratory problems. Certainly workers who develop a chronic cough or breathing problem should be evaluated by a physician. Medications, if necessary, may improve the symptoms so they can return to work. However, in rare instances the severity of the respiratory problems may require that a worker avoid further exposure to confinement environments.

Pulmonary Evaluation
Since adverse effects on the pulmonary system may arise from exposure to airborne contaminants, evaluation of the pulmonary system is essential to evaluating respiratory problems. Such evaluation usually involves a medical questionnaire, physical examination, pulmonary function test, chest x-rays and occasionally blood tests.

Pulmonary function is usually assessed by spirometry. Flow rates and lung volumes are measured and compared to a control population. Results from several studies involving poultry workers exposed to airborne contaminants show a slight decrease in flow volumes and flow rates. These studies suggest that pulmonary obstruction may be occurring. Exposure response studies have revealed a greater decline in pulmonary function in workers that smoke. Duration of exposure, dust, ammonia and endotoxin levels also appear to be related to pulmonary effects. Thus, the higher the dust, ammonia, or endotoxin levels, the more likely workers will have respiratory symptoms and show abnormalities in their pulmonary function test.

Environmental Measurements
Measurements can be made of most environmental hazards in poultry buildings. Dust levels, gas concentrations, microbial and endotoxin levels, humidity, temperature, and ventilation can be accurately measured using appropriate devices. An industrial hygienist, engineer, or other specialist who is familiar with air quality measurements may be needed to operate the measuring instruments and to interpret the results. Recommended levels are currently being established to protect the worker's health as well as the birds' health. When levels exceed those recommended, engineering controls. such as increasing ventilation or providing air filtration, should be initiated.

Mechanical Hazards
Unguarded fans in poultry buildings are dangerous. If fans hanging inside a building are within reach, they must have guards or screens so people cannot touch any moving parts. A 1-by-2-inch-mesh screen, placed over the intake and exhaust sides of a fan enclosure so that the screens are at least 7 inches from any moving parts, may provide such protection with relatively minor obstruction of airflow and minimal dust buildup (see Figure 2).

Figure 2. A 1-by-2-inch wire mesh, 7 inches or more from moving parts, provides protec- tion and minimizes dust buildup.

Workers operating winches for raising or lowering items such as fans, curtains, and feeder lines must be careful and avoid releasing the winch before the object is fully raised (and secured), or fully lowered. Also, augers for conveying feed into the buildings must be properly guarded. Refer to Cooperative Extension Service publication AG-481-2, Agricultural Machinery and Your Health and Safety, for more information on proper techniques for dealing with mechanical hazards.

Hearing Problems
To prevent excessive noise levels inside animal housing, extremely noisy fans should be avoided. Inexpensive rubber mounts may be installed between a fan motor and its base to further reduce noise production. If efforts to control the noise level in poultry housing cannot reduce the noise to an acceptable level, personal hearing protection devices should be utilized by workers in the building. These include ear plugs (either disposable foam and reusable rubber plugs) and hearing protector ear muffs. These devices are rated in terms of a noise reduction rating, which typically ranges from 20 to 35 dB.

People who cannot avoid loud noises should limit the amount of time they are exposed to noise, or wear hearing protection. Ear plugs or ear muffs, if worn properly, will effectively reduce loud noise. Persons who believe that they have a hearing loss should consider having an audiogram to measure their hearing.

Infections
To minimize the chance of infection of workers and birds, the use of gloves and clean work clothes and maintaining high standards of personal hygiene should be encouraged. An updated tetanus vaccination is recommended for poultry facility workers. Any injuries (whether caused by birds or not) should be thoroughly cleaned because of the high likelihood of contamination. If workers develop signs of illness or of infection, such as erythema (redness), heat, fever, yellowish drainage, or progressive swelling, they should be evaluated by a physician.

Legal Obligations

Agricultural employers have certain legal obligations under the Occupational Safety and Health Act (OSHA) and the Fair Labor Standards Act (FLSA). A summary of the OSHA and FLSA provisions are given along with many other labor guidelines in Cooperative Extension Service publication AG-444, North Carolina Farm Labor Rules and Regulations. Farm owners and managers should review the OSHA and FLSA requirements and use positive measures to prevent accidents.

It is a myth that OSHA regulations do not apply to agriculture. It is true that farms with fewer than 11 employees are exempt from inspections and some recordkeeping requirements, but in general OSHA regulations apply to any operation that has one or more employees. (Immediate family members are not considered employees).

FLSA regulations establish minimum ages for children employed in jobs that are considered hazardous. The minimum age requirement for most occupations is 16 unless certain exemptions apply. Farm operators should carefully review these requirements and the exemptions if minors are employed.

References and Additional Materials

American Lung Association of Iowa: Livestock confinement dusts and gases, Agricultural Respiratory Hazards Education Series, American Lung Association of Iowa, Des Moines, IA, Unit 4, 1986.

Wathes, C. M., H. E. Johnson, and G. A. Carpenter: Air hygiene in a pullet house: effects of air filtration on aerial pollutants measured in vivo and in vitro, British Poultry Science, 32:31-46, 1991.

Whyte, R. T., P. A. M. Williamson, and J. Lacey.: Air pollutant burdens and respiratory impairment of poultry house stockmen, Livestock Environment 1V American Society of Agricultural Engineers, St. Joseph, MI, pp. 709-717, 1993.

Donham, K. J., B. Leistikow, J. Merchant, and S. Leonard: Assessment of U.S. poultry worker respiratory risks, American Journal of Industrial Medicine, 17:73-74, 1990.

Pickrell, J.: Hazards in confinement housing—gases and dusts in confined animal houses for swine, poultry, horses, and humans, Vet. Hum. Toxicol., 33(1):32- 39, 1991.

Lenhart, S. W., P. D. Morris, R. E. Akin, S. A. Olenchock, W. S. Service, and W. P. Boone: Organic dust, endotoxin, and ammonia exposures in the North Carolina Poultry Processing Industry, Appl. Occup. Environ. Hyg. 5(9):611-618, 1990.

Morris, P. D., S. W. Lenhart, and W. S. Service: Respiratory symptoms and pulmo- nary function in chicken catchers in poultry confinement units, American Journal of Industrial Medicine, 19:195-204, 1991.

Prather, T. G.: Agricultural respiratory hazards, The University of Tennessee Agricultural Extension Service, Knoxville, TN, 1992.

Noren, O.: Noise from animal production, Animal Production and Environmental Health, D. Strauch (ed.). Elsevier Science Publishers B. V., New Amsterdam, Chapter 2, 1987.

Gay, J. E.: Plan on Hearing Tommorow? Wear Your Protection Today, National Hog Farmer, Spring, 1990, p. 30-31, 1990.

Roberts, D. E.: A Guide to Farm Safety and Health, Division of Occupational Safety and Health, N.C. Dept. of Labor, Raleigh, NC, 1990.

NIOSH Respirator Poster: Pictures of different types of respirators with description of their uses. Available from NIOSH.

Eickhoff, W. D.: North Carolina Farm Labor Rules and Regulations, Publication AG- 444* North Carolina Cooperative Extension Service, Raleigh, NC.

For more information contact:
Grant Ellington-Extension Associate
NC State University
Biological & Agricultural Engineering
Campus  Box 7625
Raleigh, North Carolina 27695-7625
PHONE: (919) 515-6793
FAX: (919) 515-6772
e-mail: Grant Ellington  ghelling@eos.ncsu.edu