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4 Identifying Noninfectious Hazards While it is essential to underscore the consideration of infectious hazards, it is also imperative to note that work with nonhuman primates also exposes personnel to various physical and chemical hazards. Few published articles describe noninfectious hazards associated with nonhuman-primate facilities, although potentially they can cause serious injuries and occupational illnesses. It is important for nonhuman-primate workers and managers to be aware of all hazards, not just infectious ones. Job hazards can be identified in several ways. Epidemiologic investigations have an important role in understanding industry-wide trends and risk factors (Robertson 1998). Most employers are required to maintain a log of workplace injuries and illnesses. Those logs and incident-investigation reports provide useful information to managers when they are evaluating causes of injury and workplace trends. Such evaluation provides opportunities for reducing injuries and exposures. Comprehensive information on identification of hazards in laboratory and research animal settings is available (NRC 1995, 1997), and there are widely accepted principles and guidelines for establishing and implementing effective occupational health and safety programs (International Labour Office 1998; NSC 1996, 1997). These topics are discussed further in Chapters 6 and 7. The following descriptions of hazards and sources of exposures, injuries, and illnesses (summarized in Tables 4-1 and 4-2) are provided as a tool for individuals whose responsibility is to identify the hazards to personnel who work with nonhuman primates. The identification of the
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TABLE 4-1 Summary of Physical Hazards Hazard Type and Operation Precautionary Measures Animal bites and scratches. Animal handling, husbandry Tranquilize, anesthetize, train, or restrain animals to prevent bite and scratch injuries; use heavy leather or Kevlar® gloves and arm covers; remain at safe working distance from animals; clean all wounds immediately, obtain medical attention Needle and other wounds from sharp objects. Surgical procedures, phlebotomy, injections Use safe needle systems when possible; do not recap needles; dispose of contaminated sharp devices in rigid waste container for disposal; clean wound site immediately, obtain medical attention Slips, trips, and falls. Work in animal housing, cage-wash, other areas Maintain good housekeeping, remove objects that could cause tripping and liquid or oily slip hazards; use slip-resistant footwear, flooring; maintain all stairs and elevated work platforms in good condition; use carts or dollies to transport animals or heavy objects; plan work so that heavy loads are not carried Overexertion and repetitive strain injuries. Performing animal, cage, material handling Do not exceed heavy-lift limits; design equipment and tasks to avoid awkward postures and motions and high repetitions; seek medical attention if early signs of musculoskeletal injury persist Traumatic crushing and laceration hand injuries. Moving cages, other heavy objects Mobile cage and cart handles should be located so as not to expose hands. Crushing injuries from door frames, other adjacent objects; use two persons for moving heavy-wheeled equipment noninfectious hazards should also involve a qualified health and safety professional with training in ergonomic hazards. PHYSICAL HAZARDS Bites and Scratches Work with nonhuman primates exposes personnel to bite and scratch wounds that not only present zoonotic disease concerns but also can require general medical care, such as suturing and traditional wound management. A wound to the hand may preclude an injured worker from normal occupational activities to allow the wound to heal. Treatment of these wounds is discussed in greater detail in Chapter 9. Prevention of such injuries, which includes cage design, animal handling techniques
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Hazard Type and Operation Precautionary Measures Steam and thermal burns. Autoclaves, cage washers, heated pressure washers Steam and pressure systems must be designed and maintained in accordance with ASME codes; use protective eyewear, face shield, thermal-protective gloves; kerosene-heated or gasoline-powered steam-spray units cannot be operated inside because of potentially toxic carbon monoxide emissions Noise. Nonhuman-primate holding rooms, other areas where animals are vocal; work near cage washers, other loud mechanical equipment Conduct sound-level surveys in operations that seem loud; implement a hearing conservation program for all personnel who are exposed at or above 85 dbA (or equivalent daily noise dose); provide hearing protection for high-noise operations; educate personnel on the hazards of noise-induced hearing loss and on the hearing-conservation program Allergens. Exposure to animal dander, bedding, latex, and other potential allergens. Minimize exposure to airborne allergens by use of dust-capture ventilation and personal protective dust respirators; remain alert to signs suggestive of an allergic reactions (e.g., rhinitis, conjunctivitis, coughing, sneezing, wheezing) Heat stress. High-temperature environments, use of PPE that does not allow dissipation of body heat Provide frequent breaks and drinking water; reduce level and duration of exertion when more protective equipment is worn in high temperatures; consider using personal cooling devices in situations of extreme heat or exertion and tools, and personal protective equipment (PPE), are also presented in later chapters. Needles and Other Medical Sharps Research protocols and general animal husbandry expose workers to various medical sharps that can cause puncture wounds and lacerations. Examples are needles and syringes used for phlebotomy and injection, scalpels and other surgical instruments, dental equipment, and scraping and cutting tools used in cleaning and other daily operations. As with bites and scratches by nonhuman primates, exposures to sharps in a manner that breaks the skin has the potential for not only infection but also injury and disability. Needle stick injuries are also an important source of exposure to
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bloodborne pathogens. Revision to OSHA’s bloodborne pathogens standard added new requirements for employers to adopt engineering and work practice controls that would eliminate or minimize employee exposure from hazards associated with bloodborne pathogens. As a component of the Exposure Control Plan, employers must take into account new changes in medical technologies and document consideration of commercially available and effective safety devices. This may take the form of an annual review and should list the devices under consideration. The review should describe the devices evaluated for use, the method used to evaluate those devices, and justification for the eventual selection of new devices. Slips, Trips, and Falls Slips, trips, and falls are a common cause of traumatic injury to workers in nonhuman-primate facilities. They are not specific to nonhuman-primate facilities; any work setting where floors are wet and there are residues of cleaning agents, feces, or tripping hazards presents a high risk of slip and fall injuries. Personnel carrying heavy loads on wet floors are at high risk of a slip or fall injury. Deteriorated stairs, ladders, and step stools have caused injuries in some facilities. Using slip-resistant footwear helps to reduce the likelihood of such injuries. Guidelines have been established for preventing these injuries (NSC 1997). Overexertion Handling and carrying nonhuman primates, heavy equipment, large containers of feed, and other heavy or awkward objects present the risk of musculoskeletal injury. Such injuries commonly are related to a specific and identifiable work task or movement, but they oftentimes occur in people who have pre-existing injuries or are suffering from pathologic conditions. Regardless of a person’s medical condition, the risk of injury increases with the weight of the load, the awkwardness of the load and lifting movement, and the number of repetitions. The National Institute for Occupational Safety and Health (NIOSH) has issued a guide for evaluating lifting operations and specifying limits (NSC 1996). Work activities that are performed repetitively (more than 100 times per day) or for extended periods have an increased risk of causing musculoskeletal disorders. These types of work injuries and illnesses differ from acute traumatic injuries, such as lumbar strain following the lifting of a single heavy object. Repetitive strain injuries and cumulative trauma disorders are characterized by a slower development of impairment and disability and commonly involve a relatively low-force task that workers
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do not recognize as causing their painful and disabling condition. For example, handling hundreds of cages in the same way every day is an example of the kind of situation in which laboratory animal workers have suffered musculoskeletal disorders. Hand Injuries from Cage Moving and Cleaning Operations In nonhuman-primate operations that use portable cages, serious hand injuries have occurred when workers have only the exterior cage framework to grasp when moving cages. Many types of wheeled-cage systems weigh several hundred pounds and lack handles that allow for biomechanically efficient gripping and movement. Gripping the vertical exterior framework commonly exposes workers’ hands to crush injuries when they try to move the bulky cages through doorways and in crowded areas. Gripping vertical corner pieces also exposes the hands and forearms to scratches by the nonhuman primates when the cages are occupied. As cages are replaced, new mobile cage units with handles that facilitate safe movement should be obtained. Units that lack such handles or that are not designed to allow safe movement should be modified. Pressurized-steam and heated-water washers are used to clean nonhuman-primate caging and housing units. Steam washing systems can be portable units or can operate with a centralized steam supply within the facility. Direct skin contact with the steam washing stream or with noninsulated piping or handles can cause burn injuries that can be severe. Eye contact with a direct stream of pressurized steam can cause serious eye injury, including blindness. Pressurized-steam washing units must be engineered in accordance with American Society of Mechanical Engineers (ASME) codes (ASME 2001) and incorporate features that minimize the potential for operator steam and thermal injuries. Design features should include a control valve that automatically stops pressurized steam flow unless the operator is gripping it. The design of dispensing wands and nozzles should be based on ergonomic principles so that excessive gripping pressure is not required to activate the steam flow or to hold onto the unit. Steam distribution pipes and hoses must be insulated where personnel could touch the surfaces. All components that could be pressurized must be rated for the maximal foreseeable pressure. PPE that should be worn during use of steam washer units includes: Eyeware in accordance with American National Standards Institute Standard Z87 for use under a protective face shield Splash-protective outer garments to prevent liquid splashes from reaching the head, skin, and undergarments
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Thermal protective gloves Hearing protectors if noise reaches or exceeds 85 dbA per 8-hour time-weighted average (TWA) Stationary rack washers and autoclaves are commonly used in nonhuman-primate facilities to clean and disinfect mobile cage and housing systems. Burn hazards are controlled by maintaining protective guards, panels, or insulation on the equipment. Thermal protective gloves and arm covers should be used for any operation in which direct skin contact could occur. In addition to heat and steam, autoclaves present hazards associated with pressure. Personnel who operate or maintain autoclave equipment must be trained, certified, or otherwise specifically qualified for such work, because of the high temperature and pressure hazards. Lockout/ tagout work practices, which are focused on preventing electrical, chemical, and/or steam energy from harming employees, are required for many maintenance operations on this equipment. Kerosene-heated portable units can be used only outside and in well-ventilated areas and if not left unattended for extended periods of time. The products of combustion can include carbon monoxide and other toxic emissions that can create unhealthful air contamination. Noise Work in nonhuman-primate housing areas and such activities as cage washing can expose personnel to noise that can cause material and insidious hearing loss over time. Excessive noise may also occur with certain species of nonhuman primates through their vocalization or cage displays. It is recognized that noise-induced hearing loss will develop from workplace exposures when a person is exposed to 85 dbA or more during an 8-hour workday. Operations that seem loud and impair communication between personnel should be evaluated with sound-measurement instruments. Personnel who are exposed to more than 85 dbA per 8-hour TWA must be included in a hearing-conservation program that includes training, use of hearing protectors, and audiometric testing. Allergens Personnel working in nonhuman-primate settings must be alert to symptoms and signs of allergic reactions. Inhalation allergens may include airborne animal dander and bedding. Contact allergens causing dermatitis may include gloves and other protective clothing. In one study
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of laboratory-animal associated allergies, 23.6% of nonhuman-primate handlers reported allergic symptoms (Aoyama and others 1992). Acute asthma has been reported after exposure to nonhuman-primate dander (Petry and others 1985). Exposure to allergenic proteins in latex that is used for protective gloves and other equipment has been well documented (Levy and Leynadier 2001). It should be noted that masks that are suitable for protection against allergens are not the same as those to be worn for protection from splash exposures. Hazards Associated with Using Personal Protective Equipment Gloves, protective garments, and eyewear are of great value in forming a protective barrier against some types of hazards, but they can also create hazards themselves. Use of protective equipment in high temperatures must take into account the risk of serious heat-stress injuries and dysfunction. Personnel should be provided with appropriately scheduled break periods, allowing them to replenish their volume losses of water and minimize the effects of reduced cooling ability when PPE is being used under high ambient temperature conditions. Respiratory protective equipment must be selected on the basis of the specific airborne hazards present, and it must be medically determined that a person is fit to use it. Protective eyewear can become fogged by perspiration and exhaled breath. Such impairment of vision can create a hazard by decreasing visual acuity and decreasing the user’s ability to avoid animal bites and other hazards. Special attention must be given to providing personnel with high-quality protective eyewear that allows them to do their jobs and have appropriate eye protection. CHEMICAL HAZARDS Several chemical hazards can be encountered in work with nonhuman primates (Table 4-2), such as disinfectants and volatile anesthetics. It is critical to maintain an inventory of hazardous chemicals to use material safety data sheets, and to train workers in the hazards of and precautions for work with chemicals (NRC 1997; NSC 1997). The potential risks of exposure to hazardous chemicals used in experimental protocols should also be considered. For example, the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine) is commonly used in nonhuman-primate models of Parkinson’s disease.
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TABLE 4-2 Summary of Chemical Hazards Chemical Hazard and Operation Precautionary Measures Chemical disinfectants and cleaning solutions. Sodium hypochlorite, phenolic solutions, hydrogen peroxide, quartenary ammonium compounds, chlorine dioxide solutions, glutaraldehyde Prevent splash exposures to corrosive solutions by using face shields or safety goggles; avoid contact by use of impervious gloves, apron, sleeve covers, boots, other chemical-impervious equipment; where potentially injurious gaseous or aerosol air-contaminant exposures are possible, provide capture exhaust ventilation or respiratory protection Volatile anesthetics. Isofluorane, halothane, nitrous oxide, enflurane Use a scavenging anesthesia system to capture waste anesthetic gases; vacuum or mechanical venting of scavenging system is most effective; do not use electrocautery or other sparking equipment where oxygen and anesthetic gases are being released Disinfectants Disinfectant solutions are used extensively in nonhuman-primate settings and have been the cause of skin and eye irritation and corrosive burn injuries. Disinfectant cleaners that are in common use include: Bleach (sodium hypochlorite) pH-optimized bleach (pH 7.2) Chlorine dioxide solutions Quaternary ammonia mixtures Phenolic cleaners Hydrogen peroxide-peracetic acid cleaners Glutaraldehyde and formaldehyde fumigant All of these cleaners have the potential for causing corrosive injury to the eyes and skin as a result of direct liquid splashes. The choice of protective eyewear and chemical-protective footwear, gloves, and other clothing depends on how the disinfectant is being applied. Application of a disinfectant in accordance with the manufacturer’s label with a hand mop can generally be performed safely if the user wears protective eyewear, gloves, boots, and coveralls or an apron that provide a barrier to direct splashes. An industrial hygienist or safety professional should be consulted on safety precautions if fumigation or pressurized sprayer application of chlorine dioxide, pH-optimized bleach, hydrogen peroxide,
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or aldehyde disinfectants will be conducted. Respiratory protection is commonly specified for such operations. Volatile Anesthetics Volatile anesthetic agents are used in nonhuman-primate operations during surgical procedures performed for animal health care and research-protocol purposes, typically including: Halothane Nitrous oxide Enflurane Isoflurane Most of the volatile anesthetic agents are potentially toxic and have effects on the liver and nervous system and evidence of increased risk of adverse reproductive effects. NIOSH has issued guidelines for control of exposure to anesthetic agents in surgical operations (NIOSH 1977). Exposures can be reduced by scavenging vented fumes from rebreathing anesthetic units, using tight-fitting endotracheal tubes and induction masks, and filling vaporizer units carefully so that spillage does not occur. However, administration of these agents to animals can still result in release of anesthetic vapors into the area around the anesthetic equipment and around the animal’s mouth and nose, since waste anesthetic gas scavenging systems are generally imperfect.
Representative terms from entire chapter: