4th National Symposium on Biosafety

Physical Hazards in Research Animal Facilities

William C. Cole, DVM
Associate Director, Laboratory Animal Resources
Merck & Co., Inc.
PO Box 4, WP44-201
West Point, PA 19486-0004
215-652-6708

Most of us take physical hazards for granted. Just about everywhere within the animal environment is some kind of physical hazard. But, as I thought about it, I realized we could be getting too complacent; that maybe we could reexamine some of the procedures, and through risk assessment and procedural changes, create a safer work environment for both the personnel and the animals.

My presentation today will discuss this subject by describing similar functions that are performed in an animal facility, particularly those of animal care. Later presentations will focus on technical manipulations.

The major functions that are performed in an animal facility are: material movement, literally tons of material are moved miles everyday; sanitation / sterilization, and the environment where this work is performed; and animal handling and manipulation, some institutions handle hundreds to thousands of animals daily. All of these functions have the potential to be a physical hazard.

I will also discuss other hazards, especially those to the animals. We should not lose sight of the fact that the animal's environment needs to be safe for them. If you will please read the vision again, you will see it's: Good Research through a Safe Environment for both Animals and Man.

The first function we will discuss is Material Movement. This will include caging, and other equipment that are large, bulky and heavy. We are talking about tons of supplies that must be moved daily and the hazards they can create. Hazards to the animals as well as personnel. We will also discuss some of the ways to reduce the potential risk for the hazard.

A typical animal room ready to receive animals will contain large animal cages. Those cages must move in and out of the room through narrow doorways, and also down narrow hallways. Generally speaking, the cages will just fit! Note the marks along the side of the door frame; obviously the cages did not clear the passage way a time or two.. This can create what we refer to as "a knuckle buster". Hand, finger and arm injuries are probably the most common injury experienced, mainly due to the movement of large equipment through narrow openings. To lower the risk of cage movement often requires two people. Also note the best place to place your hands on the rack. Use the part of the rack that is facing you, instead of placing your hands along the side where they are not protected. Designing facilities with this large equipment in mind is very important so that adequate space is available.

Doorways are also important for another reason. In most facilities, animal rooms are under negative pressure. It is difficult to maintain adequate closure for doors that open into the room. This next slide shows why it is not a good idea to have doors open out into the corridor. Collisions like this are a physical hazard.

This slide demonstrates a rodent rack rolling over a floor drain. Note the caster is off the ground, even though the floor slope is hardly noticeable. With the height of the rack, a slight slope in the floor is enough to cause the rack to tip, potentially on someone. When designing animal room floors, drains frequently should be located in the corners of the room rather than the center.

In addition to animal caging, there is movement of supplies and other equipment. This will often require the use of powered hand trucks and fork lifts. In the hands of an untrained person, these too can be a physical hazard. Therefore, proper training is essential. In addition, preventive maintenance to the equipment is very important.

Material movement can also create strains and pulls on individual's backs and legs. The proper design of equipment and facilities, and training of personnel can help reduce these injuries. Supplies usually are reduced to individual items, i.e. bags of feed. Most of the food and bedding is moved one bag at a time. The next two slides demonstrate the techniques for lifting items using the legs and back. Again, personnel training is the key to performing the function correctly. The responsibility for this training should be at all levels including the individual worker performing the function.

The second function to discuss is Sanitation / Sterilization. The next lide demonstrates a typical nonhuman primate room. The person in the room is providing either daily cleaning, or cage decontamination prior to moving the cages to cagewash. There are several things to notice in this slide: 1) The individual is about 6 foot tall so it is reasonably easy for him to clean the top lever; however, there are often shorter individuals working in our facilities. Working at these heights can be difficult; 2) Notice also that he is griping a nozzle connected to a water hose. The nozzle has a trigger on it so he is constantly gripping with his hand as he moves the nozzle back and forth. This can cause hand fatigue and can create repetitive motion injuries; 3) Notice also, the floor is very wet and slippery. Slips and falls are probably the second most common physical hazard encountered in an animal facility. Wearing proper personal protective equipment (PPE), in particular nonslip rubber boots, can reduce the risk of slips and falls.

The next slide demonstrates a typical dog room; notice the different types of floor surfaces related to the function served by the floor. This room is organized with a center service isle with pens along each wall. The isle functions to move supplies and personnel, while the floor under the pens is for washing and drainage. When designing these facilities, the isle floor can be more level and a nonslip surface, while the floor under the pens can be sloped more and have a slicker surface. This design will make cleaning easier while reducing the risk of slips and falls.

Notice the water hose station in the next slide. This station contains live steam. Without proper controls, a person working in this room is at risk for a severe burn. Even hot water at "house" temperature (140º F) can burn an individual. Because of the potential for severe burns, many facilities today are not including live steam in the design of the animal room. For older facilities that have steam in the animal rooms, constant checking, preventative maintenance of the equipment and caution are the key words!

Ultimately all cages will come to the cagewash area. This area has the potential for many physical hazards. The room contains many pieces of large equipment such as rack and tunnel washers and acid dip areas. All of these create heat, humidity, and very hot water, under high pressure.

The function of sanitation requires the use of large quantities of cleaning compounds: basic detergents and acid cleaners. This slide shows a 30 gallon drum of detergent to remind us that we may be working with soap and water, but with the volumes and concentrations of these chemicals, they can cause a serve chemical burn if handled improperly. I would also point out the "Flammable" sign. These products will ignite if in large bulk quantities and consequently require labeling by the Department of Transportation. Material Safety Data Sheets are required on all these chemicals. Individuals must be familiar with them and the standard operating procedures for their use, and must be trained to work with the materials. In addition, all individuals must understand safety precautions and emergency procedures in case of an accident.

This next slide demonstrates the environment in the cagewash area; heat and humidity. With older facilities and equipment, there was not much that could be done to prevent this. It was considered to expensive and energy inefficient to air condition this area; so the rooms were "sweat tanks". Now, with more efficient HVAC systems and cagewashers, and improved facility design, most of the hot air and water can be contained. This will reduce the heat and humidity and the water on the floor. So, the rackwasher in this slide would normally have the steam vented through the cagewasher and not out the door. The heat from the cage and any remaining steam will be drawn into the HVAC system through this large hood over the cagewasher door.

Working in the cagewash area can also put a strain on an individual's back. Washing thousands of cages requires frequent stoping, bending and lifting. This slide demonstrates cleaning rodent boxes. Notice the worker must bend over, pick up boxes, put them on the machine, and repeat the steps hundreds of times. When the cages get to the other end, he must do it all again, this time filling the cages with bedding. Often times we accept this as the only way to perform this function. However, with some thought and effort, this work environment can be improved. This slide shows a Lift Table, an inexpensive item that will allow the working height to be adjustable. It may take longer to perform the work, but it will be much easier on the person's back.

The next slide demonstrates another repetitive motion function performed in the cagewash room. This individual is placing stoppers and sipper tubes on water bottles. Not particularly challenging if doing only one or two racks. However, if there are hundreds to be done daily, there is risk of injury. The Allied Trades companies are designing a device that performs this function with just a pull of a handle. Much easier then a twist and a turn, a thousand times a day.

This slide demonstrates an autoclave being loaded, ready for use. In this case, it is clean cages and bedding that are being prepared for pathogen free rodents. It could also be to decontaminate infectious material. The autoclave is potentially on of the most dangerous pieces of equipment in the animal facility. Autoclaves can literally explode like a bomb if they are not functioning properly. It's also one of the most necessary. Preventative maintenance is essential. The maintenance staff must make sure the equipment is working properly, which often means weekly visits. Equally important is training. The individuals operating the equipment must understand it's operation to be able to react quickly and safely if something should happen.

The next function to discuss is Animal Handling and Manipulation. This slide demonstrates the potential for bites and scratches. Animal bites and scratches will often strain the relationship between animal care personnel and Safety personnel. Every bite injury must be reported and usually gets returned with a note requesting evaluation of the handling procedures to reduce the incidence. I will usually respond by saying, "but we have 25 thousand animals and we handle most of them daily, sometimes twice a day, so one or two bites a week isn't bad"! However, it does make sense to evaluate periodically your animal handling procedures to look for ways to reduce the risk from bites and scratches. Animal care personnel as well as Safety should be an integral part of this evaluation.

This next series of slides show examples of how handling procedures can be modified to be safer and better for both the animal and the individual worker. Many institutions did, and still do, catch nonhuman primates by hand. It often seems to be the easiest and fastest way, but often times the animals would escape as this picture shows. In this picture, notice the door to the cage is open in the "up" position. This can be a problem as the door can drop down on either the animal handler's arm, or on the monkey's limb. Note also that the animal is under the net. Someone still must remove the animal; and with the twisting and turning it can be very easy to injure the monkey. Safer ways to handle these animals should be considered. This next slide is such an example. To move monkeys from cage to cage, use a tunnel that allows them to jump. This requires no handling or anesthesia. Much better for all. If the animal does require restraint, the monkey can be trained to the pole and collar technique, as depicted in this slide. This method is safe and, through positive reinforcement, is much better for the animal. The animal likes it because they usually get a treat and it is provides them interest and activity. Certainly alternate methods are available if one will take the time and effort to look for them.

There are other hazards to consider with animal manipulation. Bottled gas cylinders create a potential risk if they are handled or stored impropely. Other hazards such as noise, eye injury, inhalation, UV light and radiation must be considered. This slide shows personnel wearing PPE for hearing protection; however, when the dogs start barking, it's noisy for the animals as well. Features can be designed into the animal room to provide sound attenuation that are effective and sanitizable. All facilities should have eyewash stations, showers and sinks.

Animal allergies: Dr. Bascom discussed this subject in some detail. It appears that rodents and rabbits are most commonly involved; and that up to 50% of the work force may become allergic. This is a significant problem that is becoming more apparent. There are some procedures that can be used to reduce the risk of contracting allergies: work within a HEPA-filtered hood, use of specialized bedding dumping stations that pull the dust and debris away from the person, and wearing appropriate PPE. It is important to remember that the PPE used must be comfortable or it will not be used! The animal care staff should be involved early when developing special safety requirements. The personnel will be more responsive to the change, they will be more active in promoting training and they will help develop new ideas.

Office of Health and Safety, Centers for Disease Control and Prevention, 1600 Clifton Road N.E., Mail Stop F05 Atlanta, Georgia 30333, USA Last Modified: 1/2/97
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Physical Hazards in Research Animal Facilities