Biological hazards include potential exposures to allergens, infectious zoonotics (animal diseases transmissible to humans), and experimental agents such as viral vectors. Allergens, ubiquitous in animal care facilities, are one of the most important health hazards yet frequently overlooked. More on these later.

Finally there are the physical hazards associated with animal research facilities. The most obvious are slips and falls from working in wet locations and the ergonomic hazards of lifting, pushing, pulling, and repetitive tasks. Other physical hazards often unnoticed are electrical, mechanical, acoustic, or thermal in nature. Ignoring these can have potentially serious consequences.

A written program is the first step and describes how the Hazard Communication Standard (HCS) will be implemented in the facility. The other basic tenants of the Hazard Communication Program (HCP) include maintaining a chemical inventory and associated material safety data sheets (MSDS), ensuring proper labeling of all chemical containers and fully training employees prior to work assignments and whenever the hazard changes. MSDS must be immediately available and employees must know where and how to find them. They are vitally important in emergencies and should be carried to the emergency room with the patient in the event of an exposure. Inadequate or incorrect labeling is a source of many accidents and exposures and a common OSHA citation. Clearly label all chemical containers with the contents and appropriate hazard warnings.

Sterilents and preservatives are frequently used in animal research facilities. Ethylene oxide, formaldehyde, and chlorine dioxide are a few of the most common. OSHA has specific standards for ethylene oxide (29CFR1910.1047) and formaldehyde (29CFR1910.1048) that stipulate requirements for initial and periodic monitoring, protective equipment and clothing, training, and designating regulated areas among others. A qualified industrial hygienist should conduct hazard evaluations and exposure assessments if these chemicals are used. Monitoring can be done with a portable infrared spectrophotometer or sorbent tubes and pumps.

Where animal surgeries are performed, anesthetic gases pose another potential exposure concern. Examples are isoflurane, enflurane, and halothane. Halogenated anesthetic agents have been linked to reproductive effects in women and neurological effects in exposed workers. OSHA recommends conducting air sampling for anesthetic gases every six months to evaluate worker exposures and to check the effectiveness of control measures. Sampling that provides direct, immediate, and continuous (real-time) readout of anesthetic gas concentrations in ambient air utilizes a portable infrared spectrophotometer. Since this method provides continuous sampling and instantaneous feedback, sources of anesthetic gas leakage and effectiveness of control measures can be immediately determined.

Although OSHA has not established permissible exposure limits (PEL) for the anesthetic gases, other agencies and organizations have set recommended exposure limits. ACGIH set Threshold Limit Values (TLV) of 75 ppm for enflurane and 50 ppm for halothane as 8-hour time-weighted averages (TWA). NIOSH recommends 2 ppm as an upper limit or “ceiling” value for a period not to exceed one hour for all halogenated anesthetic gases. Prudence dictates minimizing exposures to anesthetic agents. Peak exposures occur during induction and also the post-operative recovery phase. Take care to avoid patient exhaled air at these critical times. Containment of vapors is paramount. Use of scavenging canisters or direct exhaust systems such as fume hoods are excellent ways to do this. Perform small animal surgeries using nose cups and in exhaust hoods whenever possible. (Photo 1)

Animal research often involves use of experimental drugs and materials. Here is a simple rule to keep in mind - “what goes in will come out.” Depending on the metabolism, the materials exhaled or excreted can be more, less, or equally as hazardous as the parent material. Often with experimental materials the toxicology is not known. Ensure animal care staff are well trained and involve the principle investigator to discuss hazards and answer questions. Metabolic cages can help control aerosolization and releases. Pay attention to the proper choice of personal protective equipment (PPE) especially when applying topicals such as promoters and inhibitors. Select bedding material to provide maximum absorption with minimal chance of release.

Other frequently encountered chemical hazards include improper storage (e.g. mixing incompatible materials in the same area; incorrect labeling of containers), use of unapproved containers for flammable storage (Photo 2), and blocked and untested safety showers and eyewash stations. Pay attention to chemical storage. Keep acids and bases isolated and keep corrosives and organic solvents in separate areas. Use only UL approved containers that have self-closing lids and flame arrestors for storing flammable liquids. Make sure safety showers and eyewash stations can be accessed immediately and that they are tested routinely.

Sources of exposure to animal allergens vary with animal species. The most important allergens are found in the urine of rats and in the urine, saliva, and pelts of guinea pigs. Rat urine contains significant amounts of a protein also found in dust samples from ventilation systems of animal facilities. Exposures to rats, mice, and rabbits are frequently associated with the development of occupational asthma. Exposures to birds are associated with other respiratory diseases, including hypersensitivity pneumonitis. A person who becomes allergic to one animal species may react to other species as well. Even a low exposure to these common sources of animal allergens can result in allergies and the risk increases as the worker’s exposure increases.

The best control method for potential exposures to animal allergens is with ventilation. Evaluate the total ventilation system. Ensure the ventilation for animal housing and handling areas are separated from the rest of the facility. The ventilation rate and humidity can be increased in the animal housing areas for better dilution. Install ventilated racks or filter-top animal cages and decrease animal density (number of animals per room volume) to further reduce potential allergens.

The following are some steps workers should take in order to protect themselves from animals and animal products. Perform animal manipulations within ventilated hoods or safety cabinets when possible. Avoid wearing street clothes while working with animals and leave work clothes at the workplace. Make sure cages and animal areas are kept clean. Use absorbent pads or corncob bedding instead of sawdust to minimize dust and particulates. Finally, reduce skin contact with animal products such as dander, serum, and urine by using gloves, lab coats, and approved particulate respirators with face shields.

Primate handling is one of the most difficult tasks for animal research facilities and proper equipment is paramount to safe handling. Use chutes and tunnels to separate animals and squeeze-back cages to restrain them when necessary. Train handlers to avoid fluids and secretions at all costs. Stress the use of proper PPE. Long-sleeved labwear, face shield or mask with goggles, and arm-length reinforced leather gloves should be considered the minimum protection.

Primate cages should receive particular attention. Only trained handlers should have access to cage areas. Cages should be designed with no sharp edges or corners that could cut and infect workers. Take care to avoid placing cages near entry or exit routes. Arrange cages to prevent potential grabbing or scratching, remember the “hazard zone.”

Monkey B virus is one of the most insidious diseases primate handlers must avoid. Training is key. Handlers must understand that viral shedding is intermittent and can occur in the absence of visible lesions. Most important is that “negative today does not mean negative tomorrow.” Handlers must recognize the early symptoms of B virus infection, which are a persistant skin sore or conjunctivitis of the eyes. Report any injury or symptoms of Monkey B virus immediately.

Many injuries stem from poor housekeeping. Slips, trips, and falls are very common yet easily avoided. Start with safe and organized storage areas. Material storage should not create hazards. Bags, containers, bundles, etc., stored in tiers should be stacked, blocked, interlocked, and limited in height so that they are stable and secure against sliding or collapse. Keep storage areas free from accumulation of materials that could cause tripping, fire, explosion, or pest harborage.

Material Handling

Animal research facilities necessitate lots of material handling. Feeding, watering, and cage cleaning are daily activities. Evaluate each of these tasks to eliminate poor ergonomics. Factors that affect the likelihood of injury are repetition, poor lifting angles, and awkward posture. Train workers to recognize these factors and to avoid changing elevation and twisting while lifting. Take time to observe workers occasionally and try to spot poor techniques or methods of material handling. Consider contracting with a qualified professional to perform an ergonomic survey if necessary. Use mechanical lifting and carrying devices such as pallet jacks and hand trucks whenever possible. Make sure floors are smooth and free of cracks or lips that could catch or trip. Inspect cage racks, hand trucks, and other equipment routinely to ensure good mechanical condition. Pay special notice to the castors.

Electrical Hazards

Electrical hazards are potentially life threatening yet are found much too frequently. First, equip all electrical power outlets in wet locations with ground fault circuit interrupters, or GFCI, to prevent accidental electrocutions. GFCIs are designed to “trip” and break the circuit when a small amount of current begins flowing to ground. Wet locations usually include outlets within six feet of a sink, faucet, or other water source, and outlets located outdoors or in areas that get washed down routinely. Specific GFCI outlets can be used individually or install GFCI in the electrical panel to protect entire circuits.

Another very common electrical hazard is improper use of flexible extension cords. Do not use these as a substitute for permanent wiring. The cord insulation should be in good condition and continue into the plug ends. Never repair cracks, breaks, cuts, or tears with tape (Photo 3). Either discard the extension cord or shorten by installing a new plug end. Take care not to run extension cords through doors or windows where they can become pinched or cut. And always be aware of potential tripping hazards when using them. Use only grounded equipment and tools, and never remove the grounding pin from the plug ends. Also, do not use extension cords in series, just get the right length cord for the job.

Use of hanging pendants or electrical outlets are widespread in animal care facilities to help keep cords off floors and out of the way. Check electrical pendants for proper strain relief and type of box used. The box should be totally closed and without any holes. If it contains knockouts or holes for mounting it is not the right type for a hanging pendant.

As a final check for possible electrical hazards, look over your lighting. Protect all lights within seven feet of the floor to guard against accidental breakage. Slip plastic protective tubes over florescent bulbs prior to mounting or install screens onto the fixtures.

Compressed Gas

Use of compressed gas cylinders present many unique hazards and could be a topic for another whole article. Here are a few quick pointers. Store cylinders safely. As with chemicals segregate them according to compatibility. In addition, secure cylinders from tipping or being knocked over. Generally, this means fastening them to stands or against a wall or cabinet. Remember to turn them off at the cylinder valve when not in use. Finally, remove the regulators and install protective valve caps before moving.

Sharps

Sharps containers are ubiquitous in animal research labs and following a few safety rules can help prevent getting stuck with accident reports. Use only puncture-proof and leak-proof containers that are clearly labeled. Train employees never to remove the covers or attempt to transfer the contents. Make sure they are only used for “sharps” and they get replaced when three-fourths full to prevent overfilling.

With all the specialized equipment such as incinerators, cage racks and tunnel washers there will come a time when something breaks and requires fixing. Furthermore, a good operation and maintenance plan will minimize equipment down-time. Therefore, lockout/tagout, known as LOTO, will be one of your most important programs (Photo 4).

During the period 1992-1996 accidents from being caught in machinery killed almost 750 workers and nearly another 5,000 lost limbs from amputation². Sadly, every one of these could have been easily prevented. LOTO is a process that will prevent these accidents when followed correctly.

First, employees are trained to recognize and isolate all the energy sources for the equipment to be worked on. The employee(s) doing the work then lockout or tagout the energy sources by placing locks on the appropriate switches, valves, circuit breakers, etc. Each lock is identified as to its owner and has only one key that stays in the possession of the lock owner. When work is complete owners collect their energy source locks and the equipment is brought back online only after all locks have been removed. If an energy source cannot be locked out then it should be braced, blocked, or blanked off to prevent release. Your LOTO program should also detail steps to follow if the task will span more than one work shift.