Many pharmaceutical, biotech, and academic organizations maintain animal testing facilities. These facilities are used to obtain basic pharmacological and toxicological assessments of new APIs as well as test biomolecular pathways. Even though the predictive power of animal models for human disease has been questioned (such as the opinion piece here) and world-wide efforts to minimize animal testing has resulted in active implementation of the “3 R’s” in experimental design, animal testing remains a frequently utilized component of active research campaigns.
From an occupational hazard perspective, animal facilities present unique challenges to employee safety. One of the most difficult to control is employee exposures to LAA. Essentially, LAA are large molecular weight respiratory sensitizers to which repeated exposure can produce a sensitivity. This occurs in two phases: the first phase is called initiation and occurs when the employee is exposed to rather high levels of LAA. At some point, the immune system becomes primed and the employee becomes sensitized. The second phase is called elicitation and occurs when the sensitized individual experiences subsequent exposures. The result is an IgE-mediated immune response and the external manifestation can range from sneezing and watery eyes up to occupational asthma.
Unfortunately, there is no consensus on what is considered to be a safe threshold for LAA exposure to prevent sensitization. No authoritative body has crafted guidelines for airborne exposures. With little guidance to fall back on, many organizations have adopted a risk-based strategy to protect employees. Within the pharmaceutical sector, it is not uncommon for sites to utilize a blanket threshold of 5 ng/m3 as an eight-hour time weighted average. This number has also been applied in a few academic settings, although sometimes it is implemented as a 30-minute TWA rather than a full-shift TWA. Such a low threshold is notable because it is not necessarily health-based, but as low as reasonably achievable (ALARA).
For effective risk treatment, the onus then falls on the organization to ensure the engineering controls, building design, ventilation, and administrative controls that are in place are effective and work in tandem to keep employee exposures to LAA below the 5 ng/m3 limit. Most modern animal facilities dutifully implement such measures – including individually ventilated cages, ventilated cage change stations, HEPA filtered air into rooms with substantial air change rates, routine cleaning and disinfecting of rooms with non-porous surfaces, worker rotations, and multitude of training. However, a significant number of these organizations do not perform air monitoring to ensure their controls are effective.
Air sampling for LAA is a vital component to any LAA control program. All risk treatment options are only effective if used and implemented appropriately. Sampling for airborne animal allergens such as mouse urinary protein (MUP) and rat urinary protein (MUP) provides substantial value to any allergen control program. According to the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC), the non-profit organization that provides accreditation to animal facilities, the implementation and evaluation of an occupational safety program is of prime importance. Evaluation of risk assessments and the implemented controls can easily take center stage. Having a robust air monitoring program to complement and validate the installed risk treatment strategies will facilitate the inspection and audit process.
In conjunction with air monitoring, an effective occupational health program is also needed. Complementing the process, the occupational health aspect ensures that employees have not inadvertently developed sensitivities or other potential maladies while working within the facility (after all, animal allergens are not the only hazards to which employees can be exposed). An occupational health program should be proactive and utilize data acquired from air monitoring to identify at-risk SEGs. When executed properly, the end result is a robust process that includes safety, occupational health, employees, and management working towards the ultimate goal of safely and humanely working with research animals.
Be sure to always include an air monitoring component to your LAA control program. Doing so is an easy way to ensure your employees are protected and your risk treatment strategies are effective.
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