Labs across research and testing settings handle a broad range of hazardous biological materials as part of their daily work. Understanding which samples carry the greatest risk helps managers match workflows to the right biosafety and containment practices.
This article describes potential hazards associated with different types of laboratory samples and preventative measures that guard against personnel exposure, unintended release, and environmental contamination.
Types of biological samples and potential hazards
When individuals are working in the laboratory handling biological materials, two primary safety concerns are: the staff getting a laboratory-acquired infection (LAI) with microbe(s) present in those samples, and releasing microbe(s) in those samples to infect other individuals or contaminate the environment. Biological materials handled in laboratories can contain pathogens, features, or substances that are harmful to humans. These materials can include:
- human-derived materials (blood, tissues, cells, bodily fluids, etc.)
- recombinant or synthetic nucleic acids
- microbes or pathogens
- biological toxins
- live animals
- animal-derived materials (blood, tissues, cells, bodily fluids, etc.)
- soil or dirt
- water or wastewater
- insects or other vectors (bats)
- plants, plant pests, and plant pathogens
It’s important to consider both the known contents of a sample and any microbes that could reasonably be present. For instance, lab staff may have collected a patient specimen to test for the influenza virus. However, that patient could instead be infected with Mycobacterium tuberculosis. Similarly, depending on the region and timeframe the sample was collected, what would seem to be a benign soil or fecal sample could contain poliovirus.
Risk mitigation measures for handling biological materials
Once the type(s) of samples to be handled and their associated hazards have been identified, it is critical to conduct a risk assessment to prioritize the potential risks for each sample. This process should be used to evaluate the likelihood and consequences of exposure to or release of these materials, and to determine how the risks can be managed. This should include consideration of the types of manipulations needed when working with the materials (pipetting, centrifuging, vortexing, use of an automated liquid handler, flow cytometry, or cell sorting, etc.).
Most often, a layered approach to risk mitigation measures based on the National Institute for Occupational Safety and Health (NIOSH)’s hierarchy of controls is appropriate to minimize risks associated with handling biological materials. You may already be familiar with many of these measures for the laboratory environment, which are combined into defined biosafety levels in the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH)’s Biosafety in Microbiological and Biomedical Laboratories (BMBL).
Managers should align facility design, SOPs, and PPE selections with the BMBL level assigned for each workflow, not just each organism, and document that alignment during risk assessment and annual program reviews. Examples of risk mitigation measures that could be implemented based on your facility-specific risk assessment are described below.
Engineering controls
Engineering controls are designed to physically isolate individuals from potential hazards. When designing or renovating lab spaces, including directional airflow toward areas that may be more contaminated and not recirculating laboratory air into other areas of the building are best practices and may be requirements depending on the biosafety level of your lab. Management should ensure that cleanable, nonporous lab furnishings and equipment are purchased to facilitate easy decontamination. The containment of bioaerosols using high-efficiency particulate air (HEPA) filters and primary containment devices (biosafety cabinets, centrifuge safety cups and rotors, etc.) should be implemented wherever possible to avoid potential exposures, and management should schedule and document routine HEPA and BSC certification to verify ongoing performance.
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Administrative and work practice controls
Administrative or work practice controls are designed to change how people work and their duration, frequency, or dose of exposure to potential hazards. Management decisions regarding the development of biosafety policies, programs, and procedures; staff training; and the establishment of a positive safety culture can strongly impact biosafety outcomes. These programs are most effective when staff follow procedures designed for their specific safety needs, perform tasks as written/expected, and speak up without punishment when they have concerns about situations that impact their safety.
Personal protective equipment
PPE is the least effective risk mitigation control because it depends on individuals maintaining, putting on, wearing, using, and taking off PPE correctly every time. Leadership should monitor correct PPE use, address drift in practice in real time, emphasize the importance of reporting issues with PPE use, and model proper practices every time they enter the lab. Management should ensure sufficient sizes, makes, and models of necessary PPE is available so all lab staff have PPE that fits them and is as comfortable as possible to encourage appropriate PPE use.
Leadership’s role in preventing biosafety failures
Improper handling of biological materials can lead to LAIs among lab staff or to environmental contamination from these items. Lab managers play a central role in ensuring every new material type is assessed and that appropriate controls are put into place. Management should: 1) conduct thorough risk assessments for all lab materials and activities, 2) review the lab’s layout, ventilation, and furnishings for their appropriateness, 3) ensure equipment designed for biocontainment is used when handling biological materials, 4) create necessary biosafety policies, training, and documentation while fostering a positive safety culture, and 5) provide suitable PPE for the lab operations and enforce its use.
