Last Revised: July 25, 2023

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Aerosol producing procedures involving biological hazards or recombinant materials

There are instances on campus where biological hazards and/or recombinant materials are sonicated or homogenized in enclosed spaces, such as cold rooms or lab benches, without appropriate containment. Bacteria handled at BSL1 also present a hazard to due potential exposure to bacterial endotoxins. Using an open sonicator or homogenizer in a cold room, other enclosed space, or open lab does not ensure containment due to the potential for significant aerosol generation during use. It is also contrary to the requirement in the NIH Guidelines that “All procedures are performed carefully to minimize the creation of aerosols,” regardless of biosafety containment level (BSL-1 or BSL-2) for containment of recombinant materials (e.g., transformed bacterial cell lines). Given the nature of cold rooms, this issue is compounded by recirculating air and lack of exhaust which will inadvertently expose the operator or others that use the space over time. Sonication or homogenization of biological hazards and recombinant materials must be moved to a Biosafety Cabinet, similar containment device, or by utilization of an appropriate local exhaust system. Use ice to maintain temperature needs. Please reach out to the Biosafety team at if you have questions or would like to discuss.