Appendix A – Primary Containment for Biohazards: Selection, Installation, and Use of Biological Safety Cabinets. (pages 367-397)

Appendix A has been revised to include changes reflected in the NSF/ANSI 49-2018 as well as to provide additional guidance for improved selection, installation and use of biological safety cabinets (BSCs). Changes have been made to all Parts (previously referred to as Sections) and key updates are briefly summarized as follows:

Part 1. Introduction: The BMBL-6 includes prions among the hazardous material which may be safely manipulated in a biosafety cabinet.

Part 2. High Efficiency Particulate Air (HEPA) Filters and the Development of Biological Containment Devices: ULPA filters are introduced and their efficiency level is compared with HEPA filters. Different media types such as polytetrafluoroethylene (PTFE) used for the construction of HEPA and ULPA filters are included.

Part 3. Biological Safety Cabinets: The use of a canopy connection and an exhaust alarm is included for Class I BSCs when hazardous gases and vapors are used. Class II/Type C1 cabinets are introduced as well as the use of canopy connection (removed hard ducted) as the proper method of connecting Types A1, A2 or C1 to the building exhaust system. Class II/Type B1 cabinets are to be directly connected, preferably to a dedicated independent exhaust system. A pressure independent monitor alarm (not usually installed by the manufacturer) to signal supply fan failure should also be installed and it is connected to emergency power. The mechanical design and air balance testing of laboratory exhaust systems for Class IIB BSCs must use the Concurrent Balance Values (CBV) as indicated in the NSF/ANSI 49. A description of the CBV testing is included. A risk assessment is recommended prior to using a Class II/B2 cabinet because of the associated costs of operation. The use of a dedicated exhaust system for Class III cabinets is recommended.

The preparation of nucleic acids for PCR was added to the potential uses of a Vertical Flow Clean Bench.

Part 4. Other Laboratory Hazards and Risk Assessments

References are made to OSHA’s Permissible Exposure Limits for assessing the risks associated with hazardous chemicals and to the Public Health Agency of Canada for data on microorganisms associated with LAIs. Chemical fume hoods are recommended for work involving volatile chemicals and where biohazard containment is not required. The BMBL-6 added Class II/C1 BSCs for working with many liquid chemicals, non-volatile antineoplastic agents, etc., however these must be properly canopy vented (hard ducting of these has been removed). The bag-in/bag-out method for removal of chemically contaminated filters is included in order to minimize the risk of exposure.

Part 5. BSC use by the Investigator: Work Practices and Procedures

The application of ergonomics principles are introduced in the BMBL-6 for proper back and feet support as well as the use of elevated ergonomic arm/elbow rests on the grilles of BSC to minimize airflow disruption. BSCs equipped with specialized equipment, which have been installed by the manufacturer, must be field tested in accordance with the manufacturer’s testing methodology to ensure containment in accordance with NSF/ANSI 49-2018. When new or different equipment is placed inside the cabinet, smoke testing is required to ensure containment as per NSF/ANSI 49-2018. The manufacturer should provide the user with the certification testing methodology.

A risk assessment is recommended prior to allowing two people to work in a BSC at the same time. Where night setback modes are used, BSCs are interlocked with laboratory supply and exhaust systems to maintain negative air balance. The use of touch plate micro burners with pilot lights are to be used in BSC only with prior management approval and after a thorough risk assessment has been completed.

Disinfectants used for surface decontamination of BSCs must be suitable to laboratory needs. Clarification is provided on the use of disinfectants in liquid waste containers, to ensure that the disinfectant is at a final concentration which is effective against the microorganisms in use, when the container is filled to the designated capacity. Procedures for spill clean-up (inside the BSC) have been revised.

Part 6. Facility and Engineering Requirements

When building exhaust is used to vent Class II/B cabinets in a BSL 4 facility, the system must be designed using the CBV and must have sufficient capacity to maintain exhaust flow. The use of ultraviolet (UV) light should not be the only method of disinfection for BSCs. This section includes recommendations on what to do when UV light is used. An additional requirement for decontamination of bag-in/bag-out filters is included.

Part 7. Certification of BSCs

• The Federal Standard 209 has been replaced with ISO 1464-2015.
• Reference to NSF/ANSI 49 has been removed and replaced with NSF/ANSI 49-2018.
• Details of field testing have been removed and referenced in NSF/ANSI 49-2018 Annex F.
• Tables 1 and 2 (Selection of BSCs; Comparison of BSCs) have been revised.
• Tables 3 and 4 (Field performance testing; Applicable containment tests) ) have been removed.

Appendix B – Decontamination and Disinfection of Laboratory Surfaces and Items (pages 400-410)

Appendix B highlights the need for the appropriate selection of disinfectants and potential risk of exposure to undiluted solutions. This Appendix now includes the Antimicrobial Products—U.S. Regulations section to describe the multiple sources of oversight.

The BMBL-6 includes additional sources of environmental contamination, for example, generation of aerosols through specific procedures or splashes. In addition, hand hygiene and proper use of PPE are included as factors in preventing transmission.

The term “Cleaning” is added to the BMBL-6 under this section as a pre-requisite to disinfection or sterilization.

Contact (exposure) time has been added as the fifth factor affecting Disinfection.

The BMBL-6 has deleted the text that provided the background of Spaulding Classification. Similarly, the explanations of ‘critical’, ‘semi-critical’, and ‘non-critical’ classification of chemical germicides used on medical devices have been removed. The detailed descriptions of ‘High-level Disinfection’, ‘Intermediate-level Disinfection’ and ‘Low-level Disinfection’ have been removed here as well. These terms are briefly mentioned at the beginning of the Appendix B in reference to the applicable FDA regulation, Definitions of these terms/designations are in the Glossary.

The Decontamination section has consolidated decontamination in the Microbiology laboratory and Decontamination and Cleaning sections. Figure 1. Descending Order of Relative Resistance to Disinfectant Chemicals includes Prions as the highest order of resistance, it also includes enveloped and non-enveloped viruses instead of lipid and non-lipid viruses.

Table 1 was renamed Activity Levels of Selected Liquid Chemical Disinfectants and the concentrations and activity levels have been updated.

The BMBL-6 includes specific sections on inactivation of Select Agents with reference to the Select Agent guidance on inactivation and biosafety.

Lastly, Appendix B has a section dedicated to Hand Hygiene as part of risk mitigation, it also includes the use of alcohol-based hand sanitizers.