New & Improved!

Safe Use of Biological Safety Cabinets
September 2017 - Vol. 6 No. 7 - Page #4

Q&A with Daniel J. Scungio, MT(ASCP)SLS, CQA(ASQ)
Laboratory Safety Officer
Sentara Healthcare

MedicalLab Management: What protections do engineering controls such as biological safety cabinets (BSCs) offer clinical laboratorians and pathologists?

Daniel Scungio: BSCs represent an important engineering control in the clinical laboratory that often serves to protect users from airborne pathogens (most commonly, tuberculosis). These devices also protect users from bloodborne pathogens or chemical exposure/splash via built-in structural protections offered by the sash mechanism. Essentially, BSCs are valuable hardware tools intended to protect both users and the specimens and substances under manipulation by the user.

MLM: What departments in the clinical laboratory are most likely to utilize BSCs and other similar engineering controls?

Scungio: BSCs are most commonly found in microbiology laboratories, and many general labs utilize them for setting up cultures that will then be transferred to a microbiology lab for analysis. BSCs also are commonly used for cytology specimen preparation, since many body fluid specimens may be infectious. Other esoteric labs use them as well. BSCs can be used for amplicon (amplified DNA products) containment in the molecular laboratory, and in cytogenetics laboratories, BSCs are utilized in culture harvesting processes associated with the production of chromosome preparations.

MLM: What are the most common user-safety issues facing laboratorians that engage materials using BSCs?

Scungio: The placement and orientation of BSCs within the lab should be thoughtfully considered. For example, never place BSCs in high-traffic areas where staff movement will interfere with the airflow generated within the unit. Further, fans should never be placed near a BSC.

Depending on the classification and design purpose of the BSC, it likely does function as a chemical fume hood, so users need to exercise care and awareness of which chemicals and substances may be safely used inside.

Also, items need to be placed inside a BSC such that airflow is not impeded. Back vents should not be blocked and the front grille should be clear as well. Items should be placed at least four inches behind the front grille and work should be performed in this area as well.

MLM: What do lab directors and microbiology supervisors need to do to properly maintain the working conditions of their BSCs?

Scungio: First and foremost is proper training for all staff in the proper use of BSCs based both on manufacturer guidelines and good laboratory practices. This includes focused and deliberate loading of necessary supplies and ensuring the airflow within the BSC has reached equilibrium and any particulates have been purged before beginning work.

Regarding ongoing use, be sure to never use ultraviolet lights inside a BSC as a means of bacterial decontamination. UV lights are effective against DNA decontamination only (as used in a molecular lab). UV lights show poor effectiveness against bacteria because of shadows, dust, and decreased light intensity over time.

MLM: What regulatory bodies govern the proper use of BSCs in the clinical lab?

Scungio: The primary sources for information, regulations, and guidelines on the use and maintenance of BSCs in the clinical lab include the US Occupational Safety and Health Administration’s bloodborne pathogens standard 29 CFR 1910.1030 and the Centers for Disease Control and Prevention’s Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition (see SIDEBAR).1,2

MLM: Which laboratory staff members should be responsible for the cleaning and maintenance of BSCs, and how should these tasks be scheduled?

Scungio: All BSC users should be trained to properly maintain the equipment on a daily basis. Cabinets should be cleaned and disinfected using a standard bleach solution, then wiped down with water to prevent corrosion of metal surfaces. This should be performed at the end of each working shift and in the event of a chemical spill. Use tools (such as a long-handled wiper) to clean the inside back wall of the BSC as well.

MLM: Where should BSCs be placed in the laboratory?

Scungio: BSCs should be placed in low-traffic areas away from ceiling and wall vents, fans, or strong airflow currents in the lab. Likewise, do not place multiple BSCs in close proximity of each other in order to prevent interfering air pull from the equipment. Connections (if any) between a BSC and a ventilation system vary depending on the class and type of BSC, as well as its application. The best resource for specific details on BSC use in laboratories is Appendix A of the CDCs BMBL5.2

MLM: What is the protocol for responding to BSC alarms?

Scungio: It is important to respond to BSC alarms immediately. If there is an airflow blockage, all work should cease immediately. However, this is not the norm; BSC filters will become saturated with particulates over time, but many systems alert users in advance when a filter change should be performed, thereby avoiding blockage. Many BSC models are equipped with a magnehelic gauge that provides an approximate indication of the volume of particulate matter the HEPA filter has accumulated to date. However, there is no specified reading at which a filter change is indicated, so users must watch the gauge readings closely over time in order to know when a change must occur. A certified professional should perform all BSC filtration system changes and certifications. Onsite biomedical engineers are typically not trained to work on this equipment.

MLM: Any final thoughts on BSC certification?

Scungio: Annual certification of BSCs is required, as is recertification whenever a BSC unit is moved. Daily maintenance should include disinfection and a reading of the magnehelic gauge or other electronic filter reading, if included, but only certified professionals should perform maintenance; it is not typical that hospital personnel (such as biomedical engineers) are trained to safely perform maintenance or certification. A professional certifier will conduct air velocity readings, test the unit laminar airflow, and perform inspections of all electronics, test for vibrations, and check lighting. Certification agencies should provide a copy of their report to laboratory, and most agencies will label the unit with a sticker indicating the due date for the next inspection and certification cycle.

References

  1. US Department of Labor. Occupational Safety and Health Administration. Occupational Safety and Health Standards. Toxic and Hazardous Substances; Bloodborne pathogens. 29 CFR 1910.1030. Accessed 8/23/17.https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=10051&p_table=standards
  2. Centers for Disease Control and Prevention; The National Institutes of Health. Biosafety in microbiological and biomedical laboratories. 5th Edition. Accessed 8/23/17. https://www.cdc.gov/biosafety/publications/bmbl5/bmbl.pdf

Daniel J. Scungio, MT(ASCP)SLS, CQA(ASQ), has over 25 years of experience as a certified medical technologist. He worked as a laboratory generalist in hospitals ranging from 75 to 800 beds before becoming a laboratory manager, a position in which he served for 10 years. Dan is now the laboratory safety officer for Sentara Healthcare, a system of more than seven hospitals and over 20 laboratories and draw sites in the Tidewater area of Virginia. As “Dan the Lab Safety Man,” he also serves as a professional speaker, trainer, and lab safety consultant. Dan received his BS in medical technology from the State University of New York at Buffalo.

 

1910.1030(e)(2)(ii)(E)

1910.1030(e)(2)(iii)(A)

1910.1030(e)(2)(iii)(B)


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