Occupational Safety and Health Administration OSHA

This section provides guidance for clinical and research laboratory workers and employers. This guidance supplements the general interim guidance for workers and employers of workers at increased risk of occupational exposure to SARS-CoV-2.

Employers should remain alert of changing outbreak conditions, including as they relate to community spread of the virus and testing availability, and implement infection prevention measures accordingly. As states or regions satisfy the gating criteria to progress through the phases of the guidelines for Opening up America Again, employers will likely be able to adapt this guidance to better suit evolving risk levels and necessary control measures in their workplaces.

Employers should assess the hazards to which their workers may be exposed; evaluate the risk of exposure; and select, implement, and ensure workers use controls to prevent exposure. The table below provides examples of laboratory work tasks associated with the exposure risk levels in OSHA's occupational exposure risk pyramid, which may serve as a guide to employers in this sector.

Examples of laboratory work tasks associated with exposure risk levels

Lower (caution)
Medium
High
Very High
  • Performing administrative duties in non-public areas of work sites, away from other staff members.
  • Working in other areas of the laboratory, physically separate from areas where SARS-CoV-2 samples are handled, away from other staff members.

Note: For activities in the lower (caution) risk category, OSHA's Interim Guidance for Workers and Employers of Workers at Lower Risk of Exposure may be most appropriate.

  • Working in other areas of the laboratory, physically separate from areas where SARS-CoV-2 samples are handled, in close proximity to other staff members.

  • Category not applicable for most anticipated work tasks.

Note: Laboratory tasks involving potential, direct exposure to SARS-CoV-2 are generally considered very high risk.

  • Collecting or handling specimens from known or suspected COVID-19 patients.
  • Performing aerosol-generating procedures (e.g., pipetting, vortexing tubes) on samples that may or do contain SARS-CoV-2.

Until more is known about how COVID-19 spreads, the CDC and OSHA recommend using a combination of standard precautions, contact precautions, airborne precautions, and eye protection (e.g., goggles or face shields) to protect laboratory workers with exposure to the virus.

Clinical laboratory employers and workers who handle specimens associated with COVID-19 should follow both CDC's interim laboratory biosafety guidelines and OSHA's recommendations in this section.

Laboratory workers who handle clinical specimens from patients with suspected or confirmed COVID-19 or samples of SARS-CoV-2 as part of research and development work must be protected from exposure.

Follow recognized good biosafety practices to prevent or minimize the transmission of infectious agents (i.e., SARS-CoV-2). Laboratories should already be using standard precautions as specified in the general guidance and should be following standard laboratory practices. These practices should continue when working with SARS-CoV-2 samples/specimens. This includes clinical and microbiological laboratories performing routine diagnostic, analytical, or other research-related tests on serum, blood, sputum (respiratory), and other specimens.

Employers of laboratory workers are responsible for following applicable OSHA requirements, including OSHA's Bloodborne Pathogens (29 CFR 1910.1030), Personal Protective Equipment (29 CFR 1910.132), Respiratory Protection (29 CFR 1910.134), and Occupational Exposure to Hazardous Chemicals in Laboratories (29 CFR 1910.1450) standards.

Laboratory employers should routinely review standard laboratory practices and safety and health procedures with lab workers; train and test the competency of workers in appropriate implementation of these procedures and practices; and ensure consistent adherence to them.

Laboratory personnel working with samples suspected or confirmed to contain SARS-CoV-2 should immediately report to their supervisor any incidents or accidents involving potential or actual exposure to SARS-CoV-2, as well as the development of symptoms consistent with COVID-19.

Employers should implement appropriate protocols for handling, storing, and shipping specimens and ensure adherence by all laboratory workers. Packaging, shipping, and transport of specimens suspected or known to be contaminated with SARS-CoV-2 may be regulated by:

Laboratories should ensure that their facilities and precautions meet the appropriate Biosafety Level (BSL) for the type of work conducted (including the specific biological agents – in this case, SARS-CoV-2) in the lab. The CDC's Biosafety in Microbiological and Biomedical Laboratories (BMBL), 5th Edition provides detailed guidance on BSLs in Section IV - Laboratory Biosafety Level Criteria. Increasing BSL levels involves more worker training, higher levels of containment of samples and other sources of pathogens, specially-designed air handling systems, additional worker PPE, and other stricter controls. For example, at BSL-2, access to laboratories and other controlled work areas is limited when work is occurring and certain procedures are conducted in biosafety cabinets or other containment equipment. At BSL-3, in addition to controlling access to laboratories and work areas, all work involving infectious materials is conducted in biosafety cabinets or other containment equipment.

Virus isolation in cell culture and initial characterization of viral agents recovered in cultures of SARS-CoV-2 specimens (i.e., specimens from COVID-19 patients) are not recommended at this time, except at a BSL-3 facility.

Consistent with the BMBL guidance, the following procedures may be conducted at BSL-2:

  • Pathologic examination and processing of formalin-fixed or otherwise inactivated tissues
  • Molecular analysis of extracted nucleic acid preparations
  • Electron microscopic studies with glutaraldehyde-fixed grids
  • Routine examination of bacterial and fungal cultures
  • Routine staining and microscopic analysis of fixed smears
  • Final packaging of specimens for transport to diagnostic laboratories for additional testing (specimens should already be in a sealed, decontaminated primary container)

Perform activities involving manipulation of untreated specimens in BSL-2 facilities using a Class II BSC. A site-specific risk assessment should be performed to determine if enhanced biosafety precautions, such as those consistent with BSL-3, are warranted based on situational needs (e.g., high testing volumes), including when:

  • Aliquoting and/or diluting specimens
  • Inoculating bacterial or mycological culture media
  • Performing diagnostic tests that do not involve propagation of viral agents in vitro or in vivo
  • Nucleic acid extraction procedures involving potentially infected specimens
  • Preparation and chemical- or heat-fixing of smears for microscopic analysis
Engineering Controls

To maximize worker protection, perform as much work as possible in a properly maintained and certified biosafety cabinet (BSC). Class I BSCs use negative pressure and high-efficiency particulate arrestance (HEPA) filters to contain agents and protect workers and the environment. Class II and III BSCs provide higher levels of containment and filtration that also protect samples or other products in the BSC from contamination.

Ensure that all procedures involving manipulation of untreated specimens or that have the potential to generate aerosols (e.g., vortexing or sonication of specimens in an open tube, etc.) are conducted in a BSC while following BSL-3 practices. Use appropriate physical containment devices (such as sealed centrifuge rotors or safety carriers with gaskets) for centrifugation.

The OSHA Fact Sheet, Laboratory Safety Biosafety Cabinets (BSC), provides guidance on training and effective use of BSCs.

Is OSHA infection prevention guidance for laboratories the same as CDC recommendations?

  • With regard to laboratory worker infection prevention, CDC guidance may appear to differ from OSHA guidance.
  • CDC information reflects infection control recommendations that are based in part on PPE supply chain considerations.
  • OSHA's recommend infection prevention methods, including for PPE ensembles, help employers to remain in compliance with the agency's standards for respiratory protection (29 CFR 1910.134) and other PPE (29 CFR 1910 Subpart I).
  • OSHA is addressing supply chain considerations, including respirator shortages, through enforcement flexibilities, as discussed in the Enforcement Memoranda section of the Standards page.
Administrative Controls

Train all laboratory personnel on any additional procedures developed by the employer for safely handling specimens from patients with suspected or confirmed COVID-19. This includes training on the communication procedures in effect between the clinical and laboratory staff to ensure timely notification and proper labeling of suspected or confirmed SARS-CoV-2 contaminated specimens. Training must be offered during scheduled work times and at no cost to the employee.

Workers with high-risk underlying health conditions, such as heart or lung disease or diabetes, should be relocated to lower-risk environments and/or rescheduled for work that will limit their possible exposure.

Safe Work Practices

Use work practices that maximize the protectiveness of engineering controls, including BSCs. For example, if a BSC does not operate continuously, turn it on and allow it to operate for several minutes before use to allow airflow to stabilize. Similarly, wait a few moments before beginning work after inserting arms into a BSC to allow the protective air curtain around the arms to stabilize.

Use technical procedures that minimize the formation of aerosols and droplets. As a corollary, avoid procedures that generate aerosols and droplets (e.g., pipetting, vortexing tubes) and perform any necessary aerosol-generating procedures in containment (e.g., inside a BSC) and/or while using appropriate precautions, including worker PPE.

Use caution when handling needles or other sharps, and dispose of contaminated sharps in puncture-proof, labeled, closable sharps containers.

See general guidance for recommendations on the disinfection of environmental surfaces and noncritical patient-care equipment potentially contaminated with SARS-CoV-2.

Use an autoclave to inactivate infectious material in all waste before disposal. Adhere to applicable federal, state, and local regulations when disposing of laboratory waste.

Workers should avoid touching their faces, including their eyes, noses, and mouths, particularly until after they have thoroughly washed their hands upon completing work and/or removing PPE.

Personal Protective Equipment

All laboratory workers working with SARS-CoV-2 must wear appropriate PPE (29 CFR 1910 Subpart I). The BSL provides guidance for selecting appropriate PPE for the tasks that are conducted. This may include disposable nonsterile gloves, laboratory coat/gown, and eye protection when handling specimens at BSL-2 or above. The lab coat or solid-front gown should have a knit or grip cuff. Use double gloves that extend over the sleeve of the lab coat or gown.

At BSL-3, including when conducting procedures that may generate aerosols, use a NIOSH-certified N95 (or higher) respirator as part of a comprehensive respiratory protection program that meets the requirements of OSHA's Respiratory Protection standard (29 CFR 1910.134) and includes medical exams, fit testing, and training.

When using a BSC, remove the outer pair of gloves before exiting the BSC, and don a new pair when reentering the BSC.

Further Information

Biosafety in Microbiological and Biomedical Laboratories (BMBL), 5th Edition provides guidance on protecting workers in laboratory environments. The following sections may be particularly relevant:

The WHO resource, Laboratory Biosafety Manual - Third Edition, contains additional practical guidance on biosafety techniques for use in laboratories at all levels.

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