Banding Together

the Synergist

Banding Together

Making the Case for Occupational Exposure Bands

BY T.J. LENTZ AND MELISSA EDMONDSON

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Authors’ note: AIHA President John Mulhausen’s column, “Occupational Exposure Banding: No More Excuses,” in the February issue of The Synergist explored concepts and concerns for occupational exposure banding as they pertain to AIHA members. This article endeavors to clarify the intention and utility of occupational exposure banding processes, provide additional information and resources, and describe efforts to advance understanding and use of banding strategies.

Occupational hygienists and safety and health practitioners have a solid history involving the use of occupational exposure limits (OELs). The role of OELs in characterizing workplace exposures to potentially hazardous chemicals has been significant, and they also help to ensure appropriate protections are in place and functioning. In addition, OELs provide the means for hazard assessment and risk communication. Yet setting appropriate OELs is resource intensive, requiring dose-response data, exposure data, and technical expertise to accurately characterize hazards for risk management purposes. And in a world of work where the number of chemical substances in use vastly exceeds the number of chemicals with OELs, the search for additional strategies for chemical risk assessment and management began. One such strategy gaining stronger acceptance and increasing utility is occupational exposure banding and the use of occupational exposure bands (OEBs).

OVERVIEW AND HISTORY Occupational exposure banding was created to quickly and accurately assign chemicals to specific categories based on their toxicity. The output of this process is an OEB, which corresponds to a range of exposure concentrations expected to protect worker health. OEBs are assigned based on a chemical’s toxicological potency and the adverse health effects associated with exposure to the chemical, as explained in the March 2016 Synergist article “The NIOSH Decision Logic for OEBs.” While OEBs are intended to provide guidance through a process that utilizes a minimum amount of data and expertise, an OEB is not a replacement for existing OELs. Rather, OEBs allow for more timely chemical hazard assessments and inform risk management decisions for the myriad chemicals lacking OELs. In the hierarchy of OELs, OEBs are a starting point given the limited data and resources needed for their determination. By contrast, OELs from authoritative bodies are ranked at the top of the hierarchy based on considerable data, expertise, and other factors that contribute to their derivation.

Occupational exposure banding has been used by the pharmaceutical sector and by some major chemical companies over the past several decades to establish exposure control limits or ranges for new or existing chemicals that do not have formal OELs. The pioneering efforts of the pharmaceutical industry led to control banding in the late 1990s and early 2000s as a strategy that groups workplace risks into control categories or bands based on combinations of hazard and exposure information. (For further discussion of the history of occupational exposure banding and control banding, see the following publications listed in the “Resources” section below: the 1996 American Industrial Hygiene Association Journal article on exposure control limits for pharmaceutical active ingredients, AIHA’s Guidance for Conducting Control Banding Analyses, the 2010 Industrial Health paper focused on risk management in a highly regulated environment, and the 2008 Journal of Occupational and Environmental Hygiene article on the evolution of control banding.)

CONTROL BANDING VS. OCCUPATIONAL EXPOSURE BANDING Many safety and health practitioners are familiar with control banding. Control banding combines hazard banding with exposure risk management and exposure management to directly link hazards to specific control measures. In 2009, NIOSH published a comprehensive document describing the state of the science of control banding titled “Qualitative Risk Characterization and Management of Occupational Hazards: Control Banding (CB): A Literature Review and Critical Analysis.” This document identified some of the promise as well as research gaps for control banding, which led to further exploration of occupational exposure banding.

While control banding can be used in concert with the occupational exposure banding methodology, practitioners should be aware of several distinctions. For example, occupational exposure banding can be used by informed occupational safety and health professionals to make risk management and exposure control decisions, but it does not supply control recommendations directly. Instead, occupational exposure banding supplies a range of air concentrations that can be used as a target for exposure controls to ultimately drive risk reduction. In this way, occupational exposure banding allows flexibility in selecting control approaches depending on the specific situation. For a case study of the occupational exposure banding process to assess a chemical without an OEL, see the 2019 JOEH article pertaining to bisphenol A under “Resources.”

THE NIOSH PROCESS

In 2019, NIOSH released a technical report on occupational exposure banding as a process to assess chemical hazards in the workplace. The report outlines how practitioners can apply occupational exposure banding to a broad spectrum of chemicals used in occupational settings and lays out detailed instructions for assigning OEBs. The NIOSH occupational exposure banding process utilizes publicly available, but often limited, toxicological data to help users make risk management decisions. The report provides detailed instructions for obtaining relevant toxicological information from sources such as the U.S. Environmental Protection Agency Integrated Risk Information System, the Agency for Toxic Substances and Disease Registry Toxicological Profiles, the U.S. National Toxicology Program, and the International Agency for Research on Cancer. Users then compare quantitative and qualitative data gathered from these sources to the NIOSH occupational exposure banding criteria to determine the appropriate band. Banding assignments reflect the potency of the chemical and the nature of the health effects associated with exposure. OEBs range from band A (least potent/reversible health effects) to band E (most potent/serious or irreversible health effects). Each OEB is associated with a range of exposure concentrations that can be used to target occupational control strategies (see Figure 1). Through this process, users identify adverse health outcomes that are of greatest concern and what concentration levels are likely to result in such outcomes.

In order to provide greater consistency and minimize the potential for varied results among individual users assigning OEBs, NIOSH has sought to ensure the accuracy and reliability of the occupational exposure banding process through multiple phases of evaluation. For example, NIOSH has performed exercises to assess the consistency of the occupational exposure banding process with OELs. This evaluation, which involved more than 600 chemicals, found that the NIOSH Tier 1 banding process resulted in a band that included the OEL or was more stringent than the OEL for 91 percent of chemical substances. Assessments of the Tier 2 process involved over 130 chemical substances with OELs and five iterative phases. Results of these evaluations showed that Tier 2 OEBs are equal to or more stringent than the OEL for 98 percent of chemical substances tested. (See NIOSH’s webpage on the approach to occupational exposure banding to learn more about the tiered approach.)

The NIOSH technical report provides information for users to identify and assess relevant data to determine OEBs by hand, but the process can be partially automated through the accompanying occupational exposure banding e-tool. The e-tool assists the user in a more rapid OEB evaluation by populating some information from recommended sources. It also allows the user to directly enter available toxicological data (for example, point of departure values) into the tool and calculates the OEB automatically.

Figure 1. Occupational exposure bands define the range of exposures expected to be protective of worker health. The bands range from band A to band E. Band E represents the lowest range of exposure concentrations, while band A represents the highest range with values expressed for dust/particulate (mg/m3) and gas/vapor (ppm). From NIOSH: “The NIOSH Occupational Exposure Banding Process for Chemical Risk Management” (2019).

Tap on the figure to open a larger version in your browser.

Whether by hand or using the e-tool, going through the occupational exposure banding process may help practitioners identify potential health effects and target organs as well as determine health risks that should be included in health communications. The process can also inform decisions regarding control interventions, inform medical surveillance decisions, and provide critical information on chemical potency quickly.

ADVANCING UNDERSTANDING AND USE OF BANDING STRATEGIES In early 2020, AIHA partnered with NIOSH to provide a virtual occupational exposure banding workshop comprising more than 10 hours of sessions describing the logic and the strategy behind NIOSH’s occupational exposure banding process. Subsequently, AIHA collaborated with NIOSH researchers to develop and provide informational YouTube videos about occupational exposure banding, including “What is Occupational Exposure Banding?” and “How OEB Can Help You Keep Workers Safe.”

Additional efforts to promote the use of banding and improve its utility have involved periodic updates to the NIOSH occupational exposure banding e-tool. Other resources and information can be found on NIOSH’s workplace safety and health topic page on occupational exposure banding and on AIHA’s website. Presentations at national and international symposia have also been a part of the strategy by NIOSH and AIHA to increase the collective involvement of the occupational safety and health community in the banding process, thereby “banding together.”

THE FUTURE OF OEBS Government agencies such as NIOSH, OSHA, and EPA; professional communities of practice such as AIHA, the American Society of Safety Professionals, and ACGIH; and other authoritative organizations continue to explore the promise and potential of occupational exposure banding and possible new applications. For example, NIOSH is working to collaborate with toxicology and risk assessment communities and individuals in an effort unofficially named “Banding 2.0.” This project is seeking ways that banding concepts can be expanded to address chemicals that have insufficient or no toxicity data available. NIOSH is exploring the utility, sensitivity, and specificity of techniques such as quantitative structure activity relationships (QSAR), read-across, and other methods to address potential banding strategies for chemicals that cannot be banded in the NIOSH banding tool due to very limited exposure and potency data.

Other brainstorming sessions have led to discussions about whether loosely organized but collective efforts (like crowdsourcing) to band chemicals and share data might have value in promoting broader assessment and control of chemical hazards in the workplace. Some have suggested sharing case studies of chemical substances that have been assessed through the exposure banding process where the OEB assignment could be used across multiple industries and in varied occupational settings. However, such an effort would not be without complicating factors or limitations; for instance, concomitant exposures to other chemical or physical hazards might be unique to a certain industry or process.

HOW TO GET INVOLVED While interest and necessity have driven initial enthusiasm for and application of occupational exposure banding strategies, there is great potential for broader use and impact. AIHA’s Exposure and Control Banding Committee comprises representatives from varied industry sectors brought together by a commitment to banding. This group seeks to find and highlight examples and case studies where OEBs are utilized as well as gaps where training and information are needed. AIHA also has an OEB Content Priority Working Group affiliated with its Content Portfolio Advisory Group. Likewise, NIOSH researchers continue to welcome feedback regarding the occupational exposure banding process and opportunities to enhance its success and relevance. Through these collaborative efforts in the occupational safety and health community, we hope to band together and make the most effective case for OEBs.

T.J. LENTZ , PhD, is the chief of the Science Applications Branch of the Division of Science Integration, CDC/NIOSH in Cincinnati, Ohio.

MELISSA EDMONDSON, MS, CIH, CPH, is deputy chief of the Risk Evaluation Branch of the Division of Science Integration, CDC/NIOSH in Cincinnati, Ohio.

Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.

Acknowledgments: The authors express appreciation to John Baker (BSI EHS Services and Solutions [retired]), Felix Boachie (McCormick & Company Inc.), and Christine Uebel (NIOSH) for providing technical reviews and comments on earlier drafts of this manuscript.

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RESOURCES

AIHA: Guidance for Conducting Control Banding Analyses (2007).

American Industrial Hygiene Association Journal: “Performance-Based Exposure Control Limits for Pharmaceutical Active Ingredients” (January 1996).

Health and Safety Executive (HSE): Control of Substances Hazardous to Health: Approved Code of Practice and Guidance 2002, 6th ed. (2013).

Industrial Health: “Risk Level Based Management System: A Control Banding Model for Occupational Health and Safety Risk Management in a Highly Regulated Environment” (2010).

Journal of Occupational and Environmental Hygiene: “Application of the Draft NIOSH Occupational Exposure Banding Process to Bisphenol A: A Case Study” (February 2019).

Journal of Occupational and Environmental Hygiene: “History and Evolution of Control Banding: A Review” (May 2008).

NIOSH: “The NIOSH Occupational Exposure Banding Process for Chemical Risk Management” (2019).

NIOSH: “Qualitative Risk Characterization and Management of Occupational Hazards: Control Banding (CB): A Literature Review and Critical Analysis” (2009).

The Synergist: “The Banding Marches On: NIOSH Proposes a New Process for Occupational Exposure Banding” (May 2014).

The Synergist: “The NIOSH Decision Logic for OEBs: Applying Occupational Exposure Bands” (March 2016).