Occupational Exposure Bands: A Reintroduction
In the early 1900s, IH pioneers like Alice Hamilton, J.J. Bloomfield, and Phil Drinker took to the workplace to save workers’ lives and improve conditions on the shop floor. During these early decades, industrial hygienists used available medical, toxicological, and epidemiological information to make informed judgments about the relative hazard of workplace chemicals, a laborious and time-consuming process. In 1946, ACGIH published its first list of occupational exposure limits, the Threshold Limit Values. Use of OELs like the TLVs, OSHA’s permissible exposure limits (PELs), or AIHA’s Workplace Environmental Exposure Levels (WEELs), along with advances in air sampling methods, makes workplace evaluation significantly more efficient. Unfortunately, there are fewer than 1,000 OELs, leaving a significant shortage of OELs for the available chemicals. According to one recent estimate, more than 350,000 chemicals and mixtures are registered for commercial production and use.
Let me introduce (or reintroduce) a not-so-new tool to my fellow industrial hygienists: exposure banding. Occupational exposure banding is a heuristic for quickly assigning chemical substances to “bands” of exposure levels based on their associated health outcomes. The pharmaceutical industry started using exposure banding methods about twenty years ago to help them assess health hazards. Recently, NIOSH published its OEB process based on the level of knowledge about the chemical of concern. The NIOSH occupational exposure banding process considers the information from the nine standard toxicological health endpoints: (1) carcinogenicity; (2) reproductive toxicity; (3) specific target organ toxicity; (4) genotoxicity; (5) respiratory sensitization; (6) skin sensitization; (7) acute toxicity; (8) skin corrosion and irritation; and (9) eye damage or irritation.
NIOSH specifies a tiered approach to categorizing chemicals based on the skill of the assessor and the level of information. Tier 1 uses general, publicly available information such as hazard statement codes (H-codes) from safety data sheets. Tier 2 involves database searches of the nine health endpoints and requires training to conduct appropriately. Tier 3 categorization involves higher quality information such as peer-reviewed toxicology and epidemiology reports and a commensurate level of expertise to interpret the information. The NIOSH process includes five bands: Band A is the least protective and has the highest air concentrations, while Band E is the most protective and has the lowest air concentrations. In a Tier 1 assessment, considered a screening assessment, users can assign chemicals to only the more protective bands (C through E). Once more information becomes available, the assessment can move to Tier 2 and reductions in exposure levels recommended through the use of Bands A and B.
As part of your routine workplace risk assessments, most of you probably review safety data sheets and look at the H-codes and possibly other documents for individual chemical components to decide which chemicals require further evaluation. Guess what—you might be conducting at least a Tier 1 and quite possibly a Tier 2 assessment. Now think if we could share this information. The AIHA Exposure Control Banding Committee wants your help to achieve our goal of creating a public database with completed exposure bands. Please consider sharing your exposure bands with the committee by posting them to Catalyst.
For further information about exposure banding, check out the NIOSH Occupational Exposure Banding document web page. Furthermore, as chair of the Exposure Control Banding Committee, I invite you to attend any or all of the three education sessions on exposure banding offered at AIHce EXP 2020 and learn how you can help our community. Lastly, AIHA’s Exposure Control Banding Committee wishes to ask everyone interested in volunteering to attend the committee’s meeting at the conference and contribute to exposure banding.
The Synergist: “The ‘Bandits’ Speak: NIOSH Considers Feedback from Users of its Proposed Occupational Exposure Banding Process” (May 2018).
The Synergist: “The NIOSH Decision Logic for OEBs” (March 2016).