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, or AIHA’s Workplace Environmental Exposure Levels, 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. 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 20 years ago to help assess health hazards. Recently, NIOSH published its OEB process based on the level of knowledge about the chemical of concern. The NIOSH 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 the use of Bands A and B. As part of their routine workplace risk assessments, most IHs 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. This review might constitute a Tier 1 and quite possibly a Tier 2 assessment. The AIHA Exposure Control Banding Committee wants AIHA members’ 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 occupational exposure banding, see NIOSH’s web page on the topic. Furthermore, as chair of the Exposure Control Banding Committee, I invite AIHA members to attend any or all of the three educational sessions on exposure banding offered at AIHce EXP 2020. Lastly, AIHA’s Exposure Control Banding Committee asks everyone interested in volunteering to attend the committee’s meeting at the conference and contribute to exposure banding. Bryan Seal, MS, CIH, CSP, is managing principal of Contemporary Industrial Hygiene & Safety, Inc. Editor’s note: This article was originally published in different form on the SynergistNOW blog on March 4, 2020.

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