Last August, AIHA held the first in a series of planned workshops on occupational risk assessment. That workshop sought to help attendees understand the different approaches to risk assessment among government agencies and the OEHS professions. The workshop was developed to facilitate discussions on changes to the Toxic Substances Control Act (TSCA) that require EPA to evaluate and manage risks posed by existing chemicals in commerce, including chemicals used in the occupational environment. To fulfill this responsibility, EPA has been requesting occupational exposure data from affected industries. However, because of the differences between the traditional IH approach and the EPA risk assessment process, the available facility IH data sometimes does not address the range of exposures or processes of interest to EPA. A better understanding of IH exposure and risk assessment practices will benefit all stakeholders in the risk assessment community of practice.

The second workshop in the Many Paths – One Goal series, which was held on April 20, 2023, elaborated on the many reasons why IH data are collected and how approaches vary depending on the objective of the exposure assessment. For example, because OEHS professionals are often concerned with addressing potential occupational overexposures, they divide workers into similar exposure groups (SEGs) and, through exposure prioritization efforts, focus direct measurement efforts on the SEGs with the highest expected exposures. Speakers and panelists discussed, for example, that IH data sets often reflect high-end exposures to particular substances rather than a randomized assessment of the range of exposures for all workers. Moreover, in some cases, extensive exposure assessment and data collection is not feasible.

In TSCA risk evaluation, EPA must assess potential health risks from exposures for all workers within defined conditions of use (COUs), not just those with the highest exposures or for a specific facility or site. For this reason, IH data from an individual site or small set of sites—while still useful to EPA—might not be representative of the totality or variability of exposures among workers throughout the United States. EPA's risk evaluations group industry sectors into COUs (for example, manufacturing, processing) and further define specific "occupational exposure scenarios," or OESs, associated with that COU. A COU can encompass multiple OESs; similarly, an OES can be mapped to multiple COUs. (For a fuller discussion of COUs and OESs, read "Many Paths, One Goal" in the February 2023 issue of The Synergist.) Gaining an understanding of the intended uses of data and risk decisions to be made ensures that data are grouped and analyzed in a manner that meets the objectives of the risk assessment.

As discussed in the workshop, an EPA TSCA risk evaluation is intended to characterize potential human health risk, while a traditional IH assessment typically seeks to assess potential exposures for regulatory compliance purposes or to manage specific workplace risks. Further, the metrics used in IH risk assessments and EPA assessments can differ by duration (full-shift exposures or short-term exposures); the type of hazard (chronic or acute); and the objective of the risk assessment (for example, to comply with regulations or to verify the effectiveness of controls).

One challenge for OEHS professionals seeking to comply with requests for data from EPA is the amount and specificity of information (that is, data annotation) the agency seeks. This information may not be readily available in a centralized location at a company, or it may not be available at all. During a panel discussion held in the second half of the workshop, discussants noted ongoing efforts by AIHA and others to optimize and standardize approaches for data quality assurance, annotation, and analysis to facilitate the use of IH data for many applications. (See the December 2020 issue of The Synergist for more information about IH data standardization.)

Three workshops remain in the series, which is organized by AIHA and the Foundation for Chemistry Research & Initiatives (FCRI). The next workshop, to be held June 29, 2023, will focus on exposure modeling. None of the workshops will be recorded, so anyone interested in occupational risk assessment should plan to attend. Registration for the series is required. To register, visit the workshop series home page.

Resources

The Synergist: "Industrial Hygiene Data Standardization: Past Lessons, Present Challenges, and Future Directions" (December 2020).

The Synergist: "Many Paths, One Goal: Exploring Different Approaches to Occupational Risk Assessment" (February 2023).