A Model to Systematically Employ Professional Judgment in the Bayesian Decision Analysis for a Semiconductor Industry Exposure Assessment

Abstract

Bayesian Decision Analysis (BDA) uses Bayesian statistics to integrate multiple types of exposure information and classify exposures within the exposure rating categorization scheme promoted in American Industrial Hygiene Association (AIHA) publications. Prior distributions for BDA may be developed from existing monitoring data, mathematical models, or professional judgment. Professional judgments may misclassify exposures. We suggest that a structured qualitative risk assessment (QLRA) method can provide consistency and transparency in professional judgments. In this analysis, we use a structured QLRA method to define prior distributions (priors) for BDA. We applied this approach at three semiconductor facilities in South Korea, and present an evaluation of the performance of structured QLRA for determination of priors, and an evaluation of occupational exposures using BDA. Specifically, the structured QLRA was applied to chemical agents in similar exposure groups to identify provisional risk ratings. Standard priors were developed for each risk rating before review of historical monitoring data. Newly collected monitoring data were used to update priors informed by QLRA or historical monitoring data, and determine the posterior distribution. Exposure ratings were defined by the rating category with the highest probability--i.e., the most likely. We found the most likely exposure rating in the QLRA-informed priors to be consistent with historical and newly collected monitoring data, and the posterior exposure ratings developed with QLRA-informed priors to be equal to or greater than those developed with data-informed priors in 94% of comparisons. Overall, exposures at these facilities are consistent with well-controlled work environments. That is, the 95th percentile of exposure distributions are ≤50% of the occupational exposure limit (OEL) for all chemical-SEG combinations evaluated; and are ≤10% of the limit for 94% of chemical-SEG combinations evaluated.

An Integrated Approach to Assess Exposure and Health-Risk from Polycyclic Aromatic Hydrocarbons (PAHs) in a Fastener Manufacturing Industry

“…As a result, many measured data are needed from different periods leading to a massive burden on both manpower and cost for the industry involved. On the other hand, if only a small amount of field sampling data were available for a similar exposure group (SEG), the Bayesian decision analysis (BDA) can be chosen as an approach for determining the exposure profile [ 1 , 2 , 3 , 4 , 5 ]. In principle, BDA can provide a transparent method for incorporating the relative certainty of the information or data used to produce a judgment probability chart [ 3 , 6 ].…”

Health Risk Assessment of Photoresists Used in an Optoelectronic Semiconductor Factory

“…In a recent risk assessment conducted by Torres et al. (), benzene was not identified as a process chemical. Their decision has been criticized (Paek & Gassert, ), as previous reports have detailed the presence of benzene in the fabrication process (Jones et al., ; Paek & Gassert, ; Torres et al., ).…”

“…(), benzene was not identified as a process chemical. Their decision has been criticized (Paek & Gassert, ), as previous reports have detailed the presence of benzene in the fabrication process (Jones et al., ; Paek & Gassert, ; Torres et al., ). Similarly, the exposure scenario we have assessed did not monitor benzene in the photolithography process as it was not identified as a process chemical.…”

Exposure Reconstruction and Risk Analysis for Six Semiconductor Workers With Lymphohematopoietic Cancers

“…The company provided monitoring data for normal operations on Line A (2006 to 2010), Line C (2004 to 2010), and Line D (2001 to 2008), as well as for maintenance tasks on Line A (2007 to 2009). These data were supplemented by monitoring data newly collected by the authors in 2011 for normal operations and maintenance tasks on Lines A and C. The monitoring data are described in more detail by Torres et al 15 Of the company monitoring data, 62.2%, 59.7%, and 48.0% of measurements were below limits of detection on Lines A, C, and D, respectively. Of the authors' monitoring data, 84.6% and 95.6% of measurements were below limits of detection on Lines A and C, respectively.…”

“…We define “recognized lymphohematopoietic carcinogen” as a chemical, biological, or physical agent that has been classified as a human carcinogen that targets the lymphohematopoietic system by an authoritative agency such as the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), or the US Environmental Protection Agency (EPA). To support this effort, we used an exposure assessment performed in the same workplace 15 to develop a job-exposure matrix (JEM) containing qualitative and quantitative data, when available, about exposures to process agents and anticipated process by-products. With this JEM, the magnitude of the six workers' potential cumulative occupational exposure was reconstructed.…”