Annals of Occupational Hygiene Advance Access originally published online on November 14, 2008
Annals of Occupational Hygiene 2009 53(1):33-40; doi:10.1093/annhyg/men070
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Skin Exposure to Aliphatic Polyisocyanates in the Auto Body Repair and Refinishing Industry: III. A Personal Exposure Algorithm
1 Department of Preventive Medicine and Environmental Health, College of Public Health, University of Kentucky, 121 Washington Avenue, Lexington, KY 40536, USA
2 Occupational and Environmental Medicine Program, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
3 Department of Work Environment, School of Health and Environment, University of Massachusetts Lowell, Lowell, MA 01854, USA
* Author to whom correspondence should be addressed. Tel: +859-218-2234; fax: +859-257-9862; e-mail: youcheng.liu{at}uky.edu
Objectives: Isocyanate skin exposure may play an important role in sensitization and the development of isocyanate asthma, but such exposures are frequently intermittent and difficult to assess. Exposure metrics are needed to better estimate isocyanate skin exposures. The goal of this study was to develop a semiquantitative algorithm to estimate personal skin exposures in auto body shop workers using task-based skin exposure data and daily work diaries. The relationship between skin and respiratory exposure metrics was also evaluated.
Methods: The development and results of respiratory exposure metrics were previously reported. Using the task-based data obtained with a colorimetric skin exposure indicator and a daily work diary, we developed a skin exposure algorithm to estimate a skin exposure index (SEI) for each worker. This algorithm considered the type of personal protective equipment (PPE) used, the percentage of skin area covered by PPE and skin exposures without and underneath the PPE. The SEI was summed across the day (daily SEI) and survey week (weekly average SEI) for each worker, compared among the job title categories and also compared with the respiratory exposure metrics.
Results: A total of 893 person-days was calculated for 232 workers (49 painters, 118 technicians and 65 office workers) from 33 auto body shops. The median (10th–90th percentile, maximum) daily SEI was 0 (0–0, 1.0), 0 (0–1.9, 4.8) and 1.6 (0–3.5, 6.1) and weekly average SEI was 0 (0–0.0, 0.7), 0.3 (0–1.6, 4.2) and 1.9 (0.4–3.0, 3.6) for office workers, technicians and painters, respectively, which were significantly different (P < 0.0001). The median (10th–90th percentile, maximum) daily SEI was 0 (0–2.4, 6.1) and weekly average SEI was 0.2 (0–2.3, 4.2) for all workers. A relatively weak positive Spearman correlation was found between daily SEI and time-weighted average (TWA) respiratory exposure metrics (µg NCO m–3) (r = 0.380, n = 893, P < 0.0001) and between weekly SEI and TWA respiratory exposure metrics (r = 0.482, n = 232, P < 0.0001).
Conclusions: The skin exposure algorithm developed in this study provides task-based personal daily and weekly average skin exposure indices that are adjusted for the use of PPE. These skin exposure indices can be used to assess isocyanate exposure–response relationships.
Keywords: auto body refinishing • exposure assessment • exposure modeling • hexamethylene diisocyanate • isocyanates • PPE • skin exposure • task-based exposure metrics
Received March 16, 2008; in final form September 6, 2008