Task-Based Lead Exposures and Work Site Characteristics of Bridge Surface Preparation and Painting Contractors

Abstract

This study of bridge painters working for small contractors in Massachusetts investigated the causes of elevated blood lead levels and assessed their exposure to lead. Bridge work sites were evaluated for a 2-week period during which personal and area air samples and information on work site characteristics and lead abatement methods were gathered. Short-duration personal inhalable samples collected from 18 tasks had geometric means (GM) of 3 μg/m³ to 7286 μg/m³. Full-shift, time-weighted average (TWA) inhalable samples (⩾6 hours) collected from selected workers and work sites had GMs of 2 μg/m³ to15,704 μg/m³; 80% of samples exceeded the permissible exposure limit (PEL) of 50 μg/m³, on average by a factor of 30. Area inhalable samples collected from three locations ranged from 2 μg/m³ to 40,866 μg/m³ from inside the containment, 2 μg/m³ to 471 μg/m³ from a distance of <6 meters, and 2 μg/m³ to 121 μg/m³ from >6 meters from the containment. Seventy nine percent of the area samples from inside the containment exceeded the PEL on average by a factor of 140. Through observations of work site characteristics, opportunities for improving work methods were identified, particularly the institution of engineering controls (which were only occasionally present) and improvement in the design and construction of the containment structure. The high levels of airborne lead exposures indicate a potential for serious exposure hazard for workers and environmental contamination, which can be mitigated through administrative and engineering controls. Although these data were collected over 10 years ago, a 2005 regulatory review by the Occupational Safety and Health Administration (OSHA) of its lead in construction standard reported that elevated lead exposures and blood lead levels, high occurrence of noncompliance with the lead standard, and nonimplementation of newer technology especially among small painting firms employing <10 workers are still widespread. As a result, the findings of this study are still quite germane even a decade after the introduction of the new OSHA standard.

Keywords:

• bridge painting
• construction industry
• inhalable exposure
• lead exposure assessment
• task-based sampling

ACKNOWLEDGMENTS

This study was funded by NIOSH jointly to the University of Massachusetts, Lowell and Boston University (5 R01 OH03177). The authors would like to thank and acknowledge Andrew Kalil, Marvin Lewiton, and Jim Hathaway for their contribution to field sampling; Pam Bennet and Pam Kocher for conducting worker interviews; Robert Blicksilver of the U.S. Department of Labor for providing information on estimates of painters employed by small contractors; Aleksandr Stefaniak for review of this manuscript; and Bill Miller for the discussions on the error-in-variables models. We would also like to thank the contractors and workers who participated in the study.

Notes

^A LOD samples: Assist painter n = 2, Abrasive blasting (inside helmet) n = 2, Activities <6 meters from containment n = 4.

^B Minimum variance unbiased estimator (MVUE) of the arithmetic mean (AM).

^C Calculated based on the 95th percentile of task exposure corrected or uncorrected for respirator use for tasks (from Appendix).

^A Average exceedance factor for job titles.

^A LOD samples: Activities <6 meters from containment n = 3, Activities >6 meters from containment n = 2, Setup tarps n = 10, Supervise n = 1, Takedown tarps n = 1.

^B Minimum variance unbiased estimator (MVUE) of the arithmetic mean (AM).

^A LOD samples: IOM Inside containment n = 6, IOM outside containment (<6 meters) n = 9, IOM outside containment (> 6 meters) n = 10, CFC outside containment (<6 meters) n = 10, Cyclone inside containment n = 3.

^B Minimum variance unbiased estimator (MVUE) of the arithmetic mean (AM).