A task-based approach to assessing lead exposure among iron workers engaged in bridge rehabilitation

Am J Ind Med. 1997 Mar;31(3):310-8. doi: 10.1002/(sici)1097-0274(199703)31:3<310::aid-ajim7>3.0.co;2-0.


The assessment of worker exposures to airborne contaminants in the dynamic environment present at most construction sites poses considerable challenges to the industrial hygienist. In this study, we applied a task-based approach to the assessment of lead exposure among structural steel iron workers engaged in a large, complex bridge rehabilitation project. We evaluated the usefulness of task-based exposure data for the development of worker protection programs. Task-specific and multitask samples were collected, and operation-specific and 8-hr time-weighted averages were calculated. The task-specific data showed significant differences in exposure levels among different tasks. Arithmetic mean exposures varied from 1,357 micrograms/m3 lead for torch cutting and 989 micrograms/m3 for scaling to 31 micrograms/m3 for reaming and 4 micrograms/m3 for drilling. Our task-specific data were compared with the task-based exposure levels presented by OSHA in its Lead Exposure in Construction-Interim Final Rule (29 CFR 1926). There was good general agreement between our results and OSHA's reported data. Task-based data were very useful in exposure assessment and much more precise than full-shift and operation-based measurements in guiding strategies for worker protection. These findings suggest that task-based data should routinely be collected in evaluating exposure to lead and perhaps other toxic substances in construction work.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Air Pollutants, Occupational / analysis*
  • Environmental Monitoring / methods
  • Humans
  • Lead / analysis*
  • Maximum Allowable Concentration
  • Metallurgy
  • Occupational Exposure / analysis*
  • Occupational Exposure / standards
  • United States
  • United States Occupational Safety and Health Administration


  • Air Pollutants, Occupational
  • Lead