Exposures during Use of a Powered Abrasive Saw to Cut Asbestos-Containing Cement Pipe
1Cardno ChemRisk, Pittsburgh, PA
Joshua Maskrey, BS
A simulation study was conducted to quantify historical exposures of workers and bystanders to asbestos during dry cutting of a cement pipe containing 10-15% chrysotile and 25-30% crocidolite. The results were compared to those in the historical literature for cement pipe cutting activities.
Situation / Problem:
How would exposures produced during use of a powered abrasive saw to cut asbestos-containing cement pipe compated to the data reported in the historical literature?
A saw operator made two cuts on a segment of asbestos-containing pipe using a gasoline powered cut-off saw fitted with an abrasive cutting wheel. Cutting was performed in two environments: aboveground and in a shored trench. Personal samples and area (bystander) samples for airborne asbestos fibers were collected during the 30-minute cutting period and analyzed using phase contract microscopy (PCM, NIOSH 7400). A subset of the aboveground samples were analyzed using transmission electron microscopy (TEM, NIOSH 7402) to determine the fractions of chrysotile and crocidolite present in the samples.
Results / Conclusions:
PCM results for total asbestos (longer than 5 µm, aspect ratio > 3:1) were as follows (average ± standard deviation): aboveground personal, 4.6 ± 3.3 f/cc; trench personal, 12 ± 7.2 f/cc; aboveground area, 0.64 ± 0.49 f/cc; trench area, 1.0 ± 0.79 f/cc. TEM results demonstrated that the samples contained approximately 77% chrysotile and 23% crocidolite. PCM fiber concentrations were found to be similar to historical data reported for comparable sampling durations and methods and less than those reported as peaks or sampled using an unknown sampling method. Unlike other studies, a large subset of samples received TEM analysis, which illustrated the importance of characterizing results by fiber type. It was determined that the chrysotile and crocidolite fractions in the air samples were relatively consistent with the bulk content.
Sampling and Analysis
Exposure Assessment Strategies
Acknowledgements and References
List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).
Anders Abelmann, coauthor; Cardno ChemRisk, Chicago, IL
Jason T. Lotter, coauthor; Cardno ChemRisk, Chicago, IL
Aaron M. Chapman, coauthor; Cardno ChemRisk, Washington, DC
Melanie D. Nembhard, coauthor; Cardno ChemRisk, San Francisco, CA
John M. Wilmoth, coauthor; RJ Lee Group, Monroeville, PA
Richard J. Lee, coauthor; RJ Lee Group, Monroeville, PA
Dennis J. Paustenbach, coauthor; Cardno ChemRisk, San Francisco, CA
What learning level(s) is the presentation content geared towards?
Novice - new to the job, role, or task, with no or limited knowledge of the content.
Competent - can perform to basic standards; has a thorough understanding of the content area but limited practical/work experience in the application of the content/concepts.
Experienced - has a thorough understanding of the content area and work experience including application and evaluation of the content/concepts in a variety of contexts; can vary performance based on unique situations.
Expert - has extensive content knowledge and deep understanding of their discipline, notices features and meaningful patterns, can reason through new information, can invent new or better ways to do a job.