NIOSH Air Sample Results Summary, World Trade Center Site, Sept-Oct

NYC 9/11 Public Portal Document

Summary Report to the New York City Department of Health;

NIOSH Air Sample Results for the World Trade Center Disaster Response Centers for Disease Control and Prevention National Institute for Occupational Safety and Health

From September 18 through October 4, 2001, National Institute for Occupational Safety and Health (MOSH) personnel (and contractors) collected air samples in areas immediately adjacent to the debris pile and on personnel actively involved in rescue efforts on or in the vicinity of the debris pile to characterize occupational exposures during the disaster response at the World Trade Center site in New York City, NY. This report is a compilation of sampling efforts that were undertaken over the course of providing technical assistance to the New York City Department of Health (NYCDOH), and were used to identify potential hazards and to recommend appropriate protective measures where needed for the workers whose exposures were sampled. As a result of this activity, workers using acetylene torches to cut metal beams were found to have hazardous exposures to carbon monoxide; this information lead to interventions that addressed the problem. Because these findings are based on limited sampling, they may not be representative of more general exposures. However, they are consistent with those reported by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA). The area air samples were collected in the immediate vicinity of workers at a height approximating their breathing zone. The personal air samples were collected on workers with the sampling device placed in the worker’s breathing zone. Additional bulk sampling was conducted and results were included in the daily summaries to the NYCDOH. Blank sampling was also performed for quality assurance; these results are not included in this report.

Asbestos; A total of 827 air samples were collected for asbestos. No fibers were detected in over 50% (455) of these air samples as determined by phase contrast microscopy (PCM). The remaining 372 air samples indicated time-weighted average (TWA) concentrations ranging up to 0.89 fibers/cc as determined by PCM. Twenty-five of these samples exceeded the NIOSH recommended exposure limit (REL) and the OSHA permissible exposure limit (PET) of 0.10 fibers/cc. In addition, 119 of these air samples were analyzed for asbestos by transmission electron microscopy (TEM), a more sensitive analytical method that can distinguish between asbestos and non-asbestos fibers. No asbestos fibers were detected in over 45% (56) of these air samples as determined by TEM. The remaining 63 air samples indicated TWA concentrations ranging up to 0.063 asbestos fibers/cc as determined by TEM, none of which exceeded the NIOSH REL and the OSHA PEL of 0.10 fibers/cc. These TEM results indicate that the vast I

CONFIDENTIAL, CITY_2IMCl00_003402503 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

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