Chain of Custody Form Instructions for WTC Building Sampling

NYC 9/11 Public Portal Document

■ Settled dust samples were analyzed using Health Implications of Polarized Light Microscopy or PLM. PLM FindingsZRecommendations identifies and distinguishes types of fibers, ■ Exposure to fibrous glass is known to cause rashes including asbestos or fibrous glass, by shape and and upper respiratory irritation. These sampling the pattem/color of their appearance. TEM, a results suggest that fibrous glass should be more sensitive form of analysis, was conducted as considered in choosing the mode and frequency an additional check on all dust samples in whicli of clean up. PLM testing did not detect levels of asbestos. ■ The negative air data and low levels of asbestos Fibrous glass and other contaminants in dust suggest that clean up practices seem to be ■ Fibrous glass was detected in settled dust samples largely effective in eliminating asbestos exposure. from 23 (40.4%) of the residential unit samples, ■ Although both the asbestos and fibrous glass 11 (42.3%) of the common area samples, and 9 were found in dust, both types of particles can (64.3%) of the outside samples. The percentage become airborne if disturbed. Therefore, ATSDR of fibers in indoor samples that were fibrous glass is recommending that people continue to conduct ranged from 2% to 35%. frequent cleaning with HEPA vacuums and damp ■ No fibrous glass was detected in background dust cloths/mops to reduce the potential for exposure samples. in accordance with NYC Department of Health guidance. ■ Fibrous glass was detected in many of the locations previously cleaned. ■ ATSDR is recommending additional monitoring of residential units in lower Manhattan. ■ Samples continue to be analyzed for other contaminants, including crystalline silica, mica, ■ ATSDR continues to work with the New York gypsum, and calcite, as well as the total amount of City Department of Health, and other federal dust and fibrous glass in the air. and state agencies, to provide information on sampling results to the citizens of New York City and help interpret the possible health effects of contaminants found.

O2-OI5l.indd February 13. 2002

NYC-VVTC_000149605