NYC-WTC_000205221

NYC 9/11 Public Portal Document

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I Centers for Disease Control and Prevention National Institute for Occupational Safety and Health Interim Air Sampling Report Thursday, September 20, 2001

Investigators from the National Institute for Occupational Safety and Health (NIOSH) 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 potential exposures. Below are the interim sampling results for Thursday, September 20, 2001.

Air Samples

Asbestos I • 130 personal and 13 area air samples were collected by NYDOH contractors o Most personal sample 8-hour time-weighted average concentrations were below 0.05 fibers/cc as determined by PCM (two were 0.08 fibers/cc) o Most short-term exposure limit samples were below 0.05 fibers/cc (one was 0.68 S fibers/cc) o All area sample results were below 0.008 fibers/cc as determined by PCM I ( Crystalline silica • 6 personal and 2 area air samples were collected for crystalline silica o No crystalline silica was detected on any of the air samples

Metals • 11 area air samples were collected for metals I ! o Nothing of concern was found regarding metal analysis I

Respirable Dust • 6 personal air samples were collected for respirable dust o Personal sample 8-hour time-weighted average concentrations were below 0.05 mg/m’

Total Dust • 5 persona] air samples were collected for total dust o Personal sample 8-hour time-weighted average concentrations were below 1.0 mg/m^

Volatile Organic Compounds (VOCs) • 1 air sample was collected on a thermal desorption tube (used as a screening teclmique) o Compounds identified included benzene, toluene, and polynuclear aromatic f hydrocarbons which have been attributed to products of combustion o Concentrations of VOCs were well below established limits • 15 personal and 3 area air samples were collected with charcoal adsorbent tubes o Concentrations of VOCs on all samples were below detectable limits

K.M. Wallingford 10/4/01

CITY_21MC100_007222527

NYC-WTC_000205221