NYC-WTC_000234666

NYC 9/11 Public Portal Document

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 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 • 54 personal and 5 area air samples were collected by NYDOH contractors o Most personal sample 8-hour time-weighted average concentrations were below 0.025 fibers/cc as determined by PCM (two were 0.08 fibers/cc) o All area sample results were below 0.008 fibers/cc as determined by PCM

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

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’

Metals • 5 area air samples were collected for metals o Nothing of concern was found regarding metal analysis

Crystalline silica • 4 personal air samples were collected for crystalline silica o No crystalline silica was detected on any of the air samples

Volatile Organic Compounds (VOCs) • 1 air sample was collected on a thermal desorption tube (used as a screening technique) o Compounds identified included benzene, toluene, and polynuclear aromatic hydrocarbons which have been attributed to products of combustion o Concentrations of VOCs were well below established limits • 9 air samples were collected with charcoal adsorbent tubes o Concentrations of VOCs on all samples were below detectable limits

CITY_21MC100_003280807

NYC-WTC_000234666