NYC-WTC_000209173

NYC 9/11 Public Portal Document

Centers for Disease Control and Prevention National Institute for Occupational Safety and Health Interim Air Sampling Report Wednesday, September 26, 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 Wednesday, September 26,2001.

Air Samples

Carbon Monoxide • 7 real-time personal breathing zone samples were collected for carbon monoxide o Most 8-hour time-weighted average concentrations were below 8 ppm (a construction worker had an 8-hour time-weighted average concentration of 20 ppm) o A single peak of 596 ppm was observed on a construction worker on the debris pile

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

Diesel Exhaust (Elemental Carbon) • 2 personal and 2 area samples were collected for diesel exhaust (elemental carbon) o Personal air sample concentrations were below 0.011 mg/m^ o Area air sample concentrations were below 0.015 mg/m^

Respirable Dust • 4 area air samples were collected for respirable dust o Personal sample 8-hour time-weighted average concentrations were below 0.08 mg/m^

Volatile Organic Compounds (VOCs) • 5 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_006532259

NYC-WTC_000209173