Asbestos Monitoring at the WTC Site

(September 13 - 27, 2001)





Financial District
OSHA has taken approximately 40 air and bulk samples in the Financial District (the location east of Broadway and south of John Street). Results ranged from "non-detected" to 0.041 fibers per cubic centimeter (f/cc). Further analysis showed all fibers to be non-asbestos. Results showed levels consistent with safe and acceptable standards. OSHA ceased sampling in the Financial District on Sept. 21.

Warm Zone
A 90-square block surrounding the World Trade Center complex and plaza has been designated a secure area with controlled access. It extends south of Chambers Street, west to Broadway, south to Rector Street and east to near the Hudson River. OSHA continues to collect samples; more than 150 bulk and air samples were taken in the "Warm Zone" through Sept. 24. Asbestos levels remain safe and consistent, ranging from non-detected to 0.086 f/cc.

Hot Zone/Rubble Pile
What has come to be known as "ground zero", the hot zone is the World Trade Center complex area itself. It includes the remains of both WTC towers, 7 WTC, and other partially collapsed buildings.

During this time period, OSHA took 65 air samples and seven bulk samples in the hot zone. Results showed levels ranging from 0.004 to 0.140 f/cc. The level of 0.140 revealed 90 -95% mineral wool fibers and is below safe levels.

All sampling has resulted in what OSHA considers safe levels of exposure; still, the agency is recommending workers in the immediate area of the rubble pile wear respirators. OSHA continues to conduct monitoring for asbestos throughout the warm and hot zones. Results will be posted periodically on this page.

To see a grid map showing asbestos monitoring at specific sample locations in New York click here.


Permissible Exposure Limit (PEL) for asbestos is 0.1 f/cc as an 8-hour time-weighted average.

Excursion Limit(or short-term exposure limit) is 1 f/cc over a 30-minute period.
(NOTE: For more information on environmental monitoring in New York, see the Environmental Protection Agency's website at http://www.epa.gov/).

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