Asbestos Update, January 2002
Why are government agencies testing for asbestos in Lower Manhattan?
Asbestos was used in the construction of a portion of the World Trade Center (WTC). It was found in samples of dust and debris collected near the WTC site in the first few weeks after the WTC disaster. Extensive air monitoring for asbestos was begun in the first few days after the collapse to monitor levels at the site and in the surrounding neighborhoods.
The Environmental Protection Agency (EPA) is currently sampling for airborne asbestos at more than twenty monitoring locations near the disaster site and in the nearby community. The City Department of Environmental Protection (DEP) is also conducting testing at additional sites in the community.
What health effects have been associated with asbestos?
Exposure to asbestos is associated with asbestosis (scarring of the lungs) and cancer. The risk of developing these diseases depends on the level (dose) and the length of time exposed (duration). The more asbestos that is inhaled or ingested, the greater the risk for developing disease.
In the community setting, air-sampling results have generally found low levels of asbestos. Experts believe that the likelihood of developing disease from limited, short-term, low-level exposures associated with the WTC incident is low. In the occupational setting, where the duration and intensity of asbestos exposure can be greater, there is a greater risk to workers. Workers need to use the correct protective equipment to reduce exposure.
What standards are being used to assess whether there are elevated levels of asbestos?
Since there are no standards for asbestos in outdoor air, City, State, and Federal agencies have decided to use the most protective indoor air standard to test for asbestos in the outdoor air. This standard is the Asbestos Hazard Emergency Response Act (AHERA) standard of 70 structures per square millimeter (s/mm2). The AHERA standard is normally used to decide when children may re-enter school buildings following asbestos-removal activities.
What are the results to-date of outdoor air monitoring for asbestos?
Between September 11, 2001 and January 22, 2002, EPA collected and analyzed 4,946 samples for airborne asbestos in lower Manhattan. Thirty-one of the 4,946 samples exceeded the AHERA standard. Of those thirty-one samples, 27 were collected before September 30, indicating that most of the elevated samples occurred within the first three weeks after the attack. Four elevated samples (October 9, November 27, December 27 and January 14) have been detected since September 30, the levels ranged from 72 - 204 s/mm2 Levels at these locations were not elevated on days before or after these dates, indicating temporary elevations.
As air monitoring continues, it is possible that additional results will show occasional, short-term increases of asbestos levels above the AHERA standard. In general, brief exposures to low levels of airborne asbestos would not be expected to result in long-term health effects.
Where can I find more information on the WTC-related environmental testing?
Daily WTC-related reports that contain results of sampling for air, water, and dust - including asbestos and Particulate Matter - are posted online at the U.S. Environmental Protection Agency's website, epa.gov. DEP results can be obtained at nyc.gov/dep. WTC-related information can also be found at the New York City Department of Health's Web site at nyc.gov/health.
