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The U.S. Environmental Protection Agency (EPA) and other federal, state and local agencies have collected extensive environmental monitoring data from the World Trade Center site and nearby areas in Manhattan, Brooklyn and New Jersey. Since September 11, EPA has taken samples of the air, dust, water, river sediments and drinking water and analyzed them for the presence of pollutants that might pose a health risk to response workers at the World Trade Center site and the public. The samples are evaluated against a variety of benchmarks, standards and guidelines established to protect public health under various conditions. EPA is collecting data from 17 fixed monitors in and around ground zero and is using portable sampling equipment to collect data from a range of locations.
Air: Fixed Monitors in New York and New Jersey:
Asbestos - EPA analyzed 33 samples taken in and around ground zero on October 11 and 12. All samples showed results less than 70 structures per millimeter squared, which is the Asbestos Hazard Emergency Response Act (AHERA) standard for allowing children to re-enter school buildings after asbestos removal activities. This brings the total number of air samples collected and analyzed for lower Manhattan to 777, with 27 samples above the standard.
Four air samples taken in New Jersey on October 11 and 12 showed results less than the school re-entry standard. This brings the total number of samples collected and analyzed in New Jersey to 102, with zero above the standard.
Asbestos - Eight steel/building samples were collected from the debris pile on October 11. One sample (bulk steel) contained 2.68% asbestos (chrysotile).
Staten Island Landfill:
Air (Asbestos) - 68 samples were taken from October 10 through October 13; all of the results were below the AHERA standard used for allowing re-entry into schools.
Ambient Air Sampling:
VOCs - Sampling for volatile organic compounds (VOCs) was conducted on October 12 in the smoke plume on the debris pile at ground zero. There is a general decrease in overall VOC levels, including benzene as compared to October 11. Benzene exceeded the OSHA time- weighted average permissible level at one location in the pile at ground level.
Dioxin - Ten samples were collected on October 2 and analyzed for dioxin/furans. Four of the samples showed results above the guideline level at which EPA would take some type of action to reduce people's exposure. This guideline level assumes a 30-year exposure scenario. One of the samples taken near the southwest corner of Building #5 of the World Trade Center was nominally above guideline level adjusted to a 1-year exposure duration. These levels do not pose a short-term health affect but should be monitored if they persist for a longer period of time. All other locations had results that were generally lower than previous dioxin data on September 27.
PCBs - The results of three samples collected on October 4 showed no detectable levels of PCBs.
Carbon Monoxide - A direct reading of carbon monoxide was detected at 19 parts per million (ppm) at one location (Greenwich and Liberty). This is above the National Ambient Air Quality Standard (NAAQS) 8-hour average of 9 ppm, but is below the NAAQS 1-hour average of 35 ppm and the OSHA permissible level of 50 ppm.
U.S. Government Website