Fallout from US attacks no longer poses public health risk

Fears that the massive dust pall created by the devastation of buildings and aircraft in 11 September’s terrorist attacks would introduce asbestos and other harmful substances into the local air and water supplies, are now receding with the publication of monitoring results by the US Environmental Protection Agency (EPA).

Following health concerns expressed after the attack (see related story), on 18 September, the EPA gave the all-clear for air and drinking water supplies close to both the World Trade Center and the Pentagon. It also announced that the Federal Emergency Management Agency, FEMA, had granted up to $83 million for the EPA to continue its involvement in the clean-up and monitoring of environmental conditions in both metropolitan areas.

Air sampling began on the day of the disaster when initial fears centred on the potential for asbestos contamination and possible production of dioxins from the incineration of PCBs from office equipment and planes. Although EPA testing indicated elevated asbestos levels in the rubble, these are thought to be from asbestos products used in flooring materials or other substances as it was understood that asbestos had not been used in the construction of the World Trade Center buildings. Throughout the past week, the highest levels of asbestos have been detected within one-half block of ground zero – the clean-up site for the buildings.

Ten continuous stationary air monitoring stations are now in place around ground-zero, monitoring ambient air quality in the general Wall Street district of Manhattan, as well as in Brooklyn. These will remain on site and continue to monitor for levels of asbestos, PCBs, lead and polycyclic aromatic hydrocarbons (PAHs) throughout the clean-up period. In addition, the EPA is bringing in equipment similar to that used after the Gulf War to sample emissions from the Kuwaiti oil fires, to provide instant analysis of volatile organic compounds (VOCs). To date, of the 50 air samples taken in the vicinity, the vast majority are reported to have either non-detectable or below established levels of concern for asbestos, lead and volatile organic compounds. Plans are also in place to monitor air in the surrounding New York metropolitan area.

In lower Manhattan, the City of New York has also been involved in efforts to clean anything coated with debris dust. This involves spraying water over buildings, streets and pavements to wash down the accumulated dust before it has the opportunity to become airborne. Again, the majority of the 62 dust analyses completed by the EPA fell below the EPA’s definition of “asbestos containing material” – 1% asbestos. Areas sampled above this level were being cleaned up by one of the EPA’s 10 high efficiency particulate arresting vacuum trucks, and then resampled. The trucks were also used to clean streets and pavements in the Financial District ahead of Monday’s return to business.

In Manhattan, drinking water was tested at 13 sampling points and at a sewage treatment plant, and asbestos levels were found to be well below the EPA’s level of concern. A similar monitoring and testing regime has been established around the Pentagon site, and results here have found no levels of asbestos to concern the EPA.

The $83 million allocation to the EPA by FEMA is provided in the form of a Total Project Ceiling cost, but at present the EPA is working with emergency funding of $23.7 million. If costs exceed this level, FEMA will authorise EPA to tap additional funding in increments of $15 million.

Protection of key workers is a major focus of the clean-up operation involving the EPA working in close coordination with both the US Air Force Centre for Environmental Excellence and the US Coast Guard. Here the main aim is to get protection facilities in place as soon as possible. The EPA has also recommended that debris at both blast sites continue to be kept wet to reduce the amount of airborne dust. As part of the additional funding to be provided by FEMA, EPA will be responsible for any hazardous waste disposal, general site safety and provision of sanitation facilities for many of the search and rescue workers to wash the dust off working clothes after each shift.

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