STATEMENT OF DR. GEORGE D. THURSTON, Sc. D.
COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS
UNITED STATES SENATE
RE: THE AIR POLLUTION EFFECTS OF
THE WORLD TRADE CENTER DISASTER
FEBRUARY 11, 2002
Thank you for holding this hearing, and for giving me this opportunity to contribute to the process of examining the environmental consequences of the attacks of September 11th.
I am George D. Thurston, a tenured Associate Professor of Environmental Medicine at the New York University (NYU) School of Medicine. My scientific research involves investigations of the human health effects of air pollution.
I am also the Director of the National Institute of Environmental Health Sciences' (NIEHS) Community Outreach and Education Program at the NYU Department of Environmental Medicine. A goal of this outreach program is to provide an impartial scientific resource on environmental health issues to the public and to decision-makers, and this is my purpose in testifying to you here today.
In the aftermath of the attack of September 11th and the subsequent anthrax bio-terrorism, we have come to realize that terrorism is more than a security threat: it can also represent an environmental health threat. On September 12th, my research Center received an urgent request from the Office of the Director of the NIEHS, one of the National Institutes of Health, to respond to environmental impacts of the attack of September 11th by doing whatever we could to monitor the air pollution that was resulting from the disaster’s dust and fires, and to assess its environmental health consequences. That very evening, we sent a research team into the World Trade Center Disaster Zone to collect numerous samples of the dust from locations surrounding Ground Zero. Figure 1 shows a map of the locations where we collected settled WTC dust samples on the evening of the 12th and on the 13th of September.
Our NYU Medical School research team also set up an ambient air monitoring station at the NYU Downtown Hospital at Beekman Street, just 5 blocks to the east-northeast of ground zero. We sampled for various types of particle air pollution: ultrafines, soot, fine particles, and inhalable particles from Friday, September 14th until the end of 2001, when the fires had been extinguished. Although our work is far from complete, we have weighed these samples to determine the ambient particulate mass concentrations, as well as analyzed the ambient air pollution samples and the WTC dust for their constituents. Our sampling data, therefore, applies to the general public living and working in the vicinity of the disaster, rather than to exposures at Ground Zero. So my testimony today focuses only on those community exposures and possible health effects among the general population in the downtown Manhattan area of New York City.
East River Hudson River
Figure 1. Sites of NYU Sampling of World Trade Center Dust on 9/12 and 9/13/2001.
It is of interest to note that the NYU Downtown Hospital was founded many years ago after an earlier terrorist bomber attack on Wall Street on September 16, 1920 that killed dozens of New Yorkers, and it was felt that downtown New York City needed a local hospital ready to respond to such emergencies. Some 81 years later, when this city needed it, the NYU Downtown Hospital was ready, and met that need. Moreover, despite having to run on diesel power and being in an emergency status, the hospital aided our environmental assessment efforts by providing us with space and power on its second floor, where we could run our sampling lines out to sample pollution in the ambient air.
Our analyses of the WTC dust samples revealed that some 99 percent of the dust was as particles too large to be breathed deeply into the lung, being largely caught in the nose, mouth and throat when inhaled. This large dust, however, contained approximately one-third fiberglass, with much of the remainder as alkaline cement dust. This large dust was, therefore, quite caustic and irritating to the eyes, nose and throat, consistent with the now famous “World Trade Center cough” that nearby residents reported. Only trace amounts of asbestos were found in our samples. The less than one percent that was as PM2.5, or the particles that would reach deepest in the lung, was found to have a neutral pH, with no detectable asbestos or fiberglass. Thus, while our analyses are consistent with the government’s conclusion that the WTC dust is not likely to have short or long-term serious health impacts on otherwise healthy local residents, we found that it is very irritating and capable of causing the symptoms reported by many residents.
Figure 2. The Mass Size Distribution of WTC Dusts.
Our sampling of the ambient air pollution at NYU Downtown Hospital showed that air pollution levels were quite high in the first weeks following the attack, especially at night, but then diminished as the fires were brought under control. By early October, soot levels in the downtown area were generally similar to those that we measured at the NYU Medical School in Midtown (at First Ave. and 26th St.), although levels occasionally climbed in downtown on clear, calm nights throughout the fall. In Figure 3, the solid line on the left shows the declining trend in soot levels in September through December. Overall, our independent air pollution sampling results were largely consistent with the data reported by the U.S. EPA. In particular, although short-term peaks in PM2.5 particulate matter air pollution for a few hours did occur at night, the 24-hr. averages were of PM2.5 were within the legal limits set by the U.S. air quality standards.
Figure 3. Concentrations of Black Carbon (Soot) and PM10 Mass
Measured at NYU Downtown Hospital.
Despite the fact that individual pollutants in the community were apparently at safe levels for otherwise healthy persons in the general population, this does not mean that no effects might have been experienced by especially susceptible individuals, such as infants or persons with pre-existing respiratory disease. In addition, it is impossible to know what potential interactive effects might have occurred among the various pollutants, even at these low levels. Ultimately, only epidemiological follow-up studies of possible effects among especially susceptible individuals will provide a fuller determination of the issue of possible health effects from the various pollutants in the WTC plume.
Finally, I feel strongly that we must make sure to learn all the lessons that we can from this horrible catastrophe regarding the communication of risk to the public in such emergency situations. Something like what happened to New York City on September 11th could, unfortunately happen again, and we must be prepared. It is an understatement to say that the public is skeptical of government pronouncements of safety in such situations. In this case, I feel that the EPA was too quick to declare the air “safe”, and did not well enough define what was meant by that term. Although the fine particle pollution was not of a level that would make otherwise healthy people very sick, the dust was caustic and irritating, causing many to have severe and upsetting symptoms, including eye, nose, and throat irritation. This caused people to further doubt governmental pronouncements of safety, even after more complete data were available confirming the EPA position. As a result, the press turned to the academic research community of New York City to fill the void. Fortunately, New York City is itself blessed with vast resources, including a host of some of the finest educational and research institutions in the world. Other locales may not have such local resources as were available in New York City, and be less able to meet such a disaster.
It has been my duty and honor to play a role in the academic effort to answer the environmental questions that New Yorkers had, and still have. But we must improve the current situation. While we cannot create governmental trust where there is none, I believe that we should draw from what happened in New York City to help the nation better cope with such situations in the future. The government should designate a suite of environmental parameters to be measured in such situations, and designate the appropriate health standards most appropriate for comparison in such short-term exposure situations. Moreover, I recommend that we create a mechanism by which blue-ribbon panels of the leading independent experts in the U.S. are formed in advance, perhaps by the National Academy of Sciences, to be on stand-by in case, God forbid, such an emergency occurs again. If this is done, there would then be an independent expert panel ready to be assembled, briefed, and to then give their quick-turnaround assessment of the public’s environmental risks, and of the appropriate actions that are needed to protect public health. Without such a new mechanisms, I fear that any future such disasters may be accompanied by the same unfortunate confusion, doubts, and distrust. Let us act now to help preclude this risk communication problem in the future.
Thank you for the opportunity to testify on this important issue.