September 11, 2001

The destruction of the two towers of The World Trade Center in lower Manhattan on September 11, 2001, was a three-headed monster. Research had been done on the effects of plane crashes, building collapses, and hazardous fires, but there was no precedent for all three happening at once on a scale that was televised, but hard to imagine. The seismic shock waves of the two collapses were measured as far away as 425 kilometers as they spread through the Northeast, and the earth below the buildings subsided as much as 30 feet (9 meters). The environmental effects of this technological and natural disaster are so complex they will not be fully assessed for years.

We have seen that an important concept in considering pollution is synergism, the interaction of different substances in which the combined effect is greater than the sum of the effects of the separate substances. The World Trade Center disaster could become the defining example of synergetic pollution from a point source. When the towers collapsed, the debris clouds threw toxic heavy metals, organic compounds, and particulates in the air and water in an environmental witch's brew that turned Ground Zero into a toxic cauldron that contained the following and much, much more:

When the towers collapsed, thousands of people died, and thousands more were caught in toxic clouds. Little monitoring took place in the initial clouds, but it is probable that many people had a lifetime's worth of exposure to these chemicals and particulates in a few minutes. The doses varied from those in the debris clouds, to those in the rescue effort, to those in the surrounding areas. We know that responses to doses of pollution vary as well: some 10-15% of the general population have hyper-responsive airways that would make them react more to air-borne pollutants, and some have compromised immune systems as well. We know that 1,600 New York firefighters experienced medical problems, some 400 of whom had to be placed on medical leave. Hundreds of other people reported to area hospitals with breathing problems. Despite all EPA and OSHA assurances that the long-term environmental and health effects from the disaster are not going to be significant, the dose-response curve for such a complex mix of pollutants is not known.

The 16-acre site, Ground Zero, endures. Workers removing over 1,000,000 tons of debris called the area the "crater," as they tried to keep the Hudson River out of the area while excavating toward the bottom; the force of 220 floors collapsing made it difficult in some places to distinguish compressed steel and crushed concrete from bedrock. They wanted the new buildings and memorials that rise from the site to be on firm footings, on sacred ground.


"Environmental Studies of the World Trade Center area after the September 11, 2001 Attack," U.S. Geological Survey, Open File Report )FR-01-0429.

"EPA AND OSHA Web Sites Provide Environmental Monitoring Data, " OSHA National News Release, October 3, 2001.

Maremount, Mark, and Jared Sandberg. 2001. "Weighing Risks: Tests Say Air is Safe, But Some People Feel Ill Near Ground Zero," The Wall Street Journal, Dec. 26.

Miller, Julie Ann. 2001. "Science News of the Year," Science News, Dec.22/Dec. 29.