An independent analysis of air around Ground Zero shows the collapse of the World Trade Center towers spewed enormous amounts of potentially lethal, extremely tiny particles unrecognized by the U.S. Environmental Protection Agency's air monitoring. The ominous findings by scientists at the University of California, Davis, contradict repeated assurances by EPA Administrator Christie Whitman that the air around the wreckage largely was safe to breathe.
"They had an unprecedented situation, and they applied the usual approaches," said Thomas Cahill, a physicist and international authority on air pollution who led the study. He released early results Monday that showed lung-penetrating pollutants in startling concentrations, about 500 times more than what's in the air on the smoggiest days in the Sacramento Valley.
The Sept. 11 collapse of the 110-story skyscrapers crushed concrete, glass, computers, electrical wiring, carpeting, furniture and everything else in the building, then burned and broiled the compressed, pulverized mass for weeks. In the super-heated rubble the material disintegrated into extremely small particles, which were released into the air for weeks. "It's like having a large power plant at ground level with no stack," Cahill said.
UC Davis released its findings amid mounting questions of why firefighters, cleanup workers and some residents are plagued by chronic coughing and other respiratory problems if the air truly has been safe.
Cahill's study has not been published nor peer-reviewed. The EPA, while aware of the work, has not seen the data.
The EPA came under heavy criticism Monday during a U.S. Senate subcommittee hearing for telling New Yorkers the pollution posed no problem, according to news reports.
EPA regional administrator Jane Kenny said the agency "used the most extensive data ever" in assessing air quality in the neighborhood around the World Trade Center site.
In New York, at least 2,500 of the 10,000 members of the Fire Department have respiratory problems, said Tom Manley, health and safety officer for the Uniformed Firefighters Association, their labor union. He said about 700 are out on medical leave.
In following standard monitoring protocols, EPA officials passed over what many health experts consider the deadliest air pollutants: invisible "very fine" and "ultra-fine" particles that can slip past the body's defenses, lodge deep in the lungs and possibly pass into the bloodstream to invade and weaken the heart.
Some research has linked exposure of fine particles to chronic respiratory disease and premature deaths from heart attacks, asthma, emphysema and other illnesses. So small are the particles that it would take 1 billion to fill the period at the end of this sentence.
A weeks-long inundation of fine particles would be especially threatening to people with lung and heart conditions, said Kent Pinkerton of UC Davis, an expert on the health effects of particulate pollution.
"They are going to be the ones most at risk," Pinkerton said. "But for most people who are healthy, they probably would be able to handle it."
The EPA is considering updating its pollution standard to account for the finest particles, Raymond Werner, the agency's regional chief of air monitoring programs, said in an interview Monday. The EPA collected fine particles around the World Trade Center site for future reference.
But the science of collecting, measuring and assessing the health effects of such tiny particles is young, and Werner said the agency lacks data.
"The health community hasn't established evidence that there's a direct health effect," he said. If not conclusive, the evidence is worrisome, said Robert Nolan, a specialist on particulate pollution at the City University of New York in Brooklyn.
"There are a lot of reasons to believe that people who inhale very fine particles have a higher risk of lung cancer," he said.
Nolan lives within four miles of Ground Zero. "I have been coughing for four months," he said.
In a way, the UC Davis findings are just scientific confirmation of what New Yorkers believe through common sense, said Michael Barasch, a New York lawyer who has filed health claims against the city on behalf of nearly 1,000 firefighters, plus some police and sanitation workers.
For months, he detected the scent of danger in the air. "It was that acrid smell. It was clearly electrical things burning," said Barasch, whose office is two blocks from Ground Zero. "Every single person you would speak to knew it was not safe."
The UC Davis analysis is continuing, but Cahill said he felt obligated to share results quickly to help New Yorkers take precautions to protect their health.
Cahill's team sent a custom-designed air sampler to New York in October at the request of Robert Leifer, a scientist with the U.S. Department of Energy's Environmental Measurements Laboratory. The project was not funded by the government; the UC Davis researchers donated their time.
Cahill, 65, is a professor emeritus of physics and atmospheric sciences. He has used his background in nuclear physics to pioneer methods and tools for analyzing aerosols -- tiny particles suspended in the air -- and has led more than 40 studies on pollution around the world, including several in national parks and in the basins of Lake Tahoe and Mono Lake.
The Ground Zero monitoring showed the fallout had subsided by late December, when Cahill's team stopped sampling. He said rain probably has cleared the air outside, but he is concerned about New Yorkers returning to contaminated buildings.
"These-size particles ... travel like a gas. They penetrate windows, doors, everywhere," he said. "You don't feel it, and you can't see it."
He recommended throwing away carpeting and fabrics that cannot be thoroughly washed, and cleaning everything else with water -- not by vacuuming, which blows particles around. He suggested that people handling the cleanup wear soaking wet masks in lieu of respirators.
Fine particles almost always are byproducts of human activities, produced through combustion, typically power plants, or gasoline and diesel engines.
In trying to understand the presence of a high volume of extremely fine particles at the World Trade Center site, Cahill combed through reports and photographs of the towers' collapse. He believes the answer is in the way the second tower came down.
Whereas the first tower fell laterally, the second tower dropped vertically, like a rock. "You have 180,000 tons of mass moving at 120 miles per hour," Cahill said.
By his assessment, the superheated core of the building, buried under a giant pile of rubble with little to no oxygen, created a pressure cooker that broiled the concrete, glass, computers and everything else into infinitesimally small particles that were exuded in a gassy, lingering haze.
The pollutants his team examined were collected beginning Oct. 2 from a rooftop at 201 Varick St., about one mile north of Ground Zero.
From the first few days, the scientists found high concentrations of "very fine" and "ultrafine" particles lasting two to three hours.
The Ground Zero readings surprised Nolan at the City University of New York in Brooklyn. "These numbers of fine particles are higher than I ever expected -- they're off the chart," Nolan said.
The conventional analysis used by the EPA captured the same range of particle sizes but averaged them in a way that smooths out the extraordinary peaks of the smallest particles.
EPA spokeswoman Nina Habib Spencer said the agency was obligated to follow its established monitoring methods.
"We are an agency of numbers and an agency of standards, and we adhere to those standards," she said Monday in an interview. "Just remember, those standards weren't built in a day. ... We based what we said to the public on our data, and the standards we have available to us."
The EPA collected samples, mostly in December, in three smaller size categories, down to 0.3 microns, according to Werner. Results of that sampling are not yet available.
The UC Davis team's assessment was for even finer particles still. Their system collected and sorted particles smaller than 2.5 microns, in six categories down to 0.09 microns.
Even at those vanishingly small dimensions, size matters: The smaller the speck, the harder it is for the body to flush out.
Further, a mass of very small particles poses a greater risk than an equal mass of larger particles because each particle surface potentially can react with body chemistry to damage cells. The EPA readings may have met the criteria for safe air, Cahill said, but the standard is inadequate under the circumstances.
"The aerosols from the World Trade Center are so anomalous that the criteria are irrelevant," he said.
Bruce Case, former director of the EPA's Center for Environmental Epidemiology, agreed. "This was a unique event in many ways, and one of those ways was the types of human exposures produced," said Case, an asbestos disease specialist now at McGill University in Montreal.
"We don't yet know what those were, and I think it is possible that the data that has so far been reported, since it used traditional methods, was not necessarily the most relevant data."
Beyond particulates, much of the EPA's investigation has focused on the release of cancer-causing pollutants such as lead and chromium, and asbestos fibers, contained in the fireproof The UC Davis sampling found no asbestos fibers small enough to be inhaled. Nor did it turn up worrisome levels of toxic metals.
Case said the emphasis on asbestos turned out to be misplaced. "What happened to the glass and concrete?" he asked. "There is no question that it was inhaled. How much? By whom? With what immediate and long-term effects?"
Case predicted that the health fallout from the World Trade Center attack will continue indefinitely. "Regrettably," he said, "what we have here is a human experiment on a grand scale."
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