A UC Davis scientist who led the air monitoring of the smoldering ruins of the World Trade Center said dangerous levels of pollutants were swirling about the site at the same time the U.S. Environmental Protection Agency assured the public that the air was safe to breathe.

Thomas Cahill, a professor emeritus of physics and atmospheric science, headed the scientific team that studied the aerosols from the fuming site in lower Manhattan during the weeks right after Sept. 11, 2001.

In an interview Tuesday, Cahill called the conditions for people working at ground zero without respirators "brutal" and said conditions were only slightly better for those working or living in adjacent buildings.

"The site was hot for months. The metals burned into fine particles. They rose in a plume and moved over people's heads on most days. There were at least eight days when the plume was pushed down into the city. Then people tasted it, smelled it and saw it. But people who worked in the pile were getting it every day. The workers are the ones that I worry about most," Cahill told The Chronicle.

Cahill's data found that the pollution included very fine metals, which interfere with lung chemistry; sulfuric acid, which attacks lung cells; carcinogenic organic matter; and very fine insoluble particles such as glass, which travel through the lungs and into the bloodstream and heart.

He is expected to present his latest findings at a national meeting of the American Chemical Society in New York today.

Cahill's comments echo a report issued in August by the EPA inspector general, an internal watchdog on the agency. The inspector general concluded that under White House influence, the EPA issued misleading assurances that there was no health risk from air pollution after the attack.

A week after the attack, the EPA announced that the air near ground zero was safe to breathe, but the agency did not have enough information to make such a guarantee, the inspector general's report said.

"Christie Whitman was too premature to say it was safe," Cahill said Tuesday. "I think the EPA should have known. The EPA had its own reports saying it could be dangerous. Why didn't the EPA bring in their own people from all over the country? They could have. Never thought of it. They did later. But not in the time that mattered."

WHITE HOUSE PRESSURE

The White House "convinced EPA to add reassuring statements and delete cautionary ones" by having the National Security Council control EPA communications, the inspector general's report found.

Marianne Horinko, EPA acting administrator, has defended her agency's post-Sept. 11 statements about air quality, saying the agency put out "the best information we had, based on just the best data that we had available at the time."

The EPA's public messages stand at the center of the confirmation of Utah Gov. Mike Leavitt to replace former EPA administrator Whitman, who resigned in May.

Sen. Hillary Rodham Clinton, D-N.Y., pledged last week to block his appointment unless the White House takes responsibility for telling the EPA to disseminate misleading reassurances.

Cahill heads the DELTA Group, which stands for Detection and Evaluation of Long-range Transport of Aerosols, an association of scientists at several universities and national laboratories. The U.S. Energy Department asked the group to monitor air quality in New York. The group has studied global transport of aerosols from the Gulf War oil fires in Kuwait in 1991, volcanoes, dust storms and worldwide factory emissions in China.

HEALTH CONCERNS

In the two years since the attack, thousands of New Yorkers have contacted the World Trade Center health registry, reporting cases of persistent coughs, wheezing, shortness of breath and sinus inflammation.

A year ago, the New York Fire Department reported that up to 500 employees may have to retire early as a result of respiratory disability or chronic breathing problems caused by their exposure to dense clouds of dust, smoke and fumes at the site.

Cahill's first report in 2002, based on 8,000 air samples collected a mile from the complex, found high levels of very fine airborne particles that could increase risk of lung damage and heart attacks.

The new data confirm four classes of pollutants at levels higher than what Cahill's group found in Kuwait or China, Cahill said. Tons of concrete, glass, furniture, carpets, insulation, computers and paper were reduced to debris piles that burned for three months.

In that hot pile, some of the elements combined with organic matter and abundant chlorine from papers and plastics and then escaped to the surface as metal-rich gases. They burned or chemically decomposed into very fine particles capable of penetrating deeply into human lungs, Cahill said.

©2003 San Francisco Chronicle

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