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Profile: Thomas Cahill

Positions that Thomas Cahill has held:

  • UC Davis professor emeritus of physics and atmospheric sciences and a research professor in applied science, heads the UC Davis DELTA Group

Thomas Cahill was a participant or observer in the following events:

A team of specialists from UC Davis, the Detection and Evaluation of Long-range Transport of Aerosols (DELTA) Group, sends the results from their first samples (see October 2, 2001-Mid-December, 2001) to the Lawrence Berkeley National Laboratory’s Advanced Light-Source Lab. Since October 2, the group has been conducting air sampling from the roof of 201 Varick St., located one mile north-northeast of the WTC site, at the request of the Department of Energy. According to the team, data indicates that the WTC plume “in many ways [resembles] those seen from municipal waste incinerators and high temperatures processes in coal-fired power plants.” A summary report of the data concludes: “The size fractions above 1 micrometer contained finely powdered concrete gypsum, and glass, with soot-like coatings and anthropogenic metals, but little asbestos. Composition in the very fine size range (0.26 > Dp > 0.09) was dominated by sulfuric acid and organic matter, but, including polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and glasslike silicone containing aerosols.” [JOM, 12/1/2001; Dateline (Univ of Calif, Davis), 2/15/2002; Chemical and Engineering News, 2/18/2002]

Entity Tags: DELTA Group, US Department of Energy, Thomas Cahill

Timeline Tags: Environmental Impact of 9/11

The Delta Group releases a final report on air quality data collected in Manhattan between October and December, 2001 (see October 2, 2001-Mid-December, 2001). Thomas Cahill, PhD, Delta Group member, is a noted expert on composition and transport of ultra-fine airborne particles. Dr. Cahill explains that World Trade Center aerosols contained high levels of sulfur, sulfur-based compounds, and very fine silicon that probably came from the thousands of tons of glass that had been in the WTC buildings. The presence of these fine particles decreased during the month of October. The largest spike in very fine particle levels measured 58 micrograms per cubic meter which Cahill says was “an extremely high peak.” The sampling also indicated that there were almost always high concentrations of coarse particles—those about 12 micrometers to 5 micrometers in diameter—present in the air near the WTC site. “These particles simply should not be there,” Cahill says. “It had rained, sometimes heavily, on six days in the prior three weeks. That rain should have settled these coarse particles.” He says their presence suggests the hot debris pile was continually generating the larger particles. The study also determined the chemical composition of the dust it sampled. Some of the metals found in the air occurred at the highest levels ever recorded in the United States. Metals present at high levels included iron, titanium (some associated with powdered concrete), vanadium and nickel (often associated with fuel-oil combustion), copper and zinc. Mercury, lead, and asbestos were present at low levels. [On Earth, 2002; Dateline (Univ of Calif, Davis), 2/15/2002; Chemical and Engineering News, 2/18/2002]

Entity Tags: DELTA Group, Thomas Cahill

Timeline Tags: Environmental Impact of 9/11

The EPA’s National Ombudsman’s office convenes a hearing on the environmental issues that resulted from the attacks on the World Trade Center. Hugh Kaufman, the EPA ombudsman’s chief investigator, remarks during the hearing that he believes the EPA, as well as state and city officials, have intentionally utilized inferior testing methods in order to avoid finding evidence that environmental conditions threaten public health. “I believe EPA did not do that because they knew it would come up not safe and so they are involved in providing knowingly false information to the public about safety,” Kaufman, says. “Not just EPA, the state and the city, too. We also had testimonies that all the agencies—local, state, and federal—have been consorting together every week to discuss these issues.” [CNN, 2/24/2002] Numerous experts testify at the hearing, criticizing the EPA’s response to the September 11 attacks, including David Newman, an industrial hygienist with the New York Committee for Occupational Safety and Health (NYCOSH); Dr. Thomas Cahill, of the University of California at Davis; Marjorie J. Clarke, PhD, an adjunct professor at Lehman and Hunter College, City University of New York; Alison Johnson, Chairman of the Chemical Sensitivity Foundation, among others. Government officials and employees were invited to participate—including officials from the EPA, the Federal Emergency Management Agency, the US Geological Survey, the governor’s office, state agencies, the mayor’s office and city agencies—but did not appear. “This is the first time this has happened in this type of hearing,” Hugh Kaufman, tells United Press International. [United Press International, 2/24/2002; Environmental Protection Agency, 2/25/2002 pdf file]

Entity Tags: Marjorie J. Clarke, PhD, Thomas Cahill, Hugh Kaufman, US Geological Service, Jerrold Nadler, Federal Emergency Management Agency, Alison Johnson, Cate Jenkins, PhD., Environmental Protection Agency

Timeline Tags: Environmental Impact of 9/11

A team of scientists from the University of California at Davis, known as the DELTA group, complete a study on the composition of the toxic gases released during fires burning at the World Trade Centers following the September 11 attacks. DELTA scientists release their report at a meeting of the American Chemical Society in New York. The study concludes that samples taken from the World Trade Center site contained four types of particles that the EPA considers harmful to human health: ultra-fine particulate matter composed of heavy metals known to cause lung damage, sulfuric acid harmful to pulmonary cells, ultra-fine glass particles that can travel through the lungs to the bloodstream and heart, and high-temperature carcinogenic organic matter. [Reuters, 9/11/2003]

Entity Tags: DELTA Group, Thomas Cahill

Timeline Tags: Environmental Impact of 9/11

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