Friday, September 08, 2006

The World Trade Center Disaster and the Health of Workers: Five-Year Assessment of a Unique Medical Screening Program

The World Trade Center Disaster and the Health of Workers: Five-Year Assessment of a Unique Medical Screening Program

An estimated 40,000 men and women worked at Ground Zero, the former site of the
World Trade Center (WTC) in New York City, and at the Staten Island landfill, the
principal wreckage depository in the days, weeks, and months after September 11, 2001
(Levin et al. 2004). These workers and volunteers included traditional first responders such as firefighters, law enforcement officers, and paramedics as well as a diverse population of operating engineers, laborers, ironworkers, railway tunnel cleaners, telecommunications workers, sanitation workers, and staff of the Office of the Chief Medical Examiner. These men and women carried out rescue-and-recovery operations, restored essential services, cleaned up massive amounts of debris and, in a time period far shorter than anticipated, deconstructed and removed remains of buildings. Many had no training in response to civil disaster. The highly diverse nature of this workforce posed unprecedented challenges for worker protection and medical follow-up.

Workers were exposed to a complex mix of toxic chemicals and to extreme psychological trauma. These exposures varied over time and by location (Landrigan et al. 2002; Lioy et al. 2002). Combustion of 90,000 L of jet fuel immediately after the attacks created a dense plume of black smoke containing volatile organic compounds (VOCs, including benzene), metals, and polycyclic aromatic hydrocarbons (PAHs). The collapse of the “twin towers” (WTC 1 and WTC 2) and then of a third building (WTC 7) produced an enormous dust cloud containing thousands of tons of coarse and fine particulate matter (PM), cement dust, glass fibers, asbestos, lead, hydrochloric acid, polychlorinated biphenyls (PCBs), organochlorine pesticides, and polychlorinated dioxins and furans (Clark et al. 2003; Landrigan et al. 2004; Lioy et al. 2002; McGee et al. 2003). EPA 4 estimates of airborne dust ranged from 1,000 μg/m3 to over 100,000 μg/m3 (U.S. EPA 2002). The high content of pulverized cement made the dust highly caustic (pH 10-11) (Lioy et al. 2002; Landrigan et al. 2004).

Dust and debris gradually settled, and rains on 9/14 further diminished the intensity of outdoor ambient dust exposure. However, rubble removal operations repeatedly reaerosolized the dust, leading to continuing intermittent exposure for many months. Fires burned both above and under ground until December 2001 (Banauch et al. 2003; Chen and Thurston 2002; U.S. EPA 2003). Air levels of certain contaminants remained elevated well into 2002, with spikes in benzene and asbestos levels occurring as late as March and May 2002 respectively (U.S. EPA 2003).

The full report can be found here: