Short-term and medium-term health effects of 9/11

Summary

The New York City terrorist attacks on Sept 11, 2001 (9/11), killed nearly 2800 people and thousands more had subsequent health problems. In this Review of health effects in the short and medium terms, strong evidence is provided for associations between experiencing or witnessing events related to 9/11 and post-traumatic stress disorder and respiratory illness, with a correlation between prolonged, intense exposure and increased overall illness and disability. Rescue and recovery workers, especially those who arrived early at the World Trade Center site or worked for longer periods, were more likely to develop respiratory illness than were other exposed groups. Risk factors for post-traumatic stress disorder included proximity to the site on 9/11, living or working in lower Manhattan, rescue or recovery work at the World Trade Center site, event-related loss of spouse, and low social support. Investigators note associations between 9/11 exposures and additional disorders, such as depression and substance use; however, for some health problems association with exposures related to 9/11 is unclear.

Introduction

The Sept 11, 2001 (9/11), terrorist attacks exposed many people to a wide range of horrific events: they saw planes crashing into buildings, people falling from buildings, and the collapse of the World Trade Center (WTC) towers; they were trapped in the dust cloud; and they witnessed injury and death.¹ Many lost relatives, friends, and colleagues. Rescue and recovery workers found body remains and personal effects of the deceased. Many people experienced stress, fear, and uncertainty. In the weeks after 9/11, public areas in New York City were covered with pictures of missing people, many of whom had died in the attacks. Furthermore, thousands of people were temporarily or permanently unable to return to their homes, workplaces, or schools.

Additionally, the collapse of the WTC towers exposed many to substances that have been shown to adversely affect health. Routine environmental monitoring equipment in lower Manhattan was damaged and destroyed in the aftermath of the attacks, which made it difficult to quantify exposure to the massive dust cloud generated by the collapsing towers and potentially to toxic substances that permeated the clean-up site, residences, and workplaces in the area. Sampling for asbestos, organochlorine compounds, volatile organic compounds, and polycyclic aromatic hydrocarbons began between Sept 14 and Sept 21, 2001.2, 3, 4, 5 The dust and debris contained powdered concrete, gypsum, glass fibres, chrysotile asbestos, polycyclic aromatic hydrocarbons, steel, and several metals such as lead, aluminum, antimony, chromium, molybdenum, and barium.6, 7 The dust was highly alkaline (pH up to 11) and had high concentrations of particulate matter capable of causing respiratory irritation and damage.⁶ The destroyed buildings also contained electrical cable coated in polyvinyl chloride, some of which was incinerated during and after the collapse of the towers, which caused the release of dioxins and other chlorinated organic compounds into the atmosphere.⁶

Studies of the health effects of 9/11 have generally focused on three distinct populations: directly exposed groups (rescue and recovery workers, volunteers, lower Manhattan residents, people who worked in the lower Manhattan area, school staff and students, and passers-by on 9/11; table); those indirectly exposed in New York City (eg, who were not near the WTC site on 9/11 or during the weeks afterwards, and who did not lose a loved one or a job as a result of the attacks); or those indirectly exposed throughout the USA and internationally.

This Review investigates the health effects of the 9/11 terrorist attacks in the short and medium terms to establish what has been learned, and to identify areas in which further research is needed.