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Health Effects and Occupational Exposures Among Office Workers Near the World Trade Center Disaster Site

Trout, Douglas MD, MHS; Nimgade, Ashok MD, MPH; Mueller, Charles MS; Hall, Ronald MS; Earnest, G. Scott PhD

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Journal of Occupational and Environmental Medicine: July 2002 - Volume 44 - Issue 7 - p 601-605
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The collapse of the World Trade Center (WTC) after the attack on September 11, 2001, has affected a large number of people in the New York City (NYC) area, likely including all of the approximately 500,000 workers in southern Manhattan. A survey of Manhattan residents approximately two months after the WTC disaster found that 10% reported symptoms consistent with current depression and 8% reported symptoms consistent with posttraumatic stress disorder (PTSD) (among respondents who lived near the WTC the prevalence of PTSD symptoms was 20%). 1 A national survey several days after the WTC disaster found that 44% of adults reported symptoms of stress, and that stress reactions varied according to many variables (including region of the country the persons were from). 2 Despite these recent studies, there remains limited available information concerning health issues among persons indirectly affected by large-scale disasters. 3,4

Responding to a request from the US Department of Health and Human Services (DHHS) in November 2001, the Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (NIOSH), evaluated concerns related to post-September 11th occupational exposures and health effects among DHHS workers at the Federal Office Building (Federal Building), 26 Federal Plaza, NYC. 5 Here we summarize reported symptoms and occupational exposures among this group of office workers who were indirectly affected by the WTC disaster.


Medical Evaluation

This study was performed as part of the NIOSH Health Hazard Evaluation Program; worker participation was by informed consent. The evaluation primarily concerned DHHS employees in the NYC Federal Building, which is approximately 5 blocks northeast of the WTC site. Employees from the DHHS Regional Office in Dallas, Texas, served as a comparison group and were administered a similar questionnaire. A comparison group was included in this survey because building occupants, in general, are known to experience a variety of symptoms sometimes attributed to their work environment. The group of employees from the Dallas Regional Office was chosen as the comparison group because it was felt by DHHS administrators in Washington, D.C. to be similar in many respects to the group of DHHS employees in the NYC Federal Building in terms of number of employees, type of work, and work location (several hundred employees performing primarily office/administrative work in a large building in an urban setting).

After information concerning the NIOSH evaluation was distributed to all DHHS employees at each location, all DHHS employees at each location were invited to participate in the survey. The surveys were performed on December 4 to 5, 2001 (NYC), and on December 12, 2001 (Dallas). The questionnaire was self-administered and included questions about work duties and location, current symptoms, selected information on past medical history, and questions related to activities directly or indirectly related to the WTC attack. Along with questions concerning constitutional symptoms (such as headache, eye, nose, and throat irritation, and respiratory symptoms) occurring in the four months before the survey, the questionnaire included two series of questions assessing symptoms of depression and PTSD occurring in the month before the survey. Eleven questions pertaining to depression were adapted from the 20-question Center for Epidemiologic Studies Depression Scale (CES-D). 6 Possible responses ranged from (0) ‘rarely’ to (3) ‘always’ in a 4-point scale. Persons were defined as exhibiting ‘depressive symptoms’ if the sum of their responses exceeded 12. 7 The questions related to PTSD included 17 questions derived from diagnostic criteria for PTSD found in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). 8,9 Persons who provided an affirmative response to these questions according to the diagnostic criteria were defined as exhibiting ‘PTSD symptoms.’ The prevalence of symptoms was compared between workers in NYC and those in Dallas using the prevalence ratio (PR) and 95% confidence intervals (95% CI). A 95% CI that excluded one, or a significance level of P ≤ 0.05, was considered to indicate a statistically significant finding.

Industrial Hygiene Evaluation

An industrial hygiene assessment was conducted that included area air sampling in representative areas of the Federal Building for asbestos, 28 different elements, volatile organic compounds, total dust, fine particles, polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and carbon monoxide. Bulk samples of settled material were collected at an air intake and analyzed for elements and asbestos. 5 One of the primary goals of the industrial hygiene evaluation was to assess whether compounds present at Ground Zero of the WTC site after September 12, 2001, 10 had migrated into the Federal Building.


Medical Evaluation

One hundred ninety-one (68% of the 279 available) workers in NYC and 155 (47% of the 328 available) workers in Dallas completed the questionnaire. Selected characteristics of the two groups of participants are presented in Table 1. Of note, the groups were similar in terms of age, gender, race, current cigarette use, and history of respiratory conditions. The group of NYC employees had a lower percentage of employees with at least some college education. Dallas employees were more likely to report conditions consistent with atopy (allergies, hayfever, skin allergies, eczema). To evaluate the potential role of residential exposure to contaminants from the WTC site, the survey included a question concerning zip code of residence since the WTC disaster. Among the workers in NYC, four persons (2% of the 191) reported living in lower Manhattan (defined by a northern boundary of zip codes 10013 and 10002—approximately corresponding to Charlton St. and Broome St.); further analysis of the data based on location of residence was not performed.

Description of Survey Participants

Table 2 presents a summary of symptoms reported occurring in the four months before the survey. Table 3 summarizes information concerning reported use of counseling and medical services, and Table 4 presents the number and percentage of participants from NYC and Dallas meeting our definitions of depressive or PTSD symptoms. Selected characteristics of workers in NYC are summarized in Table 5 regarding the presence of these symptoms; of note, persons with two or less confidants* were more likely to report both depressive and PTSD symptoms than those with three or more. There were no significant differences in the reporting of depressive or PTSD symptoms among workers with college education or more compared to those with a high school education or less.

Reported Constitutional Symptoms
Use of Medical and Counseling Services
Prevalence of Mental Health Symptoms by City
Prevalence of Mental Health Symptoms Among Workers in NYC by Selected Characteristics

The prevalence of symptoms varied by agency (examples of DHHS agencies at each of these sites are the Centers for Medicare/Medicaid Services and the Administration for Children and Families) within DHHS at both sites. For example, among agencies with eight or more participants, the prevalence of eye irritation ranged from 27 to 81% in NYC and 0 to 21% in Dallas, and the prevalence of depressive symptoms ranged from 0 to 45% in NYC and 0 to 29% in Dallas.

Industrial Hygiene

One of two samples of settled dust (obtained at a ventilation outdoor air intake) indicated the presence of chrysotile asbestos (in the range of 1% to <3%). None of the 13 air samples for fibers revealed asbestos. The 12 area air samples collected inside the building indicated that concentrations of many of the potential contaminants were below the limit of detection for the method used; there was no indication of an occupational exposure hazard to these various compounds. 5


Our survey indicates that workers in NYC were more likely than those in Dallas to report a wide variety of constitutional symptoms, and many were still symptomatic at the time of the NIOSH survey. We found that the NYC and Dallas groups were similar in terms of most demographic characteristics that we surveyed. We did find that the Dallas workers reported a higher background prevalence of conditions consistent with atopy. If this characteristic had an effect on the reported symptoms, it would likely lead to greater symptom reporting among the Dallas workers and therefore, to an underestimate of the difference in symptom prevalence between NYC and Dallas workers. Utilization of medical services for reported constitutional symptoms did not differ significantly between workers at the two sites. No occupational exposures to substances at concentrations that would explain the reported constitutional symptoms were found; however, we were unable to assess potential exposures of these workers in the time immediately after the WTC disaster. We observed an elevated prevalence of symptoms of depression and PTSD among workers in NYC compared to those in Dallas, and despite the fact that counseling services were utilized to a greater extent among workers in NYC, approximately 1/3 of those surveyed in NYC felt they would benefit from additional counseling.

The variability of reported symptoms by agency, along with the fact that we have no reason to believe potential exposures to environmental contaminants immediately after the WTC disaster varied by agency for these workers, suggests that factors not fully assessed in our evaluation may be important in understanding the reported symptoms. Among these other factors, the nature of organizational social support in response to the disaster, as well as more general work organization factors, may be important. 11 Regarding the former, our data suggest that improving social support within an organization may be beneficial with regards to minimizing depressive and PTSD symptoms in a postdisaster situation.

Our evaluation has several limitations. First, participants in our survey from both NYC and Dallas may not be representative of the entire workforces at those locations because participation was incomplete. Second, our questionnaire asked participants to report symptoms which are nonspecific and could potentially be affected by many factors we did not assess (including various types of both work-related and nonwork-related factors), but which may possibly have differed between the two work locations. Regarding such potential work-related factors, we are limited in our ability to assess whether work-related symptoms reported among workers in NYC may be related to factors directly related to the WTC attack or some other preexisting problems in the building. And third, our environmental survey in NYC was conducted more than two months after the WTC attack; it is possible that changing outdoor environmental conditions (such as changes in the wind and changes in the type or quantity of contaminants being produced at the WTC site) would alter the type and concentration of contaminants present in the Federal Building.

Clinicians and public health professionals must be aware that constitutional and mental health symptoms must both be addressed among persons in the NYC area indirectly involved with the WTC disaster. Further clinical follow-up and surveillance activities will be needed to help improve our understanding of currently reported symptoms and the potential for long-term health effects related to the WTC disaster.


The authors thank Joseph Hurrell, PhD, Richard Driscoll, PhD, Bruce Bernard, MD, MPH, Sherry Baron, MD, MPH, and Allison Tepper, PhD for their assistance in designing this survey and in preparation of this manuscript.


1. Galea S, Ahern J, Resnick H, et al. Psychological suquelae of the September 11 terrorist attacks in New York City. NEJM. 2002; 34613: 982–987.
2. Schuster MA, Stein BD, Jaycox LH, et al. A national survey of stress reactions after the September 11, 2001, terrorist attacks. NEJM. 2001; 34520: 1507–1512.
3. Landrigan PJ. Health consequences of the 11 September 2001 attacks. Env Health Perspect. 2001; 109 (11): A514–A515.
4. Sprang C. Vicarious stress: patterns of disturbance and use of mental health services by those indirectly affected by the Oklahoma City bombing. Psychological Rep. 2001; 89: 331–338.
5. National Institute for Occupational Safety and Health. Hazard Evaluation and Technical Assistance report: 26 Federal Plaza, New York Cincinnati, OH: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention; NIOSH.HETA 2002-0038-2870.
6. Radloff LS. The CES-D scale: a self-report depression scale for research in the general population. Applied Psychological Measurement. 1977; 1: 385–401.
7. Andresen EM, Malmgren JA, Carter WB, Patrick DL. Screening for depression in well older adults: evaluation of a short form of the CES-D. Am J Prev Med. 1994; 102: 77–84.
8. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Washington, DC; 2001.
9. North CS, Nixon SJ, Shariat S, et al. Psychiatric disorders among survivors of the Oklahoma City bombing. JAMA. 1999; 2828: 755–762.
10. National Institute for Occupational Safety and Health. Interim report for HETA 2001-0554, New York City Department of Health (World Trade Center). Summary report to the New York City Department of Health: NIOSH air sample results for the World Trade Center disaster response. February 2002.
11. Elkin AJ, Rosch PJ. Promoting mental health at the workplace: the prevention side of stress management.In: Occupational Medicine: State of the Art Reviews, Worksite Health Promotion. 1990; 5(4): 739–754.
©2002The American College of Occupational and Environmental Medicine