Vidyya Medical News Service
Volume 6 Issue 255 Published - 14:00 UTC 08:00 EST 11-Sep-2004 Next Update - 14:00 UTC 08:00 EST 12-Sep-2004
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MMWR reprint: Physical health status of World Trade Center rescue and recovery workers and volunteers --- New York City, July 2002--August 2004

In the months after the September 11, 2001, attacks on the World Trade Center (WTC), concerns grew about the health consequences of exposures sustained by persons involved in the rescue and recovery response. In addition to the estimated 10,000 Fire Department of New York (FDNY) personnel, an estimated 30,000 other workers and volunteers potentially were exposed to numerous psychological stressors, environmental toxins, and other physical hazards. These concerns prompted CDC's National Institute for Occupational Safety and Health (NIOSH) to support the WTC Worker and Volunteer Medical Screening Program, which provided free, standardized medical assessments, clinical referrals, and occupational health education for workers and volunteers exposed to hazards during the WTC rescue and recovery effort. During July 16, 2002--August 6, 2004, the program evaluated 11,768 non-FDNY workers and volunteers. This report summarizes data analyzed from a subset of 1,138 of the 11,768 participants evaluated at Mount Sinai School of Medicine during July 16--December 31, 2002. These data indicated that a substantial proportion of participants experienced new-onset or worsened preexisting lower and upper respiratory symptoms, with frequent persistence of symptoms for months after their WTC response work stopped. These findings underscore the need for comprehensive health assessment and treatment for workers and volunteers participating in rescue and recovery efforts.

The clinical program included a single screening evaluation consisting of medical- and exposure-assessment questionnaires, physical examination, pre- and post-bronchodilator (BD) spirometry, complete blood count, blood chemistries, urinalysis, chest radiograph, and mental health screening questionnaires. Participants were recruited through outreach that included community and union meetings, mailings, and articles in the media. Eligibility for the screening program was based on arrival date and duration of exposure to the site* rather than on symptomatology. Institutional review board approval and informed consent were obtained for data aggregation and analyses.

The subset of 1,138 program participants was predominantly male (91%) and non-Hispanic white (58%), with a median age of 41 years (range: 21--74 years). Non-Hispanic blacks and Hispanics accounted for 11% and 15% of the population, respectively. The largest occupational sectors represented in this sample were technical and utilities (25%), law enforcement (21%), and construction (18%). Numerous other occupational groups accounted for the remaining 36%; 89% were union members.

Of the 1,138 participants, 525 (46%) worked on WTC rescue and recovery efforts on September 11, 2001, and 963 (84%) worked or volunteered during September 11--14, when exposures were greatest. During that period, a total of 239 (21%) participants reported using appropriate respiratory protection (i.e., full- or half-face respirators) (1). The median length of time worked on the WTC effort was 966 hours (range 24--4,080 hours). Of the 610 examinees present in lower Manhattan on September 11, a total of 313 (51%) reported being directly in the cloud of dust created by the collapse of the WTC buildings, and an additional 191 (31%) reported exposure to substantial amounts of dust.

A participant was considered to have a WTC-related symptom if the symptom either first developed (incident) or worsened (exacerbated) while working or volunteering on the WTC effort. WTC-related lower respiratory symptoms were reported by 682 (60%) of the sample, and 836 (74%) reported WTC-related upper respiratory symptoms. A total of 450 (40%) examinees had WTC-incident lower respiratory symptoms that persisted to the month before screening, and 565 (50%) reported WTC-incident and persistent upper respiratory symptoms (Table 1). Among the 851 participants who reported persistent WTC-related symptoms, an average of 32 weeks (range: 7--63 weeks) had elapsed since either they stopped working at the site or since the end of May 2002, when site cleanup was officially completed. On examination, 527 (46%) had nasal mucosal inflammation. Other respiratory abnormalities (e.g., abnormal nasal turbinates or sinuses, rhonchi, and wheezing) were less common.

All participants underwent spirometry before and after an inhaled BD using standard techniques (2). A total of 360 (33%) participants had abnormal spirometry findings (Table 2), primarily because of results suggesting restriction; 84 (23%) had a significant§ post-BD response. A total of 22 (27%) of those with airway obstruction had a significant BD response consistent with asthma.

Compared with a general population sample of employed, adult, white males (National Health and Nutrition Examination Surveys [NHANES III]) (3), the 599 participants who had never smoked had a higher prevalence of abnormalities on spirometry (31% versus 13%), which was attributable to a higher prevalence of restriction (21% versus 4%).

Participants experienced numerous other symptoms (Table 3), including a substantial proportion with incident and persistent musculoskeletal symptoms, such as low back pain (16%) and upper or lower extremity pain (16% and 13%, respectively). Other incident and persistent symptoms included heartburn (15%), eye irritation (14%), and frequent headache (13%). Overall, 364 (23%) of the sample reported previously receiving medical care for WTC-related respiratory conditions. A total of 214 (19%) of examinees reported missing work because of WTC-related health problems (median: 10 days; range: 1--364 days).

Reported by: SM Levin, MD, R Herbert, MD, JM Moline, MD, AC Todd, PhD, L Stevenson, MPH, P Landsbergis, PhD, S Jiang, MS, G Skloot, MD, Mount Sinai School of Medicine, New York, New York. S Baron, MD, P Enright, MD, Div of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, CDC.

Editorial Note:

The findings in this report indicate that a substantial proportion of program participants had new-onset and persistent upper and lower airway symptoms, musculoskeletal symptoms, and gastrointestinal symptoms. In addition, a substantial proportion of participants had respiratory abnormalities on spirometry. This preliminary analysis is consistent with earlier reports from WTC screening programs conducted by FDNY (4,5), which documented a substantial proportion of respiratory symptoms in emergency response workers. These findings suggest a need for continued monitoring and appropriate treatment of WTC responders.

NIOSH recently funded a program that will provide continued medical screening of responders for an additional 5 years. Through philanthropic sources, a WTC Health Effects Treatment Program was established to provide further clinical evaluation and treatment to responders at no cost. Thus far, this program has provided approximately 3,587 services to 844 responders, 40% of whom lacked health insurance.

A substantial proportion of workers evaluated in this program had low forced vital capacity (FVC). Restrictive lung diseases (low FVC) typically develop during a long period and are not the consequence of airway irritant exposures such as those experienced by WTC workers. Reduction in FVC might be attributable to air trapping rather than true restriction (i.e., pseudo-restriction), a hypothesis supported by the increase of FVC into the normal range after inhaled BD in 29% of the workers with low FVC. Further analyses that include lung volume measurement might clarify the implications of these findings.

The destruction of the WTC towers resulted in the release of high levels of airborne contaminants (6). The Environmental Protection Agency estimated that potential dust exposures ranged from 1,000 µg/m3 to >100,000 µg/m3 in the hours after the towers' collapse. Exposures were attributed primarily to smoldering fires (until December 2001), dust resuspension, and diesel exhaust from heavy equipment. WTC dust contained pulverized (alkaline) cement, glass fibers, asbestos, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated furans and dioxins. WTC dust was highly alkaline (pH: 9.0--11.0) (7). The deposit of larger particles in the upper respiratory tract might have resulted in persistent upper airway inflammation. Highly irritant, respirable particles are likely to have accounted for lower airway symptoms and clinical findings. Administration of respirable particulate (particles <2.5 µm in diameter) WTC dust to rodents resulted in lower airway hyper-responsiveness (8). Thus, the findings in WTC examinees are consistent with current understanding of WTC exposures; however, the persistence of symptoms for >1 year after the 9/11 event is a new finding and requires further study.

The findings in this report are subject to at least three limitations. First, no reliable statistics exist on the size or composition of the exposed worker/volunteer population, so determining participation rates for the screening program is not possible, and generalizations to all WTC-exposed workers should be made with caution. Second, the screened population might overrepresent those most affected; those screened earlier might not be representative of all persons screened with regard to WTC exposures or health outcomes, and persons examined earlier might have had more severe health problems and sought out the program for that reason. However, preliminary analyses of exposure data among all persons examined through January 2, 2004, demonstrate similar patterns of acute and longer-term WTC exposures. Additional analyses of data for the remainder of the cohort will address concerns regarding health outcomes of persons screened later in the program. Finally, because of the absence of pre-9/11 symptom prevalence and pulmonary function tests (PFTs) for these participants, the ability to measure accurately the impact of WTC exposures on responders' health is limited. Because of the absence of an unexposed control group, spirometry data from this sample were compared with those of NHANES III (3).

This report underscores the need for comprehensive occupational health assessment and treatment for rescue workers and volunteers as part of all emergency preparedness programs. Guidelines for professional emergency response workers have been developed (1). The results described in this report suggest that disaster preparedness also should include 1) planning for rapid provision of suitable respiratory and other protective gear and 2) provision of medical care for first responders and nontraditional responders (e.g., persons from construction trades, utility workers, and other occupational groups).


The findings in this report are based, in part, on contributions by S Carroll, H Juman-James, D Stein, J Weiner, K Leitson, N Nguyen, other staff, and patients of the World Trade Center Worker and Volunteer Medical Screening Program; labor, community, and volunteer organizations.


  1. Jackson BA, Peterson DJ, Bartis JT, et al. Protecting Emergency Responders: Lessons Learned from Terrorist Attacks. Santa Monica, California: RAND Corporation, 2002. Available at
  2. American Thoracic Society. Standardization of spirometry. Am J Respir Crit Care Med 1995;152:1107--36.
  3. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general US population. Am J Respir Crit Care Med 1999;159:179--87.
  4. Prezant D, Weiden M, Banauch G, et al. Cough and bronchial responsiveness in firefighters at the World Trade Center site. N Engl J Med 2002;347:806--15.
  5. Feldman D, Baron S, Bernard B, et al. Symptoms, respirator use, and pulmonary function changes among New York City firefighters responding to the World Trade Center disaster. Chest 2004;125:1256--64.
  6. McGee J, Chen L, Cohen M, et al. Chemical analysis of World Trade Center fine particulate matter for use in toxicologic assessment. Environ Health Perspect 2003;111:972--80.
  7. Landrigan P, Lioy P, Thurston G, et al. Health and environmental consequences of the World Trade Center disaster. Environ Health Perspect 2004;112:731--9.
  8. Gavett S, Haykal-Coates N, Highfill J, Ledbetter A, Chen L. World Trade Center fine particulate matter causes respiratory tract hyperresponsiveness in mice. Environ Health Perspect 2003;111:981--91.

* Minimum of 24 hours working/volunteering during September 11--30, 2001, or >80 hours during September 11--November 30, 2001, either south of Canal Street, the Staten Island landfill, or the barge loading piers. Employees of the Office of the Chief Medical Examiner also were eligible, regardless of hours worked. FDNY and State of New York employees had access to other screening programs and were not eligible for this program.

After official site closure, exposure levels were reduced markedly.

§ Defined by using the American Thoracic Society criteria or an increase in either forced expiratory volume in 1 second (FEV1) or forced vital capacity (FVC) of >12% and >0.2 L, respectively.

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Table 2

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Table 3

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