GROUND ZERO: ASSESSING THE RESPIRATORY IMPACT
NEW YORK CITYOn September 11, 2001, more than 11,500 firefighters were exposed to the collapse of the World Trade Center (WTC) and the massive blaze at Ground Zero. For many survivors, that exposure appears to have affected their respiratory as well as psychological health. In addition to grief at the loss of 343 fallen comrades, they must also cope with chronic cough, sore throat, and, in some cases, asthma-like symptoms.
However, some small measure of good may come out of that dreadful day: In treating the 20% to 30% of workers who have developed cough and other respiratory symptoms, health care providers are gaining an improved understanding of how intense exposures to airborne pollutants affect respiratory function in healthy individuals, experience that may help guide future interventions.
The World Trade Center
fire probably represents the single greatest exposure in recent history to respirable
particulates in an urban environment, David J. Prezant, MD, Deputy Chief
Medical Officer of the Fire Department of the City of New York (FDNY) told RESPIRATORY
REVIEWS. Dr. Prezant, who is also a pulmonologist at Montefiore
Medical Center in New York City, was present when the twin towers collapsed.
At the annual meeting of the
American College of Chest Physicians in Philadelphia, Dr. Prezant described
the conditions immediately following the first towers collapse: The
particulate matter was so thick that the sky was literally black, adding
that it was dark as midnight, with incredible dust, particulate matter all
around me that was suffocating [and] difficult to swallow. He stressed,
Thats what people were inhaling during the first few hours after
The immediate health consequences of exposure to this particulate matter were tremendous coughing and eye irritation, but longer-term problems have since become apparent. As of early November, Dr. Prezant and his colleagues had treated more than 4,000 people who had developed an acute cough. A number have also developed chronic cough, and a small number have presented with asthmatic symptoms, Dr. Prezant noted.
Dr. Prezants patients nicknamed the most prevalent effect on firefighters and paramedics the WTC cough: Its a persistent cough,
a sore throat, and interestingly enough,
an accompanying GI irritation, he said. The reflux-like symptoms, which may worsen cough, might have been triggered by swallowed particulates, Dr. Prezant speculated. Roughly two thirds of the group with cough had a dry cough and some degree of GI irritation. Most cough symptoms arose within the first week after exposure, and they were most severe at the end of week 1 through week 2, said Dr. Prezant. However, he has since noted a second wave of coughing, weeks later.
All of the firefighters and paramedics who survived the collapse on September 11 or who have worked at Ground Zero since then are undergoing regular, thorough screening for adverse health effects. Given the hazardous nature of their jobs, FDNY employees receive routine health examinations. Thus, as Dr. Prezant noted, We are, despite this horrific event, in a very fortunate medical situation: ... we have pre-WTC [medical information, including] spirometry, chest
x-rays, bloods, urines, hearing tests, and cardiograms on every firefighter and every EMS employee who was there. This baseline data, coupled with post-WTC and follow-up data, will allow Dr. Prezant and colleagues to gauge fully the exposures health impact. Dr. Prezant noted that they are examining 140 rescue workers each day to get [the examinations] done as rapidly as possible, so that we wont miss a window of opportunity to detail acute events.
After completing health questionnaires and undergoing hearing and spirometric evaluations, the workers are tested for heavy metals: urine mercury, urine beryllium, serum lead, and serum cadmium. Additionally, serum is analyzed for PCBs, dioxins, and hydrocarbons. Data are subdivided according to whether initial exposure occurred during the collapse and the initial dust cloud (group 1); after the collapse, on day 1 and 2, when particulate matter was still very high (group 2); or later on in the week, days 3 through 7, when particulate matter was present but reduced (group 3). Light-duty and vacationing firefighters serve as a control (extremely low-exposure) group.
Of 100 firefighters
given methacholine challenge, 25 showed hyperreactivity, as defined by a
PC20 of less than 16, said Dr. Prezant; 18% had a PC20
of less than 8. If you use the more strict criteria of a PC20
of less than 8, there is a significant difference in hyperreactivity [rate] between
group 1, the unique high-exposure collapse group, and group 2, [who]
came in later on day 1 and day 2, noted Dr. Prezant, who conducted tests
with Montefiore fellow Gisela Banauch, MD. But, he cautioned, this hyperreactivity,
without a prior history of asthma, cigarette smoking, or allergic history
is not clear evidence for asthma unless it persists and is accompanied by
other symptoms. He also noted that incidence might be lower than what might be
found for the general population with similar exposures, due to the healthy
worker effect: We do not allow asthmatic firefighters to work full duty,
nor does the FDNY hire candidates with asthma.
In terms of parenchymal disease, weve only seen four episodes of bacterial pneumonia, but we did see one case of allergic alveolitis. Allergic alveolitis is a very unusual finding, but, fortunately, we have not seen any additional cases, Dr. Prezant remarked. [The] firefighter developed allergic alveolitis and
an ARDS chest x-ray pattern and was admitted to NYU Medical Center. He subsequently responded to corticosteroids and is expected to recover fully. Dr. Prezant does not expect to see any additional cases, as the condition tends to present in the first weeks following exposure.
INORDINATE ATTENTION TO AIRBORNE TOXIC SUBSTANCES
Relative to the very real risk presented by particulate matter, there has been an inordinate amount of attention given by the media to exposure to airborne toxic substances, such as heavy metals, asbestos, and silica, Dr. Prezant argued. Preliminary results showed no elevations in the levels of these substances in the vicinity of Ground Zero, he added, although he acknowledged that the acceptability of some of the levels sampled at the site is currently a matter of debate. However, because smoking and asbestos exposure are thought to have a synergistic effect on lung cancer risk, Dr. Prezant encourages tobacco cessation among the approximately 15% of the department who use tobacco, and he will stress new cessation programs in the next year.
To reduce cough and asthma symptoms, we instituted the first wide-scale distribution of inhaled corticosteroids to a large work force ever, said Dr. Prezant. AstraZeneca donated a large supply of inhaled budesonide; this preparation was chosen for its ease of use and its single-ingredient formulation: Its not a metered-dose inhaler
[and] it does not have a bronchodilator, which could mask wheezing and acute respiratory distress in workers whose symptoms might warrant further evaluation and consideration for other work duties, he explained. Under his supervision, paramedics evaluated nearly 8,000 rescue workers and distributed nearly 4,000 inhalers to firefighters and EMS personnel with cough or mild respiratory symptoms. The initiative gave our firefighters the ability to receive early treatment and continue to perform urgently needed rescue work, said Dr. Prezant, who hopes it will also serve to limit the cascade of chronic inflammation leading to chronic cough, asthma, and obstructive airways diseases in these workers. For rescue workers whose cough has not responded to budesonide, additional medications are being offered, including antibiotics, cough suppressants, nasal decongestants, bronchodilators when appropriate, and treatments for gastrointestinal reflux.
Mimi Zucker, PhD
1. Prezant DJ. Surviving the WTC collapse: a personal and medical perspective. Paper presented at: CHEST 2001 (Meeting of the American College of Chest Physicians); November 7, 2001; Philadelphia, Pa.