World Trade Center dust-inhalation: assessing the fallout.

www.thelancet.com/respiratory Published online August 14, 2015 http://dx.doi.org/10.1016/S2213-2600(15)00318-5 1 Nearly 14 years after Al-Qaeda’s Sept 11, 2001, terrorist attacks on the World Trade Center (WTC) in New York City, USA, residents and others exposed to dust from the collapsed buildings continue to suff er and die from respiratory diseases—while eff orts to study the epidemiology of these cases have been hampered by gaps in environmental sampling data, experts tell The Lancet Respiratory Medicine. The WTC Health Registry is “the largest post-disaster public health registry in US history, tracking the long-term physical and mental health of more than 71 000 people, both responders and survivors, directly exposed to the WTC disaster”, notes Alice Welch (New York City Department of Health & Mental Hygiene, New York, NY, USA). US Government-funded studies have used WTC registry data. But information about WTC exposures remains surprisingly “obscure”, notes Raja Flores, professor of thoracic surgery at Icahn School of Medicine, Mount Sinai, New York, NY, USA. “There are confl icting reports about exposure levels of carcinogenic substances such as asbestos. Also, diff ering techniques were used to obtain these measurements, which can lead to confl icting reports.” “Essentially, all useful opportunities for monitoring were lost”, says Morton Lippmann (Nelson Institute of Environmental Medicine, New York University, New York, NY, USA). “Government agencies came in and did a lot of monitoring but they made a fundamental early mistake: they looked only ‘under the lamp-post’. Their monitors were off -the-shelf equipment for fi ne-particle monitoring; they became clogged and screened out larger toxic particles.” “A major challenge in studying shortand longterm health eff ects of WTC dust is that no systematic environmental exposure data were collected, in particular in the acute phase”, agrees Paolo Boff etta (Icahn School of Medicine). “Available measurements are likely to be non-representative, and therefore only partially useful for retrospective exposure assessment.” Researchers Paul Lioy and Michael Gochfeld visited Ground Zero 4 days after the Sept 11 attacks to collect dust samples, reports Gochfeld (Environmental and Occupational Health Sciences Institute, Rutgers University, New Brunswick, NJ, USA). Lioy died on July 8, 2015. “We were concerned with the sluggishness of the sampling, and the prevailing sense that ‘dust is dust’”, Gochfeld recalls. “In reality, WTC dust proved to be extremely complex. We felt that the EPA (US Environmental Protection Agency) did not take the dust seriously enough, soon enough. It was an embarrassment that all the electricity had been knocked out in the blocks around Ground Zero and EPA did not have a backup, contingency sampling procedure or equipment, and relied on a sluggish contracting process to bring in outside industrial hygiene and safety people. That was true for all domains—not just dust sampling.” “It would be a reasonable question to ask whether we are prepared for another attack”, Gochfeld adds. WTC-associated respiratory disorders are “heterogeneous clinically, physiologically, and likely etiologically”, says Albert Miller (Mount Sinai Beth Israel, New York, NY, USA). They are “best characterised in fi rst responder rescue and recovery workers in whom likelihood and severity of disease is related to intensity and timing of exposure—presence at Ground Zero within hours [of the buildings’ collapse] and entrapment in the dust plume”. Nor do these cases always fi t easily into existing clinical-diagnostic categories of asthma, chronic bronchitis, reactive airways syndrome, or bronchiolitis, Miller notes. “They may not respond well to medications used for these diagnoses”, he adds. Thousands of school children in Lower Manhattan were exposed to the collapsed buildings’ dust plumes, and subsequent environmental dust exposures. “Asthma prevalence after Sept 11 among children younger than 5 years of age enrolled in the WTC Health Registry was higher than national estimates, and was associated with dust exposure in all age groups of children”, notes WTC Health Registry medical director James Cone (New York, NY, USA). “Adult residents and offi ce workers in Lower Manhattan also experienced an increased prevalence of new-onset asthma following Sept 11, 2001, associated with exposure to the dust cloud, residential dust and damage, and not having evacuated from homes.” Children’s exposures to WTC dust “occurred during a very vulnerable developmental window, when lung development could have been aff ected to predispose these children to COPD as adults”, notes pediatrician Leonardo Trasande (New York University School of Medicine, New York, NY, USA). Children’s respiratory symptoms are comparable to those of adults, he notes. Possibly because of ingestion of dusts, gastro-oesophageal refl ux disease (GERD) is also common among exposed children, his team found. Cardiometabolic disruption in exposed children could be due to dioxins in the dust—and might leave these children prone to cardiovascular disease later in life, Trasande worries. While the precise biological mechanisms underlying WTCassociated respiratory disorders remain unclear, airway restriction with air trapping and bronchial-wall thickening on CT has been noted by researchers—as has increased residual volume, airway hyperreactivity, and improvement with bronchodilators “suggesting obstructive lung disease along with interstitial processes”, Cone notes. “Distal airway involvement is also suggested as a further mechanism since increased airway resistance has been measured in a group of WTC-exposed residents and area workers with lower respiratory symptoms and normal spirometry.” Feature World Trade Center dust-inhalation: assessing the fallout