Workers involved in the September 11th 2001 World Trade Center (WTC) rescue and recovery operations in New York have developed asthma at a much higher rate than would be expected in the population at large, a new survey from the city’s Health Department reveals. The survey also shows that using a respirator reduced the risk of asthma development.
The results of the survey are published in the 27th August online issue of Environmental Health Perspectives (EHP online).
Rescue and recovery workers involved in the events of 9/11 were a diverse group ranging from firefighters and police officers to construction workers, volunteers and others.
New York City Health Commissioner, Dr Thomas R. Frieden said:
“The dust from the World Trade Center collapse appears to have had significant respiratory health effects at least for people who worked at the site.”
Rescue and recovery workers exposed to the dust and debris arising from the terrorist attacks on the WTC are showing elevated rates of new asthma says the report which drew data from the World Trade Center Health Registry of 71,000 people.
The report only covers the rescue and recovery workers, it does not include office workers or residents.
The findings showed that 3.6 per cent of the 25,000 rescue and recovery workers in the Registry developed asthma after working at the WTC site, a rate that is 12 times more than would be expected from the rest of the adult population over the same time period.
The survey spans 2003 and 2004 and found that rescue and recovery workers who arrived at the WTC site soon after the twin towers collapsed or worked there over a long period had elevated risk of developing asthma. The group that arrived on the day of the event and worked there more than 90 days had the highest rate of new asthma, 7 per cent.
Workers who used respirators or masks on September 11th and 12th reported lower rates of newly-diagnosed asthma (4.0 and 2.9 per cent respectively) compared to those workers who did not use respirators (6.3 and 4.5 per cent respectively). The risk went up the longer the workers did not wear respirators or masks.
The survey did not distinguish between different types of respirator or mask, nor between those who used them correctly and those who did not. Respirator and mask use went up as the clean operation progressed, but many workers did not wear them from day 1.
Those workers who did not use respirators or masks until months after they started working at the site had two to three times higher asthma incidence compared to those who used respirators from the start. Although respirators were found to be effective, all groups had higher risk of newly developed asthma.
Dr Frieden said that:
“These findings reflect the critical importance of getting appropriate respiratory protection to all workers as quickly as possible during a disaster, and making every effort to make sure workers wear them at all times. The events of 9/11 were unprecedented, and with the urgency of rescue operations and the difficulty of prolonged physical exertion with most types of respirators, there are no easy answers, even in retrospect.”
The survey found no differences among the various occupations involved in the 9/11 events, but there was a significant link with the part of the site they worked on. Those caught in the dust cloud, or who worked on the debris pile itself had higher rates of asthma (4.9 and 4.5 per cent respectivey). Presumably this is because they inhaled more dust.
Lorna Thorpe, New York City Health Department’s deputy commissioner for the division of epidemiology, and co-author of the report told the New York Times:
“This corroborates with other studies to say that the risk of respiratory symptoms in workers was elevated after 9/11.”
She said every worker involved in ground zero should sign up for health monitoring or seek medical help.
One of the drawbacks of the study is that because the registry is a self-selecting one, it may have attracted more people who developed asthma than those who did not, and it may include people who said they developed asthma after 9/11 because they were not sure if they had it before.
The WTC Registry was set up in 2003 to track the health of people exposed to the collapse of the World Trade Center and those who worked at the site. It is a collaboration between the New York City Health Department and the US Centers for Disease Control and Prevention’s Agency for Toxic Substances and Disease Registry (ATSDR), backed by funding from the Federal Emergency Management Agency (FEMA).
Another study will be looking at the respiratory health of people enrolled in the Registry, and how the events of 9/11 may have affected rates of cancer.
“Asthma Diagnosed after September 11, 2001 among Rescue and Recovery Workers: Findings from the World Trade Center Health Registry.”
Katherine Wheeler, Wendy McKelvey, Lorna Thorpe, Megan Perrin, James Cone, Daniel Kass, Mark Farfel, Pauline Thomas, and Robert Brackbill.
Environ Health Perspect EHP In-press, Online 27 August 2007.
doi:10.1289/ehp.10248
Click here for links to Abstract and Full Text of Article (PDF reader required).
Click here for more information about the World Trade Center Health Registry.
Written by: Catharine Paddock