John Downes reports on a health initiative set up in the wake of the World Trade Center attacks.
The pictures of two planes crashing into the World Trade Center towers on September 11th, 2001 are, even today, traumatic for those who viewed them.
The appalling images, relayed relentlessly for days on TV screens worldwide, were all too swiftly followed by other, even more terrifying shots of people throwing themselves from buildings, trying to save themselves from death.
Yet disturbing as these images were for those of us watching from armchairs in Ireland and elsewhere, for individuals living and working near the WTC site at the time of the attacks, they had an even more shocking and immediate effect.
Moreover, being not just a witness to but a participant in the aftermath of the attacks will have taken a physical and psychological toll on those involved. Trying to track the long-term after-effects of such major attacks on such a disparate group of people, however, is no easy matter.
From people riding the subway at the time, to those involved in the rescue effort, they are far from a homogenous group. Anywhere between one and two million people are thought to have been exposed.
The WTC health registry, a collaborative effort involving the New York City Department of Health and Mental Hygiene, the federal agency for toxic substances and disease registry, and others hopes to do just this.
By conducting confidential telephone surveys with anybody working at or near the WTC site around the time of the attacks, it will eventually allow health professionals to track and investigate possible trends in illness and recovery - and help create guidelines which could save lives in any future disasters.
Dr Deborah Walker is the project director of the WTC registry. To date, it has signed up approximately 70,000 people, who will be contacted at two to three-yearly intervals over the next 20 years to see if they have experienced any changes in their physical or mental health. There is no payment for those involved.
"If anyone is not feeling well, the first step should be to see a doctor, regardless of whether it is related to 9/11 or not. But the registry means we can do an analysis to reassure people if it is related to 9/11," she explains. "We are also going to match it against cancer registries, which could allow early screening if there is a high rate of a particular type of cancer."
Similar health registries were set up following the Oklahoma City bombing in 1995, Walker says. The technique was also pioneered among Vietnam veterans. But the WTC registry differs in the sheer scale and amount of information which it hopes collect.
Interestingly, participants are not allowed access to individual information it compiles about them, removing the threat of the data contained in the registry being used in any future compensation claims Instead, the registry is to publish more general breakdowns of the information it collates.
People who enrol in the registry are asked questions ranging from the demographic, such as their address and age, to their physical health both before and after the attacks. Other questions seek to find out if they witnessed any particularly disturbing events at the time to assess the extent of their mental health trauma.
The survey also includes two standard mental health tests, which aim to find out if the respondent has been experiencing psychological problems.
According to Ms Barbara Hannigan of Trinity College, Dublin, there is a real need for such information. An expert in post-traumatic stress management, she says individuals can develop physical, mental and emotional problems as a result of a major trauma such as the WTC bombings.
Symptoms range from panic attacks, loss of appetite and headaches to sleeping difficulties, flashbacks and feelings of anger, helplessness and guilt. Without adequate treatment, these can deteriorate over a period of time.
"If there aren't psychological supports or medical intervention, it can tend to give people the idea they are going crazy. They internalise the trauma," she says. "What is happening is the mind is revisiting events in an attempt to store the event in a way that makes more sense."
"So initiatives such as the WTC registry are very very useful," she says. "Once you can categorise any trauma, you can know the likely effect."
After an event, people can also feel forgotten about, she says. This can sometimes lead to anger and a sense of loss.
And indeed, this might in part explain the high enrolment levels in the registry to date. Of the tens of thousands who enrolled, Walker estimates that less than 25 gave Irish addresses in their contact details.
But three years on from the attacks, some people felt it was "almost like a civic obligation" to enrol, she says. "Some people said, "I want you to be able to track my health," says Walker. "And they liked the idea that they will be able to go to the website and be kept informed."
Registry factfile
*As of 2nd of July 2004, the latest date for which figures are available