Detective James Zadroga was one of thousands of New York City police officers assigned to the smouldering ruins of Ground Zero after the twin towers collapsed on September 11, 2001. He clocked something close to 470 hours there, breathing in the putrid, dust-choked air as the salvage and recovery effort unfolded in the following months.
Emergency medical technician Timothy Keller, meanwhile, recalled coughing up 'bits of gravel' from his lungs in the days following the disaster, so thick was the air with acrid smoke and dust. Felix Hernandez also joined the thousands who helped sift through the wreckage in the desperate search for survivors and victims.
All three 'first responders' to the site have died in the past nine months. Zadroga, 34, developed black lung disease and mercury on the brain and died in January. Keller, 41, died in June last year due to heart failure complicated by bronchitis and emphysema. Hernandez, meanwhile, was diagnosed with various respiratory diseases. Becoming too weak to climb stairs, he retired in 2004 and died in October last year. All three were non-smokers with no medical history of pulmonary disease before the attacks.
Then, earlier this month, came the similarly tragic death of paramedic Debbie Reeve who also worked at the Ground Zero site. Despite being only 41, she had contracted mesothelioma, a rare lung cancer. 'The only risk factor she has for developing this cancer at such a young age is her exposure to asbestos and other unknown carcinogens while working at the former World Trade Centre site,' said her doctor, Reynaldo Alonso. 'It is reasonable to state that her exposure at Ground Zero was the cause of her cancer.'
The families of at least 23 deceased Ground Zero workers claim they were victims of respiratory illnesses brought about by their long exposure to the toxic air around the Ground Zero site which then carried throughout the rest of the city and beyond - air that, two days after the towers fell, was declared safe for New Yorkers by the Environmental Protection Agency (EPA).
Up to 5,000 other Ground Zero workers have gone to federal court seeking permission to wage a class-action suit accusing officials and contractors of exposing workers to dangerous toxins. Some reports claim there could be up to 130,000 nationwide, who can expect symptoms to emerge in the next few years as a result of breathing in the air around Ground Zero.
Yet on September 13, 2001, Christine Todd Whitman - who at that time was in charge of the EPA - announced that the 'EPA is greatly relieved to have learned that there appears to be no significant level of asbestos dust in the air in New York City'.
Such comments have resulted in another class action, this time launched by 12 plaintiffs on behalf of students, workers and residents of lower Manhattan and Brooklyn. Their suit contends that Ms Whitman's statement stretched the truth as far and wide as the plume of smoke that billowed from Ground Zero in the aftermath of the attack. They seek a proper clean-up of lower Manhattan, the establishment of a medical monitoring fund and damages for those suffering.
Among the 12 plaintiffs is Jenna Orkin, a Brooklyn resident who spearheads the World Trade Centre Environmental Organisation and runs its website, www.wtceo.org . She said she had spent US$5,000 on asbestos abatement for her apartment after tests revealed it was infected by deep layers of dust that settled on her windowsills following the collapse.
Ms Orkin's son attends Stuyvesant High School in the Tribeca area of the city which, she said, was hastily reopened in an act of defiance against terrorists but at great compromise to its students' health, who were later exposed to particles during the loading of debris on to barges in an effort to clear the site.
'We used to think that the EPA were too hasty in ruling the area safe, and that's what was in the inspector general's report of 2003,' she said. 'But in fact there was a memo revealed to the New York Post which showed that it wasn't simply premature but that they were lying. They not only knew it was unsafe, but they had every reason to know. Those buildings amounted to a zip code of their own; they were cities that went up in toxic smoke and dust.'
Manhattan Federal Judge Deborah Batts agreed. In her 83-page pre-trial opinion released in February, she accused Ms Whitman and the EPA of repeatedly and knowingly misleading the public about the safety of the air in the days after the attacks. She sided with the complaint lodged by Ms Orkin and her fellow plaintiffs that thousands of people living, working, and attending school in downtown Manhattan and in Brooklyn were exposed to contamination after the EPA misled them about air quality. She not only denied the EPA's motion to dismiss the case, but refused to grant Ms Whitman immunity, declaring her statements so 'deliberate and misleading' they 'shock the conscience'.
'No argument can be made that Ms Whitman could not have understood from existing law that her conduct was unlawful,' Judge Batts wrote.
For all the city's fear of a chemical attack in the aftermath of the disaster, it might as well have already happened. The collapse of both 110-storey buildings created a cloud of hazardous, pulverised substances including fibreglass, freon, mercury, lead, 492,700 litres of transformer oil and about 2,000 tonnes of asbestos.
The site then burned and smouldered for another three months while the wind lifted and spread the toxic particles around the city.
The situation is now so grave that John Howard, formerly the director for occupational safety and health, was recently named September 11 health co-ordinator in an effort to oversee the health impacts of working at Ground Zero. His responsibilities include the distribution of funds for medical screenings and monitoring the health of so-called 'first responders' to the site.
Yet for many this is too little, too late. 'They [the EPA] didn't measure small particles at all - they didn't see it, therefore as far as they were concerned it didn't exist,' said Ms Orkin citing a report by Thomas Cahill, a professor emeritus of physics and atmospheric science at the University of Davis in California, who studied the aerosols from the fuming site in lower Manhattan during the weeks after September 11, 2001. Having taken 7,000 samples across the world, the ultra-fine particles emanating from Ground Zero were the most toxic he had come across, even beating readings taken from burning Kuwaiti oil fields.
'The site was hot for months,' he told the San Francisco Chronicle. 'The metals burned into fine particles. They rose in a plume and moved over people's heads on most days. There were at least eight days when the plume was pushed down into the city ... people who worked in the pile were getting it every day. The workers are the ones I worry about most.'
Yet Ms Orkin maintains that a far wider area of the city was exposed to a cloud of toxins. 'The fires burned for three months,' she said. 'The kids at Stuyvesant were exposed to the barge operations until May. There are still apartments downtown that haven't been cleaned properly since the towers came down. My personal belief - not speaking as a plaintiff - is I think we could have a criminal case.'
Whether or not the suit ultimately succeeds in its aims, medical evidence continues to grow. A startling new study by Columbia University's Centre for Children's Environmental Health revealed that around half the babies born to 329 non-smoking women living close to Ground Zero who were pregnant at the time of the disaster, had DNA with significant levels of combustion-related toxins.
These 'have the potential to damage development and increase the risk of cancer', according to Frederica Perera, the centre's director, who said that dangerous polycyclic aromatic hydrocarbons, or PAHs, were found in umbilical-cord blood obtained when the women gave birth at four lower Manhattan hospitals. The Columbia team is tracking the health and growth of children, now about four years old, and comparing their health to that of 730 children in the upper Manhattan and Bronx area.
While babies born after the attacks typically had shorter gestations, were underweight and had smaller head circumferences, their parents face the risk of respiratory problems and diseases that may take years to reveal themselves. The final count of victims from that fateful day looks set to be revised long into the future.