THOUSANDS of rescue workers who dug through the rubble of Ground Zero are still suffering respiratory problems, probably caused by inhaling air thick with pulverised concrete.
An unprecedented United States government programme to monitor the health effects on those who led the desperate effort to find survivors or victims’ bodies has recorded cases of asthma, pneumonia and bronchitis, as well as depression.
Research into the illnesses suffered by 11 September recovery teams has taken on a political flavour, with Hillary Clinton, the New York senator, demanding to know why the White House toned down warnings of toxins in the air.
However, the long-term health problems of workers who combed the World Trade Centre may result in screening for those who respond to future disasters.
Dan Kochensparger worked on his hands and knees to sift through cement, metal and other debris at Ground Zero. He remembers air heavy with specks of dust. His breathing problems came later.
"The air was pretty much filled the whole time. We didn’t realise it at the time but in a lot of the photo documentation we had done there were particles in the pictures," said Mr Kochensparger, a hazardous materials specialist who came to New York with an emergency response team from the Ohio fire department.
"People in our business don’t think about the long-term effects of our work," said Robert Zickler, a fire chief and captain of Ohio Task Force One, which combed the wreckage for ten days.
The US government’s tracking programme is the first to follow the health of rescue workers so closely.
Doctors now believe the air particles were mostly pulverised concrete. When inhaled, they can burn the lungs. When swallowed, they can inflame the stomach lining, causing heartburn.
Mr Kochensparger went home from New York with a cold and a persistent cough. His doctor diagnosed pneumonia and bronchitis. He wasn’t alone.
About 7,500 of the estimated 30,000 workers who toiled at the ruins have been examined in the $12 million (8 million) government programme.
Early results show 48 per cent have suffered ear, nose and throat problems, such as nasal congestion, hoarseness, headaches and throat irritation. Thirty per cent have pulmonary problems, including shortness of breath, persistent coughs and wheezing.
About 19 per cent of workers have been diagnosed with post-traumatic stress disorder - at least double the rate seen in the general population.
"We are seeing people now in our screening program - two years later - who are still suffering symptoms," said Dr Stephen Levin, co-director of the US screening programme.
It’s too early to determine whether any of the workers will one day suffer from lung or other types of cancer as a result, he said. A final report on the workers’ health is expected next spring.
Mrs Clinton is threatening to use her seat on a US senate environment committee to block the appointment of a new US environment chief if the White House doesn’t answer her questions on air-quality reports issued in the days after 11 September.
White House officials intervened to tone down a press release put out by the US’s Environmental Protection Agency on 18 September, 2001, it has emerged.
The final release left out a line about the risk of deadly contaminants in the air.
"We go in and answer calls for the safety of other people; that’s what we are paid to do. But there also need to be things in place to look out for our safety," said Robert Hessinger, a paramedic on the Ohio rescue team who found that he had breathing trouble soon after leaving New York.