A decade after terrorists attacked the World Trade Centre in New York, studies have shown firefighters exposed to dust from the attacks are more likely to get cancer, while September 11 rescue workers still suffer high illness rates generally.
Data gathered on more than 27,000 police officers, firefighters, and construction and municipal workers revealed that many suffer continuing ill-health.
A separate study showed that firefighters exposed to toxic dust and chemicals in the aftermath of the outrage had a 19 per cent increased risk of cancer.
However, scientists found that death rates among emergency staff and civilians who survived the attacks were lower than those of the wider New York City population, the studies published in The Lancet medical journal on Friday said.
“The events of that day changed the historical trajectory of America and the world. They have had – and continue to have – profound consequences for health,” the journal said in an editorial.
The studies were published in a special edition of the journal to commemorate the 10th anniversary of the terrorist attacks.
Almost 3000 people died when Islamic extremists flew two passenger jets into the World Trade Centre twin towers on September 11 2001. Among them were 343 firefighters.
The collapsing buildings released choking clouds of dust and debris containing toxic substances, including known cancer chemicals.
More than 50,000 rescue and recovery workers are estimated to have provided assistance after the attacks.
One of a series of studies published in The Lancet found New York City firefighters who rushed to the doomed Twin Towers are 19 per cent more likely to have cancer than their non-exposed colleagues and a comparable section of the city’s population.
There were 263 cancer cases in the exposed firefighters compared with 238 expected from general population data, while from a non-exposed group there were only 135 compared with 161 expected from the general population.
The study, led by David Prezant, chief medical officer of the Fire Department of the City of New York (FDNY), and colleagues, looked at 9853 male firefighters with health records dating back to well before September 11.
Among the exposed group, the recorded cases of cancer affected various parts of the body including the stomach, bowel, skin, prostate, bladder and pancreas.
Researchers found less lung cancer than expected – only nine cases instead of the 21 they expected to see. All nine cases involved smokers.
Conversely, they found 12 cases of thyroid cancer in the study group, compared to the six they might have expected based on rates in the general public.
“An association between WTC exposure and cancer is biologically plausible because some contaminants in the WTC dust, such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and dioxins, are known carcinogens,” wrote the researchers.
Another study in the Lancet showed a high burden of both physical and mental illness in the estimated 50,000 rescue and recovery workers involved in the attacks.
Data gathered from more than 27,000 of those workers, who enrolled in a federally-funded monitoring program, showed that 28 per cent had developed asthma, 42 per cent sinusitis, and 39 per cent gastro-oesophageal reflux disease.
Twenty-eight per cent had depression, 32 per cent had post traumatic stress disorder and 21 per cent had panic disorder, said the study by Juan Wisnivesky, of the Mount Sinai School of Medicine in New York state.
“Our findings show a substantial burden of persistent physical and mental disorders in rescue and recovery workers who rushed to the site of the WTC and laboured there for weeks and months 10 years ago,” the study said.
Despite the findings, another study found that so far World Trade Centre-exposed rescue workers and civilians had lower death rates than New York’s general population.
However, this was not thought to be surprising because of the long time it took for deaths to result from illnesses caused by exposure to toxic substances.
People in full time employment also tended to be healthier than the general population, the authors pointed out.
Because the attacks happened in a business district and presumably involved people who were fit enough to be reporting to work, the study group was probably healthier than the general public to begin with, said New York City’s health commissioner, Dr Thomas Farley.