Six months after the federal government added cancer to the list of sicknesses covered by the $4.3 billion World Trade Center fund, a New York City health department study has found no clear link between cancer and the dust, debris and fumes released by the burning wreckage of the twin towers.
The study was by far the largest to date. It examined 55,700 people, including rescue and recovery workers at the World Trade Center site, on barges or at the Staten Island landfill where debris was taken, in the nine months after Sept. 11, 2001, as well as residents of Lower Manhattan, students, workers and passers-by exposed on the day of the terrorist attacks.
Over all, there was no increase in the cancer rate of those studied compared with the rate of the general population, researchers concluded after looking at 23 cancers from 2003 to 2008. The prevalence of three cancers were significantly higher — multiple myeloma, prostate and thyroid — but only in rescue and recovery workers, and not in the rest of the exposed population.
And the researchers noted that those were very common cancers and that the number of people who received diagnoses of them was small. In one of many counterintuitive findings, the incidence of cancer was not higher among those who were more intensely exposed to the toxic substances than among those who were less exposed.
Given the lack of evidence of a link between the debris from Sept. 11 and cancer, some epidemiologists had questioned the decision by the government in June to add 50 different types of cancer to the list of illnesses covered by the James Zadroga 9/11 Health and Compensation Act, signed by President Obama in early 2011. That decision to add cancer to the list meant that people with other sicknesses more strongly linked to ground zero were likely to receive less money.
Dr. Thomas A. Farley, the health commissioner in New York City, said in an interview on Monday that it was too soon to take the study as a repudiation of the federal government's decision.
"Cancers take 20 years to develop," Dr. Farley said, "and we might see something different 20 years down the line." But echoing Dr. John Howard, head of the National Institute for Occupational Safety and Health, who made the final decision on covering cancer, the commissioner added, "You don't want to wait 20 to 30 years to get a definitive answer to which people may be suffering today."
Dr. Alfred I. Neugut, an oncologist and professor of epidemiology at the Mailman School of Public Health at Columbia University, said he was not surprised by the study. "I think, given the time frame and the exposures," he said, "that there wasn't a high likelihood that there would be an elevated risk, certainly for cancer, and to the degree that it was, it would not be for the cancers that they're finding."
Dr. Neugut said he sympathized with people who had cancer that they attributed to the disaster, but added that their emotional response was not necessarily scientifically valid. "The 9/11 attack was a terrible thing, but it doesn't cause everything in the world," he said. "Cancer is a very specific outcome, and in most exposures, you have to be exposed for an extended time before you get the cancer."
Initially, the money set aside by the law — $2.8 billion to compensate victims and $1.5 billion for monitoring and treatment costs not covered by health insurance — covered mainly respiratory illnesses. (Mental health problems were included in the treatment fund but not the compensation fund.) Studies by the city health department have found asthma and post-traumatic stress disorder to be linked to the 2001 attacks. But cancer is expected to be far more expensive to treat and, perhaps, to compensate, since many cancer patients cannot work or have died.
The recent study was released on Tuesday, and was to be published in Wednesday's issue of The Journal of the American Medical Association — too late to influence Dr. Howard's decision, but perhaps not too late to influence public opinion going forward and to affect whether Congress will decide to replenish the victim compensation fund should more money be needed.
The fund has not yet begun making payments, and it is supposed to make its final payments in 2016-17. In the meantime, some police officers and other rescue and recovery workers who worked at ground zero and have cancer have been receiving enhanced pension benefits based on a 2005 state law that said they were presumed to have contracted cancer from the ground zero substances.