The famed 1964 surgeon general's report that permanently tied smoking to lung cancer came out more than a decade after a series of studies showed the link. The Environmental Protection Agency has taken decades to decide about other carcinogens. Howard's agency, NIOSH, has a conservative reputation as well.
But with this decision, Howard broke from that history.
"I think this was a special case," said Richard Clapp, a professor emeritus of environmental health at Boston University.
No question, bad stuff was in the air and on the ground. Asbestos, lead, mercury, PCBs and dioxins were all found at the smoldering World Trade Center site for months after the terror attacks. Dioxins have been associated with promoting the growth of some pre-existing cancerous cells, Clapp noted.
Previous studies have shown some of the contaminants — like asbestos, arsenic and soot, for example — have led to cancers in workers exposed to hefty amounts for long periods of time.
The fallout was a terrible mixture of toxins with significant potential to harm people, said Elizabeth Ward, an American Cancer Society vice president and cancer researcher who headed the advisory panel that made the recommendation to Howard.
"This was a really unique exposure," said Ward. Based on the best available evidence, the panel decided it was likely that people could get cancer, she said, and that it was better to offer help now than when it was too late.
Indeed, Howard and Ward have a number of supporters in the public health and scientific community who think it was the wisest decision, given the large human need.
"I think for Dr. Howard, it's a very tough decision to make. I'm sure he knew that whatever he said, people are going to complain about it," said Daniel Wartenberg, an epidemiology professor at the University of Medicine & Dentistry of New Jersey.
"In my view, I hope he is wrong. I hope no one gets sick," he added.
A mere two years after 9/11, former New York City police detective John Walcott, 47, was successfully treated for a common type of leukemia that doesn't hit most people until about age 60.
Walcott arrived at the World Trade Center just after the second tower fell and spent months searching for human remains — on the pile, in empty buildings nearby, and later at the city landfill where the rubble had been taken.
He was so sure his cancer would eventually be covered by the federal program, he dropped his negligence lawsuit against the city last winter, as was required to remain eligible for the fund.
He is well aware that some scientists question whether illnesses like his were really caused by ground zero toxins. But he has no doubts.
"My heart told me I got it from there," he said.
Howard's statement about the program, and the advisory panel's report: http://www.cdc.gov/niosh/topics/wtc/stacpetition001.html
AP Medical Writer Mike Stobbe reported from Atlanta.
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.