A group of 9/11 responders has contracted blood cancers at an unusually young age, and top doctors suspect the disease was triggered by an unprecedented "synergistic mix" of toxins at the World Trade Center site.

The WTC Medical Monitoring Program is now studying a group of Ground Zero workers, including cops, construction workers and volunteers, suffering from cancers such as leukemia, lymphoma and multiple myeloma.

"The kind of thing that worries us is that we have a handful of cases of multiple myeloma in very young individuals ... a condition that almost always presents late in life," said Dr. Robin Herbert, co-director of the program at Mount Sinai Hospital.

"That's the kind of odd, unusual and troubling finding that we're seeing already," she says in an interview with the New England Journal of Medicine, which comes out today.

The WTC monitoring program has examined more than 20,000 workers, but so far has focused on respiratory ailments.

Click here to read the full New York Post report.