Federal officials have announced the multi-billion dollar World Trade Center Health Fund will cover 50 different types of cancer.

Two years ago, when the Fund was created, cancer was completely excluded from the list of ailments that were covered.

Some top scientists insist this is not wise, because there's no hard evidence to support the federal government's declaration that 50 kinds of cancer could be caused by exposure to World Trade Center dust, but the Jersey head of the World Trade Center Medical Monitoring and Treatment program disagrees.

Dr. Iris Udasin, a professor of environmental and occupational medicine at Robert Wood Johnson Medical School, says there's hard evidence that some of the cancers are increased in the population of 9/11 responders- but "there's also biological plausibility - meaning that the exposures in question certainly could have caused the cancers that we're seeing in our World Trade Center responders."

She says, "I'm very happy that we're going to be able to make sure that all the people who have those cancers get proper medical care for their illnesses …You take a large group of people like the New York City firefighters and they very clearly had health information on people before 9/11 and after 9/11 - and they were able to show that for at least certain cancers, there were elevations after 9/11 - that's extremely significant."

Dr. Udasin adds while the conventional medical wisdom is that it may take decades to develop cancer, "In some cases, certain kinds of cancers, some of the rare cancers and some of the blood cancers come on very quickly…Those are the ones that we feel we've been able to more likely than not attribute to their World Trade Center exposures."

She also says, "It's so important to be able to continue to monitor these people and make sure they are doing the right kinds of preventive behaviors and screening behaviors…While there continues to be disputes about the scientific reliability of adding certain cancers to the list, I think it's better to get people the right medical care while you're trying to figure out the answer to that question….It behooves us as a society to make sure that people have good medical care after they've done something that's considered a government service."