The World Trade Center Health Program was established within the HHS by the 2010 James Zadroga 9/11 Health and Compensation Act.
Eligible responders and survivors get free treatment for certain conditions that may have been caused by the attacks.
A union of New York City police officers petitioned the program to add prostate cancer to the list of covered health conditions in May, leading to the HHS proposal.
That petition was actually the second attempt to add prostate cancer to the list of covered conditions. A review in 2011 also considered adding the disease, but studies rejected the claims that there was a disproportionate prevalence among 9/11 responders.
The new petition relied on more recent research, however, that showed responders were 17 percent more likely to develop prostate cancer due to the presence of arsenic and cadmium, both cancer-causing substances, at the World Trade Center site.