Three former members of the New York City fire department who had responded to the World Trade Center after the Sept. 11 terrorist attacks died on the same day this week.

Daniel Heglund, Howard Bischoff and Robert Leaver died Monday, according to NY1, which reported that each of the men suffered from cancer.

"Even after he was first diagnosed with leukemia in 2003, he never wanted to be called a 9/11 victim," Leaver's widow, Rosaria, told the New York Daily News. "He would say, 'The innocent people in the towers were the victims. Don't ever call me a victim. I was a first responder.' "

Some types of cancers are among the illnesses covered by the Sept. 11 compensation fund, but it's unclear whether there's a link between the disease and the wreckage and debris left after the attacks.

"About 99.9 percent of us wouldn't change anything that happened. Even after 9/11 and what went on afterwards, we were firemen," Heglund's brother, FDNY Capt. Paul Heglund, told the Daily News. "That's what we do."

Daniel Heglund spent 21 years with the department, Leaver had a 20-year FDNY career and Bischoff was a 19-year veteran. All three retired in 2003, and Leaver and Bischoff were longtime friends, the Daily News reported.

Their deaths served as "a painful reminder that, 13 years later, we continue to pay a terrible price for the Department's heroic efforts on September 11th," Fire Commissioner Daniel A. Nigro said in a statement.

Sen. Kirsten Gillibrand (D-N.Y.) echoed Nigro, saying in a statement: "While we honor these men, and mourn their loss, it is a stark reminder that 13 years later, the health effects of 9/11 are far from over, and will be with us for many years to come."