Members of the New York City Fire Department carry flags across the Brooklyn Bridge after attending memorial observances on the 13th anniversary of the 911 attacks at the site of the World Trade Center in New York, September 11, 2014. Politicians, dignita
Members of the New York City Fire Department carry flags across the Brooklyn Bridge after attending memorial observances on the 13th anniversary of the 911 attacks at the site of the World Trade Center in New York, September 11, 2014. Politicians, dignitaries and victims' relatives were gathering in New York, Washington and Pennsylvania on Thursday to commemorate the nearly 3,000 people killed in al Qaeda's attack on the United States 13 years ago on September 11. REUTERS/Brendan McDermid (UNITED STATES - Tags: DISASTER SOCIETY ANNIVERSARY POLITICS)
Members of the New York City Fire Department carry flags across the Brooklyn Bridge after attending memorial observances on the 13th anniversary of the 911 attacks at the site of the World Trade Center in New York, September 11, 2014. Politicians, dignitaries and victims' relatives were gathering in New York, Washington and Pennsylvania on Thursday to commemorate the nearly 3,000 people killed in al Qaeda's attack on the United States 13 years ago on September 11. REUTERS/Brendan McDermid (UNITED STATES - Tags: DISASTER SOCIETY ANNIVERSARY POLITICS)

Three retired New York firefighters who responded to the 9/11 attack at the World Trade Center and exposed to toxins died on Monday of cancer.

They were Daniel Heglund, Robert Leaver and Lieutenant Howard Bischoff. The three retired from service in 2003 after 21, 20 and 19 years, respectively, of service.

Leaver, 56, and Bischoff, 58, were childhood friends in Brooklyn who were diagnosed with leukemia and colon cancer, respectively. Upon his diagnosis, Leaver insisted the real victims are the civilians since he was a first responder, said Rosaria, his widow.

Fifty-eight-year-old Heglund died of esophageal cancer. His funeral was scheduled at 10:30 am on Friday at the Centerport Volunteer Firehouse, while Leaver's funeral is at 10 am on the same day at West Nyack's Francis of Assisi Church. Bischoff's funeral is slated on Saturday, 11 am at St Aloysius Church in Jackson, New Jersey.

The three are among the over 850 first responders made up of paramedics and firefighters who acquired cancer, which is a job hazard that went with their duties at the World Trade Center site. Besides the first responders, over 30,000 people are suffering from various ailments as a result of the al-Qaeda attack on the Twin Tower and Pentagon.

Commenting on the irony of losing all three 9/11 heroes on the same day and on the month commemorating the 13th anniversary of the incident that shook not only the US but led to many changes in international travel and financial transactions, Fire Commissioner Daniel Nigro said, "Losing three firefighters on the same day to WTC-related illnesses is a painful reminder that, 13 years later, we continue to pay a terrible price for the department's heroic efforts on September 11th."

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