September 11, 2001 started out like any other Tuesday for then 28-year-old Thomas Phelan, a Circle Line Statue of Liberty ferry cruise captain.
Little did he know that in just a matter of hours, he would be hailed a hero for saving hundreds of lives after 19 men hijacked four airplanes, and deliberately crashed into the World Trade Center and the Pentagon.
On what is now dubbed as one of the nation's darkest days, Phelan was one of the many selfless individuals who helped evacuate people from Lower Manhattan after the terror attack.
He loaded people into his ferry and transported them to safety. Unbeknownst to him, while he was making sure others were safe, he was putting himself in harm's way.
"He brought supplies, rescue workers & was a huge part of the operation," said a post on the NYC Fire Wire Facebook page.
More than 2,977 people were killed in New York, Washington, and Shanksville, Pennsylvania, where one of the planes crashed. However, the death toll continues to rise even today.
Phelan, who later became a city firefighter before getting promoted to marine pilot, was among the thousands of people, including those who lived, worked, or studied nearby, first responders, volunteers, and cleanup workers, who have since been diagnosed with cancer linked to the 9/11 attacks.
The Centers for Disease Control and Prevention's World Trade Center Health Program is convinced that the spike in cancer diagnoses among these groups of people is the result of exposure to carcinogens and pollutants in the aftermath of the attacks.
Unfortunately, Phelan lost his battle to the disease at the age of 45 on March 16, according to the authorities.
Social media has been flooded with tributes to the American hero, and those who worked with him also had nothing but great things to say about their fallen colleague.
Paul Iannizzotto, who once worked in the same firehouse as Phelan wrote on Facebook that his former colleague was "Always a stand-up guy, always doing the right thing, and will be sorely missed. Rest easy brother."
A similar sentiment was echoed by Maura Buckley, who wrote on the NYC Fire Wire Facebook page.
"I'm so sad! A true hero and gentleman," she wrote. "He would help anyone and everyone any chance he could. I just can't believe this and honestly don't understand why it's always the good ones we lose way to early."
"RIP MY BROTHER We got from here," wrote Joe Guzaman, a fellow New York firefighter. "You can be ower guardian angel and watch over us and guide us to safely. You'll be missed. ðŸ™ðŸ™"
On Twitter, New York City Mayor Bill de Blasio had some kind words to say about Phelan.
"In our city's darkest hour, FDNY firefighter Thomas Phelan's heroism saved hundreds of lives," he tweeted. "We will never forget his service and sacrifice."
Sadly, Phelan's death wasn't the only loss the FDNY suffered this week.
Firefighter Keith Young, also succumbed to cancer that is believed to have been caused by the toxic pollutants he was exposed to during the 9/11 rescue missions.
To make matters even worse, Young's wife also died from cancer in 2012, so he was the sole caretaker of their kids.
"His kids are strong as rocks, they will always have their FDNY family looking after them," wrote NYC Fire Wire.
It's unclear when Young's funeral will be held, but Phelan's has been scheduled for Tuesday, March 20. He will be interred in Brooklyn.
May they rest in peace. Our thoughts and prayers are with the families of these heroic men. They're gone too soon, but they left a legacy that won't be easily forgotten.