A firefighter who helped find victims of the 11 September 2001 attack on New York City, including his own brother, has died of cancer, aged 46.
Daniel Foley's pancreatic cancer was related to the months he spent assisting with recovery efforts at Ground Zero.
He had "miraculously" been the one to find the body of his elder brother - also a firefighter - in the rubble.
So far, 221 firefighters have died from illnesses related to the attack.
Mr Foley passed away on 22 February. The Uniformed Firefighters Association (UFA) mourned the loss, tweeting: "This is becoming a living nightmare for all of us."
Mr Foley joined the city's fire department in 1998. His brother Thomas was among the first responders to the 2001 terrorist attack that devastated the city.
We extend our deepest condolences to the friends and family of retired Firefighter Daniel Foley. Another hero we lost due to post 9/11 related illness. This is becoming a living nightmare for all of us. #343andCounting pic.twitter.com/1JqGYd721C— UFA NYC Firefighters (@UFANYC) February 24, 2020
When his brother went missing in the aftermath, Mr Foley joined the rescue efforts.
Lieutenant Mickey Conboy, who worked with Mr Foley, told CBS New York: "On the first night, Danny promised his mother and father he wouldn't come home until he bought his brother home with him."
Eleven days later, Lt Conboy said Mr Foley "miraculously" found his brother in the rubble of the World Trade Center. He could have stopped working with the rescue company that day, Lt Conboy added.
"But Danny came back each day and joined the company working at the trade centre to find all the Americans that were killed that day. And he didn't stop until we all were done, on that last day in May of 2002."
Mr Foley is survived by his wife and five children.
Up to 80,000 people - including firemen, police officers, emergency workers, contractors and cleaning staff - are believed to have rushed to the aid of victims in the aftermath of the attacks. Many were exposed to toxic debris in the air, like asbestos, lead, and pulverized concrete.
They join an estimated 400,000 people believed to have been exposed to these contaminants, or suffered injury that day, according to the US Centers for Disease Control and Prevention.
In 2018, the president of the UFA told the BBC that roughly one in eight firefighters who were at Ground Zero had since come down with cancer.
Last year, Congress voted to extend a medical compensation fund for the first responders, volunteers and survivors that was due to expire in 2020.