If "devastation, destruction and carnage" has a smell, that's what engulfs one 9/11 first responder when he closes his eyes, plunging him back into the horror of 16 years ago.
"I can block it out, everything I saw and did, but if I shut my eyes, the smell just overwhelms me, it brings me to places I don't like going," John Feal told news.com.au. "Certain things trigger it. I stay away from them."
The demolition supervisor, now 51, arrived at the World Trade Centre the day after the shattering terror attacks. Five days later, he was seriously injured when a 3600kg piece of steel from the wreckage of the collapsed Twin Towers crushed his left foot.
The wound became septic and Feal almost died. In the end, he "lost about an inch past my toes".
John has had more than 30 surgeries linked to the injury, with his hip and knee still needing to be replaced. He has regular injections and every day, he's in physical pain, "on a scale of 1-10, about 400".
Now director of the FealGood Foundation advocating on behalf of 9/11 emergency personnel, Feal believes post-traumatic stress disorder is the biggest killer of his fellow recovery workers.
A 2016 report found that around 12 per cent of those who entered ground zero developed PTSD and some cognitive impairment.
"I was diagnosed with PTSD. I did therapy for years, or I wouldn't be here today," said Feal, who battled recurring nightmares for a long time after the attacks. "I'd guess it would be the number one killer — it just wouldn't show up in the coroner's report."
Not only does trauma cause mental health problems, it also compromises your immune system, he points out.
"My injuries are gruesome and horrific but I'm not sick," he said. "My injury pales in comparison to others.
"I've been to about 178 funerals, so how do you complain? These cancers and horrible illnesses, I'm seeing really good men and women dwindle away because of what they did 16 years ago.
"People have forgotten about them. It's sad. We're programmed to move on."
'NEVER FORGET? I'LL PUNCH THEM IN THE MOUTH'
Feal has been advocating for compensation and healthcare for September 11 rescuers ever since the attacks that killed 2996 people and injured more than 6000.
He and a handful of other ground zero emergency workers managed to push through the Zadroga 9/11 Health and Compensation Act in 2010, guaranteeing support for five years.
The act was named for James Zadroga, a New York City Police Department officer who died of a respiratory disease attributed to his efforts in the rubble of the World Trade Centre after the attacks.
In 2015, that bill was extended to 75 years for those who were injured or fell ill as a result of their selfless assistance with the rescue and recovery effort.
"It was a lot of hard work," said Feal, of the legislation. "We had to stay vigilant. The Republicans pushed us every step of the way."
He was right to remain on guard, as these heroes are having to fight again, against proposed changes to the World Trade Centre Health Program included in Donald Trump's 2019 budget.
The budget suggests the separation of the special health program from the National Institute for Occupational Safety and Health.
Many believe this will mean cuts to staff and resources, and sick people having to fend for themselves.
The Daily Show star Jon Stewart joined the campaigners in Washington on Monday, accusing the White House of "screwing them".
Feal said the proposal was "insulting", adding that he blamed Congress even more than the "repulsive human being" Trump.
"They need us to jump through hoops, beg, crawl and plead ... just leave us alone," he said. "They call themselves fiscal conservative hawks. Every bill has to be funded.
"These are people who come out and say, 'Never forget 9/11.'
"We'll go back to DC and I'll punch them in the mouth."
'THE SPIRIT OF PEOPLE IS BEING TAKEN FROM THEM'
In September, it will be 17 years since this appalling and senseless act of terror, yet it remains seared into the minds of people around the world.
The first responders came from all over the US, with 43 of 50 states represented at the scene. Now, 83,000 rely on the World Trade Centre health program, tens of thousands of whom contracted cancer as a result of the devastation.
And Feal warns there is likely to be "another wave" of sickness and death, since asbestos cancers can take more than 20 years to appear.
"This is not a New York issue, it's a national issue," said Feal. "They want to remove the administrator and replace it with something else. The overlap of bringing in new people and systems will kill people.
"John Smith who gets his pills every week might only get them every six months or year. A cancer patient might not get surgery until it's too late.
"It's all about humanity. The whole world seems less and less human.
"I'm 51. A third of my life has been 9/11 now ... Everything we've done, there have always been roadblocks and obstacles."
Nevertheless, Feal's belief in America remains firm, and he will continue to dedicate his life to fighting for the rescuers who risked their lives to protect others on that fateful morning.
"I consider myself the most patriotic person I know," he said. "I hate that the spirit of people is being taken from them because the government keeps taking things from us.
"Bad politics, corruptions and greed have infected the United States."