Brendan McDonough (21) was the only one of the Granite Mountain Hotshots firefighters crew who survived the Arizona wildfires. For the first time he spoke about how he heard his brothers' cell phones ringing in the fire truck and he knew they were all dead.

On June 30 McDonough and his colleagues were fighting a fire at Yarnell Hill, suddenly the wind changed direction and overcame all 19 men.

McDonough spoke to ABC for the first time and said, “I've asked myself a million times, why aren't they sitting here with me?”

He has also vowed to continue his career as a firefighter saying, “I can't fail them.”

Part of the hotshot team for three seasons, McDonough was back at the fire station in Prescott when his colleagues were overcome by the fire. His captain had assigned him to the role of lookout to watch the fire’s movement and monitor weather changes.

McDonough described the agonizing moment just after he had been told they were all dead. he heard his colleagues' phones ringing in the truck where they had been left behind as their wives and loved ones called.

He said, “Whoever didn't bring their phone, I could hear phones ringing, knowing that it was their wives, their family.”

The Irish American firefighter described the heartbreak he felt when he had recieved the call that the men were all dead.

“I sunk. Sunk into my seat, I sunk into myself...I asked a million times, "Why am I sitting here and why isn't someone else? Why aren't they sitting here with me?"'

He described June 30 as a “typical day...not threatening.” However at 4pm the wind began to change and his team saw the flames coming for them.

McDonough disputes claims that the crew did not notice the change. He said, “From where they were, they could see it picking up.”

The team said they would contact him if they needed anything and his captain Jesse Steed said, ”All right, I'll see you soon.”

At 4.47pm the men were forced to deploy their emergency fire shelters in a last ditch effort to save their lives. Although the rescue services tried to reach them all 19 men were confirmed dead.

He said, “Why wasn't I there with them?

“That's all I could think, to pray for their safety... I'm kind of numb at that point. I'd cried a lot. And I came to a point where I just didn't have any more tears.”

The 19 men had ten children between them and two of the men would soon be first-time fathers. McDonough said he could hardly face their families.

“Coming home, that was the worst feeling ever.

“Knowing that these families would see me, but not anyone else off that crew. No one. I was the only person they're going to see.”

McDonough went on to speak at a memorial for the men and attended the 19 funerals.

Last week Deputy state forester Jerry Payne blamed the crew’s leader Eric Marsh, who perished with his men, for violating fire fighting rules.

McDonough does not blame any of the men. He said I never question the decisions they've made.

“I never questioned them before, why should I question them now? It's not their fault. Wasn't a bad decision.”

He added that he would continue to fight fires. He said, “I can't stop trying because I feel like they somewhat look to me because I'm the only one left.”

Here’s the full ABC interview: